Magnetic disk storage is a critical component of the computer revolution. IBM was a pioneer in this area. This article surveys the major IBM computer disk drives introduced in the 1950s, 1960s and early 1970s. Disk storage is a group of data storage mechanisms for computers; data are transferred to planar surfaces or disks for temporary or permanent storage. ... A Lego RCX Computer is an example of an embedded computer used to control mechanical devices. ... now. ... The 1950s was the decade spanning the years 1950 to 1959. ... The 1960s decade refers to the years from January 1, 1960 to December 31, 1969, inclusive. ... The 1970s decade refers to the years from 1970 to 1979, inclusive. ...

The basic mechanical arrangement of hard disk drives hasn't changed since the IBM 1301. Disk drive performance characteristics are specified the same way today as they were in the 1950s. A modern (2004) PC hard drive is included for comparison. The reader may wish to calculate the ratio of cost-per-megabyte between the IBM 1301 and the 2004 PC hard drive. Few products in history have enjoyed such a meteoric decline in cost and size with such a stellar improvement in capacity. 2004 (MMIV) was a leap year starting on Thursday of the Gregorian calendar. ... One of the first PCs from IBM - the IBM PC model 5150. ... Typical hard drives of the mid-1990s. ...

IBM 350

IBM 305 at U. S. Army Red River Arsenal

IBM 350 RAMAC restored at the Computer History Museum

The IBM 350 was part of the IBM RAMAC 305, the computer that introduced disk storage technology to the world on September 4, 1956. RAMAC stood for "Random Access Method of Accounting and Control." Its design was motivated by the need to replace the punch card tub file used by most businesses of the time. The 350 stored 5 million 7-bit characters (about 4.4 megabytes). It had fifty 24-inch diameter disks with 100 recording surfaces. Each surface had 100 tracks. The disks spun at 1200 RPM. Data transfer rate was 8,800 characters per second. Two independent access arms moved up and down to select a disk and in and out to select a recording track, all under servo control. A third arm was added as an option. Several improved models were added in the 1950s. The IBM RAMAC 305 system with 350 disk storage leased for $3,200 per month. The 350 was officially withdrawn in 1969. Image File history File links BRL61-IBM_305_RAMAC.jpeg IBM 305 RAMAC, Photo by U. S. Army Red River Arsenal File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... Image File history File links BRL61-IBM_305_RAMAC.jpeg IBM 305 RAMAC, Photo by U. S. Army Red River Arsenal File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... Image File history File linksMetadata Ramac. ... Image File history File linksMetadata Ramac. ... IBM 305 at U. S. Army Red River Arsenal The IBM RAMAC 305 was the first commercial computer that used magnetic disk storage. ... September 4 is the 247th day of the year (248th in leap years). ... 1956 (MCMLVI) was a leap year starting on Sunday of the Gregorian calendar. ... Punched cards (or Hollerith cards, or IBM cards), are pieces of stiff paper that contain digital information represented by the presence or absence of holes in predefined positions. ... The term servo can refer to: Servomechanism - usually just shortened to servo, is a device used to effect mechanical motion for a specified distance. ... The 1950s was the decade spanning the years 1950 to 1959. ...

The 350's cabinet was 60 inches (approx. 1.52 meters) long, 68 inches (approx. 1.72 meters) high and 29 inches (approx. 74 centimeters) deep. IBM had a strict rule that all its products must pass through a standard 29.5 inch (approx. 75 centimeters) doorway. Since the 350's platters were mounted horizontally, this rule presumably dictated the maximum diameter of the disks.

In an interview^[1] published in the Wall Street Journal with Currie Munce, research vice president for Hitachi Global Storage Technologies, which acquired the IBM's storage business, said the entire RAMAC unit weighed over a ton and had to be move around with forklifts and delivered via large cargo airplanes. According to Munce, while the storage capacity of the drive could have been increased above five megabytes, the marketing department at IBM was against a larger capacity drive because they didn't know how to sell a product with more storage. The Wall Street Journal is an influential international daily newspaper published in New York City, New York with an average daily circulation of 1,800,607 (2002). ... Hitachi Global Storage Technologies is a wholly-owned subsidiary of Hitachi, Ltd. ...

