NBS TECHNICAL NOTE

Information Handling

in the National Standard

Reference Data System

290

FRANZ L. ALT

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U.S. DEPARTMENT OF COMMERCE

National Bureau of Standards
National Standard Reference Data System

The National Standard Reference Data System is a government-wide effort to give to the

technical community of the United States optimum access to the quantitative data of physical

science, critically evaluated and compiled for convenience. This program was established in 1963 by the President's Office of Science and Technology, acting upon the recommendation of the Federal Council for Science and Technology. The National Bureau of Standards has been as- signed responsibility for administering the effort. The general objective of the System is to coordinate and integrate existing data evaluation and compilation activities into a systematic, comprehensive program, supplementing and expanding technical coverage when necessary, establish- ing and maintaining standards for the output of the participating groups, and providing mechanisms for the dissemination of the output as required.

The NSRDS is conducted as a decentralized operation of nation-wide scope with central co- ordination by NBS. It comprises a complex of data centers and other activities, carried on in government agencies, academic institutions, and nongovernmental laboratories. The independent

operational status of existing critical data projects is maintained and encouraged. Data centers

that are components of the NSRDS produce compilations of critically evaluated data, critical re- views of the state of quantitative knowledge in specialized areas, and computations of useful functions derived from standard reference data. For" operational purposes, NSRDS compilation activities are organized into seven categories as listed below. The data publications of the NSRDS, which may consist of monographs, loose- leaf sheets, computer tapes, or any other useful product, will be classified as belonging to one

or another of these categories. An additional "General" category of NSRDS publications will include reports on detailed classification schemes, lists of compilations considered to be Standard

Reference Data, status reports, and similar material. Thus, NSRDS publications will appear in the following eight categories

Category

12

34

5

6

78

Title General

Nuclear Properties

Atomic and Molecular Properties

Solid State Properties

Thermodynamic and Transport Properties

Chemical Kinetics

Colloid and Surface Properties

Mechanical Properties of Materials
UNITED STATES DEPARTMENT OF COMMERCE • John T. Connor, Secretary

NATIONAL BUREAU OF STANDARDS • A. V. Astin, Director

NBS TECHNICAL NOTE 290

ISSUED July 1, 1966

Information Handling

in the National Standard

Reference Data System

Franz L. Alt

Office of Standard Reference Data

Institute for Basic Standards

National Bureau of Standards

Washington, D.C., 20234

NBS Technical Notes are designed to supplement the Bureau's regular publications program. They provide a means for making available scientific data that are of transient or limited interest. Technical Notes may be

listed or referred to in the open literature.

For sale by the Superintendent of Documents, U.S. Government Printing Office, Washington, D.C., 20402

Price 25 cents
Contents

Page

Introduction 1 1.1. Plan of approach 1 1.1.1. Development of NSRDS 1 1.1.2. Recommendations '- 2

1.2. Organization of NSRDS 3

1.3. Information services 4

1.3.1. General 4

1.3.2. Compilation-production services. 4

1.3.3. Inquiry services 4 Mechanized information system for NSRDS 4

2.1. General considerations 4

2.1.1. Philosophy of computerselection. 4

2.1.2. Arguments in favor of mechanization 5

2.1.3. Obstacles to mechanization 5

2.1.4. Size and location of computer. _. 6

2.1.5. Computer characteristics 7

2.2. Functions of the system 7

2.2.1. Information retrieval 7

2.2.2. File updating 8

2.2.3. Aids to publication 9

2.2.4. Other computer functions 9

2.3. Input to the file 10

2.3.1. Keypunching 10

2.3.2. Print reading 10

2.3.3. Data available from data centers. 10

2.3.4. Equipment and format 11

2.—Continued

2.4. Information storage

2.4.1. Form of data

2.4.2. Arrangement of data

2.4.3. Compact storage

2.4.4. Storage of instructions

2.4.5. Storage devices

2.5. Access to the computer

2.5.1. Man-machine interaction

2.5.2. Long-distance access

2.5.3. Administrative arrangements

3. Proposed interim system

3.1. Characteristics of the operation

3.2. Inquiry services

3.2.1. Getting started

3.2.2. Referral

3.2.3. Reference

3.2.4. Documentation

3.2.5. Data service

3.3. Publication services

3.3.1. Types of services

3.3.2. Preparing for mechanization

3.4. Preparatory activities

3.4.1. Information gathering

3.4.2. Bibliography

3.4.3. Classification

3.4.4. Indexing and abstracting

4. Conclusions

ir
Information Handling in the National Standard Reference

Data System

Franz L. Alt

A preliminary plan is presented for the selection, acquisition, intellectual organization,

and storage of the information which will underlie the Information Services Operation of the National Standard Reference Data System, as well as for methods of locating desired information items in storage, retrieving, and displaying or communicating them. Questions

of the use of computers for these purposes are discussed, including selection of equipment,

arrangement of digital storage, input format, remote access, and the economics of choosing

certain functions of the system for mechanization. Also, an interim system, based on con- ventional and, in the main, manually operated files, is described. Key Words: Computer-aided inquiry service, data retrieval, file mechanization, infor- mation retrieval, standard reference data.

1. Introduction

1.1. Plan of Approach

1.1.1. Development of NSRDS

The present report describes proposed plans for

e handling of information in the National

andard Reference Data System (NSRDS). It concerned with the information with which the stem deals, with the logical organization of this

formation, its acquisition and physical storage;

th methods of locating desired information items

storage, retrieving and displaying or comanicating them.

It is expected that the information system of

3RDS will undergo evolutionary changes for a imber of years. The later stages of this devel- •ment can not yet be foreseen with complete

irity, because NSRDS itself is developing.

Estails of the system design will depend on certain rameters (e.g., size and rate of growth of the

ta collection) whose eventual values are not yet

town, or on changes in technology which are

tely to develop during the next few years, and

l the solution of some of the research problems

liich will be undertaken by NSRDS itself. Despite all this uncertainty about the future

velopment of the information system, two facts erge which have been adopted as basic policy

cisions and which underlie all other decisions

be made: (1) Ultimately the NSRDS informan system will involve the use of large electronic

gital computers in a crucial way (though not

cessarily to the complete exclusion of manual

ethods). (2) At present the introduction of

ich computers into the principal operations of

SRDS would be premature.

These two statements are plausible in themlves and will become more so in the course of

scussing the economics of computer operation

section 2 of this report. From them we infer

iimediately that we should distinguish at least vo periods in the operation of NSRDS : the longmge future, during which the operation will be

laracterized by computer use; and the near

future, which will have a different regime—as we

shall argue, conventional and in the main manually operated files, combined with information

stored in human minds.

This leaves several questions still to be answered.

First, it may appear plausible that the transition

to the computer system should be gradual or in

a number of steps, rather than all at once. Sec- ond, one may ask whether there should be one

or more intermediate periods, characterized by

methods which differ both from the ultimate large

computer system and the initial manual file sys- tem. Such intermediate methods would differ

from mere transitional steps on the way to full computer operation, by definition, in that the

former call for some investment in hardware or procedures which would be retained more or less without change. A more detailed discussion of

these questions given later in the present report

will favor a gradual transition from manual to computer operation, but without recourse to costly

intermediate techniques that would be discarded

before economic use is made of the investment.

A third open question is that of time. A

precise prediction of how soon a computer can be

used effectively and economically is not possible

at present, but it seems likely that the initial manual information system will remain in operation

for at least three years, possibly longer. The

speed of phasing from a preponderantly manual

to a preponderantly machine system will depend

upon the activities and development of the Technical Data Centers and other as yet unforseeable

factors. At each stage during this gradual transition there should be ample opportunity for us to make decisions more confidently as we observe the

system in operation.

Not only will the transition to machine methods be gradual; in some instances it should not

take place at all. For example, it is not clear that

inquiries can be answered reliably in toto by a machine. We may find that machine methods can be

used to narrow a search to a few choices, the final
selection to be done by humans, or vice versa, hu- mans to perform a preliminary screening and

switching of inquiries. . . The successive systems are not quite independent

of each other. It is easy to see that a choice between alternative procedures in the computerbased system might be influenced by the way in

which the same feature has been handled in the

preceding (manual or intermediate) system.

Similarly, and more importantly, the design of the

initial and any intermediate system should preferably avoid anything that might impede transition to the most desirable form of the ultimate computer system. In order to facilitate the exposition, we therefore propose to discuss the longrange information system first, and the short-range one afterwards. . Thus, the present report is organized as follows.

The next section summarizes the main results. The remaining portions of section 1 describe the

organization and functions of NSRDS to the ex- tent needed for our discussion of the information

system. A more complete description has been

given elsewhere,1 and readers familiar with it may

bypass these sections. Next, section 2 develops the

ultimate computer-based system as far as our pres- ent ideas go. This is followed in section 3 by a

description of the system envisaged for the next

few years, and finally by a few comments on the

transition between the two. We have' referred to the long-range system as the "ultimate" one. By this we do not mean that

it will be frozen forever; rather, that we have

taken into account everything that we can foresee

about it at this time. The system will undoubtedly

undergo further changes, but they must be disregarded in our present planning.

We envisage NSRDS not as an entity all by it- self but as one of a number of information activities constituting the emerging National Scientific

and Technical Information System currently under study by COSATI. In particular, we en- deavor to keep NSRDS compatible with the information systems of AEC, NASA, DDC, the Clearinghouse for Federal Scientific and Technical In- formation, and other agencies.

1.1.2. Recommendations

In this section we summarize briefly the principal results of the study, especially as they lead to recommendations for action. It has already been

mentioned, and will become more evident in later

sections, that these results are still somewhat tentative. This is unavoidable, in view of the uncertainty of many of the premises on which they are

based. The best that can be done at this time is to give a full presentation of the pros and cons for

each of the major decisions. In order to enable

the reader to find this information selectively, if

1 E. L. Brady and M. B. Wallenstein, National Standard Ref- erence Data Hyntem—Plan of Operation. NSRDS-NBS 1, U.S. Government Printing Office, 1964.

he so desires, the following list of recommend;

tions is cross-referenced to those sections of th

Note in which he may find a discussion of unde ; I lying assumptions, facts, and arguments and|_

where applicable—of alternatives which were co i sidered. It will become clear that many of the I recommendations, especially those intended for ii plementation several years hence, are subject

| change in the interim, if such change should I come advisable, e.g., through new informal i about the availability and rate of generation : q data, about the operation of data centers, abo-i performance and cost of computers, and the opt

ating experience of the Office of Standard Refff

ence Data itself. Svmvmary of Recommendations

1. A conventional manual data file system 11 the near future. (1.1, 3)

2. A system based on a digital computer for t more distant future. (1.1, 2)

3. Begin rendering services using System (1)

once. (1.1, 3.2.1, 4)

4. Plan on the bulk of System (2) being imp

mented in 3 to 5 years. (1.1)

5. Transition from (1) to (2) in steps, but wi1|

out major investment in any temporary interme

j ate system. (1.1,4)

6. Aim at man-machine cooperation rather th

at complete mechanization of information i trieval. (2.1.3, 2.5.1)

7. Share time on a large general-purpose co puter operated by NBS. (2.1.4, 2.5.3)

8. Obtain an external storage unit of about

| million words capacity, with a transfer rate of

least 1 to 2 megabits per second, for exclusive v by OSRD. (2.1.5, 2.4.5)

9. Establish in the office of OSRD a console : direct on-line access to the computer. (2.J

2.5.1)

10. At a later stage, similar consoles should,

available throughout the country, for connect1

to the computer by long-distance telepho

(2.1.5, 2.5.2)

11. Use of the computer to include informat

retrieval, file updating, aid to publication (edit:, and typesetting) , and housekeeping. (2.2)

12. OSRD to devise standard formats for k

punching of data, e.g., into 80-column punclj

cards, these formats to be observed as far as p

sible by OSRD and all Data Centers. (2.3.4)

13. The burden of keypunching by OSRD to relieved by using machinable data punched

other sources, or for other purposes, and data g

erated by computers or automatic print read)

(2.3.3)

14. Data in the master file to be arranged i properties or, more generally, by homogene|

groups of related properties. (2.4.2) i 15. Functions of one or more variables to be r I resented, where appropriate, by approximat
r

Eblynomials (or other series) using maximal

I Intervals. (2.4.3)

3 16. Use of the computer to be in "batch" mode

henever possible; remote on-line access to comuter from OSRD when necessary for efficient ian-machine interaction. (2.5.1)

i 17. Future results of critical evaluation of data

> be assembled in a separate file in OSRD. When

o standard reference data available, data in1 Juries to be answered with best data in the literaare, with suitable disclaimer. (3.2.1, 3.2.5)

18. Initially, a large fraction of all inquiries

<?ceived will be referred to experts; number of

eferrals should gradually drop but not to zero.

3.2.2)

19. Technical area managers, Data Centers,

IBS scientists and occasionally others to be used

s experts for replying to inquiries. (3.2.2)

20. Use of citation indexes, bibliographic couling, and other aids to literature referencing to e explored. (3.2.3)

21. Graphical information to be handled by

omputer-controlled curve plotter, or if this is ot possible, by microfiche. Control of the latter

if ystem by central digital computer to be studied.

3.2.4) 22. Publication of NSRD Series to be con- inued ; a periodical, especially with bibliographic

Information, to be considered later. (3.3.1)

1 23. Computer aid9 to publication to be coninued, and further development especially of

diting codes to be pushed. (3.3.2)

m 24. Needs of potential users as to frequency,

ypes, and form of information to be established

'through user surveys. (3.4.1)

W 25. Concurrently with the start of information

'Services, OSRD to broaden its information by a

tibliographic survey of existing data compila-

- ions, and by a questionnaire to prospective users.

