Early IBM disk storage
Encyclopedia
IBM
IBM
International Business Machines Corporation or IBM is an American multinational technology and consulting corporation headquartered in Armonk, New York, United States. IBM manufactures and sells computer hardware and software, and it offers infrastructure, hosting and consulting services in areas...

 manufactured magnetic disk storage
Disk storage
Disk storage or disc storage is a general category of storage mechanisms, in which data are digitally recorded by various electronic, magnetic, optical, or mechanical methods on a surface layer deposited of one or more planar, round and rotating disks...

 devices from 1956 to 2003, when it merged its hard disk drive business with Hitachi's. Both the hard disk drive (HDD) and floppy disk drive (FDD) were invented by IBM and as such IBM's employees were responsible for many of the innovations in these products and their technologies. The basic mechanical arrangement of hard disk drives has not changed since the IBM 1301. Disk drive performance and characteristics are measured by the same standards now as they were in the 1950s. Few products in history have enjoyed such spectacular declines in cost and size along with corresponding improvements in capacity and performance.

IBM manufactured 8-inch floppy disk drives from 1969 until the middle 1980s but was not a significant manufacturer of smaller sized floppy disk drives. IBM always offered its magnetic disk drives for sale but did not offer them with OEM terms and conditions until 1981. By 1996 IBM had stopped making hard disk drives unique to its systems and was offering all its HDDs on an OEM basis.

IBM has used many terms to describe its various magnetic disk drives, such as Direct Access Storage Device
Direct access storage device
In mainframe computers and some minicomputers, a direct access storage device, or DASD , is any secondary storage device which has relatively low access time relative to its capacity....

, Disk File and Diskette File; however, here the current industry standard terms, hard disk drive and floppy disk drive are used.

IBM 350

The IBM 350 disk storage unit, the first disk drive, was announced by IBM as a component of the IBM 305 RAMAC computer system on September 13, 1956. Simultaneously a very similar product, the "IBM 355 Random Access Memory" was announced for the IBM 650
IBM 650
The IBM 650 was one of IBM’s early computers, and the world’s first mass-produced computer. It was announced in 1953, and over 2000 systems were produced between the first shipment in 1954 and its final manufacture in 1962...

 computer system. RAMAC stood for "Random Access Method of Accounting and Control."

Its design was motivated by the need for real time accounting in business. The 350 stored 5 million 7-bit (6-bits plus 1 odd parity bit
Parity bit
A parity bit is a bit that is added to ensure that the number of bits with the value one in a set of bits is even or odd. Parity bits are used as the simplest form of error detecting code....

) characters (about 4.4 megabyte
Megabyte
The megabyte is a multiple of the unit byte for digital information storage or transmission with two different values depending on context: bytes generally for computer memory; and one million bytes generally for computer storage. The IEEE Standards Board has decided that "Mega will mean 1 000...

s). It had fifty 24 inches (609.6 mm) 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. An access mechanism moved a pair of heads up and down to select a disk pair (one down surface and one up surface) and in and out to select a recording track of a surface pair. 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.

US Patent 3,503,060 from the RAMAC program is generally considered to be the fundamental patent for disk drives. This first ever disk drive was initially cancelled by the IBM Board of Directors because of its threat to the IBM punch card business but the IBM San Jose laboratory continued development until the project was approved by IBM's President.

The 350's cabinet was 60 inches (152 cm) long, 68 inches (172 cm) high and 29 inches (74 cm) deep. IBM had a strict rule that all its products must pass through a standard 29.5 inch (75 cm) doorway. Since the 350's platters were mounted horizontally, this rule presumably dictated the maximum diameter of the disks.

The RAMAC unit weighed over a ton, had to be moved around with forklifts, and was delivered via large cargo airplanes. According to Currie Munce, research vice president for Hitachi Global Storage Technologies
Hitachi Global Storage Technologies
Hitachi Global Storage Technologies is a wholly owned subsidiary of Hitachi, Ltd., it is expected to be sold to Western Digital in third calendar quarter 2011. Hitachi GST developed hard disk drives, enterprise-class solid state drives, and external storage solutions and services used to store,...

 (which acquired IBM's storage business), the storage capacity of the drive could have been increased beyond five megabytes, but IBM's marketing department at that time was against a larger capacity drive, because they didn't know how to sell a product with more storage.