As of 2006, the Computer History Museum in Mountain View, California has a RAMAC disk drive which it is restoring. The Computer History Museum in Mountain View. ... Mountain View is a city in Santa Clara County, in the U.S. state of California, USA. The city gets its name from the views of the Santa Cruz Mountains. ...

IBM 353

The IBM 353 used on the IBM 7030, was similar to the IBM 1301, but much faster. It had a capacity of 2,097,152 (2^21) 72-bit words (64 data bits and 8 ECC bits) and transferred 125,000 words per second. The IBM 7030, also known as Stretch, was IBMs first attempt at building a supercomputer. ...

IBM 355

The IBM 355 was announced on September 14, 1956 as an addition to the popular IBM 650. It used the same mechanism as the IBM 350 and stored 6 million decimal digits. Data was transferred to and from the IBM 653 magnetic core memory, an IBM 650 option that stored just sixty 10-digit words, enough for a single sector of disk or tape data. September 14 is the 257th day of the year in the Gregorian calendar (258th in leap years). ... 1956 (MCMLVI) was a leap year starting on Sunday of the Gregorian calendar. ... IBM 650 front panel, showing bi-quinary indicators IBM 650 front panel, rear view The IBM 650 was one of IBM’s early computers, and the world’s first mass-produced computer. ...

IBM 1405

The IBM 1405 Disk Storage Unit was announced by 1961 and was designed for use with the IBM 1401 series medium scale business computers. The 1405 stored 10 million characters on a single module. Each module had 25 large disks, yielding 50 recording surfaces. The disks spun at 1200 RPM. The Model 1 had one module, the Model 2 had two modules, stacked vertically. Each recording surface had 200 tracks and 5 sectors per track. Data was read or recorded at 22,500 characters per second. A single arm moved in and out and up and down. Access time ranged from 100 to 800 milliseconds (Model 2). 1961 (MCMLXI) was a common year starting on Sunday (the link is to a full 1961 calendar). ... The IBM 1401 was a variable wordlength decimal computer that was announced by IBM on October 5, 1959 and marketed as an inexpensive Business Computer. It was withdrawn on February 8, 1971. ...

IBM 1301

The IBM 1301 Disk Storage Unit was announced on June 2, 1961. It was designed for use with the IBM 7000 series mainframe computers and the IBM 1410. The 1301 stored 28 million characters on a single module (25 million characters with the 1410). Each module had 20 large disks and 40 recording surfaces, with 250 tracks per surface. The 1301 Model 1 had one module, the Model 2 had two modules, stacked vertically. The disks spun at 1800 RPM. Data was transferred at 90,000 characters per second. June 2 is the 153rd day of the year in the Gregorian calendar (154th in leap years), with 212 days remaining. ... 1961 (MCMLXI) was a common year starting on Sunday (the link is to a full 1961 calendar). ... The IBM 700/7000 series was a series of incompatible large scale (mainframe) computer systems made by IBM through the 1950s and early 1960s. ... Mainframes (often colloquially referred to as big iron) are large and expensive computers used mainly by government institutions and large companies for legacy applications, typically bulk data processing (such as censuses, industry/consumer statistics, ERP, and bank transaction processing). ... The IBM 1410 was a variable wordlength decimal computer that was announced by IBM on September 12, 1960 and marketed as a midrange Business Computer. It was withdrawn on March 30, 1970. ...

A major advance over the IBM 350 and IBM 1405 was the use of a separate arm and head for each recording surface, with all the arms moving in and out together like a big comb. This eliminated the time needed for the arm to pull the head out of one disk and move up or down to a new disk. Seeking the desired track was also faster since, with the new design, the head would usually be somewhere in the middle of the disk, not starting on the outer edge. Maximum access time was reduced to 180 milliseconds. Microphotograph of a hard disk head. ...

The 1301 also featured heads that were aerodynamically designed to fly over the surface of the disk on a thin layer of air. This allowed them to be much closer to the recording surface, which greatly improved performance.

The 1301 was connected to the computer via the IBM 7631 File Control. Different models of the 7631 allowed the 1301 to be used with a 1410 or 7000 series computer or shared between a 7000 and a 1410 or between two 7000's.