!.[ 3.4.2)

26. Establishing a small thesaurus of subject

d index terms, indexing the present OSRD library

to ollection, and abstracting of library books to be

it 'Pursued in this order, and concurrently with in- luiry-answering service. Library personnel to be

it-ised in inquiry answering in order to gain experit' nee. (3.4.3, 3.4.4)

27. Mechanization of a small part of the col- lection to be attempted soon. (4)

1.2. Organization of NSRDS

j Physical properties of materials, which are the

[ subject matter with which NSRDS deals, have

)een divided into a number of technical areas. To

.^late seven such areas have been defined: (1) nu- clear data, (2) atomic and molecular data, (3)

;olid state data, (4) thermodynamic and transport

1 properties, (5) chemical kinetics, (6) colloid and

W surface properties, and (7) mechanical properties.

Dther areas may be added later, but these seven

rnseem to come close to exhausting our present

iti concern.

The organization dealing with these subjects

consists of the Office of Standard Reference Data

(OSRD), located at the National Bureau of Standards, and a number of Technical Data Centers,

mostly outside of NBS. Many of these Data Centers are sponsored and operated by other agencies

some antedate the existence of NSRDS. A few

are located at NBS, and some operate elsewhere

under contract with NBS. Each Data Center has

cognizance over a certain domain, usually falling

within, but narrower than, one of the seven technical areas. The domain of a technical Data Center may be characterized by a set of physical

properties (e.g., infrared spectra) or materials

(e.g., metals) or occasionally of other criteria (e.g.,

low temperature), or by a combination of such

criteria. The designation of certain organizations

as Technical Data Centers of NSRDS, the delimitation of their scope, and coordination of their

activities are among the responsibilities of OSRD.

In addition there are data compilation projects

directly under the cognizance of OSRD.

It is recognized that the presently existing Data

Centers cover only a small part of the entire

domain of standard reference data. It is desirable

that new centers should be established, or old ones expanded, at a rapid rate. It must be recognized,

however, that even in the best of circumstances

it will take years before Data Centers will even approach complete coverage of the entire field of

standard reference data, and it is unlikely that

such completeness will ever be attained. As a

result, a larger burden will have to be placed on OSRD, at least initially.

In particular, OSRD will have to engage in a survey of existing data compilations in all fields,

which can be used as a basis for information services until a better foundation is furnished by the

Data Centers. It will also, in some cases, contract with organizations or individual scientists for producing compilations, critical evaluation and re- views, computation of certain useful functions

derived from standard reference data, and even

experimental measurements. All these activities can be provided by OSRD as opportunities offer themselves, but a more systematic and exhaustive

coverage of the field will depend on the expansion

of the Data Center system.

Within OSRD there is an Area Manager for

each of the seven technical areas, plus one for in- formation system design and research; in addition,

OSRD operates an Information Service at NBS.

In a certain sense, the organization and activities

of this Information Services Operation (ISO) are the main subject of the present report, although some relevant questions about Data Center activities will also have to be discussed.

ISO is' expected to consist of four units, con- cerned with (1) compilation-production services,

(2) inquiry services, (3) the data file operation,

and (4) analysis and user relations.
1.3. Information Services

1.3.1. General

It is the responsibility of the Information Services Operation "to provide the services to the

technical community that are determined to be

useful and maintain the collection of data that

will constitute the data center at the National

Bureau of Standards—indexing, filing, storing,

and retrieving data as required."

We distinguish two kinds of services : scheduled

and nonscheduled. It is too early to make a firm

estimate of the relative size of these two kinds of

information activities. Indications are that they

will be of comparable magnitude.

1.3.2. Compilation-Production Services

Scheduled services include the dissemination of

information, either periodical or occasional, on

our own initiative. It is expected that some of

this will be handled, as it is now in a few cases, by the technical data centers, with or without as- sistance from OSRD. The central information

service operation will not duplicate any of these

efforts but will attempt to provide additional

publications covering the field of reference data

in general, or cutting across the lines of several

data centers, or falling between them. A periodical current awareness service is one of the likely

activities contemplated for ISO. Preparation of

revised editions of data handbooks is an example

of activities of the technical data centers.

In general, the publication of monographs, a?

|

the primary means of supplying data to users, is perhaps the most important single function o1 NSRDS. Such monographs, while concentrating on the tabulation of critically evaluated data, wil

in addition contain such relevant information oi the generation and application of the data as i likely to be helpful to the user (cf. sec. 3.3.1)

1.3.3. Inquiry Services

We may visualize four kinds of action taken i: response to requests for information : (a) referral

(b) reference; (c) documentation; (d) data in- formation. They are increasingly specific in th

order in which they are listed. Referral mearij

that the question is referred to another organize

tion, generally one of the technical data center though occasionally an organization outsid

NSRDS. It is expected that the requestor woul

be informed of the referral. The reply may I sent to the requestor, preferably via OSRD. B

reference is meant a listing of relevant literature Documentation goes one step further and includ*

furnishing of micro-stored or hard copies of tl referenced literature. "Data information" impli<>

furnishing not only a listing of the requested dat

but also any necessary explanation, caution, et (cf. sec. 3.2).

The choice among these actions must be ke]

flexible at all times. It would be undesirable

decide that OSRD will furnish only one kind

reply.

2. Mechanized Information System for NSRDS

2.1. General Considerations

2.1.1. Philosophy of Computer Selection In this section we discuss the advantages and

drawbacks of mechanization primarily in the light

of their concrete effects, rather than of their imponderable consequences.

The use of digital computers for information

retrieval is one of the most widely discussed is- sues in science administration today. A number

of entire new organizations are being set up for

this purpose, and large vested interests are at play.

In such a situation one is easily tempted into extra- neous considerations: having a computer is con- sidered "good advertising," it lends an appearance

of progress and importance to an organization, it attracts prospective customers. We propose to

resist these temptations and to examine the possible uses of computers in NSRDS strictly on their

merits. Accordingly, we will compare the cost of

computer versus manual operation and the cost differences among different computer types; we

will examine the advantages in speed and ease of

distant access to a mechanized file, and the possible

loss in quality and convenience of direct access to a manual file kept on the spot. We must keep in

mind, however, that an analysis based on these fa tors alone is likely to understate the value of aut

j mation. Experience in other fields has shown th

the introduction of computer methods is often f

<

lowed by unforeseeable, or at least unforesee,

rapid progress in other respects. Noteworthy e amples are in the analysis of x-ray crystal I graphic data and of bubble chamber observatioi I where the use of computers was followed by au(

j mation of data acquisition and has led to a mail- fold expansion in the amount of scientific inti- mation obtained by these methods.

At present there is not enough informati,:i

available to enable us to make a quantitati|3y

study of the cost and performance of computers p be used several years from now. We have to r<| on some general and qualitative observations a i experience in other fields, but there will be ti e to verify the findings so obtained before comn - ting ourselves definitely to one or another cou e of action. The arguments to be presented in

next two sections give qualitative support to «

contention that a digital computer will ultimat ;y be economical for NSRDS. In addition we si II argue that sharing time on a large compute] if preferable to operating a smaller computer I
. i A SKDS alone. Finally, rather than insisting on

j )inplete mechanization of every phase of the

locess, we shall aim at an optimal division of laj, or between man and machine.

isi

2.1.2. Arguments in Favor of Mechanization

(a) Size of collection. There is as yet no re- able basis for estimating the magnitude of our

iformation collection. For planning purposes

e are using an order of magnitude of 100 m-llion

ords. (See sec. 2.2.1.) It seems plausible to

s that the ultimate size may differ from this estiiiate by possibly a factor of 10, but probably not

y a factor of 100, in either direction. It should

fe several years before we get to figures of this

wjllagnitude. Size alone is rarely a sufficient rea-

. : >n for automation, unless it gets to be truly excesve; if a collection of 100 million words were to

? used only in the way in which one uses, say, a

I -lephone directory or library card file, mechaniition would not be worthwhile. Taken together

r ith the following arguments, however, the esti- mated size is an added consideration in favor of

;k:techanization.

(b) Mechanization becomes advantageous when

lere are frequent occasions for searching through

le entire file or large portions of it. An example

the search for materials whose boiling points lie stween given limits. Whether or not searching

required depends on the way in which the file is

- rganized ; for example, the telephone directory

not properly organized for finding people living n a given street. Indexing is a method of organing a file so as to allow the answering of certain

.r pes of questions without a major file search. It eems extremely unlikely that we should be able to aicipate all our information needs by measures

1 f this kind, and therefore file searches will be

| eeded from time to time. It is impossible at pres-

; it to estimate their frequency, but the argument

•nds weight to the demand for mechanization.

1 (c) Updating a file, correction of errors, addi-

,: '^!jfon of new results, etc., are greately facilitated by

•

' lechanization. This consideration has prompted

°'' s, for example, to use cards and machine methods

1 f type composition in preparing the next edition

mw "Crystal Data Tables." It is likely that the

' rtra cost incurred will be more than offset by sav-

: lgs in preparing the first subsequent edition.

(d) Methods of bibliographic coupling and of

itation referencing are greatly aided by mechanixtion. Arguments will be advanced in section

- 2.4 below to show that these methods are of parailar importance for the Standard Reference

be ti(i)i)ata Program.

(e) The operation both of OSRD and of the

ata centers will be facilitated by remote access

in

' o the file, which in turn presupposes mechaniza-

•ttojjion. More will be said about this below. (See

' ecs. 2.5.1, 2.5.2.) >M (f) In some of the data centers, the introducel ion of machine methods will be aided by the fact

pater

that some of the experimental measurements used

in the generation of data are set up for automatic

recording and digital encoding of results.

2.1.3. Obstacles to Mechanization

The introduction of computers into the process

of information retrieval is hindered by the same

difficulty which characterizes most other computer

applications : our present inability to give a rigor- ous description of the procedure which the computer is to follow. In human information re- trieval, e.g., in a library, not only is the memory of

the librarian an important tool, but every user of a library uses clues, lines of reasoning, and other

mental processes of which he himself is not aware. Such an imperfectly formulated procedure is well

adapted to the human mind but is of no help with

computers.

There are two ways to overcome our lack of un- derstanding of the problem. One is a program of

research into the formulation of the information

retrieval problem. For this, in turn, there are two

alternatives : investigate and, if possible, formalize

the customary human procedure; or develop new

methods which are more suitable for machines. It

is, of course, not true that the computer would

have to use the same procedure as is used by humans; but it has to use some procedure which is completely formulated, and one way to formulate

it is to start with the familiar human procedure

try to make explicit the mental processes which we

use without being aware of them, see whether they

contain any elements which can be formalized, and

if so, translate them into computer programs. If

this is possible, it may be preferable to inventing an

entirely new and untried approach to the problem.

The other way out is partial mechanization

limit the use of the computer to those fragments

of the whole problem for which a rigorous for- mulation can readily be found, and leave the rest to humans as before. In this case one has to pay

special attention to the interaction between man

and machine, to the smooth transfer of information from one to the other. This brings up another

problem possibly as formidable as the first : often

input and/or output are the principal bottlenecks

in automatic computation. Indeed, there are clas- sical cases of systems in which the introduction of

computers was not profitable until all functions of

the system had been mechanized, thus reducing the

relative magnitude of input and output. There

are other examples in which, on the contrary, the

use of computers was made uneconomical by the

attempt at complete mechanization, resulting in

excessively complicated computer programs; a more modest approach, limited to the most fre- quently required functions of the system, gave most

of the benefits for a small fraction of the cost. Thus, a reasoned choice between the two possible

approaches must be made. The decision does not

necessarily have to go all one way; compromises

are possible. For the information system which

5
we are considering here, it seems likely that some

functions should be reserved to humans for a long

time to come, possibly forever. We are thinking

especially of the checking, screening, and editing

of output, and of the formulation of questions by

successive steps. The latter problem may be

viewed as that of assigning a sufficient number of

pockets for information to assure that no single

pocket contains more than a few items. Retrieved

information would then be in the form of a pocket

of information or a small number of such pockets.

Resolution beyond this point by machine methods

alone may not be economical.

On the other hand, the problems in man-machine

communication which these functions generate,

although they are severe, do not seem insurmountable. Indeed, we envision that the human user

will interfere repeatedly in the computer process, aided by conveniently designed facilities for inserting instructions and for display of intermediate

computed results. Such collaboration or dialogue

between user and machine is expected to be a characteristic feature of our information system.

2.1.4. Size and Location of Computer

Anyone in need of the services of a computer

should first examine whether to acquire a computer exclusively for his own use or to obtain time on somebody else's computer. (We may dis- regard the third alternative, of acquiring a computer and making some of its time available to outsiders.) For prospective users in the Federal

government such an examination is specifically

prescribed by the Bureau of the Budget.

Of the various uses of the computer in the work

of NSRDS, probably the most demanding requirement is the retrieval of specific item9 of information, or sets of such items, in response to requests. It will be seen that other uses—e.g., in updating

the information file, assistance in publication,

housekeeping—are les9 exacting and fit well into a system designed specially for the information

retrieval functions.

