NAT L INST. OF STAND S TECH R.I.C

A111D3 fil21flT

NIST

* PUBLICATIONS ^ NIST SPECIAL PUBLICATION 260-118

U.S. DEPARTMENT OF COMMERCE/Technology Administration/National Institute of Standards and Technology

Standard Reference Materials:

Calibration of NIST Standard Reference Material 3202 for

18-Track, Parallel, and 36-Track, Parallel Serpentine,

12.65 mm (0.5 in), 1491 cpmm (37871 cpi),

Magnetic Tape Cartridge

MQrk P. Williamson

QC

100

.U57

260-118

1992

C.2
The National Institute of Standards and Technology was established in 1988 by Congress to "assist

industry in the development of technology . . . needed to improve product quality, to modernize

manufacturing processes, to ensure product reliability . . . and to facilitate rapid commercialization . . . of products based on new scientific discoveries."

NIST, originally founded as the National Bureau of Standards in 1901, works to strengthen U.S.

industry's competitiveness; advance science and engineering; and improve public health, safety, and the

environment. One of the agency's basic functions is to develop, maintain, and retain custody of the

national standards of measurement, and provide the means and methods for comparing standards used

in science, engineering, manufacturing, commerce, industry, and education with the standards adopted

or recognized by the Federal Government.

As an agency of the U.S. Commerce Department's Technology Administration, NIST conducts basic

and applied research in the physical sciences and engineering and performs related services. The Institute does generic and precompetitive work on new and advanced technologies. NIST's research facilities are

located at Gaithersburg, MD 20899, and at Boulder, CO 80303. Major technical operating units and their principal activities are listed below. For more information contact the Public Inquiries Desk, 301-975-3058.

Technology Services

• Manufacturing Technology Centers Program

• Standards Services

• Technology Commercialization

• Measurement Services

• Technology Evaluation and Assessment

• Information Services

Electronics and Electrical Engineering

Laboratory

• Microelectronics

• Law Enforcement Standards

• Electricity

• Semiconductor Electronics

• Electromagnetic Fields1

• Electromagnetic Technology1

Chemical Science and Technology

Laboratory

• Biotechnology

• Chemical Engineering 1

• Chemical Kinetics and Thermodynamics

• Inorganic Analytical Research

• Organic Analytical Research

• Process Measurements

• Surface and Microanalysis Science

• Thermophysics2

Physics Laboratory

• Electron and Optical Physics

• Atomic Physics

• Molecular Physics

• Radiometric Physics

• Quantum Metrology

• Ionizing Radiation

• Time and Frequency1

• Quantum Physics1

Manufacturing Engineering Laboratory

• Precision Engineering

• Automated Production Technology

• Robot Systems

• Factory Automation

• Fabrication Technology

Materials Science and Engineering

Laboratory

• Intelligent Processing of Materials

• Ceramics

• Materials Reliability1

• Polymers

• Metallurgy

• Reactor Radiation

Building and Fire Research Laboratory

• Structures

• Building Materials

• Building Environment

• Fire Science and Engineering

• Fire Measurement and Research

Computer Systems Laboratory

• Information Systems Engineering

• Systems and Software Technology

• Computer Security

• Systems and Network Architecture

• Advanced Systems

Computing and Applied Mathematics

Laboratory

• Applied and Computational Mathematics2

• Statistical Engineering2

• Scientific Computing Environments2

• Computer Services2

• Computer Systems and Communications2

• Information Systems

'At Boulder, CO 80303.

2 Some elements at Boulder, CO 80303.
NIST Special Publication 260-118

Standard Reference Materials:

Calibration of NIST Standard Reference Material 3202 for

18-Track, Parallel, and 36-Track, Parallel Serpentine,

12.65 mm (0.5 in), 1491 cpmm (37871 cpi),

Magnetic Tape Cartridge

Mark P. Williamson

Advanced Systems Division

National Computer Systems Laboratory

National Institute of Standards and Technology

Gaithersburg, MD 20899

U.S. DEPARTMENT OF COMMERCE, Barbara Hackman Franklin, Secretary

TECHNOLOGY ADMINISTRATION, Robert M. White, Under Secretary for Technology

NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY, John W. Lyons, Director

Issued July 1992
National Institute of Standards and Technology Special Publication 260-118

Natl. Inst. Stand. Technol. Spec. Publ. 260-118, 52 pages (July 1992)

CODEN: NSPUE2

U.S. GOVERNMENT PRINTING OFFICE

WASHINGTON: 1992

For sale by the Superintendent of Documents, U.S. Government Printing Office, Washington, DC 20402-9325
Preface

Standard Reference Materials (SRM's) as defined by the National Institute of

Standards and Technology (NIST) are well-characterized materials, produced in

quantity and certified for one or more physical or chemical properties. They are used to assure the accuracy and compatibility of measurements throughout the

Nation. SRM's are widely used as primary standards in many diverse fields in

science, industry, and technology, both within the United States and throughout

the world. They are also used extensively in the fields of environmental and

clinical analysis. In many applications, traceability of quality control and

measurement processes to the national measurement system is carried out through

the mechanism and use of SRM's. For many of the Nation's scientists and

technologists, it is therefore of more than passing interest to know the details

of the measurements made at NIST in arriving at the certified values of the SRM's

produced. The NIST Special Publication 260 Series is a series of papers reserved

for this purpose.

The 260 Series is dedicated to the dissemination of information on different

phases of the preparation, measurement, certification, and use of NIST SRM's.

In general, much more detail will be found in these papers than is generally

allowed, or desirable, in scientific journal articles. This enables the user to assess the validity and accuracy of the measurement processes employed, to judge

the statistical analysis, and to learn details of techniques and methods utilized

for work entailing greatest care and accuracy. These papers also should provide

sufficient additional information so SRM's can be utilized in new applications

in diverse fields not foreseen at the time the SRM was originally issued.

Inquiries concerning the technical content of this paper should be directed to

the author(s). Other questions concerned with the availability, delivery, price,

and so forth, will receive prompt attention from:

Standard Reference Materials Program

Bldg. 202, Rm. 204

National Institute of Standards and Technology

Gaithersburg, MD 20899

William P. Reed, Chief

Standard Reference Materials Program
OTHER NIST PUBLICATIONS IN THIS SERIES

McKenzie, R. L., ed., NIST Standard Reference Materials Catalog 1990-91, NIST Spec. Publ. 260 (January

1990)

Michaelis, R. E., and Wyman, L. L., Standard Reference

Materials: Preparation of White Cast Iron

Spectrochemical Standards, NBS Misc. Publ. 260-1

(June 1964). COM74-1 1061**

Michaelis, R. E., Wyman, L. L., and Flitsch, R., Standard

Reference Materials: Preparation of NBS CopperBase Spectrochemical Standards, NBS Misc. Publ. 260-2 (October 1964). COM74-11063**

Michaelis, R. E., Yakowitz, H., and Moore, G. A., Stan- dard Reference Materials: Metallographic Characterization of an NBS Spectrometric Low-Alloy Steel Standard, NBS Misc. Publ. 260-3 (October 1964).

COM74- 11060**

Alvarez, R., and Flitsch, R., Standard Reference Materials: Accuracy of Solution X-Ray Spectrometric

Analysis of Copper-Base Alloys, NBS Misc. Publ. 260-5 (March 1965). PB 168068**

Shultz, J. I., Standard Reference Materials: Methods for the Chemical Analysis of White Cast Iron Standards,

NBS Misc. Publ. 260-6 (July 1965). COM74-

11068**

Bell, R. K., Standard Reference Materials: Methods for the Chemical Analysis of NBS Copper-Base

Spectrochemical Standards, NBS Misc. Publ. 260-7

(October 1965). COM74- 11067**

Richmond, M. S., Standard Reference Materials:

Analysis of Uranium Concentrates at the National

Bureau of Standards, NBS Misc. Publ. 260-8

(December 1965). COM74-1 1066**

Anspach, S. C, Cavallo, L. M., Garfinkel, S. B., Hutchinson, J. M. R., and Smith, C. N., Standard Reference

Materials: Half Lives of Materials Used in the Preparation of Standard Reference Materials of

Nineteen Radioactive Nuclides Issued by the National

Bureau of Standards, NBS Misc. Publ. 260-9

(November 1965). COM74-1 1065**

Yakowitz, H., Vieth, D. L., Heinrich, K. F. J., and

Michaelis, R. E., Standard Reference Materials: Homogeneity Characterization of NBS

Spectrometric Standards II: Cartridge Brass and LowAlloy Steel, NBS Misc. Publ. 260-10 (December

1965). COM74- 11064**

Napolitano, A., and Hawkins, E. G., Standard Reference

Materials: Viscosity of Standard Lead-Silica Glass,

NBS Misc. Publ. 260-1 1 (November 1966).

Yakowitz, H., Vieth, D. L., and Michaelis, R. E., Stan- dard Reference Materials: Homogeneity Characterization of NBS Spectrometric Standards III: White

Cast Iron and Stainless Steel Powder Compact, NBS

Misc. Publ. 260-12 (September 1966).

Menis, O., and Sterling, J. T., Standard Reference Materials: Determination of Oxygen in Ferrous Materials—SRM 1090, 1091, and 1092, NBS Misc. Publ. 260-14 (September 1966).

Yakowitz, H., Michaelis, R. E., and Vieth, D. L., Stan- dard Reference Materials: Homogeneity Characterization of NBS Spectrometric Standards IV:

Preparation and Microprobe Characterization of W20% Mo Alloy Fabricated by Powder Metallurgical

Methods, NBS Spec. Publ. 260-16 (January 1969).

COM74- 11062**

Paule, R. C, and Mandel, J., Standard Reference Materials: Analysis of Interlaboratory Measurements on

the Vapor Pressure of Gold (Certification of Standard

Reference Material 745). NBS Spec. Publ. 260-19

(January 1970). PB190071**

Paule, R. C, and Mandel, J., Standard Reference Materials: Analysis of Interlaboratory Measurements on

the Vapor Pressures of Cadmium and Silver, NBS

Spec. Publ. 260-21 (January 1971). COM74-1 1359**

Yakowitz, H., Fiori, C. E., and Michaelis, R. E., Standard

Reference Materials: Homogeneity Characterization

of Fe-3 Si Alloy, NBS Spec. Publ. 260-22 (February

1971). COM74-1 1357**

Napolitano, A., and Hawkins, E. G., Standard Reference

Materials: Viscosity of a Standard Borosilicate Glass,

NBS Spec. Publ. 260-23 (December 1970). COM71-

00157**

Sappenfield, K. M., Marinenko, G., and Hague, J. L., Standard Reference Materials: Comparison of Redox

Standards, NBS Spec. Publ. 260-24 (January 1972).