The IBM 1301 Model 1 leased for $2,100 per month or could be purchased for $115,500. Prices for the Model 2 were $3,500 per month or $185,000 to purchase. The IBM 7631 controller cost an additional $1,185 per month or $56,000 to purchase. All models were withdrawn in 1970.

IBM 1302

The IBM 1302 Disk Storage Unit was introduced in September 1963. Improved recording quadrupled its capacity over that of the 1301, to 117 million 6-bit characters per module. Average access time was 165 ms and data could be transferred at 180 K characters/second, more than double the speed of the 1301. A second arm accessed a separate group of 250 tracks. As with the 1301, there was a Model 2 with twice the capacity. The IBM 1302 Model 1 leased for $5,600 per month or could be purchased for $252,000. Prices for the Model 2 were $7,900 per month or $355,500 to purchase. The IBM 7631 controller cost an additional $1,185 per month or $56,000 to purchase. The 1302 was withdrawn in February 1965. 1963 (MCMLXIII) was a common year starting on Tuesday (the link is to a full 1963 calendar). ... 1965 (MCMLXV) was a common year starting on Friday (the link is to a full 1965 calendar). ...

IBM 1311

IBM 1311 Disk Drives - Model 2 (Slave) & Model 3 (Master).

The IBM 1311 Disk Storage Drive was announced on October 11, 1962 and was designed for use with several medium-scale business and scientific computers. The 1311 was about the size and shape of a top-loading washing machine and stored 2 million characters on a removable IBM 1316 disk pack. Each disk pack was 4 inches high, weighed 10 pounds (4.5 kg) and contained six 14-inch diameter disks, yielding 10 recording surfaces (the outer surfaces were not used). The 10 individual R/W heads were mounted on a common actuator which was moved in and out hydraulically and mechanically detented at the desired track before reading or writing occurred. The disks spun at 1500 RPM. Each recording surface had 100 tracks with 20 sectors per track. Each sector stored 100 characters. Seven models of the 1311 were introduced during the 1960s. They were withdrawn during the early 1970s. Image File history File links BRL64-IBM_1311_DiskDrives. ... Image File history File links BRL64-IBM_1311_DiskDrives. ... October 11 is the 284th day of the year (285th in leap years) in the Gregorian calendar. ... 1962 (MCMLXII) was a common year starting on Monday (the link is to a full 1962 calendar). ... Front-loading washing machine. ... The 1960s decade refers to the years from January 1, 1960 to December 31, 1969, inclusive. ... The 1970s decade refers to the years from 1970 to 1979, inclusive. ...

Models of the 1311 disk drive

1. Must be drive 1 on an IBM 1440, IBM 1460, or IBM 1240 system. Contains the controller and can control up to 4 – Model 2 drives. Introduced October 11, 1962. Withdrawn February 8, 1971.
2. Slave drive. Could have any special feature incorporated that the master drive (drive 1) had incorporated. Introduced October 11, 1962. Withdrawn January 6, 1975.
3. Must be drive 1 on an IBM 1620 or IBM 1710 system. Contains the controller and can control up to 3 – Model 2 drives. Did not support any special features. Introduced October 11, 1962. Withdrawn May 12, 1971.
4. Must be drive 1 on an IBM 1401 system. Contains the controller and can control up to 4 – Model 2 drives. Introduced October 11, 1962. Withdrawn February 8, 1971.
5. Must be drive 1 on an IBM 1410, IBM 7010, or IBM 7740 system. Contains the controller and can control up to 4 – Model 2 drives. Direct Seek comes standard on this model. Introduced January 7, 1963. Withdrawn May 12, 1971.
6. No information available, probably a master drive (drive 1). Introduced March 5, 1968. Withdrawn February 2, 1971.
7. No information available, probably a master drive (drive 1). Introduced March 5, 1968. Withdrawn February 2, 1971.

