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IBM 0662

From Alfawiki
Adapted from the English Wikipedia article IBM 0662, available under CC BY-SA 4.0Updated 9 August 2025
IBM Magnetic Disk Storage Division
Company typeDivision
IndustryComputer storage devices
Founded1956
Defunct2003
FateDivested to Hitachi
ProductsHard disk drives (HDD), Floppy disk drives (FDD)
ParentIBM

IBM was a manufacturer of magnetic disk storage devices from 1956 until 2003, at which point it divested its hard disk drive division to Hitachi. The company pioneered both the hard disk drive (HDD) and floppy disk drive (FDD), with numerous advancements in these technologies driven by IBM’s engineers. Since the introduction of the IBM 1301, the core mechanical structure of hard disk drives has largely remained unchanged, and performance standards established in the 1950s continue to be referenced today. Over time, these devices have experienced dramatic decreases in cost and physical dimensions, alongside substantial improvements in storage capacity and operational speed.

From 1969 until the mid-1980s, IBM manufactured 8-inch floppy disk drives but did not establish a significant presence in the smaller 5.25- or 3.5-inch floppy drive markets. Although IBM consistently produced magnetic disk drives, it only began offering them under original equipment manufacturer (OEM) agreements starting in 1981. By 1996, IBM had discontinued manufacturing HDDs exclusively for its own systems and shifted entirely to marketing all drives as OEM products.

IBM has employed multiple designations for its magnetic disk storage devices, including direct-access storage device (DASD), disk file, and diskette file. This article adopts the widely accepted industry terminology of hard disk drive (HDD) and floppy disk drive (FDD).

IBM 350

The IBM 350 disk storage unit, recognized as the first-ever disk drive, was introduced by IBM on September 14, 1956, as an integral component of the IBM 305 RAMAC system. A related model, the IBM 355, was announced for use with the IBM 650 RAMAC system. The initial prototype was delivered to Zellerbach Paper Company in June 1956, with commercial shipments commencing in November 1957 to customers including United Airlines.

Engineered to address real-time accounting requirements, the IBM 350 stored five million 6-bit characters (equivalent to 3.75 MB) across fifty-two disks each measuring 24 inches in diameter. These disks featured one hundred recording surfaces and tracks combined. Operating at a rotational speed of 1200 rpm, the device achieved a data transfer rate of 8,800 characters per second. Its access mechanism allowed read/write heads to move selectively across disk pairs and tracks. Several enhanced variants were introduced during the late 1950s. The IBM RAMAC 305 system paired with the 350 was leased at a rate of $3,200 monthly. Production of this unit ceased in 1969.

Patent US3503060, originating from the RAMAC development program, is regarded as foundational technology for disk drives. Initially, IBM’s Board of Directors halted this project due to concerns about its potential impact on punch card sales; however, development persisted until it gained approval from IBM’s president.

The physical dimensions of the 350’s cabinet were approximately 60 inches in length, 68 inches in height, and 29 inches in width. Weighing close to one ton, transportation required forklifts and cargo aircraft. According to Currie Munce from Hitachi Global Storage Technologies—the company that acquired IBM’s storage division—marketing teams initially hesitated to promote higher capacity versions due to uncertain demand, although models with double capacity were released in 1959.

Acknowledging its historical importance, the RAMAC 350 was designated an International Historic Landmark by The American Society of Mechanical Engineers in 1984. Restoration efforts began in 2002 under Al Hoagland’s leadership in partnership with Santa Clara University; later, the restored unit was moved to the Computer History Museum, where it remains on public display.

IBM 353

The IBM 353, designed for use alongside the IBM 7030, bore resemblance to the IBM 1301 but offered a higher data transfer speed. It provided storage for 2,097,152 (221) 64-bit words, equivalent to 134,217,728 bits, and achieved a transfer rate of 125,000 words per second. A prototype delivered in late 1960 was notable as the first disk drive to feature one head per surface that floated on compressed air, continuing the approach introduced with the earlier IBM 350. Production versions incorporated self-flying heads similar to those used in the IBM 1301.