COM72-50058**

Hicho, G. E., Yakowitz, H., Rasberry, S. D., and

Michaelis, R. E., Standard Reference Materials: A

Standard Reference Material Containing Nominally

Four Percent Austenite, NBS Spec. Publ. 260-25

(February 1971). COM74-11356**

iv
Martin, J. F., Standard Reference Materials: National

Bureau of Standards-US Steel Corporation Joint Pro- gram for Determining Oxygen and Nitrogen in Steel, NBS Spec. Publ. 260-26 (February 1971). PB

81176620**

Garner, E. L., Machlan, L. A., and Shields, W. R., Stan- dard Reference Materials: Uranium Isotopic Standard

Reference Materials, NBS Spec. Publ. 260-27 (April

1971). COM74-1 1358**

Heinrich, K. F. J., Myklebust, R. L., Rasberry, S. D., and

Michaelis, R. E., Standard Reference Materials:

Preparation and Evaluation of SRM's 481 and 482

Gold-Silver and Gold-Copper Alloys for

Microanalysis, NBS Spec. Publ. 260-28 (August

1971). COM71-50365**

Geller, S. B., Standard Reference Materials: Calibration of NBS Secondary Standard Magnetic Tape (Computer Amplitude Reference) Using die Reference

Tape Amplitude Measurement "Process A-Model

2," NBS Spec. Publ. 260-29 (June 1971). COM71-

50282**

Gorozhanina, R. S., Freedman, A. Y., and Shaievitch, A.

B. (translated by M. C. Selby), Standard Reference

Materials: Standard Samples Issued in die USSR (A

Translation from die Russian), NBS Spec. Publ. 260-

30 (June 1971). COM71-50283**

Hust, J. G, and Sparks, L. L., Standard Reference Materials: Thermal Conductivity of Electrolytic Iron SRM

734 from 4 to 300 K, NBS Spec. Publ. 260-31

(November 1971). COM71-50563**

Mavrodineanu, R., and Lazar, J. W., Standard Reference

Materials: Standard Quartz Cuvettes for High Accuracy Spectrophotometry, NBS Spec. Publ. 260-32

(December 1973). COM74-50018**

Wagner, H. L., Standard Reference Materials: Comparison of Original and Supplemental SRM 705, Nar- row Molecular Weight Distribution Polystyrene, NBS

Spec. Publ. 260-33 (May 1972). COM72-50526**

Sparks, L. L., and Hust, J. G, Standard Reference Materials: Thermal Conductivity of Austenitic Stainless

Steel, SRM 735 from 5 to 280 K, NBS Spec. Publ. 260-35 (April 1972.) COM72-50368**

Cali, J. P., Mandel, J., Moore, L. J., and Young, D. S., Standard Reference Materials: A Referee Method for the Determination of Calcium in Serum NBS SRM

915, NBS Spec. Publ. 260-36 (May 1972). COM72-

50527**

Shultz, J. I., Bell, R. K., Rains, T. C, and Menis, O., Standard Reference Materials: Mediods of Analysis

of NBS Clay Standards, NBS Spec. Publ. 260-37

(June 1972). COM72-50692**

Clark, A. F., Denson, V. A., Hust, J. G, and Powell, R.

L., Standard Reference Materials: The Eddy Current Decay Mediod for Resistivity Characterization of

High-Purity Metals, NBS Spec. Publ. 260-39 (May

1972). COM72-50529**

McAdie, H. G, Gam, P. D., and Menis, O., Standard

Reference Materials: Selection of Thermal Analysis

Temperature Standards Through a Cooperative Study

(SRM 758, 759, 760), NBS Spec. Publ. 260-40

(August 1972) COM72-50776**

Wagner, H. L., and Verdier, P. H., eds., Standard Refer- ence Materials: The Characterization of Linear

Polyediylene, SRM 1475, NBS Spec. Publ. 260-42

(September 1972). COM72-50944**

Yakowitz, H., Ruff, A. W., and Michaelis, R. E., Stan- dard Reference Materials: Preparation and

Homogeneity Characterization of an Austenitic Iron- Chromium-Nickel Alloy, NBS Spec. Publ. 260-43

(November 1972). COM73-50760**

Schooley, J. F., Soulen, R. J., Jr., and Evans, G. A., Jr., Standard Reference Materials: Preparation and Use of Superconductive Fixed Point Devices, SRM 767,

NBS Spec. Publ. 260-44 (December 1972). COM73-

50037**

Greifer, B., Maiendial, E. J., Rains, T. C, and Rasberry,

S. D., Standard Reference Materials: Powdered LeadBased Paint, SRM 1579, NBS Spec. Publ. 260-45

(March 1973). COM73-50226**

Hust, J. G, and Giarratano, P. J., Standard Reference

Materials: Thermal Conductivity and Electrical

Resistivity Standard Reference Materials: Austeniuc

Stainless Steel, SRM's 735 and 798, from 4 to 1200

K, NBS Spec. Publ. 260-46 (March 1975). COM75-

10339**

Hust, J. G, Standard Reference Materials: Electrical Resistivity of Electrolytic Iron, SRM 797, and Austenitic Stainless Steel, SRM 798, from 5 to 280 K,

NBS Spec. Publ. 260-47 (February 1974). COM74-

50176**

Mangum, B. W., and Wise, J. A., Standard Reference

Materials: Descripdon and Use of Precision Thermometers for die Clinical Laboratory, SRM 933 and

SRM 934, NBS Spec. Publ. 260-48 (May 1974).

Superseded by NIST Spec. Publ. 260-1 13. Carpenter, B. S., and Reimer, G. M., Standard Reference

Materials: Calibrated Glass Standards for Fission

Track Use, NBS Spec. Publ. 260-49 (November

1974). COM74-5 1185**

v
Hust, J. G., and Giarratano, P. J., Standard Reference

Materials: Thermal Conductivity and Electrical

Resistivity Standard Reference Materials: Electrolytic Iron, SRM's 734 and 797 from 4 to 1000 K, NBS

Spec. Publ. 260-50 (June 1975). COM75-10698**

Mavrodineanu, R., and Baldwin, J. R., Standard Refer- ence Materials: Glass Filters As a Standard Reference

Material for Spectrophotometry-Selection, Preparation, Certification, Use-SRM 930 NBS Spec. Publ. 260-51 (November 1975). COM75- 10339**

Hust, J. G., and Giarratano, P. J., Standard Reference

Materials: Thermal Conductivity and Electrical

Resistivity Standard Reference Materials 730 and

799, from 4 to 3000 K, NBS Spec. Publ. 260-52

(September 1975). COM75-1 1 193**

Durst, R. A., Standard Reference Materials: Standardization of pH Measurements, NBS Spec. Publ. 260-53 (February 1988, Revision of December 1975

version).

Burke, R. W., and Mavrodineanu, R., Standard Refer- ence Materials: Certification and Use of Acidic Potas- sium Dichromate Solutions as an Ultraviolet

Absorbance Standard, NBS Spec. Publ. 260-54

(August 1977). PB272168**

Ditmars, D. A., Cezairliyan, A., Ishihara, S., and

Douglas, T. B., Standard Reference Materials: Endialpy and Heat Capacity; Molybdenum SRM 781, from

273 to 2800 K, NBS Spec. Publ. 260-55 (September

1977). PB272127**

Powell, R. L., Sparks, L. L., and Hust, J. G, Standard

Reference Materials: Standard Thermocouple Material, Pt-67: SRM 1967, NBS Spec. Publ. 260-56

(February 1978). PB277172**

Barnes, J. D., and Martin, G. M., Standard Reference

Materials: Polyester Film for Oxygen Gas Transmission Measurements SRM 1470, NBS Spec. Publ. 260-

58 (June 1979). PB297098**

Velapoldi, R. A., Paule, R. C, Schaffer, R., Mandel, J., and Moody, J. R., Standard Reference Materials: A

Reference Method for die Determination of Sodium

in Serum, NBS Spec. Publ. 260-60 (August 1978).

PB286944**

Verdier, P H., and Wagner, H. L., Standard Reference

Materials: The Characterization of Linear

Polyethylene (SRM 1482, 1483, 1484), NBS Spec.

Publ. 260-61 (December 1978). PB289899**

Soulen, R. J., and Dove, R. B., Standard Reference

Materials: Temperature Reference Standard for Use

Below 0.5 K (SRM 768), NBS Spec. Publ. 260-62

(April 1979). PB294245**

Velapoldi, R. A., Paule, R. C, Schaffer, R., Mandel, J., Machlan, L. A., and Gramlich, J. W., Standard Refer- ence Materials: A Reference Method for the Deter- mination of Potassium in Serum, NBS Spec. Publ. 260-63 (May 1979). PB297207**

Velapoldi, R. A., and Mielenz, K. D., Standard Reference

Materials: A Fluorescence Standard Reference Material Quinine Sulfate Dihydrate (SRM 936), NBS Spec.

Publ. 260-64 (January 1980). PB80-132O46**

Marinenko, R. B., Heinrich, K. F. J., and Ruegg, F. C,

Standard Reference Materials: Micro-Homogeneity

Studies of NBS Standard Reference Materials, NBS

Research Materials, and Other Related Samples, NBS

Spec. Publ. 260-65 (September 1979). PB300461**

Venable, W. H., Jr., and Eckerle, K. L., Standard Refer- ence Materials: Didymium Glass Filters for

Calibrating die Wavelength Scale of Spectrophotometers-SRM 2009, 2010, 2013, and 2014, NBS Spec.

Publ. 260-66 (October 1979). PB80-104961**

Velapoldi, R. A., Paule, R. C, Schaffer, R., Mandel, J., Murphy, T. J., and Gramlich, J. W., Standard Refer- ence Materials: A Reference Method for die Deter- mination of Chloride in Serum, NBS Spec. Publ. 260-67 (November 1979). PB80-110117**

Mavrodineanu, R., and Baldwin, J. R., Standard Refer- ence Materials: Metal-On-Quartz Filters as a Standard

Reference Material for Spectrophotometry SRM

2031, NBS Spec. Publ. 260-68 (April 1980). PB80-

197486**

Velapoldi, R. A., Paule, R. C, Schaffer, R., Mandel, J., Machlan, L. A., Garner, E. L., and Rains, T. C,

Standard Reference Materials: A Reference Method

for die Determination of Lithium in Serum, NBS

Spec. Publ. 260-69 (July 1980). PB80-209117**

Marinenko, R. B., Biancaniello, F., Boyer, P. A., Ruff, A. W., and DeRobertis, L., Standard Reference Materials: Preparation and Characterization of an Iron- Chromium-Nickel Alloy for Microanalysis, NBS

Spec. Publ. 260-70 (May 1981). PB84-165349**

Seward, R. W., and Mavrodineanu, R., Standard Refer- ence Materials: Summary of the Clinical Laboratory

Standards Issued by the National Bureau of Standards, NBS Spec. Publ. 260-71 (November 1981).

PB82-135161**

Reeder, D. J., Coxon, B., Enagonio, D., Christensen, R. G.; Schaffer, R., Howell, B. F., Paule, R. C, and

Mandel, J., Standard Reference Materials: SRM 900,

Antiepilepsy Drug Level Assay Standard, NBS Spec.