In 2002, the Magnetic Disk Heritage Center began restoration of an IBM 350 RAMAC in collaboration with Santa Clara University. In 2005, the RAMAC restoration project relocated to the Computer History Museum
Computer History Museum
The Computer History Museum is a museum established in 1996 in Mountain View, California, USA. The Museum is dedicated to preserving and presenting the stories and artifacts of the information age, and exploring the computing revolution and its impact on our lives.-History:The museum's origins...

 where efforts to restore the drive for public display continue.

IBM 353

The IBM 353 used on the IBM 7030
IBM 7030
The IBM 7030, also known as Stretch, was IBM's first transistorized supercomputer. The first one was delivered to Los Alamos National Laboratory in 1961....

, was similar to the IBM 1301, but with a faster transfer rate. It had a capacity of 2,097,152 (221) 64-bit words (two 32 data bit half words each with 7 ECC bits) and transferred 125,000 words per second. Unlike the flying heads of the 1301, the 353 used the older head design of the IBM 350 RAMAC.

IBM 355

The IBM 355 was announced on September 14, 1956 as an addition to the popular IBM 650
IBM 650
The IBM 650 was one of IBM’s early computers, and the world’s first mass-produced computer. It was announced in 1953, and over 2000 systems were produced between the first shipment in 1954 and its final manufacture in 1962...

. It used the same mechanism as the IBM 350 and stored 6 million 7-bit 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.

IBM 1405

The IBM 1405 Disk Storage Unit was announced by 1961 and was designed for use with the IBM 1401
IBM 1401
The IBM 1401 was a variable wordlength decimal computer that was announced by IBM on October 5, 1959. The first member of the highly successful IBM 1400 series, it was aimed at replacing electromechanical unit record equipment for processing data stored on punched cards...

 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).

IBM 1301

The IBM 1301 Disk Storage Unit was announced on June 2, 1961. It was designed for use with the IBM 7000 series
IBM 700/7000 series
The IBM 700/7000 series was a series of large-scale computer systems made by IBM through the 1950s and early 1960s. The series included several different, incompatible processor architectures. The 700s used vacuum tube logic and were made obsolete by the introduction of the transistorized 7000s...

 mainframe computer
Mainframe computer
Mainframes are powerful computers used primarily by corporate and governmental organizations for critical applications, bulk data processing such as census, industry and consumer statistics, enterprise resource planning, and financial transaction processing.The term originally referred to the...

s and the IBM 1410
IBM 1410
The IBM 1410, a member of the IBM 1400 series, 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 1410 was similar in design to the very popular IBM 1401, but it had one...

. The 1301 stored 28 million characters on a single module (25 million 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.

A major advance over the IBM 350 and IBM 1405 was the use of a separate arm and head
Disk read-and-write head
Disk read/write heads are the small parts of a disk drive, that move above the disk platter and transform platter's magnetic field into electrical current or vice versa – transform electrical current into magnetic field...

 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.

The 1301 was the first disk drive to use 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.

IBM 1311

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
Washing machine
A washing machine is a machine designed to wash laundry, such as clothing, towels and sheets...

 and stored 2 million characters on a removable IBM 1316 disk pack
Disk pack
A Disk pack is a layered grouping of hard disk platters . A disk pack is the core component of a hard disk drive. In modern hard disks, the disk pack is permanently sealed inside the drive...

. Seven models of the 1311 were introduced during the 1960s. They were withdrawn during the early 1970s.

Models of the 1311 disk drive:
  1. Had to be drive 1 on an IBM 1440
    IBM 1440
    The IBM 1440, a member of the IBM 1400 series, was an IBM computer designed as a low-cost system for smaller businesses. It was announced on October 11, 1962 and withdrawn on February 8, 1971....