IBM 355

Introduced on September 14, 1956, the IBM 355 expanded storage capabilities for the widely used IBM 650. It utilized the IBM 350 mechanism but included up to three access arms instead of just one. The unit stored six million decimal digits plus an additional 600,000 sign indicators. Data transfer involved moving entire tracks between the magnetic core memory of the 653—an optional component offering sixty signed 10-digit words—sufficient to hold a single disk track or tape record.

IBM 1405

Announced in 1961 for the IBM 1400 business computer series, the IBM 1405 Disk Storage Unit came in two variants: Model 1 held 10 million alphanumeric characters (60 million bits) across 25 disks, while Model 2 doubled this capacity to 20 million characters (120 million bits) on 50 disks. The disks rotated vertically at a speed of 1,200 revolutions per minute.

Each disk surface contained 200 tracks subdivided into five sectors (top surfaces numbered sectors 0–4; bottom surfaces sectors 5–9). Sector sizes were either 178 or 200 characters. Between one and three forked access arms were equipped with two read/write heads each—one per disk side—and could move both vertically and horizontally under electronic control to reach specific tracks and disks. Reading or writing a sector required approximately 10 milliseconds.

Access times varied from as low as 100 milliseconds up to a maximum of 700 milliseconds for Model 1 and extended to around 800 milliseconds for Model 2. The latter featured 100,000 sectors containing either 200 characters in move mode or 178 characters in load mode, which added a word mark bit per character. Model 1 had half this number of sectors.

IBM 7300

The IBM 7300 Disk Storage Unit was developed for use with the IBM 7070, with IBM releasing a second model in 1959. Nevertheless, following the launch of the IBM 1301 on June 5, 1961, customers using the IBM 7070 and IBM 7074 preferred the newer IBM 1301 over the IBM 7300. The technology underlying the IBM 7300 shared elements with earlier units such as the IBM 350, IBM 355, and IBM 1405.

IBM 1301

Unveiled on June 2, 1961, the IBM 1301 Disk Storage Unit was aimed at the 7000 series mainframe computers as well as the IBM 1410. Each module could store up to 28 million characters (168 million bits), or slightly less—25 million characters—with the IBM 1410 configuration. The system comprised twenty-five large disks and forty user-accessible recording surfaces, each containing approximately two hundred fifty tracks. Model 1 consisted of a single module; Model 2 stacked two modules vertically. Disks rotated at a speed of eighteen hundred revolutions per minute and transferred data at ninety thousand characters per second.

A significant advancement was the implementation of an individual arm and read/write head for each recording surface arranged together like a comb. This architecture minimized seek times by removing the need to reposition heads between disks and initiating seeks near disk centers, reducing maximum access time to approximately one hundred eighty milliseconds.

The IBM1301 also pioneered aerodynamically designed flying heads that hover on a thin air cushion above disk surfaces, allowing closer head-to-disk spacing and enhancing overall performance.

Connection was managed through the IBM7631 File Control unit, enabling compatibility with either an IBM1410 or a member of the IBM7000 series computers, as well as permitting shared usage between two systems.

Leasing costs for Model1 were $2,100 monthly or $115,500 for outright purchase; Model2 leased at $3,500 per month or could be bought for $185,000. The IBM7631 controller added $1,185 monthly or $56,000 if purchased. All models were discontinued by approximately1970.

IBM 1302

Launched in September 1963, the IBM 1302 Disk Storage Unit increased storage capacity fourfold compared to the 1301, reaching 117 million 6-bit characters per module. It offered an average access time of 165 milliseconds and data transfer speeds of 180,000 characters per second, more than twice as fast as its predecessor. Each module incorporated two separate access mechanisms dedicated to the inner and outer cylinder regions. The Model 2 version doubled the storage by stacking two modules together. Monthly leasing fees were set at $5,600 for Model 1 and $7,900 for Model 2; purchase prices stood at $252,000 and $355,500 respectively. Adding the IBM 7631 controller increased costs by $1,185 per month or $56,000 for outright acquisition. Production of the 1302 ceased in February 1965.