Publ. 260-72 (June 1981). PB8 1-220758

vi
Interrante, C. G., and Hicho, G. E., Standard Reference

Materials: A Standard Reference Material Containing

Nominally Fifteen Percent Austenite (SRM 486),

NBS Spec. Publ. 260-73 (January 1982). PB82-

215559**

Marinenko, R. B., Standard Reference Materials:

Preparation and Characterization of K-41 1 and K-414

Mineral Glasses for Microanalysis: SRM 470, NBS

Spec. Publ. 260-74 (April 1982). PB82-221300**

Weidner, V. R., and Hsia, J. J., Standard Reference

Materials: Preparation and Calibration of First Surface Aluminum Mirror Specular Reflectance Stan- dards (SRM 2003a), NBS Spec. Publ. 260-75 (May

1982). PB82-221367**

Hicho, G. E., and Eaton, E. E., Standard Reference

Materials: A Standard Reference Material Containing

Nominally Five Percent Austenite (SRM 485a), NBS

Spec. Publ. 260-76 (August 1982). PB83-1 15568**

Furukawa, G. T., Riddle, J. L., Bigge, W. G, and Pfieffer, E. R., Standard Reference Materials: Application of

Some Metal SRM's as Thermometric Fixed Points,

NBS Spec. Publ. 260-77 (August 1982). PB83-

117325**

Hicho, G. E., and Eaton, E. E., Standard Reference

Materials: Standard Reference Material Containing

Nominally Thirty Percent Austenite (SRM 487), NBS

Spec. Publ. 260-78 (September 1982). PB83-

115576**

Richmond, J. C, Hsia, J. J., Weidner, V. R., and Wilmering, D. B., Standard Reference Materials: Second

Surface Mirror Standards of Specular Spectral Reflec- tance (SRM's 2023, 2024, 2025), NBS Spec. Publ. 260-79 (October 1982). PB84-203447**

Schaffer, R., Mandel, J., Sun, T., Cohen, A., and Hertz, H. S., Standard Reference Materials: Evaluation by an ID/MS Method of the AACC Reference Method for Serum Glucose, NBS Spec. Publ. 260-80 (October

1982) . PB84-216894**

Burke, R. W., and Mavrodineanu, R., Standard Refer- ence Materials: Accuracy in Analytical

Spectrophotometry, NBS Spec. Publ. 260-81 (April

1983) . PB83-214536**

Weidner, V. R., Standard Reference Materials: White

Opal Glass Diffuse Spectral Reflectance Standards

for the Visible Spectrum (SRM's 2015 and 2016),

NBS Spec. Publ. 260-82 (April 1983). PB83-

220723**

Bowers, G. N, Jr., Alvarez, R., Cali, J. P., Eberhardt, K.

R., Reeder, D. J., Schaffer, R., and Uriano, G. A., Standard Reference Materials: The Measurement of

the Catalytic (Activity) Concentration of Seven En- zymes in NBS Human Serum SRM 909, NBS Spec.

Publ. 260-83 (June 1983). PB83-239509**

Gills, T. E., Seward, R. W., Collins, R. J., and Webster,

W. C, Standard Reference Materials: Sampling, Materials Handling, Processing, and Packaging of NBS

Sulfur in Coal Standard Reference Materials 2682,

2683, 2684, and 2685, NBS Spec. Publ. 260-84

(August 1983). PB84-109552**

Swyt, D. A., Standard Reference Materials: A Look at Techniques for the Dimensional Calibration of Stan- dard Microscopic Particles, NBS Spec. Publ. 260-85

(September 1983). PB84-1 12648**

Hicho, G. E., and Eaton, E. E., Standard Reference

Materials: A Standard Reference Material Containing

Two and One-Half Percent Austenite, SRM 488, NBS

Spec. Publ. 260-86 (December 1983). PB84-

143296**

Mangum, B. W., Standard Reference Materials: SRM

1969: Rubidium Triple-Point - A Temperature Refer- ence Standard Near 39.30 °C, NBS Spec. Publ. 260-

87 (December 1983). PB84-149996**

Gladney, E. S., Burns, C. E., Perrin, D. R., Roelandts, I., and Gills, T. E., Standard Reference Materials: 1982

Compilation of Elemental Concentration Data for NBS Biological, Geological, and Environmental

Standard Reference Materials, NBS Spec. Publ. 260-

88 (March 1984). PB84-218338**

Hust, J. G, Standard Reference Materials: A FineGrained, Isotropic Graphite for Use as NBS Thermophysical Property RM's from 5 to 2500 K, NBS

Spec. Publ. 260-89 (September 1984). PB85-

112886**

Hust, J. G, and Lankford, A. B., Standard Reference

Materials: Update of Thermal Conductivity and

Electrical Resistivity of Eleetrolytic Iron, Tungsten,

and Stainless Steel, NBS Spec. Publ. 260-90 (September 1984). PB85-1 15814**

Goodrich, L. F., Vecchia, D. F., Pittman, E. S., Ekin, J. W., and Clark, A. F., Standard Reference Materials:

Critical Current Measurements on an NbTi Superconducting Wire Standard Reference Material, NBS

Spec. Publ. 260-91 (September 1984). PB85-

118594**

Carpenter, B. S., Standard Reference Materials:

Calibrated Glass Standards for Fission Track Use

(Supplement to NBS Spec. Publ. 260-49), NBS Spec.

Publ. 260-92 (September 1984). PB85-1 13025**

vii
Ehrstein, J.R., Standard Reference Materials: Preparation and Certification of Standard Reference Materials for Calibration of Spreading Resistance Probes,

NBS Spec. Publ. 260-93 (January 1985). PB85-

177921**

Gills, T. E., Koch, W. F., Stolz, J. W., Kelly, W. R., Paulsen, P. J., Colbert, J. C, Kirklin, D. R., Pei, P.T.S., Weeks, S., Lindstrom, R. M., Fleming, R. F., Greenberg, R. R., and Paule, R. C, Standard Reference

Materials: Methods and Procedures Used at the National Bureau of Standards to Certify Sulfur in Coal

SRM's for Sulfur Content, Calorific Value, Ash Content, NBS Spec. Publ. 260-94 (December 1984).

PB85-165900**

Mulholland, G. W., Hartman, A. W., Hembree, G. G., Marx, E., and Lettieri, T. R., Standard Reference

Materials: Development of a 1 |im Diameter Particle Size Standard, SRM 1690, NBS Spec. Publ. 260-95

(May 1985). SN003-003-02665-4*

Carpenter, B. S., Gramlich, J. W., Greenberg, R. R., Machlan, L. A., DeBievre, P., Eschbach, H. L., Meyer, H., Van Audenhove, J., Connolly, V. E., Trahey, N. M., and Zook, A. C, Standard Reference

Materials: Uranium-235 Isotopic Abundance Stan- dard Reference Materials for Gamma Spectrometry

Measurements, NBS Spec. Publ. 260-96 (September

1986). PB87-108544**

Mavrodineanu, R., and Gills, T. E., Standard Reference

Materials: Summary of the Coal, Ore, Mineral, Rock,

and Refactory Standards Issued by die National

Bureau of Standards, NBS Spec. Publ. 260-97 (September 1985). SN003-003-02688-3*

Hust, J. G., Standard Reference Materials: Glass Fiber- board SRM for Thermal Resistance, NBS Spec. Publ. 260-98 (August 1985). SN003-003-02674-3*

Callanan, J. E., Sullivan, S. A., and Vecchia, D. F., Standard Reference Materials: Feasibility Study for die Development of Standards Using Differential Scanning Calorimetry, NBS Spec. Publ. 260-99

(August 1985). SN003-003-02675-1*

Taylor, J. K., Standard Reference Materials: Handbook

for SRM Users, NBS Spec. Publ. 260- 100 (September

1985). PB86-1 10897**

Mangum, B. W., Standard Reference Materials: SRM

1970, Succinonitrile Triple-Point Standard: A

Temperature Reference Standard Near 58.08 ° C, NBS

Spec. Publ. 260-101 (March 1986). SN003-003-

02722-7*

Weidner, V. R., Mavrodineanu, R., Mielenz, K. D., Velapoldi, R. A., Eckerle, K. L., and Adams, B., Standard Reference Materials: Holmium Oxide Solution Wavelengdi Standard from 240 to 640 nm - SRM

2034, NBS Spec. Publ. 260-102 (July 1986). PB86-

245727**

Hust, J. G., Standard Reference Materials: Glass

Fiberblanket SRM for Thermal Resistance, NBS

Spec. Publ. 260-103 (September 1985). SN003-003-

02687-5*

Mavrodineanu, R., and Alvarez, R., Standard Reference

Materials: Summary of the Biological and Botanical

Standards Issued by the National Bureau of Standards, NBS Spec. Publ. 260-104 (November 1985).

SN003-003-02704-9*

Mavrodineanu, R., and Rasberry, S. D., Standard Refer- ence Materials: Summary of die Environmental Research, Analysis, and Control Standards Issued by die National Bureau of Standards, NBS Spec. Publ. 260-

105 (March 1986). SN003-003-02725-1*

Koch, W. F., ed., Standard Reference Materials: Mediods

and Procedures Used at die Nadonal Bureau of Stan- dards to Prepare, Analyze, and Certify SRM 2694,

Simulated Rainwater, and Recommendations for Use,

NBS Spec. Publ. 260-106 (July 1986). PB86-

247483**

Hartman, A. W., and McKenzie, R. L., Standard Refer- ence Materials: SRM 1965, Microsphere Slide ( 10 pirn Polystyrene Spheres), NBS Spec. Publ. 260-107

(November 1988).

Mavrodineanu, R., and Gills, T. E., Standard Reference

Materials: Summary of Gas Cylinder and Penneadon

Tube Standard Reference Materials Issued by die National Bureau of Standards, NBS Spec. Publ. 260-

108 (May 1987).

Candela, G. A., Chandler-Horowitz, D., Novotny, D. B., Marchiando, J. F., and Belzer, B. J., Standard Refer- ence Materials: Preparation and Certification of an

Ellipsometrically Derived Thickness and Refractive

Index Standard of a Silicon Dioxide Film (SRM

2530), NIST Spec. Publ. 260-109 (October 1988).

Kirby, R. K, and Kanare, H. M., Standard Reference

Materials: Pordand Cement Chemical Composidon

Standards (Blending, Packaging, and Testing), NBS

Spec. Publ. 260-110 (February 1988).

Gladney, E. S., O'Malley, B. T., Roelandts, I., and Gills, T. E., Standard Reference Materials: Compiladon of Elemental Concentration Data for NBS Clinical,

Biological, Geological, and Environmental Standard

Reference Materials, NBS Spec. Publ. 260-111

(November 1987).

viii
Marinenko, R. B., Blackburn, D. H., and Bodkin, J. B., Standard Reference Materials: Glasses for

Microanalysis: SRM's 1871-1875, NIST Spec. Publ. 260-112 (February 1990).

Mangum, B. W., and Wise, J. A., Standard Reference

Materials: Description and Use of a Precision Thermometer for the Clinical Laboratory, SRM934, NIST

Spec. Publ. 260-113 (June 1990).

Vezzetti, C. F., Vamer, R. N. and Potzick, J. E., Standard

Reference Materials: Bright-Chromium Linewidth

Standard, SRM 476, for Calibration of Optical Microscope Linewidth Measuring Systems, NIST Spec.

Publ. 260-114 (January 1991).

Williamson, M. P., Willman, N. E., and Grubb, D. S., Standard Reference Materials: Calibration of NIST

Standard Reference Material 3201 for 0.5 Inch (12.65

mm) Serial Serpentine Magnetic Tape Cartridge,

NIST Spec. Publ. 260-115 (February 1991).