In a typical problem in this area, a portion of

the computer-stored information file is read and

each item in the file compared with the question

being asked, to see whether the file item is relevant

to the question. On a large fast computer only

a few microseconds are required for each comparison; for those few items which are found to be relevant, a longer process of evaluation and

output takes place. Time is saved if a number

of questions are treated simultaneously. One

may, for example, collect the questions arriving

in the course of a day into one batch and answer them in a single computer run. Each question

needs to draw on only a certain portion of the

information file, and for each portion of the file there will be, on the average, a small number of

questions to be considered.

There are so many details as yet unknown that we can obtain at best an order-of-magnitude estimate of computer time involved. Computers ofj

the incoming generation take about 1 microsecond

per (logical) instruction. If each word from thej

file is compared with an average of 5 questions,

and each comparison takes 4 instructions, thm

computer will spend 20 microseconds per words'

with a file of, say, 100 million words the daily]

computer time would be 2000 seconds. We shalli see that the rate of transferring information from

store to central processor can just keep up withH

the speed of computation. If a smaller and slower

computer were used, it could be kept busy full time. (On the Bureau's present computer, IBM

7094, the time would be something less than 2 hours

per day. ) For supporting figures see section 2.4.5^ In the choice between large and small computers, the large ones are normally less expensive;

typically, their hourly cost might be greater by a factor of ten, their output by a factor of lOOl Small computers can be justified only on grounds

other than cost, e.g., convenience of access, oi

mismatch between internal speed of a large computer and rate of input or output. No serious

argument of this kind appears to be valid in our' case, as will be seen in section 2.4.5. On the other

hand, there is a further argument in favor of a

late-vintage large computer: OSRD is expected

to lead the way in applying and demonstrating

improved ways of retrieving standard reference!

data; use of front-line equipment offers many

opportunities for exercising such leadership.

If OSRD is to use a large fast computer, it will, I in the foreseeable future, do so by obtaining com- 1- puter time from a laboratory operating such { computer, since its own needs would not keep sue! a computer fully occupied. This leads to the ques

tion whether computer programming service

should likewise be obtained from another labora

tory, or whether OSRD should build up its owi

programming staff. To this question we do no have a clear-cut answer at present. There is ai increasing trend toward professional specializatioi

in programming, as a result of which a computa

tion laboratory is in a better position to select am

train competent programmers, keep them full; employed in their special field, and offer them pro

fessional advancement. In an organization lik OSRD, a professional programmer is intellectual! I isolated, faced with a fluctuating workload of wha |

to him are "odd jobs." On the other hand, som

aspects of computer programming demand int: mate familiarity with its data file organizatioi

and benefit from the devotion of a staff whose fir.' loyalty is to OSRD. Another approach is to ha\

computer programs written by teams consistin

of people from both organizations—profession;

programmers from the computation laboratoi

teamed with data specialists with detailed prr

gramming experience from OSRD ; the "interface or communication link between these people migl

consist of flow charts and data sheets.
-

In the absence of a strong argument to the cont iv, it seems natural that OSRD should use the

I j.e general-purpose computer expected to be

liable at NBS. While remote access to comters over long distances is increasingly coming

(o use, it is economically limited to certain spe1 situations—very short problems, or frequently

?ded large problems which remain unchanged

years, so that the program and any tabular data

p permanently stored at the computer site. In

my ways close proximity to a computer is adntageous, since we envisage the OSRD operation

gradually evolving, with frequent changes in

iputer programs and additions of large quantis of data. Such operations are facilitated by

bonal contact of machine operators, program-

,'rs and users, by hand-carrying of large card

cks, and sometimes by the user's ability to influpe the policies of the computation laboratory

of which argues in favor of using the generaljirpose NBS computer.

The same reasons can be advanced against the

;Oposal that OSRD join with some or all of the

j hnical data centers of NSRDS for the establish-

| jlnt of a common computer laboratory. An addinal argument against such a plan is the political

ficulty of reaching agreement with the different

|ta centers, many of whom have their own vested

erests in computing laboratories located at their

filiations.

There is little likelihood that OSRD would outjyjj fpw the sharing arrangement. Present estimates

. mpicate that a few years from now OSRD will use

i , small fraction of the time available on present-

,_, |y computers. Even if OSRD's requirements

[ m

-ould eventually grow far beyond this estimate,

JL ;is likely that computers will also have become

y Ach faster by that time.

2.1.5. Computer Characteristics

lo i

_

; a ,If, as proposed in the preceding section, OSRD

atio iares in the general-purpose computer of NBS,

upnti ^ovision will have to be made for certain pecu-

'. ji

' rities of the OSRD operation.

ft]] }The amount of data to be stored for OSRD is

r ., ) great that it is impractical to keep them on

ji

? rds or tape and read them into the computer

I jr each run anew. In this respect OSRD is, and

. obably will remain, unique among NBS com-

''* ter users. It will be necessary to acquire a

u /urate storage component, which would be purased or rented by OSRD and reserved for its

atrplusive use, and which would be connected to nnmiTMtar main frame. Suitable

;ren(

mai

W

computer mam storage

vices are now commercially available from sev- \\ manufacturers. A secondary question which

:0D"u be resolved later is whether this storage unit

ould also contain the program instructions—an

'K rangement which is probably economical but

ijssibly in conflict with the operating system of

' i computer (cf. sees. 2.4.4, 2.4.5).

It will be mandatory, or at least highly desirable, to have facilities for remote on-line access

to the central computer. A console should be

located in the OSRD offices (and there will probably be a demand for a number of similar consoles

elsewhere in the Bureau) from which a user can

contact the central computer, wait for the end of

the current problem (or in the case of a long problem, interrupt it) , read into the computer a small

amount of instructions and data, have the instructions executed and immediately see a small volume

of results. Large-volume output would remain on

tape in the computer room and be available to the user there. The program should have access to routines and data permanently stored in the computer's internal memory, and should be able to connect the computer, under its own control, to tape stations and special external storage devices

such as the one postulated in the preceding paragraph (cf. sec. 2.5.1). It will also be desirable to have the ability to use similar remote stations in distant cities, using

commercial telephone lines. This will enable in- dividual scientists and engineers to obtain needed

data and related bibliographic information with

a minimum of effort and time loss (cf. sec. 2.5.2)

In order to enable OSRD to be compatible with

the Technical Data Centers and, in many cases, introduce recommendations for common practice

for their information handling, the NBS computer

should be able to accept programs written in the more widely used programming languages, especially those standardized by the American Standards Association. The role of NSRDS will be

facilitated if the NBS computer is of a kind commercially available throughout the United States. Finally, as we have already said, the computer

should be in the front line of development of large,

fast, and powerful computers, in order to enable

OSRD to discharge its responsibility of establishment of standards of quality, methodology including machine processing formats and such other

functions as are required to ensure the compatibility of all units of the NSRDS.

The development of special-purpose computers

for information retrieval will have to be watched.

It is not yet clear whether current efforts in this

direction will be successful nor, if they are, to what extent their novel features will come to be

included in future general-purpose computers.

2.2. Functions of the System

2.2.1. Information Retrieval Under this heading we consider the reaction of

the system to (unscheduled) requests for information. The nature of these requests can be inferred

from the experience of existing specialized data

centers. It appears that the frequency of such

requests ranges from perhaps a few dozen to over

a thousand per year, depending on the scope of

the center. Since OSRD is broader than any of

219-580 O—66
the centers examined, its work load should at least equal the higher of these figures; that is to say, we should expect to start with several requests per

day as soon as the availability of OSRD has be- come known, and to grow far beyond that number as scientists and engineers learn to use the

service. It has been the experience of other centers that a major part of these requests is not for data

but for "administrative" information—availability of publications, addresses of organizations,

etc.—and technical problems other than data

themselves. A large portion of the questions come

from the immediate neigborhood of the center

people in other parts of the same organization

which suggests that there is a need for such in- formation in technical laboratories but that the

present cumbersome methods of retrieval discourage most potential users. This observation reinforces our argument for remote access to the

mechanized data collection (cf. sec. 2.1.5).

Among requests for data we distinguish mainly

two kinds. Those of the first kind ask for a

specified property or group of properties, of a

specified material or group of materials, for specified conditions or ranges of conditions "F^** in- stance, one might ask for the optical density of

water at 20 °C, at a given wavelength, or one might demand a table of the specific heats, entropies, and enthalpies of the noble gases between

and 100 °C. Questions of the second kind ask

for materials for which certain properties have

specified Values, or lie within specified ranges ; for

instance, alcohols with molecular weights not over

102, whose boiling points at atmospheric pressure

lie between 60 and 100 °C. In this second class of questions are also the problems of identifying

materials from their spectra, from crystallographic or other properties.

These two types of questions are analogous to the direct and inverse use of a mathematical

table—to find values of the tabulated function, or

to find those arguments for which the function

has given values. In the case of properties of

materials, certain other kinds of questions are also

possible (e.g., which of the spectral lines of mercury is narrowest?) but they are comparatively

rare. Questions of the first kind will probably

predominate, if the experience of existing data

centers may be taken as a guide.

The ease with which a question of either type can be answered depends crucially on the size of

the tables and on the way in which they are or- ganized. The latter will be discussed in a subsequent section of this report. As to size, there is first of all an almost unlimited number of chemical compounds; those on which significant data

are available may number 100,000, and this number is growing rapidly. There are perhaps 1000

different properties within the scope of NSRDS.

Some of these are represented by single numbers,

others are functions of one of more variables ; each

of the latter is represented by perhaps several

hundred numbers (cf. sec. 2.4.3. below). The

are few materials for which all this informati

exists, especially if the less dependable measui

ments are omitted. We estimate vaguely that t average number of reliably measured data i each of the 100,000 materials is at present w; below 1000, and will reach and pass that numt

some years from now. A collection of all th(

data will then amount to 100 million words.2 We can obtain an independent check on t] figure, crude as it is, in the following way. T

present rudimentary library of OSRD has abc

600 volumes, of which about 400 are data. At

average of 400 pages per volume and 500 words \ \ page, this is 80 million words. Most of thij

volumes are not entirely filled with data but cc tain large sections of text; if tabular they ofl include large blank spaces ; and there is much ov

lap in the contents of different volumes. 1! number of separate data items in this collecti! might be between 10 and 20 million.

2.2.2. File Updating

The maintenance of files is a standard compu

problem, common to numerous applications,

has been the subject of a substantial techni

literature. In many respects the requirements

NSRDS are not different from those of other ; plications, and can be handled by standi

methods. File updating—the insertion of new

tries into the master file and the replacement

any old ones which need correction—is norma

done during the same computer runs which

made for the purpose of information retries If any new information for insertion in, or corr tion of, the file is received by the laboratory at a time between two such computer runs, it is recorc on tape either at once or at any time before

next computer run. Immediately before this r

all the accumulated new information is arranged in the order in which it is to be ente:]

into the master file. The main computer run tl consists in reading the master file, one entry a

time. After reading each entry we first exam

the next item on the "new information" list (taj to see whether it is to be inserted before this en

or modifies it. If neither, we put the master

entry through the information retrieval rout and proceed to the next master entry. If, h< ever, the next "new information" item does < for insertion or correction, this is carried out, new or corrected item is put through the ini mation retrieval routine, then the following "i information" item is examined in the same \

etc.We expect to use the same procedure in updat

the file of standard reference data, except to one of the new erasable mass storage media

2 Conventionally an average word is thought of as 5 ! characters. Many contemporary computers use words < characters (36 bits). Most data items are only 3 or 4 de<? digits (10-13 bits) but because of redundant notation oc space equivalent to about one word.

X
1 ilace of tape. Thus, the only additional effort re- uired for updating is that of actually examining

i

' ke new information and making the changes in

line master file; since normally only a small numier of changes occur, this effort is small compared

7 that of reading the entire master file. The

-j itter operation need not be carried out beyond

J le extent necessary for information retrieval.

tt the same time, information retrieval is always

tased on completely up to date information, since

1 1|11 corrections are made before an old item is used

-'""(or retrieval.

At We have no estimate of the rate at which new

l formation will flow into the system, but it is ob-

-I ious that if retrieval and updating runs are made

°}jaily or even weekly, only a small fraction of the

wile items will be affected by updating in an average

iotJW

2.2.3. Aids to Publication

•'Aids to and from publication" would be an

qually appropriate heading ; sometimes the existj'jtice of machine-readable information files is a

elp in editing such material for publication; at ther times, the creation of such files is facilitated

y steps taken primarily for the purpose of

aiblication. The use of machine-readable material in the

ublication process can be advantageous in several

rays. The most obvious case is that in which the

nformation is numerical and has been produced

>n a computer, so that the entire costly process of

aanual typesetting is avoided. For years, tables

•f such numbers have been produced on typewrit-

- rs or line printers controlled by punched cards or

aagnetic tape; these are of limited flexibility, the

esulting printed copy suffers from poor readabil-

' by, and column headings, pagination, etc., present

mioying problems. Since the introduction of

'ape-driven photocomposition devices has made it possible to produce printed output of letterpress

.uality directly by computer, at costs comparable

o those of manual typesetting, there is no reason

' Vhy computer-produced material should ever have

o be hand-set for printing.

Another reason for computer-controlled type

omposition is the facility for rearranging or kherwise revising the material. This is imporJT ant whenever the same material must be printed

: n several arrangements. An example is the vol-

•

' ime "Crystal Data Tables" now being prepared

or publication by photocomposition. The original information is being keypunched in essen-

- ially the same format in which it is to appear in

orint, and this part of the operation offers no great

iMvantage over manual typesetting. But from

' he keypunched information it will be possible to produce alphabetical indexes for authors, names md formulas of chemical compounds, all by auto- matic sorting, checking, and editing. In subsequent editions, only the new or revised material

•

? ent

rant! '}

-an.:

it (tail

his en

p;

aster

. s

:i toft

tJ0D<ofjtfill have to be newly keypunched, the computer

will insert it in the proper place, change pagination as needed, update the indexes. In addition

the computer can perform a large number of

checks based on the characteristics of the information : the crystallographic data satisfy certain in- equalities, abbreviations for journals occurring in

literature reference must be taken from standard

lists, the order of items can be checked etc. This

saves a large part of the proofreading effort. Against these savings must be reckoned the effort of writing special computer programs.

