Talk:History of IBM magnetic disk drives

message: It was my (admittedly undocumented) impression that the Winchester Disk was named not for the Winchester Rifle, but for the location of the IBM office on Winchester Blvd in San Jose.  Perhaps this is an urban legend but I recall hearing it many years ago.  Jim Bowery 23:35, 19 September 2006 (UTC)
replies: text: Added IBM source to article.  30-30 must be a Winchester [rifle] tooold (talk) 06:35, 21 January 2009 (UTC)
replies: text: The folklore I've heard is that the technology was named Winchester after the rifle, because the team was working on dual 30 MB drives (30+30 MB), hence the "30-30" connection with the rifle. — Loadmaster (talk) 01:09, 22 March 2013 (UTC)
replies: text:  Ken Haughton code named it Winchester for the rifle because the program was initially two thirty MB spindles in a box, called "30 - 30" by some. See his oral history, p.9.  Tom94022 (talk) 05:32, 22 March 2013 (UTC)

text: The source of the urban legend about the boulevard is not known, but it is clear from Haughton that the name came from the rifle.  Given the bredth of the urban legend it might be worth an in-line note in the article debunking it.  Tom94022 (talk) 18:37, 3 March 2016 (UTC)
thread_title: Winchester Blvd

message: Drive sizes are listed as "decimal digits" and "characters".  What are they in bytes or bits or octets? - Omegatron 15:41, May 13, 2005 (UTC)
And make sure to remember the difference between megabytes and mebibytes.
:decimal digits were either 4 or 5 bits plus 1 parity bit; characters were either 6 (BCDIC) or 8 (EBCDIC) bits plus 1 parity bit. -- 205.175.225.5 00:23, 18 March 2006 (UTC)
thread_title: Sizes

message: I used to work with these things and I'm fairly sure they had six platters not five. However the top surface of the top platter and the bottom surface of the bottom platter were not used so there were ten surfaces coated with the magnetic material, giving ten tracks per cylinder. The reason the outside surfaces were not used is that they were liable to be touched when the disk was removed from its drive. In fact operators would place their hands on the top surface to slow them down. This led at least one manufacturer to coat the top with abrasive.
Here is a photograph of the disk which shows six platters. If anything this one is even clearer. Is this enough proof to merit editing the article?
--R Cornwell 13:20, 4 May 2006 (UTC)
replies: text: I fixed it under 2311. The section on the 1311 had it right. --agr 19:11, 4 May 2006 (UTC)
thread_title: Number of platters

message: IBM 3380 redirects here, but this article doesn't say anything about it.  A netnews article I read suggests that there are still some in operation.  121a0012 19:06, 5 May 2006 (UTC)
replies: text: Thanks, I've added some info.--agr 00:07, 11 May 2006 (UTC)
thread_title:  3380 

message: I'm not sure what is meant by "the punch card tub file used by most businesses of the time."  Please elaborate.--agr 03:24, 20 September 2006 (UTC)
thread_title: Tub file?