    , IBM 1460, or IBM 1240 system. Contained the controller and could control up to four 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. Had to be drive 1 on an IBM 1620
    IBM 1620
    The IBM 1620 was announced by IBM on October 21, 1959, and marketed as an inexpensive "scientific computer". After a total production of about two thousand machines, it was withdrawn on November 19, 1970...

     or IBM 1710
    IBM 1710
    The IBM 1710 was a process control system that IBM introduced in March 1961. It used either a 1620 I or a 1620 II Computer and specialized I/O devices .The IBM 1620 used in the 1710 system was modified in several ways, the most obvious was the addition of a very...

     system. Contained the controller and could control up to three Model 2 drives. Did not support any special features. Introduced October 11, 1962. Withdrawn May 12, 1971.
  4. Had to be drive 1 on an IBM 1401
    IBM 1401
    The IBM 1401 was a variable wordlength decimal computer that was announced by IBM on October 5, 1959. The first member of the highly successful IBM 1400 series, it was aimed at replacing electromechanical unit record equipment for processing data stored on punched cards...

     system. Contains the controller and can control up to four Model 2 drives. Introduced October 11, 1962. Withdrawn February 8, 1971.
  5. Had to be drive 1 on an IBM 1410
    IBM 1410
    The IBM 1410, a member of the IBM 1400 series, 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 1410 was similar in design to the very popular IBM 1401, but it had one...

    , IBM 7010, or IBM 7740 system. Contained the controller and could control up to four Model 2 drives. Direct Seek came as 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:
  • 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.

Each IBM 1316 Disk Pack was 4 inches (101.6 mm) high, weighed 10 pounds (4.5 kg) and contained six 14 inches (355.6 mm) diameter disks, yielding 10 recording surfaces (the outer surfaces were not used). The 10 individual read/write heads were mounted on a common actuator within the disk drive 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. The disk pack was 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 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 2302

The IBM 2302 was the S/360 version of the 1302, with track formatting in accordance with S/360 DASD architecture rather than 7000 series architecture.

IBM 2305

The IBM 2305 Direct Access Storage Facility was a fixed-head disk drive originally announced in 1970 to connect to the 360/85 and 360/195 using the IBM 2880 Block Multiplexor Channel. The 2305-1 ran at 3.0 MB/second when attached using the 2-byte channel interface, and the larger 2305-2 ran at 1.5 MB/second.

The 2305 provided large-scale IBM computers with fast, continuous access to medium-sized quantities of information. Its capacity and high data rate made it ideal for systems residence functions, work files, indices and data sets that were used repeatedly. Its fast response time made it attractive as a paging device in a heavily loaded systems (where there are 1.5 or more transactions per second).

IBM 2311

The IBM 2311 Direct Access Storage Facility was introduced in 1964 for use throughout the System/360
System/360
The IBM System/360 was a mainframe computer system family first announced by IBM on April 7, 1964, and sold between 1964 and 1978. It was the first family of computers designed to cover the complete range of applications, from small to large, both commercial and scientific...

 series. It was also available on the IBM 1130
IBM 1130
The IBM 1130 Computing System was introduced in 1965. It was IBM's least-expensive computer to date, and was aimed at price-sensitive, computing-intensive technical markets like education and engineering. It succeeded the IBM 1620 in that market segment. The IBM 1800 was a process control variant...

 and (using the 2841 Control Unit) the IBM 1800
IBM 1800
The IBM 1800 Data Acquisition and Control System was a process control variant of the IBM 1130 with two extra instructions , extra I/O capabilities, 'selector channel like' cycle-stealing capability and three hardware index registers....

. The 2311 mechanism was largely identical to the 1311, but recording improvements allowed higher data density. The 2311 stored 7.25 megabyte
Megabyte
The megabyte is a multiple of the unit byte for digital information storage or transmission with two different values depending on context: bytes generally for computer memory; and one million bytes generally for computer storage. The IEEE Standards Board has decided that "Mega will mean 1 000...

s 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
Kilobyte
The kilobyte is a multiple of the unit byte for digital information. Although the prefix kilo- means 1000, the term kilobyte and symbol KB have historically been used to refer to either 1024 bytes or 1000 bytes, dependent upon context, in the fields of computer science and information...

/s.

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 2314/2319

The IBM 2314 Disk Access Storage Facility was introduced on April 22, 1965, one year after the System/360
System/360
The IBM System/360 was a mainframe computer system family first announced by IBM on April 7, 1964, and sold between 1964 and 1978. It was the first family of computers designed to cover the complete range of applications, from small to large, both commercial and scientific...

 introduction. It was used with the System/360 and the System/370
System/370
The IBM System/370 was a model range of IBM mainframes announced on June 30, 1970 as the successors to the System/360 family. The series maintained backward compatibility with the S/360, allowing an easy migration path for customers; this, plus improved performance, were the dominant themes of the...