The publication of "Crystal Data Tables" is an example of a situation in which the desire to use automatic type composition furnishes the incentive

for recording the information in machine-readable

form, and thus aids in the creation of mechanized

files. Other instances of this kind will probably

be bibliographies and acquisition lists which are

to be published in cumulative, updated form at frequent intervals. There will be other cases in

which automatic type composition will become at- tractive only after the information has been re- corded on tape for a different purpose.

2.2.4. Other Computer Functions

Even before a mechanized information file for

retrieval and updating has been created, computer

methods can be used for a number of housekeeping

functions. It has been the experience of other

information centers that some of these functions

are more easily mechanized than the information

storage and retrieval itself. For example, even while OSRD still uses a manual information retrieval system based on con- ventional library practices, a computer could conceivably be used to keep track of purchase orders,

accessions, shelving, classification, and circulation

(loans of books to users) . It is possible, however,

that mechanization at this stage, while practiced

by some other installations, may not be economical

for OSRD because of the small size of its library. It may be desirable to keep statistical information on the requests for information which are acted on by OSRD. Such information will be a promising candidate for automation after a brief

initial period of manual handling, during which

the staff becomes familiar with the number and

types of questions to be expected.

Similarly, machinable records may be helpful

in the indexing of the information collection ac- cording to properties, materials and certain classes of materials, and some other characteristics (e.g.,

by checking manually introduced index terms

against computer-stored master lists of such terms

to insure uniform nomenclature)

It may be desirable to maintain records of

sources of information other than OSRD's own

collection. These sources are primarily of two

kinds : on the one hand, knowledgeable individuals

and organizations for referral, and on the other

hand, books, papers, and unpublished reports.

The former are probably too small in number to warrant use of machine methods. The latter are
numerous, and should be the subject of a mechanized file system if it is decided that OSRD will

make use of the scientific literature to any extent. While it is debatable which of these housekeeping operations should be mechanized before the

main operation of OSRD is switched over to computer use, all of them are certainly likely to be

among the functions of the ultimate computer

system.

Apart from housekeeping operations there is an entirely different computer function which

promises to be particularly useful in the Standard

Reference Data Program, namely the retrieval of

information by means of citation indexing and the

related method of bibliographic coupling. A cita- tion index is obtained by recording, for each scientific paper or report belonging to a given field of

knowledge, all the papers cited in it (customarily

these are shown as a "list of references" at the end

of the citing paper) ; and then sorting this record

in order of the cited papers. Thus we obtain for

each paper a list of places where it has been cited. Suppose now, for example, that a scientist wishes

to find the latest value for the atomic weight of some element. He knows that this was measured some years ago, and that it may have been revised

since. He enters the index with the latest publication on this subject known to him—perhaps 5 or 10 years old— in the hope that the publication of

a subsequent revision would reference the previous

result. It is obvious that this kind of problem oc- curs frequently in operations such as the NSRDS

data centers. Other applications of a citation

index are in bibliographic coupling (finding papers which are related to a given paper in the sense of citing some of the same literature), preparation of bibliographies, current awareness programs, finding reviews of a given paper or corrections to it, etc. These examples may suffice to show

that a citation index is not only a useful tool in

many scientific undertakings in a general way, but

is also particularly applicable in an information

system such as NSRDS.

2.3. Input to the File

2.3.1. Keypunching

If, as we have said, the information file will

contain about 100 million numbers, then the problem of recording all these numbers initially in

machine-readable form is considerable. Let us assume, for example, that the information is to be punched into cards. Experienced organizations like the Bureau of the Census, where keypunching is done on a large scale, estimate the

cost at 10 to 20 cents per card. Each card holds

80 decimal digits. Our data may, on the average,

have 3 to 4 significant digits each, but since they

vary in magnitude one may have to set aside 5 to

6 card columns for each number. Some card col- umns are needed for identification; on an average, we may get 10 data numbers per card, or a total

10

of about 10 million cards, at a keypunching cost on the order of 1 million dollars. This is for the

initial effort; it would be followed by somewhat

smaller annual outlays for updating.

This is not prohibitive in comparison with the size and cost of the entire NSRDS operation, but

it is large enough to warrant serious study. For- tunately there are alternative ways of original re- cording for at least part of the collection.

Parenthetically, one might reflect for a moment

that 10 million cards fill about 200 file cabinets

again a large but not prohibitive number. There

should be no reason, however, for storing all these cards simultaneously for any length of time ; stor- age for permanent record would presumably be or tapes or other magnetic media. For instance

about 100 to 200 reels of ordinary magnetic tap<

would suffice to hold the entire collection.

2.3.2. Print Reading i The art of automatic reading of printed copi

and recording it in computer-readable form ha: been developed to a point where it is possible h

most cases, and economical in some. The princi

pal difficulties now are not in the machine recogni

tion of printed characters but in paper handling

turning of pages in books, registration (precis

location of copy relative to the reading device)

dirt and other imperfections of printed copy, spe

cial symbols and unusual type fonts, etc. Printee

tables of numbers are relatively simple and fre

of most of those difficulties; it is likely that dat; which have been assembled into printed volumes

print style and arrangement remaining complete!

uniform over many pages, can be handled by auto matic print readers at a fraction of the cost o manual keypunching. To date the main area o

practical application of automatic reading ha

been to bank checks, but the problem has bee i extensively studied, e.g., in connection with maj

chine translation of languages, and economica

solutions appear to be imminent.

2.3.3. Data Available from Data Centers Most of the data to be incorporated into th NSRDS come from technical data centers or othe

organizations engaged in compiling data, an' some of these will provide them in machine

readable form for reasons of their own. Fc

example, Professor R. Pepinsky's collection c crystallographic data is already on magnetic tap*

(This, however, is a collection which has not bee

subjected to critical evaluation, and cannot be cor sidered as standard reference data.) Other exisi ing centers use cards or various forms of punche

tape, and still others operate manually at preser but will mechanize as they grow. On the otht hand it seems likely that a majority of data centei

will always prefer manual operation.

Even then they may have occasion to recor certain sets of data in machine-readable fora
' As we have indicated, this may be done as an aid

J to printing, as in the case of the "Crystal Data

•Tables" (cf. sec. 2.2.3). Or the data may be the

fconsequence or result of numerical computations

'performed on digital computers, or the result

/

! of measurement using instruments which are -quipped with automatic recording devices. The

•Latter two uses often occur jointly and reinforce

Bach other; one of the arguments for automatic

recording of measurements may be the fact that the

results have to be subjected to certain numerical

transformations before being used. Spectromtfle feters, x-ray diffractometers, and bubble chambers

!c 'are examples of instruments which employ auto061 'fnatic recording on a large scale. m I 2.3.4. Equipment and Format

Machine-readable data coming from so many

liferent sources will appear in a variety of forms.

Different, media will" be used, such as punched

1 tbards, punched pa-per tape of varying widths, magM fiaetic tapes, and possibly others; and the format

it)|e iused with each medium will not be uniform. It

prim will be one of the functions of OSRD to coordinate

*ogi and standardize these media and formats.

jili i Conversion from one medium to another can be

pwd ijiccomplished automatically, at moderate cost, and

eras b at worst a minor nuisance, as long as the formats

y.sp used correspond to each other in a simple way.

J rint( On the other hand, conversion from one format to

.; fr 3ft different one may be easy or hard, depending on

U da iwhether the source format contains all the inforhiiii ^nation needed, and whether this information appleto I pears in approximately the same order as in the

v nit icarget format. Therefore, in order to minimize

cost i ::he difficulty of conversion of data originating in

irei ( different data centers, OSRD ought to establish

Qg h pne set of standard target formats, and suggest to

is w 3:he data centers that they use, not necessarily these

th m iout at least some formats which are easily con-

•oraic avertible to the standard ones. For convenience

':he standard formats would be expressed in terms

bf one particular medium, for example, the or- dinary 80-column punched card, since it is widely

I ased as input to computer systems and for storage

, )f information, and facilities for keypunching are 'widespread and not expensive. This would leave

II "lata centers, and indeed OSRD itself, free to use * any other medium, so long as they choose formats

"1 Which translate easily into the standard ones.

i0n

J Thus OSRD might establish, in cooperation with

j jphe data centers most concerned, standard formats

or recording data on punched cards. There

would, of course, be a different format for each

ereSH|

mm

and of data ; possibly hundreds of formats would

laye to be agreed on. The established way by

jj which computing laboratories record and exchange

1

' detailed information about formats is the "card

c 'sheet," a list of instructions for punching each

column in a card. Thus this part of the job of

01 3SRD may be described concretely as devising a ^;ard sheet for each of its card decks.

The cards may not serve directly as computer

nput nor as storage medium. In the present circumstances, cards would be transcribed to magnetic tape which would serve both purposes

better. This transcription is character-tocharacter, and is therefore cheap and reversible.

The same card sheets which describe the arrangement on cards can be used to document the contents of the tapes. In a few years, a medium

other than tape may be preferable ; the transcription, again character-to-character, would be no

problem, and the same documentation could continue to be used. At present we cannot foresee a medium which would not be compatible with the

punched card code (although in the more distant

future, there may be too few distinct card codes

available). The converse is not true; many tape

codes, e.g., cannot be transferred to cards without some added structuring.

It is entirely possible that some of the information may never be physically on cards; it may,

e.g., be recorded on paper tape by the originating

laboratory, transcribed there to magnetic tape,

transmitted to NBS over a radio information link,

and recorded again on magnetic tape. It would

nevertheless be convenient to think of the arrangement of the information as if it were on cards—as

in many cases it will be. We have so far discussed digital (numerical or

alphabetical) information. A few words are in

order about graphical information. The digital

representation of curves described in section 2.4.3 below is economical, but the conversion (consisting in the computation of a number of coefficients)

may be considered too difficult by some of the data

centers. Microfilm, mirofiche, video tape, etc., can

be used more directly for storage, and facsimile

transmission of such information is possible. At

present it is not clear how such information would

be integrated into the mainstream of digital computer operation envisaged for NSRDS. This subject is further discussed in section 3.2.4 below.

2.4. Information Storage

2.4.1. Form of Data The simplest kind of information with which

the system deals is exemplified by the statement

that the atomic weight of hydrogen is 1.00797.

This is expressed by three terms

Atomic weight — Hydrogen — 1.00797

of which one denotes a property, another a material, and the last a value. A more elaborate item

is needed to convey the information that the density of water vapor at 500 °K and a pressure of 10

atm is 0.0045967

Density — Water 500 10 — 0.0045967.

It is not necessary to record the information that

the numbers 500 and 10 represent temperature and

pressure; this information is implicit in the defi- nition of "density," as are the units in which temperature, pressure and density are given. That

is to say, the computer program for retrieving in- formation on density must contain instructions to

11
the effect that following the designation of a material there will be recorded a series of triplets of

numbers, namely two parameters representing

temperature and" pressure, and the corresponding

value of density. (Actually, the information will

be stored in more compact form, to be discussed in

sec. 2.4.3.) There will also be instructions for

adding the symbols °K and g/cm3 after the appropriate numbers in the printed output.

Properties and materials can be represented in the computer by numerical codes. For example,

the AC'S registry number might be used for materials, while properties might be denoted by arbitrary serial numbers, or by the NSRDS classifica- tion number followed by one or two digits which

specify the particular property within its class. Again, the computer program has to contain in- structions to replace these numbers by English

words in the output.

In addition to property, material, parameters,

and value, an item may contain comments, comparable to footnotes in a printed table. These may

be indications of source, such as a laboratory name

or a literature reference, or explanations, cautions,

etc. The computer program provides for printing

these where appropriate. The literature refer- ences could conceivably be used by themselves for an entirely different purpose, namely bibliographic

searches, but it is doubtful whether OSKD ought

to render services of this kind.

Apart from numerical data, there is frequent

need for data in graphical form. One may expect

that the demand for graphical data will be some- what reduced by the easy availability of numerical

information, but there will probably be a residue

of curves which must be stored and retrieved. It

is not yet clear how this is best done. One could

use a computer-driven curve plotter, though past

experiments with such a system for spectra have

not been encouraging. One could keep a manual

file of graphs (either on microfiche or as hard

copy) and use the computer only to obtain refer- ence numbers to this file. Hardware exists for

automatic retrieval of microfiche, but it would be

a foreign body incompatible with the main system.

It is possible that in the next few years an auto- matic microfiche retrieval system may be developed which can be connected to, and steered by, the

main computer.

2.4.2. Arrangement of Data Since practically all data in the system are described as properties of materials there are two

arrangements which suggest themselves naturally.

We could group data by properties, starting with

one property and listing the values of this property for all materials, then proceeding to a second

property, etc. Or we could use materials as the

major subdivision and arrange by properties under

each material.

The method which we actually propose to employ is a combination of these two obvious ones. We suggest that the set of all properties be subdivided into homogeneous groups of related properties, and that the entire data file be arranged

by this grouping. Within each property group

there would be a listing of all pertinent materials,

and under each material a listing of parameter

values, each followed by the values of the several

properties in the group. This may be illustrated

bv the example shown on the following page ( from

NBS Monograph 20).