message: The shop where I got my first operators job had a string of 4 2311s and here is what I remember about them.
One of the previous posts mentioned operators slowing them down with their hands. There were really 2 parts to a 2311, and all the disks until Winchester. There was the drive that contained the electronics, drive motors, and heads. There was also the disk pack. Storage was so expensive, thousands of dollars for one 7MB drive, that nobody thought of having all their data online and it was not necessary since everything was batch jobs. So, you would have a pack for your payroll files, one for the GL, etc. When you ran a job you would have to mount the packs that contained the data. 
Push the stop button and the drive would spin down but this took forever and who has the time? When you opened the lid there was something that engaged to prevent the disk from turning. If you just opened the top on a spinning disk this would take some damage so that was out. If you just opened the top a little you could reach up under it and get your fingers on the top platter and slow it down. I don't think lawyers to sue had been invented yet.
Once it sopped you opened the top and took the top of the case, a clear plastic tub with a handle on the top, put it over the disk. Spinning the top would attach it to the top of the disk and detach the disk from the drive. You lifted it up and stuck the bottom on to keep some of the crud out.
I don't see how any PC person can conceive of the size of one of these things. The pack was about 16 inches in diameter by about 6 inches high. In this massive area the drive could write 100 or 200 tracks (I think the 2311 had 100 and the 2314 had 200. the 2314 also doubled the number of platters) In fact when you were doing a backup of the drive you could tell how far you had gotten by going over to the drive and looking down through the glass top. The arm holding the heads came straight out from the side and on to of it was a scale with the tracks marked. You could literally look down and see what track you were up to.
Now, everybody knows that the heads are moved by that nice clean voice coil. Not the 2311s. They were hydraulic. Nice little pump, hoses, pistons, etc. In fact one of our 2311s had a small leak and when the CE came in to do preventative maintenance (There was so much mechanical stuff associated with a computer that every week the guy form IBM came and spend a few hours trying to fix things before they broke.) he would get a hand full of the little bits from the card punch and literally put them inside the disk drive to soak up the oil. —The preceding unsigned comment was added by P7willm (talk • contribs) 15:49, 22 March 2007 (UTC)
thread_title:  2311 rememberances 

message: This text "Another important IBM innovation was little noticed when it was introduced initially with the System 360, in the 2835 Storage Control for the 2305 Drums, to be attached to the high end processor models 2075 and 2095. Then it became more popular with introduction of the System/370 in 1971. IBM needed a way to load new microcode into the IBM Storage Control Units 2835 and 3830, and into the IBM System/370 Model 155 and developed the 23FD floppy disk 'read only' for this purpose."
needs help.  The first two "it"s are unknown references, other than "important IBM innovation". The text begins with the 2835, advances the time with "Then it became" to describe the System/370, then writes about both "2835... and 370 model 155" as if the two were at the same time. 
Suggest saying first what the innovation is, followed by implementations sequenced by time.tooold (talk) 05:33, 21 January 2009 (UTC)
replies: text: The subject is well covered in other articles, so I shortened the section to the bare minimum and linked to the most appropriate article/section.  Tom94022 (talk) 06:17, 21 January 2009 (UTC)
thread_title:  The floppy disk 

message: Please tell me in plain English for non-native people, what means the following saying in the introduction: a stellar improvement.  Does it mean 'great improvement' or 'fast improvement'? --Sibazyun (talk) 07:35, 13 September 2009 (UTC)
replies: text: It's gone, see if what i wrote makes more sense.  Tom94022 (talk) 22:26, 13 September 2009 (UTC)
replies: text: Thank you for the new saying. --Sibazyun (talk) 23:04, 14 September 2009 (UTC)
thread_title:  stellar? 

message: The page discusses all IBM magnetic disk drives and no Optical disk drives or other DASD devices.  As such the title is accurate and should not be changed to encompass all disk storage or all storage unless there is a commitment on the part of the editor to expand the article accordingly.  Actually it should not have been moved peremptorily in the first place, but now that it is accurately titled I hope there will be some discussion before any move.  Tom94022 (talk) 20:24, 29 July 2011 (UTC)
thread_title:  Moving this page again 

message: Many disk drives were either bundled with or attached to IBM systems and we have not identified them separately as such herein.  This is particularly true in the later years and on small systems.  The drive used on the S/360 M44 was a 2310 so for consistency it should not be listed separately just as we do not list separately the various system usages of the 667. 669, 681, etc.  Tom94022 (talk) 20:00, 8 March 2012 (UTC)
replies: text: But note that the integrated drive on the System/360 model 44 formatted the cartridge in a different way than did the IBM 2310.  The article includes the IBM 2302, which differed from the IBM 1302 only in formatting (according to the article).  It could be argued that the IBM 2302 is particularly notable because of its use on System/360, but I could also argue that the integrated drive on the System/360 model 44 is particularly notable because it represents IBM's first use of Fixed Block Architecture on System/360. John Sauter (talk) 13:29, 10 March 2012 (UTC)
replies: text: As noted above formatting is a function of the controller and the the drive; this is an article about drives.  If in fact the only difference between the 2302 and 1302 is the format then we should combine the sections.  Finally, if in fact the integrated drive on the System/360 model 44 is particularly notable because it represents IBM's first use of Fixed Block Architecture on System/360 then it probably belongs in the FBA article not hear. BTW didn't the 2311 on the 360/20 use FBA?  Tom94022 (talk) 22:31, 11 March 2012 (UTC)
replies: text: IMHO it's notable because it was the only occurrence of an integrated drive on a 360 system. Peter Flass (talk) 23:53, 11 March 2012 (UTC)
replies: text: I agree it is notable, and it is so noted in the DASD section of the S/360 article.  But it is still just a 2310 and therefore not suitable for listing as a separate section in this article. Tom94022 (talk) 00:41, 12 March 2012 (UTC)
thread_title:  S/360 M44 Disk Drive 