 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 29,176,000 characters (200×20×7294 bytes per track) 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 inches (355.6 mm) 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.

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 3330

The IBM 3330 Direct Access Storage Facility, code-named Merlin, was introduced in June 1970 for use with the IBM System/370
System/370
The IBM System/370 was a model range of IBM mainframes announced on June 30, 1970 as the successors to the System/360 family. The series maintained backward compatibility with the S/360, allowing an easy migration path for customers; this, plus improved performance, were the dominant themes of the...

 and the IBM System 360/195. Its removable disk packs held 100 MB (404x19x13,030 bytes) (the 1973 Model 11 featured IBM 3336-11 Disk Packs that held 200 MB (808x19x13,030 bytes)). Access time was 30 ms 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.

IBM 3340

The IBM 3340 Direct Access Storage Facility, code-named Winchester, was introduced in March 1973 for use with IBM System/370
System/370
The IBM System/370 was a model range of IBM mainframes announced on June 30, 1970 as the successors to the System/360 family. The series maintained backward compatibility with the S/360, allowing an easy migration path for customers; this, plus improved performance, were the dominant themes of the...

. 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.

The 3340 was developed in San Jose under the leadership of Ken Haughton. Early on the design was focused on two removable 30 megabyte modules. Because of this 30/30 configuration, the code name Winchester was selected after the famous Winchester 30-30 rifle
Winchester Model 1894
Winchester Model 1894 is a lever-action rifle which became one of the most famous and popular hunting rifles...

; subsequently the capacities were increased, but the code name stuck.

The significance of this product, and the reason that disk drives in general became known as "Winchester technology" had nothing to do with the configuration of the product. This was IBM's first drive to not unload the heads from the media. The Winchester technology allowed the head to land and take off from the disk media as the disk spun up and down. This resulted in very significant savings and a large reduction of complexity of the head and arm actuating mechanism. This rapidly became a standard design within the disk manufacturing community.

The name stuck in the USSR, Hungary and possibly other countries as an umbrella term for all hard drives; it is still in wide use today.

IBM 3350

The IBM 3350 Direct Access Storage Facility, code-named Madrid, was introduced in 1975 for use with IBM System/370. Its non-removable disk packs were sealed and included the head and arm assembly. The 3350 disk geometry was 555 cylinders, 30 heads, and 19069 bytes per track which gave the Head Disk Assembly (HDA) a storage capacity of 317,498,850 bytes. Disk units were identified as A2, A2F, B2, B2F, C2, and C2F. Each unit contained two HDAs and they were installed in "strings" of units. An A2 or A2F unit was required and attached to a "control unit" such as the IBM 3880. After the A2 could be up to 3 B2 units or 2 B2s and a C2. The C2 unit could also be connected to a control unit and with it in place then two I/O operations could be executed on the string at the same time. The "x2F" unit was a normal x2 unit, but its two HDAs also had a "Fixed Head" area over the first 5 cylinders. This Fixed Head area was intended to be allocated to the HASP
IBM Houston Automated Spooling Program
The Houston Automatic Spooling Priority Program, commonly known as HASP, was developed by IBM Federal Systems Division contractors at the Johnson Space Center in Houston. The developers were Tom Simpson and Bob Crabtree...

 or JES2
Job Entry Subsystem 2/3
IBM's MVS and z/OS operating systems use a job entry subsystem to receive jobs into the operating system, schedule them for processing by MVS or z/OS, and to control their output processing.There are three job entry subsystems; Master, JES2 and JES3...

 checkpoint area and thus would greatly reduce head motion on the device.