By saying that the properties in a group are "related" we mean merely that they are frequently

used together. We are therefore likely to save time

when looking for the answers to a group of related questions.

The property groups are "homogeneous" in the sense that the properties in a group depend on the same parameters, and are meaningful for approxi

mately the same ranges of these parameters. Thk

facilitates the storing and also the retrieval, since the same set of computer instructions can be usee

j for all properties in the group.

Finally, the arrangement by property groups h similar to that usually found in print, and there

!

fore facilitates the original recording of data. Oi

the whole, this arrangement is a natural extension

of the one to which data suppliers and users have; been accustomed. It hardly needs emphasizing

that we retain the option of employing a grouping

of properties which differs from the convent iona ' one, whenever this is advantageous for machini

retrieval. In many cases we expect that a homoi

geneous group will contain only a single property | so that we will be arranging "by properties."

2.4.3. Compact Storage

It is most important to store information in th

least possible space, both because storage capacit;

in the computer must be paid for and because th

time required for every search may increase witL

the number of words stored. We shall conside

two kinds of space savings : omission of identify

ing information, and condensation of the func

tional values themselves.

The possibility to omit identifying information

depends on details of hardware organization whicl

cannot yet be foreseen. If every storage locatioi were addressable, the identifying informatior

such as name of property and material and value

of parameters, would be replaced by the choice o

;

address. For a simple example, suppose tha

values of a function of temperature are to be store< at intervals of 10 °K in consecutive addressabl

storage locations beginning with address 12,285

Computer instructions specifying that the functio

value for any argument T is stored at addres- 12,288 + 0.1 t are sufficient for storage and re trieval, and no value of T need be stored. Othe

identifiers can be handled similarly, or one ca

store one identifier value preceding the entii group of function values to which it pertains ; fq

instance, record one value of pressure precedin

a group of numbers representing density at diffei ent temperatures.

12
ample of Arrangement of Data by Property

Groups

[From NBS Monograph 20]

•-"tT Property Group: Ideal Gas Thermodynamic Functions

C;/R (H°-El)IRT -(F°-E°)/RT S°/R

Material: H2—normal mixture

2. 71388

2. 78512

3. 81909

3. 72183

8. 45365

8. 41288

12. 27274

12. 53471

Material: HD

^''ITote: In this example, four ideal-gas thermodynamic

.::, lotions, namely C°v jR etc., have been selected as one

• - mogeneous group of related properties" and used as a

or subdivision of the data file. All depend on the same

imeter, temperature (°K), and are recorded for the ,m£e range of this parameter. This major subdivision

USfdihe me is further subdivided according to materials;

er each material there is a listing of values of temperai, each followed by the corresponding values of the

;• [ - properties.

a. Oi in practice it is unlikely that we shall work with

- .:o*'lressable, stored words. In tape and other bulk

tage media, addressing is usually by blocks of

• ::4'a. These blocks may be of fixed size or they

be variable but with limits on size imposed

ie economics of their use. The cost of retrieva single word is not much less than that for a

ole block of words. A simple procedure is to

re all identifiers common to a block of data at beginning of the block, as long as this results

blocks of manageable size. To go into a more

ailed design at this time would be premature.

Economy in the functional values leads to conts which have long been studied by the makers

mathematical tables : interpolation and approxi-

-

'•'• tion. For simplicity, consider again the case one function of one variable, say density as a

tion of temperature (at constant pressure) :

I IB

iffhit

• atioil

Density of steam, at 1 atm

[From NBS Circular 500, p. 450] Temp.

°K

800

810

820

830

840

850

Density

g/cm3 000 274 64

271 25 267 93 264 69

261 54 258 45

Differences 339 7 332 8 324 9 315 6 309

estoK —HiI the example this is tabulated at 10 deg inters. For temperatures falling between these

ues, the density can be obtained by linear inter-

. j ation with an error of not much more than one

; t in the last place. With a computer, interpolai of higher order, say the third, is quite prac-

»1. For this it would suffice to tabulate values

'\J much larger intervals, say every 50 deg. Then

density value at an intermediate temperature

K found by passing a cubic polynomial through

|§r points, two to the left and two to the right

the desired value. To save computation one

js not store the density values at all, but instead

stores the coefficients of the interpolating polynomial. This polynomial will reproduce exactly

the desired value for ^=50°, 100°, etc., and will

give a sufficiently close approximation at other

values of T. Going one step further, we note that

there is nothing sacred about these special values

of T, and no reason to insist on precise agreement

at just these points. So, instead of interpolating

between these we use a polynomial which best approximates the density function throughout the

entire interval. This, in turn, enables us to make

the interval still longer without getting intolerably

large deviations. In summary, then, we first choose a class of approximating functions—say, cubic polynomials—and a tolerance limit—say, two units in the last decimal place of the table

(2X10-8 ). We then find the longest interval, beginning at T=0, for which a cubic can be found

which approaches the given density function

within 2 X 10" 8

; and we store the end point 7\ of

this interval, together with the coefficients of the

polynomial of best fit. (The technique which ac- complishes this is the method of Chebyshev polynomials.) Then we find similarly a longest interval starting at Tu etc. It remains to discuss the choice of the class of

approximating functions, which for our example

has been cubic polynomials. If we increase the

degree of polynomials used, the interval which

each will cover increases, so that we need fewer

intervals but more coefficients for each, and more

computation to evaluate the function. The optimum compromise between these conflicting fac- tors will differ for different functions, but will in

any case be for a polynomial of higher order than

that used in manual computation. Functions

other than polynomials may be considered.

Polynomials have the double advantage that they

are easy to evaluate and easy to fit (i.e., the coeffi- cients of the optimal polynomial are easily found)

Since computers are made to carry out the arithmetic operations of addition, subtraction, multiplication, and division, the only functions which

are as easy to evaluate as polynomials are rational

functions, and they are hard to fit. They may be

used in special cases where singularities or asymptotes are present. Many kinds of orthogonal series, e.g., Fourier series, are just as easy to

fit as polynomials but are harder to evaluate.

One may put up with this drawback if the nature

of the problem seems to call for it. For example,

there is some recent work on representing spectra

by sums of Gaussians, each of them with three

parameters representing the mean frequency,

width and intensity of one line. These are not

quite orthogonal but almost so. The stored coefficients, of course, must be derived separately for each table. This effort can

largely be mechanized, but even so it is of considerable magnitude.

In some cases it may be possible and desirable

to store numerical indicators of the accuracy and/

or precision of the tabulated data. Judgments

about the reliability of data are among the princi13
pal concerns of NSRDS, and should be recorded as far as possible. For the most part such recording

will initially not require great sophistication, nor

will it add appreciably to the requirements for

storage space. For the foreseeable future the

large majority of accuracy estimates will be qualitative and will find their expression in the selec- tion of the tabular values from among several

competing measured values. Some will be numerical (such error estimates are now being tentatively assigned e.g. to tabular values on heats of

formation.) For the tables occupying large portions of memory space, e.g. properties tabulated as functions of temperature and pressure, it will fre- quently be sufficient to record one single number

representing the accuracy of the entire table. The ultimate goal of recording an error estimate

alongside each tabulated value is a long way off.

2.4.4. Storage of Instructions There is an intimate connection between the data

to be stored—in the case of the preceding section,

the coefficients of approximating functions—and

the computer instructions needed to calculate these

functions. These instructions are an integral part

of the stored information. Inasmuch as they are

different for each table (or at least, there will be

many different sets of such instructions, although some may apply to more than one table) they

might as well be stored with the data. In order

to minimize this storage, one will attempt to devise

a general -retrieval program (e.g., "polynomial

approximation"), or perhaps several such programs, applicable to different classes of tables. From such a general program, the specific program needed for a particular table is derived by

specifying a few numbers, like degree of polynomial, number of variables, etc. ; only these need

to be stored with each table. The point to note is that there is often a tradeoff

between data and instructions, and again between

special instructions applying to only a small seg- ment of data, and more general ones. Special in- structions should be stored with the data, so that no separate lookup is needed ; general ones should

be in internal computer memory, where they are always accessible. Apart from the limited size of

this memory, the major limitation on general purpose instructions is the effort of creating them.

They are so important, however, that this programming effort deserves major support.

2.4.5. Storage Devices

As stated before (sees. 2.1.2, 2.2.1) the amount

of information to be stored in our system may be

vaguely estimated at 100 million words. Internal

computer memories store usually 65,000 to 131,000

words. This may increase in the next few years, but not to anything like the volume we require.

We shall therefore have to rely on external

memory components.

Conventional external memories are magne

tapes and drums, and more recently disk files, addition, several new devices have just becoij

available, and several others are under devek

ment and may be expected to be available when

need them.

Magnetic tapes have practically unlimited <i pacity and are inexpensive. Perhaps 100 ret more or less, depending on length of bloc | would hold all our information, at a cost of a f

thousand dollars. However, most computers haj

only a small number of tape reading stations, a: I these have to be shared with other users of tj same computer. Tapes have to be mounted a|

changed manually. The time to find a particuT

item on tape (random access time) is on the ore of minutes, and the rate of reading successive i formation is too slow for our needs. Therefc

tape must be ruled out, except perhaps for an ii tial period of transition and for certain auxilia

purposes.

Magnetic drums, until recently limited in < pacity, do now have the capacity required for c applications. Disks and other existing or futi

storage devices likewise possess the necessa

capacity.

Apart from capacity, the transfer rate, i.e., i, number of words which can be transferred frc consecutive storage locations into the main frai of the computer per unit time, is critical for q

application, since for some of the simpler pre

lems it will be necessary to scan a section of si cessive storage entries and perform only a f< simple computer operations on each item, e comparison with a search request. For this pi

pose, in order to avoid delays, the transfer th

must not exceed the time required for, say, t elementary computer operations, about 10 to microseconds with today's computers, correspon

ing to a transfer rate of 2 to 4 million bits p second (cf. sec. 2.1.4). For many other purpos*

the computation to be performed with each item

information will be more complex, and therefc

the transfer rate less critical. The random access time is not critical ; anythh

below, say, one second is certainly acceptable.

Magnetic drums and disk files, which have bei in existence for several years and are well teste will easily meet all requirements. They are, hoi

ever, somewhat expensive. The newer mass sto age media, more reasonable in price, fall somewh

short in transfer rates. These are quite new ai! likely to be improved, and several companies a working on the development of large external sto age devices, so that it is likely that something sui able will be available at a reasonable price by i\ time it is needed by NSRDS.

Whatever device is used, the file of standard re erence data will be kept permanently in storage < it, and will be periodically updated. It will ther

fore be necessary (cf. sec. 2.5.3) to have tr. memory component reserved for the exclusive u

of NSRDS.

14
:t

2.5. Access to the Computer

2.5.1. Man-Machine Interaction

In the preceding sections we have frequently

lade passing reference to the ways in which the

pmputer is interrogated or instructed. A large

lit of the requests for information received by

i SRD, as well as of the new data to be incorpo-

• tted into the files, are collected and run on the

I »mputer, say, once a day, using a general infori ation retrieval and file updating program.

Iommunication with the computer will be in the

, mventional manner, i.e., using a small peripheral

iinputer or "secretary computer" questions and

I nv data are manually keypunched into cards (or,

' 4. a few systems, punched paper tape or a loosely

f icked magnetic tape), and then loaded into the

ripheral computer and there converted to mag-

'} Wic tape of a format suitable for the main com-

TMi iter, and possibly combined with input to other

•oblems ; then the whole batch is run on the main

', a jmputer, resulting in an output tape; and finally

' e output is printed on the peripheral machine

Tider the control of the output tape.

[ A similar regime will govern certain special

•oblems which have their own special programs

: 'it which can nevertheless be batched with each

: her or with other problems. In this class are

' e housekeeping problems and the preparation of

:r() iterial for publication, in which the retrieval

-"Ppi information is followed by detailed editing

f -" ; 'ocedures.

i( There is, however, another class of special prob-

'& ? ns which cannot be handled in this way. These

L

; P

[ >e the requests for information which do not fit '"to the general information retrieval program

?' ! ' f. sec. 2.2.1) . They are of great importance for

o e system because through them we learn how to v[«Uprove the general-purpose program. In most

bits

1 1 these questions it will be necessary to "feel one's

•irpof Say," asking a tentative question, awaiting the

litem j.swer, modifying the original question, etc.

berefi lis is anologous to the process of human infor-

; .ation retrieval. Librarians have made serious

myth talies of this process and report that a large fracble. hi of all requests for information need rephras-

: '* >g at least once, often several times.

D tesfi >itFor this reason it is deemed essential to have

.re. ho (nvenient facilities for man-machine "conversaisssSmi." We visualize a console in the offices of

mewl 8RD, with facilities for input by keyboard and

new a juiched cards or punched paper tape ; typewriter

•.yes i jttput ; and the ability to connect on-line to the

ffldstikin computer. It is likely that similar consoles

lingst pi be placed in other locations at NBS, where

v by t Jay will serve a variety of purposes. The main

mputer must be operated under a system which

iiipis »iows interrupting long problems in order to

:u7

e jmit short requests from the remote stations; the

'the -deration is thus characterized as time sharing

jveHlder remote control. Naturally there must be

oe differing to avoid tying up the main computer

iile input from, and output to, the remote sta-

•ns is slowly processed. A small amount of

memory is the minimum requirement for such a

buffer, but it will probably be more efficient to use one or more small satellite computers which are

on-line connected to the main computer as well as

to the remote stations. Possibly OSRD, because

of the large amount of data which it handles,

should have one such satellite computer reserved

for its own remote use.