message: The IBM System/360 Model 20 Functional Characteristics manual is on bitsavers, and it reveals on page 62 that yes, the interface to the IBM 2311 did use a 270-byte fixed block architecture.  Furthermore, the model 20 preceded the model 44, so, if you consider the model 20 a “real” System/360 then it, not the model 44, is the first use of FBA on System/360. John Sauter (talk) 04:13, 12 March 2012 (UTC)
replies: text: Are u sure that every usage by IBM of a fixed block size corresponds to what IBM meant by the term "Fixed Block Architecture?"  I'm not.  The first disk drive, the RAMAC had a fixed block size.  I don't think the phrase "Fixed Block Architecture" appears in either the S/360 M20 or M44 manuals although their data block sizes were fixed (based upon Google site search of the Bitsavers S/360 site.  To the best of my recollection, the term was first introduced by IBM in the System/38 and AS400 36 (maybe S/34) as the only surviving relic of FS and it applied to all levels of memory.  Furthermore I seem to recall, without much research, that it was then ECKD that introduced fixed block sizes but not the term FBA into S/390 (maybe E9000).  This makes the FBA article quite wrong and IMO the usage of fixed block sizes on the S/360 M44 not notable, at least in this article.  Tom94022 (talk) 18:03, 12 March 2012 (UTC)
replies: text: I don't think the name that IBM marketing calls something is very relavent to this article, which focuses on the size, speed, internal organization and announcement date of the various disk drives.  IBM has a definition of “fixed block architecture” which fits any drive that offers only fixed-size blocks of storage through its interface.  This article doesn't seem to consider the disk drive's interface to be very important, so perhaps (by the standards of this article) it is not notable that the System/360 model 44 was the first System/360 that included a disk drive for which the count-key-data interface was not provided. John Sauter (talk) 02:12, 13 March 2012 (UTC)
replies: text: I think you are confusing access method, channel and controller functions with the drive interfaces.  For both the 2311 on the M20 and the 2310 on the M44 the drive interface was not natively fixed block but could support any format imposed by its controller including CKD as in fact the 2311 did on other systems.  I bet if you looked at the formatted disk you would find CHR track format with DL fixed and KL=0.  In other words, if you looked at a formatted track you could not tell whether it was written on a system with fixed blocks or not. So I agree by the standards of this article which is all about the drives that the 2310 on the M44 is not notable for the fixed block size imposed by the M44 controller. Tom94022 (talk) 07:10, 13 March 2012 (UTC)
replies: text: Your speculation about the model 20's version of the 2311 is close but not correct.  Bitsavers has an image of the field engineering manual at IBM 2311 FE Theory of Operation.  It describes in detail the differences between the IBM 2311 models 11 and 12 (used of the System/360 model 20) and the model 1 (used on System/360 models 30 and higher through the IBM 2841).  It turns out that the model 20 uses a special format which cannot be read by the IBM 2841. John Sauter (talk) 03:32, 14 March 2012 (UTC)
thread_title:  didn't the 2311 on the 360/20 use FBA? 