IBM 3370 and 3375

IBM introduced the IBM 3370 Direct Access Storage Device in January 1979 for its for IBM 4331, 4341, and System/38
System/38
The System/38 was a midrange computer server platform manufactured and sold by the IBM Corporation. The system offered a number of innovative features, and was the brainchild of IBM engineer Dr. Frank Soltis...

 midrange computer
Midrange computer
Midrange computers, or midrange systems, are a class of computer systems which fall in between mainframe computers and microcomputers.The class emerged in the 1960s and machines were generally known at the time as minicomputers - especially models from Digital Equipment Corporation , Data General,...

s. It had 7 fixed 14 inches (355.6 mm) disks, and each unit had a capacity of 571 MB. It was the first HDD usage of thin film head technology; research on that technology started at Thomas J. Watson Research Center
Thomas J. Watson Research Center
The Thomas J. Watson Research Center is the headquarters for the IBM Research Division.The center is on three sites, with the main laboratory in Yorktown Heights, New York, 38 miles north of New York City, a building in Hawthorne, New York, and offices in Cambridge, Massachusetts.- Overview :The...

 in the late 1960s. The 3370 was a fixed block architecture
Fixed Block Architecture
Fixed Block Architecture is a disk layout in which each addressable record on disk is of the same size. The term fell out of use, since nearly all modern disk drives use this principle, termed logical block addressing and usually having a constant addressable block size of 512 bytes.- Count Key...

. The sister unit was called the 3375 and used the count-key-data architecture.

IBM 3380

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.

IBM 3390

The IBM 3390 Direct Access Storage Device series was introduced November 1989, offering a maximum storage of up to 22 gigabytes in a string of multiple drives. Cost of a storage system varied by configuration and capacity, between $90,000 and $795,000. A Model 3 enhancement to the drive family, announced September 11, 1991, increased capacity by approximately 1.5 and a Model 9 family, announced May 20, 1993, further increased capacity by an additional factor of 3 to minimum capacity of 34 gigabytes in a single drive box.

The 3390 Model 9 was the last Single Large Expensive Disk (sometimes called SLEDs) drive announced by IBM.

IBM 9345

The 9345 HDD first shipped in Nov 1990 as an RPQ on IBMs SCSE (SuperComputing Systems Extensions). Developed at IBM's San Jose, California laboratory under the code name Sawmill it was an up to 1.5 GB full height 5¼-inch HDD using up to 8 130 mm disks. It was the first HDD to use MR(Magneto Resistive)
Magnetoresistance
Magnetoresistance is the property of a material to change the value of its electrical resistance when an external magnetic field is applied to it. The effect was first discovered by William Thomson in 1856, but he was unable to lower the electrical resistance of anything by more than 5%. This...

 heads. In October 1991 the 9345 DASD was announced as part of the IBM 9340 direct channel attached, count key data (CKD) DASD subsystem family which attached to IBM mainframes including the ES/9000 processor family. The 9345 DASD Model 1 had two 1.0 GB HDDs while the Model 2 had two 1.5 GB HDDs.

9330 family of disk drives

  1. 9331 Diskette Unit models 1 and 11 contained one 8-inch FDD while the models 2 and 12 contained one 5¼-inch FDD.
  2. 9332 Direct Access Storage Device used the IBM 0667 HDD.
  3. 9333 High Performance Disk Drive Subsystem used the IBM 0664 or IBM 0681 HDDs depending upon subsystem model
  4. 9334 Disk Expansion Unit [To be determined]
  5. 9335 Direct Access Storage Subsystem This HDD used in this subsystem was developed under the code name "Kestrel" at IBM Hursley, UK, and was an 850 MB HDD using three 14-inch disks with dual rotary actuators, each actuator accessing three surfaces with two heads per surface. The HDD was in the rack mountable 9335 announced as a part of the October 1986 IBM 9370 Information System announcement. There is no known OEM version of this HDD.
  6. 9336 Disk Unit used the IBM 0662 HDD
  7. 9337 Disk Array Subsystem used the IBM 0662 HDD. In 1991 IBM introduced a family of rack-mounted, CKD 9340 DASD Subsystems based upon the 5¼-inch 9345 disk drive, code name Sawmill. The entry-level 9341/9345 subsystem connected to a 9221 processor and stored 2-24 gigabytes of information while the 9343/9345 stored 4-48 gigabytes and could take advantage of ESCON
    ESCON
    ESCON is a data connection created by IBM, and is commonly used to connect their mainframe computers to peripheral devices such as disk storage and tape drives. ESCON is an optical fiber, half-duplex, serial interface. It originally operated at a rate of 10 Mbyte/s, which was later increased to...

    . The drive capacity was either 1 or 1.5 gigabytes depending upon the model.