The optional special features were The IBM 1440 was an IBM computer designed as a low-cost system for smaller businesses. ... The IBM 1401 was a variable wordlength decimal computer that was announced by IBM on October 5, 1959 and marketed as an inexpensive Business Computer. It was withdrawn on February 8, 1971. ... The IBM 1620 was announced by IBM on October 21, 1959 and marketed as an inexpensive scientific computer. It was withdrawn on November 19, 1970. ... The IBM 1710 was a process control system that IBM marketed in the early 1960s. ... The IBM 1401 was a variable wordlength decimal computer that was announced by IBM on October 5, 1959 and marketed as an inexpensive Business Computer. It was withdrawn on February 8, 1971. ... The IBM 1410 was a variable wordlength decimal computer that was announced by IBM on September 12, 1960 and marketed as a midrange Business Computer. It was withdrawn on March 30, 1970. ... The IBM 700/7000 series was a series of incompatible large scale (mainframe) computer systems made by IBM through the 1950s and early 1960s. ... January 7 is the seventh day of the year in the Gregorian calendar. ... 1963 (MCMLXIII) was a common year starting on Tuesday (the link is to a full 1963 calendar). ... March 5 is the 64th day of the year in the Gregorian Calendar (65th in leap years). ... 1968 (MCMLXVIII) was a leap year starting on Monday (the link is to a full 1968 calendar). ...

• Direct Seek: Without this option every seek returned to track zero first.
• Scan Disk: Automatic rapid search for identifier or condition.
• Seek Overlap: Allowed a seek to overlap ONE read or write and any number of other seeks.
• Track Record: Increased the capacity of the disk by writing ONE large record per track instead of using sectors.

Drive 1 (the master drive: models 1, 3, 4, and 5) was about a foot wider than the other drives (the slave drives: model 2), to contain extra power supplies and the control logic.

The IBM 1316 Disk Packs were covered with a clear plastic shell and a bottom cover when not in use. A lifting handle in the top center of the cover was rotated to release the bottom cover. Then the top of the 1311 drive was opened and the plastic shell was lowered into the disk drive opening (assuming it was empty). The handle was turned again to lock the disks in place and release the plastic shell, which was then removed and the drive cover closed. The process was reversed to remove a disk pack.

IBM 2311

The IBM 2311 Direct Access Storage Facility was introduced in 1964 for use throughout the System/360 series. It was also available on the IBM 1130. The 2311 mechanism was largely identical to the 1311, but recording improvements allowed higher data density. The 2311 stored 7.25 million bytes on a single removable IBM 1316 disk pack (the same type used on the IBM 1311) consisting of six platters that rotated as a single unit. Each recording surface had 200 tracks plus 3 optional tracks which could be used as alternatives in case faulty tracks were discovered. Average seek time was 85 ms. Data transfer rate was 156 kB/s. 1964 (MCMLXIV) was a leap year starting on Wednesday (the link is to a full 1964 calendar). ... System/360 Model 65 operators console, with register value lamps and toggle switches (middle of picture) and emergency pull switch (upper right). ... Operator loading a 2315 disk cartridge into the IBM 1130 computer. ... A byte is commonly used as a unit of storage measurement in computers, regardless of the type of data being stored. ...

The 2311 had 10 individual R/W heads mounted on a common actuator which was moved in and out hydraulically and mechanically detented at the desired track before reading or writing occurred. The 2311 was organized into cylinders, tracks, and records. (A cylinder referred to all surfaces the same track on each of the 5 platters.) Record 0 was reserved for timing.

Because the 2311 was to be used with a wide variety of computers within the 360 product line, its electrical interconnection was standardized. This created an opportunity for other manufacturers to sell plug compatible disk drives for use with IBM computers and an entire industry was born.

IBM 2314

The IBM 2314 Disk Access Storage Facility was introduced on April 22, 1965, one year after the System/360 introduction. It was used with the System/360 and the System/370 lines. With Two Channel Switch feature it could interface with two 360/370 channels. The 2314 Disk access mechanism was similar to the 2311, but further recording improvements allowed higher data density. The 2314 stored 29.2 million characters on a single removable IBM 2316 disk pack which was similar in design to the 1316 but was taller as a result of increasing the number of disks from six to eleven. The 2316 disk pack containing the eleven 14-inch diameter disks yielded 20 recording surfaces. The drive access consisted of 20 individual R/W heads mounted on a common actuator which was moved in and out hydraulically and mechanically detented at the desired track before reading or writing occurred. Each recording surface had 200 tracks. Access time was initially the same as the 2311, but later models were faster as a result of improvements made in the hydraulic actuator. Data transfer rate was doubled to 310 kB/s. April 22 is the 112th day of the year in the Gregorian calendar (113th in leap years). ... 1965 (MCMLXV) was a common year starting on Friday (the link is to a full 1965 calendar). ... System/360 Model 65 operators console, with register value lamps and toggle switches (middle of picture) and emergency pull switch (upper right). ... IBM logo The IBM System/370 (often: S/370) was a model range of IBM mainframes announced on June 30, 1970 as the successors to the System/360 family. ...