Mavrodineanu, R. , Burke, R. W., Baldwin, J. R., Smith,

M. V., and Messman, J. D., Standard Reference Materials: Glass Filters as a Standard Reference Material

for Spectrophotometry and Selection, Preparation,

Certification and use of SRM 930 and SRM 1930,

NIST Spec. Publ. 260-1 16 (in prep).

Vezzetti, C. F., Varner, R. N., and Potzick, J. E., Standard

Reference Materials: Antirefleeting-Chromium

Linewidth Standard, SRM 475, for Calibration of Optical Microscope Linewiddi Measuring Systems,

NIST Spec. Publ. 260-117 (January 1992).

*Send order widi remittance to Superintendent of

Documents, U.S. Government Printing Office,

Washington, DC 20102. Remittance from foreign

countries should include an additional one fourth of

the purchase price for postage.

**May be ordered from: National Technical Information Services (NTTS), Springfield, VA 22161.
Conformance

The NIST SRM 3202 is specified in the testing requirements of the following

standards.:

ANSI X3.180- 1990

ISO/IEC 9661:1988

ECMA 120 - 1987

Disclaimer

Manufacturer's names and model numbers are cited solely to identify the hardware and

software used and do not imply a recommendation and are not necessarily the best

available for the purpose.

Acknowledgments

Special thanks are due to StorageTek for their assistance in modifying the Honeywell

96 tape drive, extensive technical support, and donation of read/write heads; to Honeywell for their donation of the Honeywell 96 tape drive; to Hewlett Packard for

their donation of an HP3586C selective level meter and an HP3456A digital voltmeter;

to Tektronics for their donation of the AM502 differential amplifier; and to IBM for

their technical support.

The author greatly appreciates the time, support, and guidance provided by Mr. Gerald

Taylor and Dr. Richard Thornely of StorageTek.

Appreciation is also due to Mrs. Natalie Willman of NIST for her assistance with the C

programming language, Dr. James Filliben of NIST for his guidance in statistical

analysis, and Dr. Ronald Boisvert of NIST for his contribution of the curve fitting

program.

The SRM 3202 system was developed by the author and the calibration of the SRM

3202 tapes were performed by Mr. Lloyd D. Gilmore. The project was supervised by

Mr. Dana S. Grubb, manager, Data Storage Group.

Funding for the development of SRM 3202 was provided by NIST and by several of

the members of Technical Committee X3B5, Digital Magnetic Tape.
Table of Contents

1. Introduction 1

1 . 1 Need for Standard Reference Tapes 1 1.2 Background of the NIST Secondary

Standard Reference Tape Program 2

2. Testing Methodology 3

2.1 Self-Correcting Calibration System 3

2.2 Saturation Test 3

2.3 Overwrite Test 7

2.4 Resolution Test 7

3. Description of the Measurement System 10

3.1 Tape Transport 10

3.2 Write Instrumentation and Circuitry 13

3.2.1 Peak-to-Peak Detector 13

3.2.2 Offset Adjustment of Peak-to-Peak Detector 13

3.3 Read Instrumentation and Circuitry 17

3.4 Measurement System Software 20

4. Procedure for the Selection of a Master Standard Reference 21

5. Procedure for the Use of an SRM 3202 Tape 32

5.1 Testing and Storage Environment 32

5.2 Environmental Conditioning of the Media 32

5.3 Stabilization of the Test System 32

5.4 Procedure for the Calibration of the Test System 32

5.5 Procedure for Calibrating a Tertiary Tape 34

6. Definitions 37

7. References 39

xi
List of Figures

1. Secondary Standard Calibration Data 5

2. Master Standard Calibration Data 6

3. SRM 3202 If Recording Pattern 8

4. SRM 3202 Tone Recording Pattern 9

5. Measurement System Interconnections 11

6. SRM 3202 Tape Lifter 12

7. Write Circuitry and Instrumentation 14

8. NIST Peak-to-Peak Detector Circuit 15

9. NIST Peak-to-Peak Detector Op Amp Connections 16

10. Read Instrumentation and Circuitry 18

1 1 . Read Head Current Limiting Circuit 19

12. Centerline Candidate Tapes 31

13. Saturation Curve on User's Test System 36

List of Table

1. NIST Standard Reference Tapes 2

xii
1. Introduction

1.1 Need for Standard Reference Tapes

Reliable interchange of magnetic computer storage media is an essential requirement of

modern data processing systems. Interchange is the ability of the system to extract information stored on magnetic media, such as computer magnetic tape, cassette,

cartridge, or disk, that was written by another compatible media-handling system either

within or external to the originating installation.

When the magnetically encoded data on the tape or disk are converted into electrical

signals by the reproducing system, it is necessary for the media parameters to be

compatible with the design of other reproducing or recording systems. It is inefficient

and unreliable for an electronic system to need continuous readjustment in order to handle nonuniform magnetic media.

Interchange standards define a wide variety of mechanical, electrical, and magnetic

parameters, such as length, width, thickness, longitudinal curvature, electrical

resistance, signal-to-noise ratio, etc. However, several magnetic properties, such as typical field, average signal amplitude, overwrite, and resolution, cannot be

meaningfully measured directly. Therefore, it is necessary that each type of magnetic

computer storage medium intended for interchange be produced with media properties

within given relative tolerances. In other words, there must be a "reference" against

which the media parameters can be compared and for which the data processing

systems can be calibrated.

Signal amplitude is an important parameter because different amplitudes require

different read amplifier gain settings to provide the signal level necessary for the

detection circuitry. While modern tape drives use automatic gain control, wide

variations in recorded amplitude can cause read errors. For older magnetic media with

relatively low physical recording densities (e.g., 126 flux transitions per millimeter

(ftpmm), 3200 flux transitions per inch (ftpi)), signal amplitude is the only properties

for which an Standard Reference Material (SRM) is needed.

With modern tape systems, the physical recording density has increased significantly so

that several other magnetic properties have become critical for dependable media

interchange. For example, the ability of the write head adequately to overwrite

previously recorded data is important on these media with higher physical recording

density which have lower signal amplitudes and poorer signal to noise ratios than their

low density predecessors. Other properties include typical current (a specific point on

the magnetic saturation curve), and frequency resolution (frequency rolloff).

l
1.2 Background of the NIST Secondary Standard Reference Tape Program

Earlier SRMs developed by NIST include SRM 3200 and SRM 6250, 12.65 mm

(0.5 in), open-reel tape, SRM 1600, 3.8 mm (0.15 in), cassette, and SRM 3216,

6.3 mm (0.25 in), cartridge (see table 1). SRM 3200, 6250, 1600, and 3216 are produced on a system which is entirely manual in operation. The system uses a ramp

generator for the write current and direct plotting on analog recorders.

The SRM 3217, 6.3 mm (0.25 in), cartridge is produced on a second system that is partially computer controlled and has a digital plotter.

The SRM 3201, 12.65 mm (0.5 in) cartridge was the first SRM produced on a new

generation of computer-controlled systems developed at NIST. All instruments in the

SRM 3201 and SRM 3202 test system are commercially available. The software, the

peak-to-peak detector, and other specialized digital and analog circuits were developed

by NIST.

The SRM 3202 system, the subject of this Special Publication, uses a computercontrolled arbitrary function generator to provide the write current. A computercontrolled selective level meter is used to measure the signal output amplitude on a

read-after-write pass. Tape drive motion is controlled via an IEEE-488 interface. In

addition, files for each tape tested are stored by the computer on magnetic media. The

12.65 mm (0.5 in) magnetic tape cartridge has 18-tracks recorded in parallel, or 36 tracks employing parallel serpentine recording and a physical recording density of

972 ftpmm (24689 ftpi). The SRM consists of a digital magnetic tape in its cartridge

and documentation of the tape's performance relative to the Master Standard Reference

Tape's performance, on the following properties: typical field, average signal

amplitude, overwrite, and resolution. Section 6 contains definitions of these properties

and other special terms used in magnetic tape testing.

SRM Description

3200/6250 12.65 mm (0.5 in), 32/126/356 ftpmm (800/3200/9042 ftpi), open-reel tape

1600 3.8 mm (0.15 in), 63 ftpmm (1600 ftpi), cassette tape

3216 6.3 mm (0.25 in), 126 ftpmm (3200 ftpi), cartridge tape

3217 6.3 mm (0.25 in), 252/394 ftpmm (6400/10000 ftpi), cartridge tape

3201 12.65 mm (0.5 in), 262/394 ftpmm (6667/10000 ftpi), cartridge tape

3202 12.65 mm (0.5 in), 972 ftpmm (24689 ftpi), cartridge tape

Table 1. NIST Standard Reference Tapes

The following sections explain the testing methodology, the measurement system, the

selection of the Master Standard Reference, and the usage of the SRM 3202.

2
2. Testing Methodology

This section describes the methodology used for testing saturation, overwrite, and

resolution of SRM 3202 tapes. All measurements are made on a read-after-write pass over the middle-third of the tape under test. Also, measurements are only made on

track 9 of an 18-track parallel read/write head. The measurements described in this

paper are performed using the NIST Master Standard Read/Write Head # 6

(StorageTek SN C024173). Measurements are performed on SRM 3202 tapes at the

ambient condition of 23 °C ± 2 °C (74 °F ± 4 °F), and 40 to 60 percent relative

humidity after 24 hours of acclimatization.

2.1 Self-Correcting Calibration System

The SRM 3202 Secondary Standard Reference Tapes are calibrated using a self- correcting calibration system. This scheme is fully documented in an article cited in

reference 4.

In this self-correcting scheme, there is a Master Standard Reference Tape, and several

working tapes that are calibrated against it. The data are stored in table form on

magnetic disk and a magnetic disk backup medium.

The Secondary Standard Reference Tapes will be calibrated at some later date, and

subsequent batches calibrated over a period of years. At the time of the calibration of

a batch of secondary tapes, the working tapes are run again and a correction factor

table is determined, which is defined as the differences in signal amplitude and write

current between the working tapes data when they were first run, and the current

working tapes data. If significant differences are found, this "correction" table may

then be added to the data obtained when the Secondary Standard Reference Tape is run. This will correct the system's gain adjustments which may have drifted since the

Master Standard Reference Tape was selected. See section 6 for definitions of the

Master Standard Reference Tape, Secondary Standard Reference Tape, and working

tapes.

2.2 Saturation Test

The result of the saturation test is a plot of the read signal amplitude as a function of

the write current. The tape is written with a If signal (972 ftpmm (24689 ftpi)), see appendix A, and an increasing current. Then the tape is rewound and the average of

multiple samples of signal amplitude produced by each current setting is read from the

tape and stored in a table. These values are then fitted to a third order polynomial

curve and plotted with average signal amplitude along the y axis and write current

along the x axis. Curve fitting is needed since the read signal is subject to various sources of noise, such as thermal and magnetoresistive bias noise.

3
For all tapes, the following values are calculated:

Peak amplitude (Ap) the peak average signal amplitude.

Peak current (Ip) the write current corresponding to the peak amplitude.

Typical amplitude (At) 85 percent of the peak amplitude (Ap).