IBM 1311

Introduced on October 11, 1962, the IBM 1311 Disk Storage Drive was designed for mid-range business and scientific computer systems. It stored two million characters on a removable IBM 1316 disk pack. Throughout the 1960s, seven different models were released and all were phased out by the early 1970s.

An IBM 1316 Disk Pack measures about four inches in height, weighs roughly ten pounds, and contains six disks each measuring fourteen inches in diameter with ten usable recording surfaces. The disks rotate at a speed of 1500 revolutions per minute. Each surface is divided into 100 tracks with 20 sectors per track, and each sector holds 100 characters. The disk pack is enclosed in a transparent plastic casing featuring a locking handle to ensure secure mounting and removal.

The IBM 1311 lineup comprises seven models:

  1. Master drive compatible with IBM 1440, 1460, or 1240 systems; capable of controlling up to four Model 2 slave drives. Released in 1962 and withdrawn in 1971.
  2. Slave drive designed to work with master drives; introduced in 1962; discontinued in 1975.
  3. Master drive for IBM 1620 or IBM 1710 systems; supports up to three slave drives; no additional features; phased out in 1971.
  4. Master drive tailored for IBM 1401 systems; manages up to four slaves; retired in 1971.
  5. Master drive compatible with IBM 1410, IBM 7010, or IBM 7740 systems; includes standard Direct Seek functionality; withdrawn in 1971.
  6. Presumed master drive introduced in 1968; discontinued in 1971.
  7. Presumed slave drive introduced in 1968; withdrawn in 1971.

Available optional enhancements included:

  • Direct Seek: eliminates the need to return to track zero before accessing a new track.
  • Scan Disk: allows rapid automatic searching capabilities.
  • Seek Overlap: permits concurrent seek operations alongside read/write processes when multiple drives are active.
  • Track Record: increases storage capacity by recording one large record per track rather than multiple sectors, raising total capacity to around eighteen million bits.

Master drives (Models 1,3,4,5) are equipped with additional power supplies and control circuitry and are approximately one foot wider than Model 2 slave drives.

IBM 2302

The IBM 2302 serves as the System/360 counterpart to the IBM 1302, featuring track formatting aligned with S/360 DASD standards instead of those used in the earlier 7000 series. It consists of a fixed module containing twenty-five platters utilizing forty-six surfaces for data recording. The Model 3 configuration includes a single module, while Model 4 incorporates two modules. Each module is equipped with two separate access mechanisms—referred to as access groups—dedicated respectively to the innermost and outermost sets of approximately two hundred fifty cylinders each. Each access mechanism employs one read/write head per track. The average rotational latency is seventeen milliseconds with a maximum delay of thirty-four milliseconds, and each access group has a maximum seek time of one hundred eighty milliseconds. Tracks hold up to four thousand nine hundred eighty-five bytes each; after formatting and including alternate tracks, each module’s capacity totals approximately one hundred twelve megabytes. The IBM 2302 connects to mainframe systems through the IBM 2841 Storage Control Unit.

IBM 2305

Launched in 1970, the IBM 2305 fixed-head storage unit and IBM 2835 Storage Control initially interfaced with the 360/85 and 360/195 systems through the IBM 2880 Block Multiplexor Channel.

With the debut of System/370’s Virtual Storage, the 2305 became a preferred paging storage solution on systems including the 3155, 3165, 3158, 3168, 3033, 4341, and 3081 (the latter requiring specialized microcode). It was also optimized for handling frequently accessed small data sets such as catalogs and job queues.

The 2305-1 model provides a capacity of 5.4 MB, delivering data at a rate of 3.0 MB/s via a 2-byte channel interface, with an average access latency of 2.5 ms. The larger-capacity 2305-2 offers 11.2 MB at a slower data transfer speed of 1.5 MB/s and an average access time of 5 ms.