The original Model 1 consisted of the 2314 control unit, a 2312 single drive module, and two 2313 four drive modules for a total of 9 disk drives. Only eight drives of the nine were available to the user at any one time. The ninth drive was there for a spare for the user and could also be worked on 'offline' by a Field Engineer while the other drives were in use by the customer. Each of the nine drives were mounted in individual drawers that were unlatched and pulled out to access the Disk Pack. Because of their appearance they picked up the nickname of 'Pizza Ovens'

Other 2314 Models came later: 2314 Model A with combinations of one to nine drives. 2314 Model B with 2319 disk drives were available in three, six and nine drive models. A 2844 Control Unit could be added to the 2314 Control Unit which allowed two S/360 Channels simultaneous access to two separate disk drives in the Storage Facility.

IBM 2310

The IBM 2310 Removable Cartridge Drive was introduced with the IBM 1130 in 1965. It could store 512,000 words (1,024,000 bytes) on an IBM 2315 cartridge. A single disk spun in a plastic shell with openings for the read/write arm and head. Operator loading a 2315 disk cartridge into the IBM 1130 computer. ... 1965 (MCMLXV) was a common year starting on Friday (the link is to a full 1965 calendar). ...

IBM 3330

200 MB removable disk pack without protective cover

The IBM 3330 Direct Access Storage Facility, code named Merlin, was introduced in June 1970 for use with the IBM System/370 and the IBM System 360/195. Its removable disk packs held 100 megabytes (the 1973 Model 11 featured IBM 3336 Disk Packs that held 200 megabytes). Access time was 30 millisecond and data transferred at 806 kB/s. A major advance introduced with the 3330 was the use of error correction, which made the drives more reliable and reduced costs because small imperfections in the disk surface could be tolerated. The circuitry could correct error bursts up to 11 bits long. The 3330 was withdrawn in 1983. The IBM 3330 DASD was the first IBM disk drive to use voice coil motor technology to position the read/write heads over the tracks of data. ISS (Information Storage Systems) and Memorex had both introduced voice coil actuated plug compatible versions of the IBM 2311 and 2314 in 1968 or 1969. Prior to the 3330 (e.g. 1301,1311, 2311, 2411), hydraulic units were used to position the heads of IBM drives. Image File history File links Download high resolution version (1491x1237, 737 KB) Summary Licensing File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Early IBM disk storage ... Image File history File links Download high resolution version (1491x1237, 737 KB) Summary Licensing File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Early IBM disk storage ... 1970 (MCMLXX) was a common year starting on Thursday (the link is to a full 1970 calendar). ... IBM logo The IBM System/370 (often: S/370) was a model range of IBM mainframes announced on June 30, 1970 as the successors to the System/360 family. ... The IBM System/360 (S/360) is a computer system family announced by International Business Machines on April 7, 1964. ... 1973 (MCMLXXIII) was a common year starting on Monday. ... In computer science and information theory, error correction consists of using methods to detect and/or correct errors in the transmission or storage of data by the use of some amount of redundant data and (in the case of transmission) the selective retransmission of incorrect segments of the data. ... A voice coil is the coil of wire attached to the apex of the moving cone of a loudspeaker. ... Hydraulics is a branch of science and engineering concerned with the use of liquids to perform mechanical tasks. ...

IBM 3340

The IBM 3340 Direct Access Storage Facility, code named Winchester, was introduced in March 1973 for use with IBM System/370. It was named after the famous 30-30 Winchester rifle. Its removable disk packs were sealed and included the head and arm assembly. There was no cover to remove during the insertion process. Access time was 25 millisecond and data transferred at 885 kB/s. Three versions of the removable IBM 3348 Data Module were sold, one with 35 megabyte capacity, another with 70 megabytes, the third also had 70 megabytes, but with 500 kilobytes under separate fixed heads for faster access. The 3340 also used error correction. It was withdrawn in 1984. 1973 (MCMLXXIII) was a common year starting on Monday. ... IBM logo The IBM System/370 (often: S/370) was a model range of IBM mainframes announced on June 30, 1970 as the successors to the System/360 family. ... Winchester rifle refers to an early family of repeating rifles manufactured by the Winchester Repeating Arms Company that was used widely in the United States during the latter half of the 19th century. ... In computer science and information theory, error correction consists of using methods to detect and/or correct errors in the transmission or storage of data by the use of some amount of redundant data and (in the case of transmission) the selective retransmission of incorrect segments of the data. ...