message: There is some disagreement and confusion on this, based on the edit history.
*06:47, 16 December 2011 – The 350 stored 5 million 6-bit characters ( megabytes).  (→IBM 350:  5*6/8=3.75.  The channel word was 8 bits but the data word was 6 bits - the industry uses data bits.)
*02:29, 16 December 2011 – The 350 stored 5 million 7-bit (6-bits plus 1 odd parity bit) characters ( megabytes). (→IBM 350:  you don't count the parity (ECC) bits when you quote "gigabytes" for modern HDs; you don't count the parity bits on the 350 either)
*17:23,  5 March    2007 – The 350 stored 5 million 7-bit (6-bits plus 1 odd parity bit) characters ( megabytes). (→IBM 350)
*08:01, 17 November 2006 – The 350 stored 5 million 7-bit characters ( megabytes).  (→IBM 350:   text merged from IBM RAMAC trademark)
*04:57, 16 March    2006 – The 350 stored 5 million characters ( 5 megabytes).  (→IBM 350:  minor edit)
*16:09, 27 July     2004 – The 350 stored 5 million characters. (create) 
First we need the definition of megabyte—from the article– ...one million bytes (106, see prefix mega-) generally for computer storage.
...and for byte—from the article– ... Historically, a byte was the number of bits used to encode a single character of text in a computer and for this reason it is the basic addressable element in many computer architectures. The size of the byte has historically been hardware dependent and no definitive standards existed that mandated the size... The term byte was coined by Dr. Werner Buchholz in July 1956.
So, from that we have... the term byte is never used in the 305 RAMAC Manual of Operation, as surely the system was designed before the term was even coined.  For our purposes, a character is a byte is a character.  We are dealing with 6-bit bytes, which means the machine only supports upper case characters.  Machines supporting lower case characters using 7-bit ASCII came along later. And now Wikipedia uses UTF-8 8-bit bytes.  Now, if anyone wants to precisely compare apples and oranges (1950s vs. modern HDDs), they should compare how many bits, or megabits, or gigabits they can store.
I say, the 350 stored exactly 5 * 106 bytes. That's what Five decades of disk drive industry firsts, DISK/TREND said too. – 5 megabytes – Wbm1058 (talk) 02:46, 19 October 2012 (UTC)
replies: text: The term byte today means 8 bits and has pretty much been so since 1964 or thereabouts.  The RAMAC had 3.75 megabytes in 5 million 6 bit characters is accurate and meaningful.  To say the RAMAC had 5 million bytes is to mis-inform the public.  Furthermore the RAMAC had an 8th bit which like the parity bit is irrelevant to the information content of the characters stored on the RAMAC.  My good friend, now deceased, Jim Porter agreed with this definition, not withstanding the error on the cited page.  Tom94022 (talk) 02:58, 19 October 2012 (UTC)
replies: text:  Agree with Tom94022. The claim of "5 million bytes" is flatly wrong. IBM marketed it as "five million characters", the characters being six bits each, as was common on many IBM machines of the day. That's not the same as five million bytes. Jeh (talk) 18:39, 19 October 2012 (UTC)

text: Historicaly, a byte was a string of bits that the CPU could access as a unit; it could cross word boundary and could have an arbitrary size. Ever since the advent of the IBM S/360, the unqualified term byte has frequently been used to refer to 8 bit bytes on an 8 bit boundary, especially when refering to stroage capacity. Multiplying the capacity of the 350 by 3/4 to get a size in 8-bit bytes is meaningful, if not particularly useful. Referring to the capacity as 5 million 6-bit bytes would be meaningful, but refering to it as 5 million bytes is simply misleading. Shmuel (Seymour J.) Metz Username:Chatul (talk) 18:39, 22 October 2012 (UTC)