2.5.2. Long-Distance Access Once the principle of time-shared remote control of the computer has been established, it is only

a small step to a system which places similar re- mote consoles in locations at much greater distance

from the computer, say across the country. The

hardware techniques for doing this are already in

existence; at the time of this writing, stations at the National Bureau of Standards in Washington

communicate with computers in Cambridge, Mass.,

Dartmouth, N.H., and Phoenix, Ariz. Ordinary

telephone lines are used for interconnection. This

is done not merely for experimental and demonstration purposes but for effective computation,

albeit on a small scale. The problem is thus not

a technical but an economic one. That there is a need for such facilities is made

plausible by the observation, made by many exist- ing information centers, that a large part of the

inquiries which they receive—usually more than

one-half—comes from the installation in which

they are located. One may well suspect that con- venient access to information is an important fac- tor ; that there is an equally great need for information in the many outside installations, but this

need does not express itself in inquiries because of

the slowness and inconvenience of operating over

greater distances. Indeed, to satisfy this latent

need for information may well turn out to be the

greatest accomplishment of NSRDS.

Now there are in principle two ways in which

this can be done. One can enable laboratories

throughout the country to obtain on-line connection, via long-distance telephone lines, to the central computer and information store at OSRD;

or one can duplicate this store in numerous geographically dispersed computing facilities. This

saves the cost of a long-distance telephone call for

each inquiry, but involves a much greater investment in storage equipment and the considerable

difficulty of keeping all these copies of the original

store (and of the computer programs which go

with it) exactly updated.

There is no point in drawing up a precise bal- ance sheet of costs at this time, since the information file does not yet exist, will take several years

to compile, and some cost items may change radically in the meantime. Other organizations are faced with similar problems, in particular the National Library of Medicine, and their experience

will be valuable to us. We venture the guess that

if a system had to be introduced today, the establishment of a moderate number of "secondary in- formation centers," each a copy of the primary

center at OSRD, would be optimal; but that as

15
time goes on, the optimum will shift in the direction of greater centralization. In any case, we

envisage the establishment of a nationwide net- work, either of secondary centers or of telephone

access to the primary center, as something to be

done only after the primary center itself has been

in operation for awhile.

2.5.3. Administrative Arrangements

We have already indicated that it will probably be desirable for OSRD to share the major

computing facility of the National Bureau of

Standards, but that OSRD will have to procure

for its own exclusive use a large external storage

component and a remote console. In addition,

OSRD will have a heavy share in the use of a

satellite computer to act as buffer between the re- mote console and the main computer ; it may even

require one entire satellite computer for its own

exclusive use. This computer would have to be

located in the computing laboratory—transmission at the high pulse rates used by the main computer limits the distance—and it would have to be

operated in accordance with the ground rules and

operating systems of the laboratory; probably it would be operated by computing laboratory

personnel.

The cost of main frame time will depend on the

workload. For the example given in section 2.1.4 (something less than 2 hours per day on the IBM

7094) and^at today's rates, it would be about

$80,000 per year. Future computers will do the same amount of work at far lower cost, but the

workload will undoubtedly go up. If the external

store is to be acquired by rental, the annual cost

at today's rates might be $60,000 ; only an order-ofmagnitude estimate is possible. The decision b( tween renting and purchasing will have to b made just prior to acquisition; usually the advar

tages are almost evenly balanced, and the cost di: ference is smaller than the uncertainties in %

present estimates of cost and workload. The coi of a separate satellite computer, if one is requirei

is also hard to foresee, since such smaller compu

ers come in wide price ranges ; the order of magn

tude might be $100,000 of annual rental. The co: of the remote console is very small by compariso:

It is to be assumed that the computer prograrr for information retrieval, editing, display, upda

ing, etc., will not remain static but will be in a coi tinuing state of development. This may be doi

by personnel of the Computation Laboratory, < of OSRD, or both, but in any case the services ( several full-time programmers will be require' A much larger number of people—possibly b; tween 25 and 50—will be needed to prepare inpi

data and requests for information, accept outp

data and send them to their destinations, el These will undoubtedly have to be OSR

personnel.

There will be a somewhat larger initial pr

gramming effort, extending over the first few yea

and costing perhaps several hundred thousand dc

lars—this cost depending very greatly on how ar bitious the initial general-purpose program is, how much is left for later improvement. The ii tial keypunching of data, at a few cents per woij

is an even bigger investment (cf. sec. 2.3.1).

Nevertheless, all these costs are not large in coi parison with the intellectual organization of t information. The latter will represent the pri

cipal effort of NSRDS.

3. Proposed Interim System

3.1. Characteristics of the Operation

The real-life conditions under which OSRD will

have to operate in the next few years are very dif- ferent from the ideal situation which has been

postulated, explicitly or tacitly, for the mechanized

information system described in the foregoing.

We assumed the existence of a network of technical data centers, so complete that every physical

property of materials for which measured data

exist falls into the province of one or the other

of those centers. We assumed that each center has

collected the existing measured values for all properties for which it is responsible, has critically

evaluated them and thus arrived at a collection of

slandard reference data which it continues to update. Copies of all these standard reference col- lections form the data file of OSRD, and are used

to reply to the numerous requests for information

reaching that organization day by day from all pads of the country.

In reality, it will take a long time to establish

recognized technical centers in all areas of physi16

cal science. For the next few years there will areas not covered by any center, other areas which some work is done by organizations not s hering to NSRDS, along with a small but incre; ing number of member centers operating witl

NSRDS. Even in the areas for which cent

exist, it will take time to set up criteria for t evaluation of data, and more time to perform t actual compilation and evaluation. Therefore, some areas OSRD will have no data at all, in ma

other areas it will rely on such compilations as can find in the literature or obtain through ad 1 correspondence; these will be either unevaluai

or subjected only to preliminary informal evah

tion by OSRD staff. And finally, the demand : information will not arise at once in full stren^ but will build up gradually as OSRD becor

known, as scientists and engineers get into i habit of using its services, and as they learn hi to adapt their working methods and their appro;

to new problems to the easy availability of f information.
|| In brief, this period will be characterized by

apid change in the quality and quantity of data

In j|nd in the volume of demand for services. At the

jame time, our own understanding of the situation

ill still be deficient, and will become more ade- uate only with the passing of time, through our

perience with the operation itself.

3*2. Inquiry Services

3.2.1. Getting Started The circumstances set forth at the end of the

([receding section suggest strongly that information services to scientists and engineers should be-

< ain at once, without delay, not only because the

benefits accruing to the technical community from

ihe availability of such services should not be postfl rioned by several years pending the creation of

y lata files and systems, but also because the creareifl] :jion of the systems will itself be aided by the exMt] perience which OSRD will acquire in the process

- I |f rendering services.

OS! I It follows that, in many fields, requests for data

'ill have to be answered before standard reference

ii p iata have been so designated. In such cases, rather

wya ijaan merely indicating to the inquirer that no

ill IRD are as yet available, it will be preferable to

bowl ilive him whatever information can be found in

lbq is, Jie literature or through personal inquiries. v A

T:iei ijtiitable disclaimer should be appended to such

^rwotieplies, cautioning the user that the information

.11. i.as not been evaluated by NSRDS.

since < Within OSRD, the handling of such requests is

:. of t f function of the Information Services Operation

pt'ISO). The reaction of ISO to an information

iequest may take any of the four forms listed in

ection 1.3.3 above: referral to an expert, litera- Ure reference, documentation, or data informaion. One may wonder whether the willingness to reily in terms of other than SRD would tend to verburden the organization. The charter of

jrSRDS does not commit us to anything beyond

giving information on SRD, and one could choose

) draw the line there. Actually, however, our

orkload for the proposed broader service will be

o greater than it would be for the narrower one

standard reference data had already been desige

l ated in all fields. Possibly the search for unevalated information is more laborious than the re- ieval from an organized file, but on the other

.

r

.- ai^|and a larger fraction of the inquiries will be anvered by mere referral. Thus the volume of work

hich ISO is taking upon itself is no greater than

imandl pat to which it will eventually have to get accus5_ >med anyway. Meanwhile, the broader services

ill be beneficial to ISO itself as a realistic train-

, ig ground, to the customers who need the infori nation, and most of all to the entire community by

astening the process of acquainting scientists

-^ |t

T ith NSRDS and getting them into the habit of

laking use of it.

J As stated in section 2.2.1 above, the experience

f other data centers leads us to expect that the

J.W1

areas

inoti

number of requests for information will start, once

the existence of OSRD has become generally

known, at a level of several per day, and will grow

from there. A majority of the requests will be

"administrative" and can be handled by ISO staff without difficulty. The requests for technical in- formation proper will be screened by ISO staff and processed by one of the procedures outlined

in the next few sections.

3.2.2. Referral In the early years, while NSRDS is still developing, a large portion of technical queries received is likely to be referred to experts. We expect that

this practice will gradually decrease but will never cease entirely. There are pitfalls in many

seemingly simple technical questions which can- not be avoided by the uninitiated. Until OSRD

has accumulated some experience it will be

well to have all technical answers, even those routinely prepared by OSRD from its own files, checked by a specialist. Later on it will be

possible to dispense with this for the more fre- quently occurring types of questions. Perhaps

the hardest problem, in the long run, and one for

which we have no ready answer, will be for the

ISO staff to recognize when a problem needs a

specialist.

The experts to whom questions are referred can

be taken from the following groups

(a) Technical area managers of OSRD.

(b) Data centers which adhere to NSRDS.

(c) Divisions at NBS outside OSRD.

(d) Other scientists. In general this will be the order of preference

in calling on experts, except that sometimes (c)

may precede (b). Technical area managers are

so few in number that it will often be practical to bypass them. It may be hoped that experts in

each category, if they are .unable to handle an

inquiry, will at least suggest other more suitable

experts in the higher categories.

The system used in referral must meet the fol- lowing conditions, in this order of importance : the

inquirer should receive, without undue delay and

without further effort or annoyance to him, a reply which is correct and helpful; the replying

expert should receive credit and should not be un- duly burdened; ISO should be able to add to its storehouse of experience, both technically in regard . to the specific question and administratively in 'regard to statistical distribution of

questions in general. Finally, direct back-andforth contact between inquirer and expert needs

to be facilitated for those cases where the formulation of the question itself presents problems.

It is believed that the following stepwise procedure meets all these criteria. (a) ISO ascertains what information it can

furnish from its own files. (b) If this is inadequate, ISO quickly locates a

suitable expert—-normally by a series of phone

calls—and establishes that he is able and willing to handle the inquiry.

17
(c) ISO forwards the inquiry to the expert by

phone or, if too voluminous, by mail.

(d) Simultaneously ISO informs the inquirer

of this action.

(e) The expert replies to ISO, which relays the

reply to the inquirer without delay.

(f ) ISO follows up if the reply is not forthcoming after a reasonable delay.

(g) ISO maintains statistics on inquiries re- ceived and on their disposition.

It is important that ISO consider this procedure not only as a way of satisfying the inquirer

but also as an opportunity for its own staff to deepen their understanding of the technical questions asked, so that ISO's own staff will gradually

be enabled to handle an increasing portion of

inquiries.

In regard to (b), it is likely that ISO will

rapidly—probably in a matter of months—become

acquainted with a large number of experts both at NBS and in various data centers, with their fields of specialization and with the degree of their will- ingness to handle inquiries. Initially, the NBS

Index of Technical Activities, the NAS-NRC

"Directory of Continuing Numerical Data Projects," or inquiry from OSRD technical area managers or NBS technical division chiefs will reveal

the names of suitable candidates. Ultimately, an

index of such experts, compiled and published by

ISO, may in itself become a useful addition to the

technical literature.

3.2.3. Reference

An inquiry should be answered by one or more

references to the literature if ISO is able to obtain

these references without undue effort and if, at the same time, it is impractical to provide copies of the

pertinent documents or portions of them. The

latter would be the case, e.g., for obscure journals,

unpublished reports, documents which are in the

main library of NBS but not in the collection of

ISO; also for inquiries where the reply involves

a large number of pages, too difficult to reproduce

;

and finally for inquiries answered by phone. In

all other cases, namely where an inquiry can be

satisfactorily answered by mailing copies of a few

pages from a document easily accessible to ISO,

it will be preferable to do so rather than merely to give the inquirer a literature reference.

The mam limiting factor to the use of both

reference and documentation (furnishing of

copies) will be the difficulty of locating the references. For this purpose ISO would either have

to maintain a large, well indexed and updated file of literature reference, or to undertake an ad hoc

search separately for each inquiry. Either alter- native is so laborious that there is at present no

justification for adopting it, in view of the likeli- hood that ultimately, some years from now, there

will be a mechanism for answering almost all questions from the data file itself, without refer- ring to the literature. It is therefore proposed that the use of both

referencing and documentation in answering to

18

inquiries be limited to those cases where the needed

references are obtainable without too much effort. Potentially, the job of obtaining references,

especially those to recent documents, can be greatly : facilitated by the use of a citation index. Therefore, the development of citation indexes, and of; the related subject of bibliographic coupling,

should be closely watched. Presently available

citation indexes, namely those of M. M. Kessler at the MIT library and of the Institute of Scientific

Information in Philadelphia, are somewhat defi- cient in coverage and accessibility. Nevertheless,

there are reports of encouraging trial uses of these indexes. Similar experiments are contemplated

by OSRD. (See sec. 2.2.4.)