IBM 3380

IBM 3380 disk drive module

The IBM 3380 Direct Access Storage Device was introduced in June 1980. It used new film head technology and had a capacity of 2.52 gigabytes with a data transfer rate of 3 megabytes per second. Average access time was 16 ms. Purchase price at time of introduction ranged from $81,000 to $142,200. Due to problems encountered, the first units did not ship until October, 1981.[1] Image File history File links Download high resolution version (1435x1347, 719 KB) Summary Removable drive module from w:IBM 3380 computer disk drive from early 1980s. ... Image File history File links Download high resolution version (1435x1347, 719 KB) Summary Removable drive module from w:IBM 3380 computer disk drive from early 1980s. ...

The floppy disk

Another important IBM innovation was little noticed when it was introduced with the System/370 in 1971. IBM needed a way to load new microcode into the IBM System/370 Model 158 and developed the floppy disk for this purpose. ^[2] IBM logo The IBM System/370 (often: S/370) was a model range of IBM mainframes announced on June 30, 1970 as the successors to the System/360 family. ... 1971 (MCMLXXI) was a common year starting on Friday (the link is to a full 1971 calendar). ... A microprogram is a program consisting of microcode that controls the different parts of a computers central processing unit (CPU). ... A floppy disk is a data storage device that is composed of a disk of thin, flexible (floppy) magnetic storage medium encased in a square or rectangular plastic shell. ...

IBM's "first" floppies were 8 inches in diameter and held 80 K bytes of data. Floppies were not used for regular program or data storage on the 370, but they became key to the development of the personal computer in the late 1970s. The 1970s decade refers to the years from 1970 to 1979, inclusive. ...

Disk storage in 2004

IBM sold its disk drive operation to Hitachi in 2002. For comparison purposes, the Hitachi Deskstar 7K250 PC hard drive stores 250,000,000,000 bytes (250 gigabytes) on three 3.5-inch diameter platters spinning at 7200 RPM. It has a sustained average transfer rate of 61,400,000 bytes per second over a serial ATA bus. The average seek time is 8.5 milliseconds. It weighs 640 grams (1.4 lb). Like all 3.5 inch hard drives, it is about as long as the carrying handle on an IBM 1316 disk pack. Retail price in April 2006 was about US$100. 2004 (MMIV) was a leap year starting on Thursday of the Gregorian calendar. ... Hitachi Global Storage Technologies is a wholly-owned subsidiary of Hitachi, Ltd. ... For album titles with the same name, see 2002 (album). ... Typical hard drives of the mid-1990s. ... First generation (1. ... 2006 (MMVI) is a common year starting on Sunday of the Gregorian calendar. ...

See also

• History of hard disks

To meet Wikipedias quality standards, this article or section can be improved by converting lengthy lists to text. ...

References

• Yoshiro Nakamatsu and the Floppy Disk

External links

• A Quarter Century of Disk File Innovation – IBM Journal of Research and Development, 1981 (PDF)
• IBM 1311 disk storage drive
• IBM 1311 at the Thessaloniki Science Center & Technology Museum
• 50th Anniversary: The IBM 305 RAMAC and the IBM 350 Disk Storage Unit hit 50
• EE Times: Disk drives take eventful spin
• IBM disk storage documents on bitsavers.org (PDF)
  • IBM 1311 Disk storage drive
  • IBM 2314 Direct access storage
  • Floppy

To meet Wikipedias quality standards, this article or section may require cleanup. ...

Footnotes

1. ^ Lee Gomes, "Talking Tech" The Wall Street Journal, August 22, 2006
2. ^ Floppy disks were invented in 1952 by Yoshiro Nakamatsu, eighteen years before IBM "introduced" them.