IBM 2310

The IBM 2310 Removable Cartridge Drive was announced in 1964 with the IBM 1800
IBM 1800
The IBM 1800 Data Acquisition and Control System was a process control variant of the IBM 1130 with two extra instructions , extra I/O capabilities, 'selector channel like' cycle-stealing capability and three hardware index registers....

, and then in 1965 with the IBM 1130
IBM 1130
The IBM 1130 Computing System was introduced in 1965. It was IBM's least-expensive computer to date, and was aimed at price-sensitive, computing-intensive technical markets like education and engineering. It succeeded the IBM 1620 in that market segment. The IBM 1800 was a process control variant...

; it likely first shipped with the 1130 in late 1965. It could store 512,000 words (1,024,000 bytes) on an IBM 2315 cartridge. A single 14 inches (355.6 mm) oxide-coated aluminum disk spun in a plastic shell with openings for the read/write arm and two heads.

IBM 5444

The 5444 was announced September 1969 as part of System/3. Developed at IBM's Hursley, England, laboratory under code name Dolphin it used the 5440 disk cartridge. The cartridge in turn contained one 14-inch disk. There were three models:
  • Model 1 has one fixed disk and one removable disk each with 100 tracks per surface for a disk cartridge capacity of 1.23 MB
  • Model 2 has one fixed disk and one removable disk each with 200 tracks per surface for a disk cartridge capacity of 2.46 MB
  • Model 3 has only one removable disk with 200 tracks per surface for a disk cartridge capacity of 2.46 MB

IBM 62GV

The 62GV first shipped in May 1974. Developed at IBM's Hursley, England, laboratory under the code name Gulliver with an initial capacity of 5MB. Subsequent models had 10 and 14 MB capacities. It used a rotary actuator with one 14-inch disk. During its production life it shipped 177,000 units making it the first HDD known to have shipped in excess of 100,000 units.

OEM and Small Systems HDDs

This section lists IBM manufactured HDDs offered both as an OEM product and for attachment to IBMs small systems such as the System/3, System/32, /34 & /36 and the AS/400. HDDs are identified by their OEM model number and listed chronologically by date of first customer shipment.

IBM 0680

The 0680 first shipped in 1979 on most IBM small systems and the low end of the System/370 as the 3310 direct access storage. The OEM version was announced as the 0680 in September 1981. Developed at IBM's Hursley, England, laboratory under the code name Piccolo with an initial capacity of up to 65MB, it used six 8-inch disks (210 mm).

A double capacity version, the 62SW, shipped in June 1984 but very few units were sold because its price per megabyte was the same as the 62GV.

IBM 0676

The 0676 first shipped in November 1982 as a 5247 Disk Storage Unit for the IBM System/23 Datamaster. Developed at the IBM Rochester, MN, laboratory as the 21ED it was an 8-inch HDD with an initial capacity of 15 or 30 MB in 2 or 4 210 mm disks. In 1983 it shipped as the HDD in the 5360 System Unit of the S/36. In 1984 its capacity was doubled by doubling the number of tracks per surface and it was incorporated into the 5362 System Unit of the System/36.

IBM 0667

The 0667 first shipped in August 1986. Developed the IBM Rochester, MN, laboratory under the code name "Grant", it was a 70 MB ESDI full height 5¼-inch HDD with up to 4 130 mm disks. It was offered as a feature on certain models of the PC RT (6150, 6151, 6152) and in System/36 Model System Units (5363, 5364).

IBM 0669

The 0669 first shipped in 1987. Developed at IBM Rochester, MN, it was a full-height 5½-inch HDD with a capacity of up to 115MB on up to 4 130 mm disks. It was the HDD internal to the System/36 5363 System Unit and Series 1 4956 System Unit.

IBM 0671

The 0671 first shipped in 1987. Developed under the code name "Lee" at IBM Rochester, MN, it was an up to 316 MB ESDI full height 5¼-inch HDD with up to 8 130 mm disks depending upon model. In 1988 it shipped as part of the 9404 System Unit of the IBM AS/400 system which contained two, or optionally three of these HDDs.

IBM 0681

The 0681 first shipped in April 1990. Developed at IBM's Hursley, UK, laboratory under the code name Redwing. It was an up to 857 MB full height 5¼-inch HDD using up to 12 130 mm disks. It was the first HDD to use PRML
PRML
In computer data storage, Partial Response Maximum Likelihood is a method for converting the weak analog signal from the head of a magnetic disk or tape drive into a digital signal. PRML attempts to correctly interpret even small changes in the analog signal, whereas peak detection relies on fixed...

 decoding of data. It was the drive component of the 9333 Disk Drive Subsystem which first shipped in early 1992.