3.2.4. Documentation

Under this heading we discuss, as mentioned be- fore, the furnishing of copies of documents in re- sponse to data inquiries. For the next few years

this will be discouraged by the difficulty of locat- ing references, as discussed in the preceding sec- tion. In the long run it will be superseded by the

greater ease of obtaining the data themselves from

the data file, without going to the source docu- ments. In some cases, however, it will remain de- sirable to furnish hard copies, in particular where

graphical information is involved; phase dia- grams, contour lines of electron density obtained

from diffraction patterns, shapes of spectral lines. Even though graphical information will become

less popular as numerical data becomes more readily accessible—at present some graphs serve merely

as a convenient condensed representation of numbers—a hard core of demand for copies of graphs

will persist. To this must be added requests for copies of entire tables, sometimes several pages in length.

At present the most economical way to produce

copies is the Xerox process. This presupposes that a hard copy is on file in ISO (or less conveniently,

in the NBS library). It requires no further

investment.

Let us briefly discuss some of the existing methods of partial mechanization which might be in- voked to relieve any developing bottlenecks.

,' They can be characterized as micro-optical sys-J

terns. The first to come to mind is microfilm.

Its principal advantage is to reduce the physical

size of the library. It also tends to speed up the

production of copies. It has, for the application 1 here discussed, the overriding drawback that in-1 dividual information items cannot easily be cor-j

rected, inserted or deleted ; the only way to do this

j is to remake an entire reel of film. We are likely

] to be faced with numerous cases where a single

J number in a table, or a single graph out of a set oi I charts, has to be revised. Since a space shortage 1 for the storing of documents is not likely to be I critical for some time, microfilm at present does J not appear as a promising prospect.

Microfiche, microcards, and similar systems are|

easily updated. The saving in space is less pro

nounced than with microfilm. Handling is often
irth

re difficult than with either film or hard copy,

: there are systems with automatic selection of

•ds, where handling is no problem. If at some

ure date the volume of library holdings and of

1 y transactions requiring hard copy becomes too

ge for manual operation, such a system of

• :rofiche or microcards holds promise.

3efore introducing it one should investigate, es- ially in view of the cost of transcribing an en3 document collection to the new system, how it

1 be coordinated with the digital computer oper- on envisioned for the future. It would be un-

•tunate to be saddled with a semimanual system

• copying graphical information which is in- npatible with the central digital computer sysq for the handling of numerical information.

i the other hand, with some development work

night be possible to have an integrated system,

a microfiche selector which is connected to the

rital computer, receives from the computer the

ial numbers of items to be copied, automatically

! a arches for these items and copies them, together

?tl ii|th identifying information supplied by the comfra Iter (e.g., serial number of the inquiry).

On the other hand, it may turn out that a curve

)tter directed by the computer is a more econom1 way of reproducing graphical information.

Lis possibility should be examined before a

aim iicro-optical system is proposed for installation.

line ;,mpare, in this connection, the discussion of int. transmission and storage in sections 2.3.4 and

m 1.3. above. To date, experiments with digitally

:ere produced images of spectra have not been suc-

. - >sful, but the door is not closed.

rap! The furnishing of hard copy may be required

ts f( Jfc only in reply to inquiries but also as a service

ges | data centers, in cases where the latter do not

\

r e the facilities for obtaining such copies

win 1-ectly.

3.2.5. Data Service

It is expected that ISO will be able from the

it to respond to a number of inquiries by diptly furnishing the desired data, from its own

ta file. As stated above, such information

;>uld be accompanied by a suitable disclaimer

ting that the data have not been evaluated for

* |? ^ability and therefore do not constitute stand1 reference data. As technical centers are estabhed or integrated into NSRDS, as criteria for

iluation are set up and the evaluation of data

J undertaken, ISO must incorporate the results

' jsuch evaluation into its files.

jj ]One way to do this is to set up a file of evalua-

''-,} j'e comments which is arranged in the same order

^t ( the data file itself (cf. sec. 3.4.3 below) and in

set. I'uch every comment is cross-referenced to the

ofta iipropriate data file item. When an inquiry

i <mes in, the subject is first looked up in this com1 |nts file. If a comment report is found there,

is report, together with the literature items

| ' >ss-referenced by it and the data given in these

J ms, furnish the material for the reply. If no

'mment is in the file, the data are looked up in iON

the data file and used for a reply with a disclaimer

as described above.

A more radical approach would be to segregate

the entire ISO library into two parts, SRD and

other data. This would save one look-up step for

SRD but would require frequent rearranging of

the collection, possibly affecting different parts of

the same publication in different ways. Also this

approach would probably oversimplify the problem: quite possibly the result of data evaluation

will not be a simple dichotomy into SRD and other

data but a more detailed qualitative description of

the worth of the data.

In the beginning, as we said above, all technical

responses issued by ISO should be checked by technical specialists. Gradually, ISO will learn by

experience that certain routinely recurring types

of questions do not require such checking. At first the burden of checking will have to be borne by

the technical area managers of OSRD and by cer- tain specialists elsewhere in NBS. If this load

gets too heavy because the volume of inquiries

grows faster than ISO's ability to handle them

without assistance, one of two courses are open:

either ISO acquires technically competent staff of

its own, or the flow of inquiries is restricted by

answering only in terms of standard reference

data.

3.3. Publication Services

3.3.1. Types of Services

In contrast to the inquiry services discussed in

the preceding sections, which are unscheduled and

are undertaken on receipt of requests for them, the

editorial and publication activities are scheduled

by OSRD on its own initiative. We may distinguish periodical and aperiodical publications.

The principal output not only of OSRD but of

the entire NSRDS will be monographs, especially

data compilations and evaluations. These can take

different forms. There is first of all the "National

Standard Reference Data Series" of the National

Bureau of Standards, published by the Government Printing Office, of which several numbers

have already appeared. The series will contain

tables of data compiled and evaluated under the

auspices of OSRD and related material. It is in- tended to supplement, rather than supplant, the

publication activities of technical data centers and

other interested organizations. Thus the NSRD

Series will have for primary subjects those compilations produced at NBS, or by organizations

which for some reason or other cannot undertake

publication, or those for which there is no appropriate technical data center, as well as state of art

reports, lists of compilations considered to be

standard reference data, reports on classification,

indexing, mechanization, and other topics of interest to data compilers, evaluators and users in

general.

In addition to producing the NSRD 'Series,

OSRD will publish data (usually taken from

monographs) in loose-leaf form, machine-reada19
ble media such as tapes or punched cards, or other

formats which prove to be widely useful.

OSED will also endeavor to encourage and assist data centers and other organizations in publishing their results, especially by providing

editorial help, advice on mechanization and occa- sionally financing, especially in situations where

such assistance will make the difference between

prompt publication and long delay.

As for periodical publication, it may be useful

to publish a news or current awareness service,

concerned with events in the field of data on properties of materials. New data compilations which

have been published, projects undertaken or completed, contracts awarded, new mechanization

techniques, etc., would be listed. Undoubtedly

there is plenty of material which is of interest

currently OSRD writes unpublished reports on its own activities alone, running to several pages per

month—but to collect this material from the many

organizations involved would require a considerable effort and should be done only if there is a

clear need for it. Some of this information appears in subject-oriented publications; perhaps in

time the activity of data compilation and critical evaluation will come to be considered as a field of

technical specialization in its own right, and will

increase the demand for a periodical publication

service of this kind.

Another possible activity, unquestionably useful

but requiring an even greater editorial effort,

would be a-Current bibliography on data compilation, evaluation and perhaps generation; i.e., a periodical listing of new published papers and

perhaps unpublished reports on these subjects,

giving at least the bibliographic description (author, title, place of publication) and perhaps also

abstract, critical review, and/or listing of refer- ences—the latter for use in connection with a cita- tion index and bibliographic coupling.

OSRD publications, especially those in orint or report form, will be distributed by GPO, the

Clearinghouse for Federal Technical Information,

or other appropriate agencies, rather than by

OSRD itself.

3.3.2. Preparing for Mechanization

There are several steps which OSRD has taken

or plans to take in the near future in order to

assist in the transition to mechanized publication

described in section 2.2.3. The first of these is the acquisition of a linofilm

keyboard, which produces the 15-hole punched

paper tape needed to drive the linofilm composition machine. One of the advantages of having

this device at NBS is that keypunching can now be

done under the direct supervision of the scientists responsible for the preparation of a manuscript.

This makes it unnecessary to prepare the manuscript to the same degree of perfection as if it were

sent to a printer ; rather, pencilled corrections and

verbal instructions to the keyboard operator are

acceptable, and many questionable cases can be

settled by discussion as they arise.

20

Another step in the same direction is the planne

procurement of a modified tape typewriter whic J will accept a number of special character insert]

(similar to the commercially available "Typits"

and at the same time produce a punched pape

tape. The choice of special characters, of differ! ent type fonts and other features is far moil

limited than with the linofilm keyboard, but tli| latter is more difficult to handle than the typcj

writer and does not produce an immediatel

available typed copy for quick proofreading

Therefore, and also because of its lower cost, th

tape typewriter is preferred for material of simp]

typography.

Both recording methods can be aided by pei

forming some editing functions on a compute

Several computer codes for such purposes haT

been written; so far, each of these codes wa

tailored to one particular publication. One of th efforts in which OSRD expects to engage in th near future is the production of more general],

applicable computer codes for publication editing

,

An IBM Document Writer has been acquired 1) one of the data centers located at NBS and j being used with great success for material of intei

,

mediate typographical quality.

3.4. Preparatory Activities

3.4.1. Information Gathering

As stated before, the initial period of operatio

finds OSRD with inadequate data on both tl need for its services and the tools available f( rendering them. One of the first tasks is to a>, quire some information on these two problems.

In regard to need for services, an attempt h; been made to survey the field by means of a sho:

!

questionnaire sent initially to all members of tl American Chemical Society, and later, if this

found desirable, to other interested groups. Tl

questionnaire will attempt to ascertain whie

properties of materials are most often sought i the literature, how well the existing literatmj

satisfies this need, which data compilations aj most often consulted, for which properties conj

pilations need to be prepared and data evaluate | It will also try to discover existing or incipiei

data compilations undertaken by individtiJ

scientists and not widely known. This inform:]

tion should assist OSRD in setting priorities ar distributing funds among data compilation ar evaluation projects ; at the same time it shou j indicate to ISO what kind of demand for its serJ

ices is to be expected, and it may point to sonj

existing compilations which should be added ! ISO's library. Preliminary indications are th; the number of obscure compilers to be discovert

in this way is substantial.

Another questionnaire, with a small distribute

list, will ascertain the characteristics of the knov

major data centers and similar organizationnature, volume, and format of the data they pr

duce, store, and distribute; policy in regard

answering inquiries ; and funding.
^ n

.:.

ile

to

e 1*

t f

m

tssi

•«

! Even with all these attempts it is unlikely that

He full impact of NSRDS on the technical comunity can be foreseen by an informationathering activity undertaken ahead of time,

'either the prospective users nor the producers

'lid distributors of standard reference data are

kely to anticipate the changes in project organiition and working habits which are potential

! ^ults of this "information revolution." When

1 engineer or scientist can get information on

properties of materials by turning a dial attached

> his desk—spending less effort than walking to

!iis own bookcase and turning pages in a handbook,

iid at the same time receiving answers which are

itter evaluated and more up to date—his very

linking will be directed into different channels

i ways which we cannot foresee at present.

'j/hen electronic computers were first contemplated, it was everyone's conviction that one nalonal computing center, or at most half a dozen

?gional centers, would satisfy all anticipated

imputing needs; and no survey of prospective

sers could have changed the picture. Similarly,

1 order to insure full utilization of the potential

Clients of NSRDS, it will be necessary to obtain

continuous feedback—evaluation, complaints,

nd new ideas from the users of the system ; and it

ill be necessary for the management of OSRD to ontinue to look, on its own initiative, for better

aethods and new applications.

3.4.2. Bibliography

8 A major bibliographic survey of existing comilations of quantitative data on physical and

lemical properties of materials is being underiken. It is expected that this survey will cover

' 11 existing compilations of data in the areas out- ned above, whether published in the open litera- ire or in report form ; as far as possible it should

lso include unpublished manuscript compilations,

n general, the subject of the survey would be sec- ndary publications or manuscript collections, not

ie primary publications in which newly measured

r calculated data are first communicated. A

ood example of such a survey is furnished by the

Index of Mathematical Tables" by A. Fletcher,

. C. P. Miller, and A. Rosenhead. This index is listing of all mathematical tables whose existence

he authors were able to ascertain. In the few

ears of its existence it has become an indispensable reference work. It appears that the proposed

urvey of data compilations should be published

i similar form.

It seems that the survey can best be undertaken

y a joint effort of perhaps six to twelve leading

dentists, each a recognized authority in one of

'he major subdivisions of physics and familiar

i?ith all of the important people and projects in

'hat subdivision. Each of them will be responsible for one "chapter" of the entire compilation,

'liere will be one central coordinator in charge of

evp !he entire project, whose job it will be to recruit

hapter authors, delineate their fields of responsi-

'ility and set common standards for the chapters.

nJ

The main responsibility of the chapter authors

will be to know all the likely sources of compilations in their fields; the job of actually contacting

these sources, verifying, and describing the extent of existing tabulations can be left to subordinates.