text: The bytes/bits difference is always confusing, especially when people use MB and Mb.   Recently thinking about inflation adjusted prices,   $xxx (equivalent to $yyy in 2015), if we put  xxx million characaters (equivalent to yyy megabytes today).  People are more used to megabytes (Note that the 3330 seems to have been designed for 100 million bytes.)  To further the confusion, it seems that marketers of magnetic tape (consider LTO for example) believe that bytes have four bits. Note that bit (and so also byte) has meaning in terms of hardware (something that can have two states) and in information theory (where it means something with two equal probability states).  English text has about four bits of information (entropy) per character, and so compresses about 2:1.  We could make it explicit:  (... equivalent to xxx (8 bit) megabytes).  But is that 1,000,000 byte megabytes, or 1,048,576 byte megabytes?   Gah4 (talk) 19:05, 4 November 2016 (UTC)
thread_title:  How many megabytes the first disk drive ([[IBM 350]]) stored 

message: This issue was raised again by a series of five edits on November 1 that added megabyte equivalents to the descriptions of the 353, 355, 1405, 1301 and 1311.  I am inclined, having re-read the above discussion, to change the unit from megabytes to bits.  If there is objection to that, my second choice would be to remove the megabyte descriptions.  Any thoughts? John Sauter (talk) 13:30, 4 November 2016 (UTC)
replies: text: The bytes/bits difference is always confusing, especially when people use MB and Mb.   Recently thinking about inflation adjusted prices,   $xxx (equivalent to $yyy in 2015), if we put  xxx million characaters (equivalent to yyy megabytes today).  People are more used to megabytes (Note that the 3330 seems to have been designed for 100 million bytes.)  To further the confusion, it seems that marketers of magnetic tape (consider LTO for example) believe that bytes have four bits. Note that bit (and so also byte) has meaning in terms of hardware (something that can have two states) and in information theory (where it means something with two equal probability states).  English text has about four bits of information (entropy) per character, and so compresses about 2:1.  We could make it explicit:  (... equivalent to xxx (8 bit) megabytes).  But is that 1,000,000 byte megabytes, or 1,048,576 byte megabytes?   Gah4 (talk) 19:05, 4 November 2016 (UTC)
thread_title:  again 

message: IBM had both a 353 and a 7303 disk drive for the 7030; the article mentions only the 353. Does anybody have information on the differences between the 353 and the 7303?
Shmuel (Seymour J.) Metz Username:Chatul (talk) 15:08, 14 June 2013 (UTC)
replies: text: I'll look into it, but I wonder of the whole group of 350 variants (e.g. 355, 1405, etc.) should be listed separately or within the 350 section.  It may well be that they were just rebadged models with minor changes and not worthy of separate sections.  This is what we do later on when one OEM model appears in many systems with various model numbers and/or feature codes. The 353 had a head per surface which was different than the 350 and its ilk, I don't know about the 7303 but because it was on Stretch my guess is it is a variant on the 353 and possibly should be combined with it.  I would further guess that it was a double density 353.  Will research this Tom94022 (talk) 12:55, 15 June 2013 (UTC)

text: Still looking into this; however, FWIW, the specified capacity of the 7303 at 2,097,152 64 bit words works out to about 26 MB on a 50 disk machine (the 7303 purports to use on 32 disks for data leaving the others to other purposes, 2.1*8*50/32=26.5) which suggests the 7303 is an enhanced version of a double capacity IBM 350 (only 10 million characters).  This suggests the 353 was based in the single capacity 350.  Given the 7030 shipped in 1961 it is likely the 353 never shipped but it may have been announced.  Tom94022 (talk) 19:46, 15 January 2015 (UTC)

text: Another clue - the IBM September 1960 fact sheet gave the disk capacity as "more than 1,250,000 alphabetic characters." perhaps referring to the 353.  Tom94022 (talk) 20:51, 15 January 2015 (UTC)
thread_title:  Disk drives on IBM 7030 (Stretch) - 353 versus 7303? 

message: User:Tom94022 recently removed some material from the section on the IBM 2311, and that raises the question of the appropriate level of detail. In particular, should the paragraph describe the differences among the 2311-1, 2311-11 and 2311-12 and how much should it say about those differences? Shmuel (Seymour J.) Metz Username:Chatul (talk) 16:42, 6 February 2014 (UTC)
replies: text: Sounds like it should be a table.  The guidelines have nothing that fits -  it's not "overly detailed."  A comparison of how speeds and capacities have changed over the years sounds like valuable information to me.  As I recall this article has some fairly zealous editors who work to keep it on topic, but in this case I think the mateial belongs here in some fashion or other, Peter Flass (talk) 17:31, 6 February 2014 (UTC)
thread_title:  Level of detail? 