A higher density, 1.07 GB, version was incorporated into the 9333 subsystem in May 1992.

IBM 0663

The 0663 first shipped in late 1991. Developed under the code name "Corsair", it was a full-height (1-inch high) 3½-inch HDD with up to 1 GB on up to 8 95 mm disks. It was offered as a feature on certain models of the PS/2 and RS/6000. It was the first OEM disk drive to use MR Heads
Magnetoresistance
Magnetoresistance is the property of a material to change the value of its electrical resistance when an external magnetic field is applied to it. The effect was first discovered by William Thomson in 1856, but he was unable to lower the electrical resistance of anything by more than 5%. This...

.

IBM 0664

The 0664 first shipped in November 1992. Developed under the code name "Allicat" at IBM Rochester, MN, it was a tall (3.25-inch high) 3½-inch HDD with up to 2.013 GB capacity on up to 8 95 mm disks.

IBM 0662

The 0662 first shipped in June 1993. Developed under the code name "Spitfire" at IBM Rochester, MN, it was a full-height (1-inch high) 3½-inch HDD with up to 4 GB on up to 8 95 mm disks. It was the HDD internal to the 9336 Disk Unit and the 9337 Disk Array.

The floppy disk drive

Another important IBM innovation is the floppy disk drive. IBM first introduced the 8-inch FDD in 1971 as a read only program load device. In 1973 IBM shipped its first read/write floppy disk drive as a part of the 3740 Data Entry System. IBM established early standards in 8" FDDs but never sold such products separately so that the industry then developed separate from IBM.

"Star" Series of HDDs

On October 17, 1994, IBM's Storage Systems division announced three new families of hard disk drives, the Travelstar
Travelstar
The Travelstar is a range of Hard Drives manufactured by Hitachi Global Storage Technologies mainly for use with laptop computers. Models are manufactured with capacities ranging from 40GB to 750GB, with rotational speeds ranging from 3600RPM to 7200RPM. They are available in 1.8" or 2.5" form...

 2½-inch family for notebooks, the Deskstar 3½-inch family for desktop applications and the Ultrastar 3½-inch family for high performance computer system applications.

IBM's first HDD versus its last HDDs

The following table compares IBM's first HDD, the RAMAC 350, with the last three models it manufactured in each of its "Star" series of OEM HDDs. It illustrates HDD's spectacular decline in cost and size along with corresponding improvement in capacity and performance.
Parameter (units) RAMAC 350 Ultrastar 146Z10 Deskstar 180GXP Travelstar 80GN 46-year improvement (maximum)
Announced Sep 1956 Jul 2002 Oct 2002 Nov 2002
Capacity (gigabytes) 0.004 146 180 80 48,000
Dimensions (inches) 60×68×29 4×1×5.75 4×1×5.75 2.75×0.38×3.95
Dimensions (mm) 1500×1700×700 102×25×146 102×25×146 70×9.5×100
Volume (in³) 118,320 23 23 4 29,161
Volume (litres) 1,939 0.4 0.4 0.1
Weight (lbs) 2,140 1.7 1.4 0.2 1,244
Weight (kg) 971 0.8 0.64 0.095
Power (watts) 8100 BTUs/hour (i.e., 2374 watts), up to 5500 kVA depending upon model 16 10.3 1.85 1,283
Power density (megabytes/watt) 0.0016 9,125 17,476 43,243 27,375,856
List price 57,000 1200 360 420
Price/megabyte 15,200 0.0082 0.0020 0.0053 7,600,000
Density (megabits/in²) 0.002 26,263 46,300 70,000 35,000,000
Density (kilobits/mm²) 0.003 40,708 71,765 108,500
Volume density (gigabytes/in³) 0.00000003 6 8 20 622,100,131
Volume density (megabytes/mm³) 0.000002 388 478 1,203
Latency (msec) 3 4 7 8
Average seek time (msec) 600 5.9 10.2 12 102
Data rate (megabytes/sec) 0.001 103 29.4 43.75 11,719

External links

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