Some of the chapter authors may, however, find

that their fields are so large that they have to be

subdivided into a number of smaller specialized

areas, each with a separate "section author" who

would again have to be a recognized authority in

his field of specialization and conversant with all data compilation activities in that field. Examples of chapter areas might be: nuclear struc- ture data, infrared spectra, x-ray diffraction patterns, other solid state properties, etc. These ex- amples are illustrative only ; it should be left to the

judgment of the coordinator to delimit the

chapters.

The survey will not have to start entirely from

scratch. The Office of Critical Tables of the

NAS-NRC has collected a list of some of the best known data compilations, and is continuing this

work on a small scale. OSRD has on its own as- sembled a modest collection of compilations.

These two collections could be used as starting

points. There also exist surveys in some specialized fields: for instance, the Nuclear Data Project

at Oak Ridge has made a survey of compilations

of nuclear data ; it is not yet complete, but the work

is being continued.

The publication of such a survey, apart from its importance for the National Standard Reference

Data System, would be a most valuable addition

to the technical literature and extremely useful to the scientific and technical community.

3.4.3. Classification The most important preparation for the operation of ISO, apart from gathering the information on which it is based, is the organization of this in- formation. The bibliographic survey and ques- tionnaires discussed in the previous section will result in a list of data compilations. Copies of

these will be acquired by ISO (many of them are undoubtedly already in their collection) to be used

in their inquiry-answering service. It now be- comes mandatory to devise a system of organizing

the collection in such a way that any desired item

in it can be quickly located. This problem occurs

in every library, and conventional solutions are the

first to be considered.

Books or documents in a library are located

primarily by two devices : systematic classification

and subject indexing. These two approaches are

discussed in this and the next section.

Classification begins with the selection of a clas- sification system. It has been estimated that a substantial part of the literature in the physical

sciences—probably between 20 and 50 percent of

all papers published—is concerned with data on

properties of materials. This suggests that one

should start by looking at existing classification

systems for the physical sciences as a whole. Several such systems are in widespread use : Universal

21
Decimal (UDC), Library of Congress (LC), a system used by Physics Abstracts, etc. It was decided at an early stage that none of those could

be used without change, mostly because they are

obsolete. It therefore became desirable to design

a new classification system, made specially for the

needs of NSRDS, and hope that it could somehow

be made compatible with the older and broader

systems. The price we pay for having our own

system is that we have to do all the classifying,

while with a general-purpose system one might

have hoped to leave this job in many instances to

others. This is a small effort for the present col- lection of compilations, but a much larger one for

the current literature.

Since the proposed classification system is to serve the needs of a large segment of the scientific community, it would be desirable to have it agreed

upon by general consensus and in cooperation with

the scientific societies; indeed, international uniformity would be most welcome. This, however,

would take years to achieve. It therefore be- comes expedient to proceed in two directions

simultaneously; toward the long-range goal of a broadly based, cooperatively designed classifica- tion which can be used on a large part of the

literature and is convertible to the older classifica- tions to a reasonable degree; and toward a shortterm objective of a classification adequate for the

internal operation of ISO during the next few

years. In pursuit of the long-range solution, OSRD

sponsored two pilot efforts. One proceeded empirically, in line with modern trends in documentation theory, by collecting statistics on such

features as overlap in the vocabulary of pairs of

documents, and attempting to derive clusters of

documents which ought to have fallen into the same category of the sought-after classification. On completion of this study the results were not

judged to be sufficiently promising to warrant

continued effort. The second long-range study

employed the conventional approach of selecting

prominent technical attributes as a basis for classi- fication, but differed from older attempts by its use of the most modern concepts of theoretical

physics. Further development along these lines appeared promising but would have required more

effort than it was possible at the time to devote to

this part of the program. At the same time, some

features of this approach proved adaptable to the

short-term study being conducted in parallel.

This short-term effort had started while the two

experimental long-range studies were in progress, and was completed in the main, except for some

details, a few months later. It resulted in a classi- fication of properties developed by OSRD which

is currently being used in the operation of the

ISO data file. It is strictly limited to physical

properties of materials; it avoids using as a basis

for any stage of the classification either materials,

groups of materials or any other concept. (For

instance, "thermal conductivity" appears as a cate- gory, but "thermal conductivity of aluminum," or

22

". . . of metals" or ". . . at low temperatures" an not categories.) It consists of a few hundrec

classes, which have proved to be amply adequate

for classifying the present library of ISO and wil undoubtedly be adequate for any foreseeable ex pansion of it. If it were used, e.g., for classifyin;

all scientific papers dealing with properties of ma

terials, there would probably appear some unman

ageably large classes, which would require furthe

refinement of the classification. Once the classification had been designed, th next step was to assign the volumes of the IS(

library to classes. This step has been complete!

for the present holdings but will have to be con tinued for future acquisitions. It is the success o this operation which constitutes the "proof of th pudding" for the classification system adopted.

The library contains a certain number of docu

ments which are not primarily tables of data These fall outside the classification used. The; are kept separately from the main collection ant are arranged in groups according to a simple ai hoc classification designed for the purpose.

Finally, the books are shelved in accordanc

with the classification. This step would not b entirely necessary—conceivably the books could b kept in any order, e.g., by accession number, an

a card file be used to locate the volumes bearing

desired classification number—but for the manua

operation of a small library such as ISO's shelvin

by classification number has a number of well recognized advantages.

3.4.4. Indexing and Abstracting

Conventional libraries rely on author and sut ject indexing, in addition to classification, as principal means of retrieving information.

The preparation of an index card file arrange

by authors, separately for personal and corporal

authors, is straightforward. For subject indexin

there are two methods: one uses derived inde

terms, the other uses assigned ones. Derived index terms are a recent product ( modern documentation theory. They are usuall based on statistical analyses of the vocabulary i the document. They have the virtue that they ca be produced by computers, or at least by unskille

personnel. These methods are still being deve

oped, and have not been shown to be clearly su

cessful. There is no more reason—in fact, prol

ably less reason—to expect them to be successfi

in the field of data on properties of materials tha

in other fields. Assigned index terms for a document are chos* by a person who has at least scanned the documen

is at least superficially familiar with the subje

matter, and makes a decision as to the subje

headings under which a user might expect to loc for this document. There are two systems f< doing this. In one the indexer (who in this ca

is often the author himself) is free to choose ar terms that occur to him. In the other, terms a taken from a master list or "thesaurus" if possibl

If the thesaurus contains no suitable term, tl
ea

not mi

er,

. ndexer may assign a new term and add it to the

;f 'thesaurus. This system, then, requires two steps: first, the

1 building up of a thesaurus, and second, the appli-

:ation of this to a given set of documents. The

thesaurus should be generously cross-referenced

for synonyms and for inclusion relations ("see"

and "see also" references). The difference be- :ween the two systems is smaller than might appear : a thesaurus-controlled approach can be handled so liberally that the indexer is in fact free to use any term that occurs to him, and the uncontrolled approach can be augmented by maintaining

•an alphabetical listing of all index terms used.

There remains the difference that in the thesaurus

approach the indexer has the responsibility to

search, before using any term, for synonymous, more general, and more special terms already oc- curring in the thesaurus. This task is facilitated

if the thesaurus is maintained not only as an alphabetical listing but also in a systematic hierarchical

3pk Arrangement—thus forming a bridge between in- dexing and classification. For reasons which can only be partly detailed

nere, we believe that a thesaurus-controlled ap- proach to indexing should be taken by ISO. Furthermore, a quite small thesaurus would be adequate for most purposes. In many instances the

classification according to physical properties will

ieh j alone be sufficient to locate desired items of infor-

-mation, without using the index at all. Indexing

by materials would be useful but, because of the

large number of possible terms, too cumbersome at

least in the beginning. It is suggested that a small

thesaurus be put together from the names of comjinon classes of materials (e.g., acids, oxides, al- 2ohols, cyclic compounds), common designations

TjDj }of parameter ranges or values (e.g., low-temperarpoi jture, high-pressure, critical), and a few other

ados iterms expected to be useful (e.g., catalysts, refractories, dielectrics). The existing library of ISO

•should then be tentatively indexed on these terms. This process will result in suggestions for additional index terms, which should be added to the

thesaurus and used in a second round of indexing

the collection.

•i! , A further step in the intellectual organization of

|fi •: the ISO library, after classification and indexing,

:]vi -[consists in abstracting. In other environments

'pi »the value of abstracts lies in the wide circulation

which they can be given. In the case of ISO, with

its tightly knit organization, this is a minor advantage ; it is almost as easy for the staff to work

with the documents themselves as with a set of

abstracts cards. Perhaps the chief gain accruing

from abstracting is that the process will systematically familiarize the staff with the contents of the

library.

The information to be put on the abstract card

for a document comes under the headings of

properties, materials, parameters, and other in- formation. The card should enumerate all properties of materials on which the document contains

data. On the other hand, a complete enumeration of all materials referred to in the document is probably impractical; it will be advisable to list only major classes of materials (e.g., gases, metals,

hydrocarbons ) . As for parameters, it will usually

be sufficient to list the largest and smallest value

of each parameter (temperature, pressure, etc.)

for which the document gives data; to indicate

other information or parameter values, such as the

intervals at which functions are tabulated, would

probably be superfluous detail. Finally, under

"other information" the abstract card might list applications of the materials, instrumentation of

measurement, any theoretical discussion given in

the document, evaluation of the quality of data,

etc.In summary : When a request for data is re- ceived, the searcher will first ascertain which

properties of materials are involved, and will find

these properties in the hierarchical classification. This indicates a small group of documents in

which the desired information should be looked

for. He next consults the evaluations file, which

may point to some data compilations of high

quality. Along with specialized compilations, the

large general data compilations, notably LandoltBoernstein, must be examined. In doubtful

cases, or when the request contains important

qualifications which would narrow the search, the

subject index can be consulted, which may reduce

the number of documents to be searched. If

desired, the abstract cards for these documents

are looked up, and this may exclude further documents from the search. The remaining documents are then consulted in order to locate the de- sired information.

4. Conclusions

sub

5Ul

It emerges from the foregoing pages that during

the next few years OSRD should vigorously pursue several activities in parallel. The availability

of information services should be announced,

questioners should be given the best service possible with the present manpower and information

resources of ISO, all personnel of ISO should

participate in this service and view it as an opportunity to become familiar with their subject. A

large, but gradually decreasing, fraction of in- quiries will have to be referred to experts chosen

from area managers, data centers, NBS divisions

and occasionally others. Where replies are pre- pared by ISO, all but administrative or routine ones should be checked by area managers or other

NBS scientists. Replies should not be limited to the furnishing of standard reference data but

would, in the absence of such data, supply litera23
ture references or data taken from the literature,

accompanied by a suitable disclaimer. If, however, the volume of inquiries grows too fast for the

present staff to handle, and if an expansion of the

staff at that time is not feasible, then the flow of

information would have to be restricted by limiting information services to those cases for which

standard reference data are available.

In parallel with the foregoing, ISO should develop a thesaurus of subject index terms for its col- lection, apply it to the collection, and prepare

abstracts of documents. Simultaneously it should

broaden its collection in accordance with the

results of the bibliographic survey of data- compilations now started. Further exploration is needed of the use of cita- tion indexing and bibliographic coupling in litera- ture searching; use of computers in editing and

publishing ; remote access to computers.

With these measures OSRD ought to operate

satisfactorily for a few years; and meanwhile more information would accumulate on which the

transition to mechanized operation could be based.

One other approach, however, appears desirable

and should be undertaken simultaneously with all of the above. Rather than wait for several years

and then transfer the entire operation to a computer in one move, one should select a segment oi || the operation which could be computerized before : the rest, to serve as a proving ground. For several \ reasons, the area of thermodynamic properties

appears to be an excellent candidate for this role though atomic spectra or crystal data could be considered alternatively. In these areas there is: a body of data already in machine-readable forrr or now being recorded in this form ; and severa" data centers outside NBS, as well as competent

scientists within NBS, have shown interest in suclj| a development.

In the near future we propose to identify 3

1

subset of data to serve as a basis for the development of a set of computer codes for retrieval anc

! updating. After such codes are developed—;

which will take a good deal of time—they should

be used for six to twelve months in parallel witll manual methods. Thereafter their use could b(! extended to the entire technical area of which the pilot study was a prototype, and a little later the

j manual operation for this area could be disconi

tinued. Only then would the time have come tcj look for the memory component and other special I computer features needed in the eventual mech

anized operation.

24

U.S. GOVERNMENT PRINTING OFFICE: 1966 O—219-580
Announcement of New Publications on

Standard Reference Data

Superintendent of Documents,

Government Printing Office,

Washington, D.C. 20402

Dear Sir:

Please add my name to the announcement list of new publications to be

issued in the series: National Standard Reference Data Series — National Bureau

of Standards.

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of international standards of practice; and maintenance of a clearinghouse for the collection and

dissemination of scientific, technical, and engineering information. The scope of the Bureau's

activities is suggested in the following listing of its three Institutes and their organizational units. Institute for Basic Standards. Applied Mathematics. Electricity. Metrology. Mechanics. Heat. Atomic Physics. Physical Chemistry. Laboratory Astrophysics.* Radiation Physics. Radio Standards

Laboratory:* Radio Standards Physics; Radio Standards Engineering. Office of Standard Reference

Data. Institute for Materials Research. Analytical Chemistry. Polymers. Metallurgy. Inorganic Materials. Reactor Radiations. Cryogenics.* Materials Evaluation Laboratory. Office of Standard Refer- ence Materials. Institute for Applied Technology. Building Research. Information Technology. Performance

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