Engineered for rapid and continuous access to modest data volumes, the 2305’s combination of capacity and speed made it well-suited for system-resident tasks, work files, job queues, indices, and other frequently used datasets. Its quick response time also supported heavily utilized systems requiring paging devices capable of handling over 1.5 transactions per second.

IBM 2311

The IBM 2311 Disk Storage Drive debuted in 1964 alongside the 2841 Control Unit, serving multiple IBM System/360 models as well as the IBM 1130 and IBM 1800. It also connected directly to System/360 Model 20 and Model 25 machines. All units utilized removable IBM 1316 Disk Packs, originally developed for the IBM 1311.

The Model 1 connects to most IBM mainframes via the 2841 Control Unit; for the System/360 Model 25, it links through a Disk Attachment Control providing equivalent functionality. These configurations employed IBM's count key data variable record length format within disk packs.

Models 11 and 12, tailored for the System/360 Model 20’s integrated control unit, used a fixed sector layout. Due to these formatting distinctions, disk packs are not interchangeable between Model 1 and Models 11 or 12.

Mechanically akin to the IBM 1311, the IBM 2311 enhanced recording density by storing up to 7.25 megabytes on a six-platter removable disk pack. It incorporated ten read/write heads mounted on a hydraulically actuated arm featuring mechanical detents for precise track positioning. Each platter surface contained 200 tracks plus three optional defect management tracks. The average seek time was approximately 85 ms with a data transfer rate of about 156 kB/s.

Uniform electrical interfaces across System/360 models allowed third-party vendors to manufacture plug compatible disk drives, encouraging a competitive market for IBM-compatible storage devices.

IBM 2314 Disk Access Storage Facility Model 1

Released in April 1965, the IBM 2314 Disk Access Storage Facility Model 1 was compatible with both System/360 and System/370 platforms. Featuring a Two Channel Switch capability, it could connect concurrently to two channels. Its disk mechanism resembled that of the IBM 2311 but offered increased data density.

This drive stored roughly 29 million characters on an IBM 2316 disk pack composed of eleven platters (yielding twenty recording surfaces). The actuator carried twenty read/write heads hydraulically positioned with mechanical detents across each surface’s set of approximately 200 tracks. Initial access times were similar to those of the IBM 2311 but improved over time due to enhancements in the hydraulic actuator technology. The data transfer rate doubled to around 310 kB/s.

The Model 1 was marketed as nine drives bundled with a storage control unit, arranged into one single-drive module plus two modules containing four drives each. Drives were installed in drawers for convenient disk pack handling, earning them the nickname "Pizza Ovens." At any given time, only eight drives were active; the ninth served either as a hot spare or for offline maintenance purposes. Drive addresses were configured using user-swappable plugs that allowed physical reassignment of system addresses and designation of spare units.

An upgrade via the 2844 Control Unit enabled two System/360 channels to access separate drives within the facility simultaneously.

Subsequent versions of the IBM 2314 introduced further enhancements:

IBM 2314 Direct Access Storage System - Variants

In 1969, IBM separated the original facility into distinct models, each supporting up to nine drives (with eight accessible online) connected to a 2314 Storage Control. These included:

  • The 2312 Disk Storage, which was a single-drive unit.
  • The 2313 Disk Storage, featuring four drives.
  • The 2318 Disk Storage, consisting of two drives.

IBM 2319

To compete with plug-compatible manufacturers offering storage similar to the 2314, IBM launched in 1970 an economical three-drive module named the 2319. This model was derived by removing one disk from the four-drive 2313 and rebranding it as the 2319 A1, marketed at a significantly lower lease cost. This approach reduced pricing for new clients while preserving higher fees for existing customers. The 2319-A1 connects to integrated controllers designed for System/370 Models 135 and 145. Traditional 2314 DASD units such as the 2312 or 2318 can also be linked to the 2319-A1. The subsequent 2319 B series supports configurations of three, six, or nine drives connected to a new 2314 Model B Storage Control Unit.