Typical field the minimum recording field which will produced the typical

amplitude (At).

Typical Current (It) the write current which will produce the typical field.

When a Master Standard Reference Tape is chosen and a saturation test is performed on

it, the following data are calculated:

Standard Reference Current (Ir) the typical current of the Master Standard

Reference Tape.

Standard Measurement Current (Im) 1.5 times the standard reference current (Ir)

Standard Reference Amplitude (SRA) the average signal amplitude from the

Master Standard Reference Tape when it is recorded with the Standard Measurement

Current (Im).

When a Secondary Standard Reference Tape is calibrated, the following data are compared:

Standard Reference Current (Master Standard Reference Tape)

Standard Measurement Current (Master Standard Reference Tape)

Typical Current (Test Tape)

Ratio of It to Ir Ratio of the test tape's average signal amplitude at the Standard Measurement

Current (Im) to the Standard Reference Amplitude (SRA).

Figure 1 shows a SRM 3202 saturation curve produced by this system. The x axis is the base-to-peak write current in milliamperes and the y axis is the base-to-peak

average signal amplitude in amplitude units. The amplitude units are normalized to 40

units for the peak amplitude of the Master Standard Reference Tape. Figure 2 shows

the Master Standard Reference Tape saturation curve.

Each point on an SRM 3202 saturation curve consist of the medians of at least 10

selective level meter samples at each of the 50 discrete current values. The data is then

fitted to a third-order polynomial.

4
5
'3-

6
2.3 Overwrite Test

"Overwrite" is defined as the ratio of the average signal amplitude of the residual of the

tone pattern after being overwritten by the If pattern, to the average signal amplitude of

the original tone pattern (see Figs. 3 and 4).

A tape is recorded with the tone pattern (6-bit pattern 100000) at the Standard

Measurement Current (Im). The average signal amplitude of the tone pattern is read

from the tape. The tape is then recorded with the If pattern at the standard

measurement current (Im). The average signal amplitude of the If pattern is read from

the tape. The residual average signal amplitude of the tone pattern is then measured.

2.4 Resolution Test

Resolution is defined as the ratio of the average signal amplitude at the 1.5f physical

recording density to that at the If physical recording density. See Section 6 for

definitions the 1.5f physical recording density.

A tape is recorded at the If physical recording density at the Standard Measurement

Current (Im), and the average signal amplitude is recorded.

The tape is ac bulk erased and recorded at the 1.5f physical recording density at the

Standard Measurement Current (Im). The average signal amplitude is recorded.

The ratio of the average signal amplitude at the 1.5f physical recording density to the

average signal amplitude at the If physical recording density is then calculated.

7
! 1 1 hJ i 1c 1

-jr : •j - ' k; - 1 BMW j!

-r - — . ) i ,4

_J

jr!r

in oo3E

4—>>

re o

6ao £

i—i r*i . ~~— N <E> C On « A oo n

*j 8v£>

'55c _ Qn 6 - 6 §s? co ieg

Noten

4—1 6• »—I XO >c2 & £ 8 8 3 1

WD o

1/3e • i—c H ft 8
«5 o

^ >

* *3

B

<D 4—

>

•4—

>

Oh

<DC

oH

>

B

8

>

cd 2 § c

ffl U E-i

I

©J)

©

I

8

c

e&

E
3. Description of the Measurement System

Manufacturer's names and model numbers are cited solely to identify the equipment

used and do not imply a recommendation. Such identification is essential, since the

system software must be written using the control/status codes and data formats

specified for the particular equipment. Alternative equipment may be used, but some

modification of the NIST system software will be necessary. As the instruments are set up by the software, those interested in the instruments' settings should consult the

software listings for the instrument drivers. (Source code is available on magnetic

media from NIST.)

Figure 5 shows the measurement system interconnection. It is essential that the 50 ohm

terminator be used as shown.

3.1 Tape Transport

A Honeywell 96 instrumentation tape drive was selected for the SRM 3202 test system,

since it offered the necessary stable transport velocities and provided relative ease for

modifications. The drive was modified for use with a cartridge tape feeder and 18-

track parallel recording read/write heads. Although a Honeywell standard transport

speed of 0.762 m/s (30 in/s) is used for writing, a nonstandard speed of 0.3048 m/s

(12 in/s) is used for reading. In order to accomplish this, the HP3325A frequency

synthesizer is connected to the Honeywell 96 external reference input (J7 on the A4

control logic card. J 16 must also be jumpered to indicate external reference). The

0.3048 m/s (12 in/s) is obtained by selecting 0.381 m/s (15 in/s) and then reducing the

reference frequency from the standard 3.2 to 2.56 MHz. This frequency of 2.56 MHz

was derived by dividing the desired speed by the next highest standard transport speed

and multiplying that quantity by the standard reference frequency. For example:

Desired frequency = (0.3048 ms" 1

/ 0.381 ms" 1

) * 3.2 MHz = 2.56 MHz

The Honeywell 96 vacuum column system is set to maintain a tape tension of

2.2N±0.3N(7.9 ozf ±1.1 ozf). In addition, the measurement system includes a

tape lifter, which injects a jet of air between the head and tape whenever the tape is stopped or measurements are not being performed. This effectively reduces problems

with machine drag and the possibility of head-to-tape adhesion. As shown in Figure 6,

the tape lifter is controlled using the Honeywell 96 track select lines. This provides

IEEE-488 control of the tape lifter.

10
Fluke 4250A

Power Source

HP 3456A

DVM

TEK AM 502

Diff. Amp

HP 3457A

DVM

HP 3586C

SLM

Read

Bias

Circuit

Honeywell 96

Magnetoresistive Read Head

Write Head &

Term. Circuit

NIST

Peak-to-Peak

Detector

LeCroy 9100

AFG

HP 3325A

Frequency

Generator

IBM PC AT

W/ National Instruments GPIB-PC2A

HP 7550A

Plotter

Figure 5. Measurement System Interconnections

11
Honeywell 96

Track Select Line 1

4.7 kilohm —

15 volts

10 kilohm

-AAA*— 2N3643

NPN

* Compressor - Medo Model ACO902-A1031-D2-051

1

* Solenoid - Humphery PN410741401

Figure 6. SRM 3202 Tape Lifter

12
Write Instrumentation and Circuitry

As shown in Figure 7, a LeCroy 9100 Arbitrary Function Generator (AFG) is used to produce the double density nonreturn to zero If, 1.5f, and tone pattern. The AFG is only capable of providing a maximum of 100 mA base-to-peak current from a single

waveform output channel. Therefore, the two waveform output channels were summed, resulting in a maximum 200 mA base-to-peak waveform.

3.2.1 Peak-to-Peak Detector

Figures 8 and 9 show the NIST peak-to-peak detector circuit. The peak-to-peak

detector is used only to monitor the current provided by the LeCroy 9100 AFG.

The peak-to-peak detector provides a low-noise dc output for measurement by the

digital voltmeter. The detector's response is linear within 1 percent from 350 to 1350 mV and from 250 to 500 kHz. (The detector is also linear within 2 percent from

100 kHz to 2 MHz.) The circuit design relies on the use of a particular type of

operational amplifier (Comlinear CLC-400), polypropylene or similar specification

capacitors and other selected components. While the operational amplifiers are quite

stable, the offsets should be adjusted prior to calibrating tapes.

3.2.2 Offset Adjustment of Peak-to-Peak Detector

The peak-to-peak detector is quite stable, but the offsets should be periodically

readjusted. Following is a list of steps to adjust the detector:

1) Turn the power on and let the detector warm up for at least 1 hour.

2) Ground the two differential inputs to the detector.

3) Using an oscilloscope with a high gain preamplifier capable of at least

10 mV/div sensitivity, adjust the differential amplifier. Place the scope probe on the output of the amplifier (Ul pin 6) and adjust R7 for ground level on

the oscilloscope.

4) Repeat step 3 for the linear halfwave rectifiers. Place the probe on U2

pin 6 and adjust R15, then place the probe on U3 pin 6 and adjust R21. As

U2 and U3 are subject to noise, adjust the outputs for an average level of

zero.

5) Use a high input impedance voltmeter capable of reading to 1 mV to adjust the offset of the inverting summing amplifier. Place the probe on U4

pin 6 and adjust R23 for an average reading of zero.

13
Each amplifier will drift approximately ±5 mV for output levels in the 500 mV and

higher range. This means an error of less than 1 percent even when the detector has

not been used for a period of time.

LeCroy 9100

Arbitrary Function Generator

Waveform Outputs CHI

10 ohms

HP 3457A

Digital Voltmeter

Two-Turn Write Head

Approx.

4.5 ohms (dc)

10 ohms

NIST

Peak-to-Peak

Detector

Figure 7. Write Circuitry and Instrumentation

14
15
+ 5 volts

O

O

r

0.01 micro

farad

- 5 volts

5 volts WV

10 micro

farad

0.1 micro

farad

f

0.1 micro

farad

10 micro

farad

R7, R15, R21, R23

20 kilohm

+ 5 volts

o

Figure 9. NIST Peak-to-Peak Detector Op Amp Connections

16
3.3 Read Instrumentation and Circuitry

As shown in Figure 10, the read instrumentation and circuitry is comprised of a Fluke

4250A bipolar voltage source, a Tektronics AM502 differential amplifier, a read-bias

circuit, an 18-track, parallel magnetoresistive read head, an HP 3456A digital

voltmeter (DVM), and an HP 3586C selective level meter (SLM).

The Fluke 4250A power source is required to provide 22 mA of current through each

side of the magnetoresistive read head. The voltage drop across the magnetoresistive

read head is monitored using two 50 kilohm resistors and a HP 3456A DVM. The

Fluke 4250A power source is connected in a feedback loop with the DVM. The voltage

output is then adjusted until a 0.88 V output is read by the DVM.

The voltage drop across the head is then fed to the AM502 differential amplifier. The

AM502 converts the differential signal to a single signal. The amplifier has a bandwidth of dc to 1 MHz and 500 is the gain.

The read signal is then sampled by the HP 3586C selective level meter, which is setup

with a bandwidth of 3100 Hz.

In order to protect the magnetoresistive read head from a surge in current, the output of

the Fluke 4250A power source was fitted with a crowbar circuit (see Fig. 1 1) to limit

the output current to a maximum of 75 mA.

17
Fluke 4250A

Power Source

Vout

TEK AM502

Diff. Amp.

Gain = 500

BW: DC to 1MHz

IN + IN OUT

0 0 0

IEEE-488

Bus

22 mA200 ohm V 7-VW

50kilohm

0.47 micro

farad

0.47 micro

farad

Magnetoresistive

Read Head

22 mA

W\r

40

22 mA

ohm

40 ohm

0.88 V

50 kilohm —WSr0

Vin

HP 3456A

Digital Voltmeter © Vin HP 3586C

Selective Level Meter

Figure 10. Read Instrumentation and Circuitry

18
* Fuse - 1/16 amp

* Zeners - Phillips ECG 5122A, 8.2 V, 5W

Figure 11. Read Head Current Limiting Circuit

19
3.4 Measurement System Software

The system software is menu-driven with computer control of all aspects of the tape

testing. The operator is asked to key in answers to necessary questions, such as the

type of tape to be tested and the type of test to be performed.