message: The purchase price stated for the RAMAC in IBM's first HDD versus its last HDDs is actually that of the later (~1959) double density 350 Model 3 (7.5 MB) rather than that of the original Model 1 (3.75 MB).  This is the price of the Model 3 in Montgomery Phister, Jr's "Data Processing Technology and Economics." It is possible that there never was a separate purchase price for the 350 Model 1 since it was originally bundled into the 305 System at a time when IBM was not necessarily selling products but only renting them.  However, we do have a reliable source, in Emerson Pugh’s book “Building IBM” that the rental price of the 350 Model 1 was $650/month (out of a 305 rental price of $3,200/month).  We also have from Phister that the Price:Rent ratio for the 350 Model 3 was 53 months which implies a 350 Model 1 purchase price of $31,800 $34,450. The 1956 consent decree required IBM to sell its products in addition to renting them and my recollection is that they were rigorous in establishing Rental Equivalent Selling Prices.  A 53:1 ratio is consistent with IBM's practices into the 1970s.   Therefore I believe such a calculation is a mathematical process and not original research but I can see when some might disagree.
If anyone has any reliable source for the Model 1 purchase price that would solve this problem; otherwise, it appears we have several choices:
#Go with the Model 3 purchase price, reflecting its capacity and live with the inapposite tabulation
#Use the estimated Model 1 purchase price, reflecting the calculation in a footnote
#Change the table to the Model 3 throughout
Comments and suggestions would be appreciated.  Tom94022 (talk) 18:25, 24 August 2014 (UTC)
replies: text: I would go with the $34,500 price since it is sourced and is close enough to Tom's estimate. I'd also add "($ in current dollars)."  --agr (talk) 10:04, 25 August 2014 (UTC)
replies: text: Sorry for the math error, but we got there anyhow.  Tom94022 (talk) 19:19, 25 August 2014 (UTC)
thread_title:  RAMAC Purchase Price 

message: https://en.wikipedia.org/wiki/Microdrive  — Preceding unsigned comment added by 70.36.223.208 (talk) 01:48, 2 March 2016 (UTC)
thread_title:  IBM Micro Drive should be included in final comparison? 

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thread_title:  External links modified 

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thread_title:  External links modified 

message: On mobile, so i cant (or dont want) to calculate myself, but the "mb/mm cubed" calc is clearly off. Most likely it should be "mb/cm cubed", but possibly  it's simply crap. Please recalc, and post w correct unit. Thx. קיפודנחש (aka kipod) (talk) 20:34, 27 January 2018 (UTC)
replies: text: Where is this calc - I don't find it in either the article or the talk page? Tom94022 (talk) 20:57, 27 January 2018 (UTC)
replies: text: The table near the bottom has gigabyte/in**3 and megabytes/mm**3.  I didn't check so carefully, but it looks like some might be wrong.  Gah4 (talk) 13:25, 28 January 2018 (UTC)

text: It looks like the line MB/mm3 is off by a factor of 1000 which would make it MB/cm3.  I'll check the math and correct the label.Tom94022 (talk) 02:23, 29 January 2018 (UTC)
replies: text: done Tom94022 (talk) 21:10, 13 March 2018 (UTC)
thread_title:  Density calc seems off 

message: While is easy to propose a change in the title of this article, the current LEDE is totally inappropriate for such a retitled article.  As noted above the editor proposing this change "need[s] to carefully define what is meant by the direct-access storage devices (DASDs) ..." which should include as a minimum a new LEDE consistent with the new title and any new content supporting the lede.  Tom94022 (talk) 18:40, 4 May 2021 (UTC)
thread_title: Need to revise LEDE