IBM 3310

Released on January 30, 1979, the IBM 3310 Direct Access Storage Device was aimed at IBM 4331 midrange computer systems. Each drive provided a storage capacity of 64.5 MB and utilized fixed-block architecture (FBA), compatible with DOS/VSE and VM operating systems running on S/370 platforms.

IBM 3330

The IBM 3330 Direct Access Storage Facility, internally codenamed Merlin, debuted in June 1970 for IBM System/370 and System/360/195 computers. The initial offerings included a two-drive Model 1 and a single-drive Model 2. Removable disk packs had a capacity of 100 MB each, with access times averaging 30 ms and data transfer speeds reaching 806 kB/s. A notable feature was integrated error correction using fire codes, which improved reliability and lowered costs by allowing tolerance for minor disk surface defects.

The original configuration consisted of one storage control unit (3830 Model 1) attached to a chain of up to four drives (with a maximum of eight drives per chain). In August 1972, IBM introduced the 3830 Model 2 Storage Control alongside the 3333 Disk Storage and Control, which separated control functions: the director-style 3830 could oversee multiple chains, while the first unit in each chain—the 3333—contained both a controller and two drives, capable of managing up to three additional connected 3330 units (eight drives total). The 3830 Model 2 could support two such chains (up to sixteen drives), with optional string switches allowing connection to two storage controls.

In 1973, IBM launched double-density (-11) variants—3333–11, 3330-11, and 3336–11—that doubled disk pack capacity to 200 MB. Mixing single- and double-density drives within the same chain was not supported. Field upgrades were feasible but required converting drives and migrating all data.

The IBM 3330 series was discontinued in 1983.

IBM 3340 and IBM 3344

While the IBM 3340 and IBM 3344 share many characteristics, only the IBM 3340 can function as the head of a chain; there are no A model versions of the IBM 3344, meaning that a IBM 3344 must be connected under an IBM 3340 A model acting as head of chain.

IBM 3340

Introduced in March 1973 for the IBM System/370, the IBM 3340 Direct Access Storage Facility, known by its codename Winchester, debuted with three variants: the 3340-A2 featuring two drives plus a controller, the B2 model with two drives, and the B1 model containing a single drive. Up to eight B-units could be linked to an A2 controller.

This system utilized removable data modules that integrated the head and arm assemblies; during mechanical load and unload operations, the module’s access door would open, eliminating the need to detach covers as required by earlier disk pack designs. The device offered a 25 ms access time and supported data transfer rates of 885 kB/s. Three types of IBM 3348 Data Modules were available: one with a 35 MB capacity and two versions holding 70 MB each—one of these included 500 KB of fixed heads to enable faster access. The IBM 3340 incorporated error correction features and remained in production until its retirement in 1984.

Developed under Ken Haughton in San Jose, the initial concept was based on two removable 30 MB modules, which inspired the Winchester nickname derived from the Winchester .30-30 rifle. Although storage capacities grew over time, the codename persisted.

A notable breakthrough was its economical head design that permitted heads to land on and lift off from spinning disks without unloading. This "Winchester technology" greatly simplified the head and arm mechanisms while reducing costs, eventually becoming a widespread industry standard.

The term Winchester or colloquially Winnie continued to be used through the early 1990s as a generic label for hard disk drives but has since fallen out of common use.

IBM 3344

The IBM 3344 closely resembles the 3340 but differs by employing fixed media instead of removable IBM 3348 data modules. Each spindle contains four logical drives, each providing storage capacity equivalent to a single 3348–70 module. This model is offered exclusively in dual drive configurations and does not include an A (head of string) variant. The 3344-B2F version incorporates fixed heads over certain cylinders on both drives. Both the 3344-B2 and 3344-B2F require a 3340-A2 or 3340-A2F unit to serve as head of string. Internally, the IBM 3344 shares its architecture with the IBM 3350, differing solely in control unit microcode.

IBM 3350

Launched in 1975 for IBM System/370, the IBM 3350 Direct Access Storage Facility carried the codename Madrid. It featured sealed, non-removable head-disk assemblies (HDAs) that integrated both head and arm components, establishing a design precedent for subsequent IBM DASD products. Each HDA contained 555 cylinders, utilized 30 read/write heads, and stored approximately 19,069 bytes per track, resulting in an overall capacity near 317 MB.