The program is written in C language, which allows a high degree of control of the

hardware. In addition, C can be compiled to efficient object code, is portable with

little modification between widely varying computers, and is designed for writing

structured programs. The software was written using an IBM PC AT computer with

DOS Version 3.2. Since the instruments needed for the system are all designed with

very different commands, responses and formats, the source code is unique for each

instrument. (Even very similar instruments from the same manufacturer, such as the

HP3456A and HP3457A digital multimeters, are designed with different commands

and responses.) Therefore, the substitution of other instruments will necessitate a re- write of the drivers.

The software should run properly on most IBM-compatible personal computers having

a math coprocessor, a hard disk, and DOS Version 3.2 or later. The graphics functions

used for displaying the saturation curves are specific to EGA monitors, and would

require slight modification if another monitor is used. Computer speed should

approximate that of an IBM PC AT or better.

The program is compiled using Borland Turbo C Version 1.5, although there are

several other C compilers available that would probably be satisfactory. However, the

IEEE-488 interface board used in the system must come with object code that works

with the compiler. The compiler selected should make use of the math coprocessor and

should produce relatively fast object code.

The system program should compile properly with most compilers, except for the

graphics which use library functions specific to Turbo C. Also, the input byte and

output byte functions are not specified in exactly the same way by all compilers, so modification of how these functions are specified would be needed. Segment

addressing is not used, since both the program and the data use less than 64 kbytes.

The third-order polynomial curve fitting program was developed in Fortran by Dr.

Ronald Boisvert of the NIST Computing and Applied Mathematics Laboratory.

20
4. Procedure for the Selection of a Master Standard Reference

Five centerline candidate tapes were received from each of 10 companies prior to the

expiration of the ISO/IEC JTC 1/SC 11 and TC X3B5 extended centerline call deadline

of November 30, 1990. Some companies were tape manufacturers, while others were

drive manufacturers. Randomly assigned code letters were used to designate the

companies in the data tabulated below. In alphabetical order, the companies are: BASF

Carlisle

Dysan

Fuji

IBM

Memorex

StorageTeK

TDK

3M (U.S.)

3M (Italy)

Three saturation (sat) tests were performed on each of the five tapes from each of the

10 companies. Tests were run in random order by company. These tests were made

using the Class 0 test option ("Test Tape") so that each tape was tested using its own

Typical Current and Measurement Current rather than that of a master tape, since there

was not, at this time, a master tape to use. (Since there is no common measurement

current (Im), it is not possible to make a valid comparison of the output signal

amplitudes using this particular data.)

The median Typical Current measurement for each tape was then selected.

Using the median Typical Current measurement for each tape, the five tapes were

ranked for a given company, and the median of the medians was selected to represent

that company. (For example, tape B21 pass 627 was selected to represent company B.)

21
The tapes were then ranked by Typical Current as shown below:

i ape IVlcUlall 11 Dnrllr Tf lixdllK Jll R9DZ 11 697 ins 9 11 rtj 61Q 111.1 111 1 L

J UH 79Q 111,1. 1119 J

njj 11111 1 1 . J

At

VJt / 607 1116 lll.U J

"749

1 1Z. j 0

K67 698 112.6 7

158 751 113.0 8

D34 675 114.0 9

C29 632 119.3 10

Tape C29 was a clear outlier with its very high Typical Current. So C29 was deleted

from the pool, which left an odd number of tapes. This made G47 the median tape, so

it was selected as the PMSR (Proposed Master Standard Reference) Tape. Five more

sat tests were run on G47 using the Class 3 test option (Master True):

Class Pass It Am Rank It 3 768 111.7 3.166 1 3 769 112.2 3.145 5

3 770 112.1 3.111 3 <

3 771 112.1 3.106 2

3 772 112.2 3.085 4

Median

Pass number 770 was selected, the sat test with the median Typical Current

measurement, as the Master True file to use in subsequent tests. The following data is the Master True file.

Master True Header:

g0470770.f3s filename

g0470770.f3s mtfilename

121990 monthdayyear

ldg operator

006 headnumber

3.443 Ap_for_test_tape

138.0 Ip_for_test_tape

2.926 At_for_test_tape

112.1 It_for_test_tape

112.1 Ir_for_master_true

168.2 Im_for_master_true

3.111 Am_for_test_tape_at_master_true's_Im

22
IwritefmA) A mnl l ti irlf* TTnitc rVllipillUUC Ulllli

102 0000 2 4147 OQ 0S7S

104 0000 2 5317 29t*y .t4170 i /vj 106 X VV/ • 0000 \y\_/ vy \y 2x* . 6405 IrtWJ 30 681?

108 A • 0000 v/ \yvy\y 2Xv • 7414 / Tit 31 8536

110 x x v/ • 0000 v/ v/ \yvy 2 8345 3? 93S4

112 X X A* • 0000 WW 2 9200 33 9988

114 X XT. 0000 Www 2 9989 34 8375

116 0000 3 0693 35 6636

118 x x yj • 0000 ww 3 1335 36 4096

120 0000 3 1911 37 0789

122 0000 3 2421 37 671 5

124 x *«t a 0000 vyvyv/ vy 3 2868 38 1908

126 X MV-/ a 0000 WW 3 3255 38 6405

128 0000 3 3584 J7. 39 0228 l7i-Z.O 130 x v/ 0000 wvyvy 3 3856 39jy . 3389 JJ07

132 UaVi 0000 WW 3 4075 J7.J7JJ

134 x w*~ • 0000 vy\_/V7Vy 3J . 4241 Tit

1

J7. 3Q 7869 / ooz

136 X JU» 0000 WW 3 4357 39 9910

138 ± *J \J , 0000 WW 3 4425 40 0000

140 x iv • 0000 v/V/

W

3 4448 40 0967

142 X t X* o 0000 WW 3 4427 40 0093

144 x » r • 0000 ww 3*J • 4364 TJUT Q9Q1

146 X \_/ • 0000 vyv/

w

J3 • 4262 ~Xv u*» 39 8106

148 X ~KJ > 0000 WW 3 4123 39 6491

150 x »y vy s 0000 ww 3 3949 39 4469

152 X *J X* • 0000 WW 3 3742 39 9064

154 x «y 0000 wv/v/ 3 3504 38 9298

156 X fc/ V • 0000 WW 3 3238 JO. 38 6208 vJ^V70 158 0000 3 2945 38 9803

x160vy\y • 0000 VyVyV/Vy 3 2627 »737/ • 9108 ~ 1 Vy O

x162\J£~ • 0000 \_/V_/ v/vy 3J a 2287 X» X, VJ I 37 51 58

164 0000 3 1927 37j / . 0975 \jy i u

11 DO . nnnn uuuu j. l Dty ju.DJoZ

168.0000 3.1154 36.1993

170.0000 3.0746 35.7252

(Data after 170 mA omitted as irrelevant.)

Five sat tests on each of the remaining nine tapes were run. (See data below.) The

Class 4 test option (Working True) was used so that the Standard Measurement Current

(Im) of the Proposed Master Standard Reference Tape (PMSR) would be used. That

is, tape G47 pass number 770 was used as the Master True (PMSR) file with

Im = 168.2 mA.

23
Tape Pass Median ft

B21 812 108.9

B21 813 108.8

B21 814 109.7

B21 815 Am 109.4

B21 816 Si 109.3

C29 806 119.9

C29 808 120.1

C29 809 Am 119.9

C29 810 It 120.0

C29 811 120.2

D34 796 114.2

D34 797 It 114.6

D34 799 113.9

D34 800 Am 114.8

D34 801 120.7

E35 779 111.3

E35 780 112.4

E35 781 It 111.8

E35 782 Am 111.7

E35 783 112.1

F43 817 Am 111.3

F43 818 112.6

F43 821 112.6

F43 822 111.4

F43 823 It 111.9

G47 770 112.1

H53 802 It 111.9

H53 803 Am 111.7

H53 804 111.7

H53 805 112.5

H53 806 112.4

Am

3.002

2.976

2.930

2.954

2.902

2.787

2.892

2.839

2.838

2.882

3.068

3.090

2.999

3.046

3.034

3.222

3.223

3.161

3.138

2.877

2.911

2.901

2.873

2.864

3.111 <— PMSR

3.167

3.147

3.138

3.167

3.129

24
158 774 It 112.8 2.920

158 775 113.2 2.933

158 776 111.7 2.900

158 777 111.8 2.794

158 778 Am 113.6 2.916

J64 786 110.8 2.745

J64 787 It&Am 110.9 2.711

J64 788 110.9 2.708

J64 789 111.1 2.701

J64 790 111.4 2.714

K67 791 111.8 3.163

K67 792 Am 112.6 3.139

K67 793 113.1 3.109

K67 794 113.0 3.131

K67 795 It 112.9 3.169

The saturation curves for the median Typical Current passes were plotted. Note that

the signal amplitude (Am) measurements were all made at the same Standard

Measurement Current (Im) and, therefore, may be compared with each other. All of

the curves looked smooth and satisfactory. In the data below, SRA is the Standard

Reference Amplitude, the Am value of the PMSR Tape. For ease of comparison, the

median data from the saturation curves above are shown in ascending order of Typical

Current:

Tape Pass It It/Ir Am Am/SRA

B21 816 109.3 0.97 2.902 0.93

J64 787 110.9 0.99 2.711 0.87

E35 781 111.8 1.00 3.161 1.02

H53 802 111.9 1.00 3.167 1.02

F43 823 111.9 1.00 2.864 0.92

G47 770 112.1 1.00 3.111 1.00 <— PMSR

158 774 112.8 1.01 2.920 0.94

K67 795 112.9 1.01 3.169 1.02

D34 797 114.6 1.02 3.090 0.99

C29 810 120.0 1.07 2.838 0.91

25
The signal amplitude data from the previous table is shown below in ascending order

of signal amplitude:

i ape Doer x ass 111/ OIV/A

T64 787 9 71 1 0 87

810 9Z, . 818 OJO 0 91

9 864 0 Q9

R9 1 816 O ID 9 Q09 0 Ql

Ijo / /4 Z.9ZU U.94

D34 797 3.090 0.99

G47 770 3.111 1.00 <

E35 781 3.161 1.02

H53 802 3.167 1.02

K67 795 3.169 1.02

PMSR

For signal amplitude, Tape G47 pass 770 ranks seventh overall and sixth if the Typical

Current outlier C29 is omitted. Its signal amplitude value is less than 1 percent

away from that of the median, D34.

Five overwrite and five resolution tests were run on the PMSR Tape (G47):

Pass Tone 11 Overwrite Ranking

825 .2473 2.913 .0849 4

826 .2444 2.889 .0846 3 <

827 .2453 2.870 .0855 5

828 .2447 2.944 .0831 1 829 .2402 2.874 .0835 2

Pass 1.5f if Resolution Ranking

830 .7191 2.875 .2501 3 <

831 .7149 2.907 .2459 1 832 .7082 2.878 .2460 2

833 .7383 2.898 .2547 5

834 .7236 2.860 .2529 4

— Median

Median

26
The data from passes 826 and 830 were combined (using an editor) to artificially create

the file 835 to use as the PMSR file for overwrite and resolution:

PMSR Header:

g0470835.f3o filename

g0470835.f3o mtfilename

g0470770.f3s satfilename

122890 monthdayyear

dsg operator

006 headnumber

168.2 Imformastertrue

112.1 It_for_test_tape

0.000 Ir_for_master_true

1.000 It_to_Ir

0.084 overwrite_for_test_tape

0.084 overwriteformastertrue

1.000 overwrite_test_to_master

0.250 resol_for_test_tape

0.250 resolformastertrue

1.000 resol_test_to_master

0.244 tone_mV_overwrite

2.889 lf_mV_overwrite

2.875 lf_mV_resolution

0.719 l_5f_mV_resolution

Three overwrite tests were run on the previously selected tapes from each company

(B21, C29, etc.):

Tape Pass Tone If Overwrite Ranking

B21 836 .2539 2.698 .0941 2

B21 837 .2557 2.694 .0949 3

B21 838 .2523 2.700 .0934 1

C29 874 .1883 2.618 .0719 1 C29 875 .1916 2.594 .0738 3

C29 876 .1915 2.614 .0733 2

D34 880 .2360 2.821 .0836 2

D34 881 .2390 2.831 .0844 3

D34 882 .2326 2.807 .0829 1

E35 867 .2559 2.915 .0878 1 E35 868 .2597 2.901 .0895 3

E35 869 .2575 2.901 .0887 2

27
F43 886 .2429 2.681 .0906 1 F43 887 .2425 2.637 .0919 3

F43 888 .2424 2.653 .0913 2 <-

f547 896 OZU 9444 9 880 0846 rlYlolv

H53 861 .2216 2.731 .0811 1 H53 862 .2258 2.760 .0818 2 <-

W53 njj 9Z . 710 / IV/ . 0897 uoz / j

158 842 .2226 2.757 .0807 3

158 843 .2157 2.742 .0786 1 844 . 9141 Z It 1 9 603 070

S

9Z <r\ —

J64 855 .2429 2.569 .0945 2 <-

J64 856 .2396 2.535 .0945 3

J vr+ 8^7 . 9^60 zjyjy 9z. JZ7 S90 00^7 i

IVD / Q/l Q 845 .ZJ /y z.o44 .UoJ / z < —

K67 850 .2414 2.916 .0827 1 K67 851 .2425 2.873 .0844 3

The median overwrite measurements for each tape are shown below. For ease of

comparison, the median data for the above overwrite tests are shown in ascending order

of overwrite value:

Tape Pass Overwrite Re

C29 876 .0733 1 158 844 .0795 2

H53 862 .0818 3

D34 880 .0836 4

K67 848 .0837 5 G47 826 .0846 6

E35 869 .0887 7

F43 888 .0913 8

B21 836 .0941 9

J64 855 .0945 10

PMSR

Tape G47 pass 835 ranks sixth overall and fifth (median) if the Typical current outlier

C29 is omitted.

28
Three resolution tests were run on the previously selected tapes from each company

(B21, C29, etc.).

Tape Pass 1.5f if Resolution Ranking

R7 1 CIO • 04U0 7 71A Z. MO 71/10 7Z < —

B21 840 .6288 2.711 .2319 1 B21 841 .6542 2.773 .2359 3

P7Q 877 oil 77QA 9Z.OIZ A19 .z77Q1 /yj 7Z ^<> —

C29 878 .7256 2.577 .2815 3

C29 879 .7195 2.604 .2763 1

rn4 71 on 9Z. 7A7 10 I 7^Q8 J

D34 884 .6857 2.727 .2514 1 D34 885 .6946 2.734 .2540 2 <-

C70 . /jjD .Z4oO i1 E35 871 .7512 2.912 .2579 3

E35 872 .7284 2.853 .2553 2 <-

F43 889 .6818 2.672 .2551 3

F41 son oy\J .ODOi 9 617 7z <rv. —

F41 90) 1 6S41 9 616 . 9481 Z*+ o I1

G47 830 .7191 2.875 .2501 PMSR

njj out 71 1 ^ 9z. 770 / /u 7S68 i H53 865 .7187 2.745 .2618 2 <-- H53 866 .7278 2.759 .2638 3

TS8 84S 9Z. 714 / l*f ,ZO 961108 ii 158 846 .7371 2.698 .2731 3

158 847 .7133 2.622 .2720 2 <--

T64 8S8 617Q 9Z.4ZZ 499 961 1 . ZO

1

J

Jt»4 OCA oj9 .59 10 z.3oz .zjUo Z < —

J64 860 .6067 2.424 .2502 1

K67 852 .7250 2.869 .2526 1 K67 853 .7627 2.890 .2639 2 <-

K67 854 .7629 2.836 .2690 3

29
The median resolution measurements for each tape are shown below. For ease of

comparison, the data are shown in ascending order of resolution value:

Tape Pass

839

830

859

890

885

872

865

853

847

877

Resolution Rank

B21

G47

J64

F43

D34

E35

H53

K67

158

C29

.2340

.2501

.2508

.2539

.2540

.2553

.2618

.2639

.2720

.2793

12

3

4

5

6

7

8

9

10

PMSR

Tape G47 pass 835 ranks second overall. While it would be possible to use a different

tape, this is only 1.56 percent less than that for the median value of D34.

Conclusions for PMSR:

Tape G47 pass 770 is the clear choice for Typical Current and Signal Amplitude.

Tape G47 pass 835 is the clear choice for Overwrite.

Tape G47 pass 835 is within the accuracy of the system from the median value of D34

for Resolution. While a separate tape could be used for this parameter, we propose

that G47 pass 835 be used for all parameters.

Figure 12 shows the rankings of the centerline candidate tapes. On August 13, 1991,

TC X3B5, (Digital Magnetic Tape), approved the proposed Master Standard Reference

In addition, on November 1, 1991, ISO/IEC JTC 1 SC 11, (Flexible Magnetic Media

for Digital Data Interchange) also approved this Master Standard Reference (see SC11

Resolution 4/91).

30
33335333333

§ | I |

6 d d e

31
5. Procedure for the Use of a SRM 3202 Tape

The Standard Reference Material (SRM) 3202 Tapes are to be used for calibrating

tertiary tapes for daily use. The following procedure shall be followed when using an SRM 3202 tape.

5.1 Testing and Storage Environment.

An SRM 3202 shall be used and stored within the environment specified for testing

and storage in the media standards.

5.2 Environmental Conditioning of the Media.

An SRM 3202 shall be acclimated to the testing environment for a period of at least

24 hours prior to testing.

5.3 Stabilization of the Test System.

The test system shall be allowed a minimum of 1 hour for the system components to

stabilize. Furthermore, the test system shall remain on until all testing operations are complete.

5.4 Procedure for the Calibration of the Test System.

a) To minimize the use of the SRM tape, and the risk of damage to it, test the

system for correct operation using a tape other than the SRM tape.

b) The SRM tape shall be ac bulk erased prior to use.

c) Load the SRM tape and make one complete forward and one complete reverse pass at the read or write operating tape drive speed to retension the tape.

Note: An SRM 3202 tape should never be wound at a speed significantly greater

than that for reading or writing. Greater speeds may not evenly tension the

tape.

d) Make a forward write pass with the SRM 3202 tape.

e) Rewind the tape at the same tape drive speed used for reading or writing.

f) Make a complete forward read pass.

g) Plot the saturation curve; that is, the curve of average signal amplitude versus

write current.

32
Note: Writing and reading shall only be done over the calibrated portion of the

SRM tape, which is 46 m (150 ft) from the beginning of tape (BOT) to

91 in (300 ft) from BOT. In addition, partial passes shall never be made on

an SRM tape.

h) Rewind the SRM 3202 tape at the same tape drive speed used for reading or

writing.

i) Determine the maximum average signal amplitude from the saturation curve.

j) Determine II, the minimum write current required to give an average signal

amplitude equal to 85 percent (as specified in the Standards ANSI X3.180 - 1990, ISO/IEC 9661:1988, and ECMA 120 - 1987) of the maximum average

signal amplitude. II is the current required to produce on the user's test system

the typical field for the particular SRM tape (see Fig 13).

k) Multiply II by the current calibration factor (Cc), provided with the SRM tape,

to obtain 12.

Note: Cc is the ratio of the write current required on the NIST system to produce

the reference field to the write current required on the NIST system to

produce the SRM tape's typical field.

Note: 12 is the write current required to produce the reference field on the user's

test system. The reference field is the typical field of the Master Standard

Reference Tape.

1) Multiply 12 by 1.5 to obtain 13, the measurement current for the user's test system.

m) Determine the average signal amplitude Al produced by the SRM 3202 tape at the write current 13.

n) Multiply Al by the amplitude correction factor (Ca), provided with the SRM

3202 tape, to obtain A2.

Note: Ca is the ratio of the standard reference amplitude of the Master Standard

Tape to the average signal amplitude of the SRM tape at the Standard

Measurement Current on the NIST system. A2 is the Standard Reference

Amplitude (SRA) on the user's test system.

o) The test system may now be used for the overwrite, and resolution using write

current 13 and the relationships printed in the right hand column of the box at the top of the SRM 3202 tape's saturation curve chart.

33
Overwrite is calibrated as follows:

I. Run the SRM tape to obtain Ol, the overwrite value produced by the SRM

tape on the test system.

II. Obtain the value for 02, the overwrite value that the Master Standard

Reference Tape would produce if run on the test system.

01

02 = OA

where OA is the SRM 3202 tape's overwrite value relative to the Master

Standard as shown in the right hand column of the box at the top of the

SRM 3202 tape's saturation curve chart. Repeat this procedure to calibrate

resolution.

5.5 Procedure for Calibrating a Tertiary Tape

a) Some types of tapes give a significant rise in the output signal amplitude with

usage. To stabilize the tertiary tapes, a minimum of 80 passes shall be made to minimize this effect.

Note: A pass is defined as beginning of tape (BOT) to the end of tape (EOT), or from EOT to BOT.

b) AC bulk erase and load the tertiary tape. Make one forward and one reverse pass at read or write operating tape drive speed to retension the tape.

c) Make a complete forward write pass with the tertiary tape.

Note: Writing and reading shall only be done over the same portion of the

tertiary tape as the calibrated portion of the SRM tape, which is 46 m

(150 ft) from the beginning of tape (BOT) to 91 m (300 ft) from BOT.

d) Rewind the tertiary tape at the same tape drive velocity used for reading or

writing.

e) Make a complete forward read pass with the tertiary tape.

f) Rewind the tertiary tape at the same tape drive velocity used for reading or

writing.

g) Determine the maximum average signal amplitude of the tertiary tape.

34
h) Determine the tertiary tape's typical field Itl, the minimum write current

required to give an average signal amplitude equal to 85 percent of the

maximum average signal amplitude.

i) Determine Atl, the average signal amplitude of the tertiary tape at the write

current 13.

j) The relationship of the tertiary tape's average signal amplitude to the Master

Standard Reference Tape shall be calculated from the ratio of Atl to A2

k) The overwrite and resolution relationships may now be measured for the tertiary

tape using the write current 13.

Note: It may be desirable to re-run the SRM tape at the conclusion of the above

operations to verify the stability of the test system. However, the SRM

tape should not be run more than necessary.

35
36
6. Definitions

If pattern - A repeated all ones pattern. The If pattern is recorded at a density of 972

ftpmm (24689 ftpi).

1.5f pattern - A repeated all ones pattern. The 1.5f pattern is recorded at a density of

972 ftpmm * 1.5 (24689 ftpi * 1.5).

average signal amplitude - The average peak-to-peak value of the signal output

measured over a minimum of 25.4 mm (1.0 in), exclusive of dropouts.

ftpi - flux transitions per inch.

ftpmm - flux transitions per millimeter.

Master Standard Reference Tape - A tape selected as the standard reference field, signal

amplitude, resolution, and overwrite ratio.

overwrite - The ratio of the average signal amplitude of the residual of the tone pattern

recorded at the Standard Measurement Current, after being overwritten by the If

pattern recorded at the Standard Measurement Current.

physical recording density - The number of recorded flux transitions per unit length of

track, e.g., flux transitions per millimeter (ftpmm) or flux transitions per inch (ftpi).

Reference Field - The typical field of the Master Standard Reference Tape.

resolution - The ratio of the average signal amplitude at the 1.5f physical recording

density, recorded at the Standard Measurement Current to the average signal amplitude

at the If physical recording density, recorded at the Standard Measurement Current.

Secondary Reference Tape - A tape, the performance of which is known and stated in

relation to that of the Master Standard Reference Tape.

Standard Measurement Current (Im) - A current whose value is 1.5 times the Standard

Reference Current (Im = 1.5 * It).

Standard Reference Amplitude (SRA) - The average signal amplitude from the Master

Standard Reference Tape when it is recorded with the Standard Measurement Current on the NIST Measurement System at If (972 ftpmm (24689 ftpi)). Traceability to the

Standard Reference Amplitude is provided by the calibration factors supplied with each

Secondary Standard Reference Tape.

37
Standard Reference Current (Ir) - The current that produces the Reference field.

tone pattern - The repeated 6-bit pattern 100000. The frequency of the tone pattern is one-sixth the frequency of the If signal.

typical current (It) - The write current which will produce the typical field.

typical field - The minimum recording field which, when applied to a magnetic tape,

will cause an average signal amplitude equal to 85 percent of the maximum average

signal amplitude at the If recording density.

working tapes - a tape whose signal amplitude characteristics is calibrated against the

Master Standard Reference Tape.

38
7. References

1) ANSI X3. 180-1990. " American National Standard for Information Systems.

Magnetic Tape and Cartridge for Information Interchange. 18-Track. Parallel.

1/2 inch (12.65 mm). 37871 cpi (1491 cpmm). Group-Coded-Requirements for

Recording ." American National Standards Institute, 11 West 42nd Street,

New York, NY 10036.

2) ECMA-120, 2nd edition, December 1987, " Data Interchange on 12.7 mm 18-

Track Magnetic Tape Cartridges. " European Computer Manufacturers

Association, 114 Rue du Rhone, 1204 Geneva (Switzerland).

3) ISO/IEC 9661:1988. " Information Processing. Data Interchange on 12.7 mm

(0.5 in) Wide Magnetic Tape Cartridges. 18 Tracks. 1 491 Data Bytes per

Millimetre (37 871 Data Bytes per inch) . " International Organization for

Standardization/International Electrotechnical Commission.

4) Podio, Fernando, " A New Computer-Based Self-Correcting Calibration System

for Computer Storage Media Standard Reference Materials. " Computers and

Standards: The International Journal, Vol. 4, No. 4, 1985.

5) Williamson, Mark, P.,

" The 3480 Type Tape Cartridge: Potential Data Storage

Risks, and Care and Handling Procedures to Minimize Risks. " NIST Special

Publication 500-199, November 1991.

6) Williamson, Mark, P., Willman, Natalie, E., and Grubb, Dana, S.,

" Calibration of NIST Standard Reference Material 3201 for 0.5 inch (12.65

mm) Serial Serpentine Magnetic Tape Cartridge. " NIST Special

Publication 260-115, February 1991.

NIST Measurement System Software, The software written for the SRM measurement

system is public domain. Source code is available on floppy disks to interested parties.

Please call or write to: National Institute of Standards and Technology, Data Storage

Group, Building 225, Room A61, Gaithersburg, MD 20899, Attn: Magnetic Tape

SRMs, (301) 975 -2908.

39
NIST-1 14A U.S. DEPARTMENT OF COMMERCE

(REV. 3-90) NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY

BIBLIOGRAPHIC DATA SHEET

1 . PUBUCATION OR REPORT NUMBER

NIST/SP-260/118

2. PERFORMING ORGANIZATION REPORT NUMBER

3. PUBLICATION DATE July 1992

4. TITLE AND SUBTITLE Calibration of NIST Standard Reference Material 3202 for

18-Track, Parallel, and 36-Track, Parallel Serpentine,

12.65 mm CO. 5 in). 1491 cnmrn (37871 cpi) , Magnetic Tape Cartridge

5. AUTHOR(S)

Mark P. Williamson

6. PERFORMING ORGANIZATION (IF JOINT OR OTHER THAN NIST, SEE INSTRUCTIONS)

U.S. DEPARTMENT OF COMMERCE ,„.., N NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY (NCbL ) GAITHERSBURG, MD 20899 Advanced Systems Division

7. CONTRACT/GRANT NUMBER

8. TYPE OF REPORT AND PERIOD COVERED

Final

9. SPONSORING ORGANIZATION NAME AND COMPLETE ADDRESS (STREET, CITY, STATE, ZIP) Computer and Business Equipment Manufactures

Association (CBEMA)

311 First Street, N.W.

Washington, DC 20001-2178

10. SUPPLEMENTARY NOTES

11. ABSTRACT (A 200-WORD OR LESS FACTUAL SUMMARY OF MOST SIGNIFICANT INFORMATION. IF DOCUMENT INCLUDES A SIGNIFICANT BIBUOGRAPHY OR

LITERATURE SURVEY, MENTION IT HERE.)

This publication describes the test system design and operation for the calibration of the

NIST Standard Reference Material (SRM) 3202 Secondary Standard Reference Tape for

18-track, parallel, and 36-track, parallel serpentine, 12.65 (0.5 in) , 1491 cpmm

(37871 cpi) magnetic tape cartridge. The standard reference material for this magnetic

tape cartridge will promote data interchange among computer installations. Reliable

interchange requires that the media be designed and manufactured on the basis of a comparison to a known and accepted standard reference medium.

12. KEY WORDS (6 TO 12 ENTRIES; ALPHABETICAL ORDER; CAPITALIZE ONLY PROPER NAMES; AND SEPARATE KEY WORDS BY SEMICOLONS)

average signal amplitude; master standard reference tape; overwrite; resolution;

secondary standard reference tape; standard reference current; standard reference

material; standard signal amplitude

13. AVAILABILITY UNLIMITED FOR OFFICIAL DISTRIBUTION. DO NOT RELEASE TO NATIONAL TECHNICAL INFORMATION SERVICE (NTIS).

X

XX

ORDER FROM SUPERINTENDENT OF DOCUMENTS, U.S. GOVERNMENT PRINTING OFFICE, WASHINGTON, DC 20402. ORDER FROM NATIONAL TECHNICAL INFORMATION SERVICE (NTIS), SPRINGFIELD, VA 22161.

14. NUMBER OF PRINTED PAGES

52

15. PRICE

ELECTRONIC FORM * U.S. G.P.0. : 1992-31 1-891 ;60033
NISTTechnical Publications

Periodical

Journal of Research of the National Institute of Standards and Technology -Reports NIST

research and development in those disciplines of the physical and engineering sciences in which the Institute is active. These include physics, chemistry, engineering, mathematics, and

computer sciences. Papers cover a broad range of subjects, with major emphasis on measurement methodology and the basic technology underlying standardization. Also included

from time to time are survey articles on topics closely related to the Institute's technical and

scientific programs. Issued six times a year.

Nonperiodicals

Monographs -Major contributions to the technical literature on various subjects related to the

Institute's scientific and technical activities. Handbooks -Recommended codes of engineering and industrial practice (including safety

codes) developed in cooperation with interested industries, professional organizations, and

regulatory bodies.

Special Publications — Include proceedings of conferences sponsored by NIST, NIST annual

reports, and other special publications appropriate to this grouping such as wall charts, pocket

cards, and bibliographies.

Applied Mathematics Series -Mathematical tables, manuals, and studies of special interest to physicists, engineers, chemists, biologists, mathematicians, computer programmers, and others

engaged in scientific and technical work.

National Standard Reference Data Series -Provides quantitative data on the physical and

chemical properties of materials, compiled from the world's literature and critically evaluated.

Developed under a worldwide program coordinated by NIST under the authority of the National

Standard Data Act (Public Law 90-396). NOTE: The Journal of Physical and Chemical

Reference Data (JPCRD) is published bi-monthly for NIST by the American Chemical Society

(ACS) and the American Institute of Physics (AIP). Subscriptions, reprints, and supplements are

available from ACS, 1155 Sixteenth St., NW., Washington, DC 20056.

Building Science Series— Disseminates technical information developed at the Institute on

building materials, components, systems, and whole structures. The series presents research

results, test methods, and performance criteria related to the structural and environmental

functions and the durability and safety characteristics of building elements and systems.

Technical Notes -Studies or reports which are complete in themselves but restrictive in their treatment of a subject. Analogous to monographs but not so comprehensive in scope or

definitive in treatment of the subject area. Often serve as a vehicle for final reports of work

performed at NIST under the sponsorship of other government agencies.

Voluntary Product Standards -Developed under procedures published by the Department of Commerce in Part 10, Title 15, of the Code of Federal Regulations. The standards establish

nationally recognized requirements for products, and provide all concerned interests with a

basis for common understanding of the characteristics of the products. NIST administers this program as a supplement to the activities of the private sector standardizing organizations.

Consumer Information Series— Practical information, based on NIST research and experience,

covering areas of interest to the consumer. Easily understandable language and illustrations provide useful background knowledge for shopping in today's technological marketplace.

Order the above NIST publications from: Superintendent of Documents, Government Printing

Office, Washington, DC 20402.

Order the following NIST publications -FIPS and NISTIRs-from the National Technical

Information Service, Springfield, VA 22161.

Federal Information Processing Standards Publications (FIPS PUB) -Publications in this series collectively constitute the Federal Information Processing Standards Register. The

Register serves as the official source of information in the Federal Government regarding

standards issued by NIST pursuant to the Federal Property and Administrative Services Act of 1949 as amended, Public Law 89-306 (79 Stat. 1127), and as implemented by Executive Order

11717 (38 FR 12315, dated May 11, 1973) and Part 6 of Title 15 CFR (Code of Federal

Regulations).

NIST interagency Reports (NISTIR)-A special series of interim or final reports on work

performed by NIST for outside sponsors (both government and non-government). In general,

initial distribution is handled by the sponsor; public distribution is by the National Technical

Information Service, Springfield, VA 22161, in paper copy or microfiche form.
oo

c

0) ^

H c

d) m