The lineup included models A2, A2F, B2, B2F, C2, and C2F; each housed two HDAs. The A2 and A2F models incorporated an additional electronic board that enabled connection to the control unit; these units functioned as controllers or heads of string. Drives were organized into strings beginning with an A2 or A2F unit followed by up to three B2 units or combinations involving C2 units. Typically, the A2 unit contained a string switch allowing simultaneous I/O operations on different HDAs via connections to two storage control units. Compatible controllers included the 3830 Model 2, Integrated Storage Controllers (ISC) within CPUs such as models 3148/3158/3168, as well as later backward-compatible controllers like the 3880.

The C2 units also featured controllers acting as secondary paths but primarily served as backups should an A unit’s controller fail. Valid IBM 3350 string configurations encompassed -A, -AB, -ABB, -ABBB, -AC-, -ABC-, and -ABBC- arrangements.

Models designated with "x2F" (such as A2F) incorporated fixed head zones spanning the first five cylinders on both HDAs, eliminating seek delays within this region. This feature was optimized for frequently accessed checkpoint files such as those used by HASP or JES2 spool systems, thereby enhancing performance by minimizing head movement. Additionally, it supported TSO swap data along with system swap data under MVT, SVS, and MVS operating systems—improving efficiency during context switches between users or batch jobs.

Production of the IBM 3350 series concluded in September 1994.

IBM 3370

Debuting in January 1979, the IBM 3370 Direct Access Storage Device was designed primarily for IBM 4331, 4341, and System/38 midrange systems. It incorporated seven fixed 14-inch platters, delivering a total capacity of 571 MB per unit. Notably, it was the pioneer in utilizing thin-film head technology, a development originating from IBM's Thomas J. Watson Research Center. The 3370 featured a fixed-block architecture and was compatible with DOS/VSE and VM operating systems running on S/370 platforms.

IBM 3375

The IBM 3375 served as a complementary model employing count key data architecture, tailored for OS/360 and its successor operating systems.

IBM 3380

Released on June 11, 1980, the IBM 3380 incorporated thin-film head technology and offered a storage capacity of 2.52 GB per unit, achieved through two hard disk assemblies each equipped with two independent actuators accessing 630 MB. It provided a data transfer speed of 3 MB/s and an average access time of 16 milliseconds. Initial pricing ranged between $81,000 and $142,200. Due to tribological challenges affecting the interaction between heads and media, shipments commenced in October 1981.

The default setup comprised one A-unit along with up to three B-units; each IBM 3380 contained four devices, facilitating strings of up to sixteen devices. Typically, these were connected to a 3880 storage control unit featuring dual paths, enabling two concurrent I/O operations targeting separate HDAs.

In February 1985, IBM introduced the Extended Capability Models (3380 E), which doubled the capacity to 5.04 GB per unit by utilizing two actuators with 1.26 GB each. Later, in August 1987, the Model K expanded capacity to 7.562 GB per unit with two actuators of 1.89 GB each and offered an optional four-path mode. This enhancement allowed up to thirty-two devices per string when linked to a 3990 storage control unit, supporting four simultaneous I/O operations.

The IBM 3380 series consisted of twelve models: six A-units (which served as string heads with controller logic interfacing with storage units), five B-units (connecting to either A- or C-units), and one C-unit (providing direct channel connection). Production continued until May 1996, resulting in an impressive fifteen-year lifespan that surpassed typical disk drive longevity.

IBM 3390

Introduced in November 1989, the IBM 3390 Direct Access Storage Device family provided storage capacities reaching up to 22 gigabytes distributed across multiple drives. Pricing varied from $90,000 to $795,000 depending on system configuration and total capacity.

A typical IBM 3390 string includes a central A unit containing four or eight devices and can be optionally extended by one or two B units holding as many as twelve devices each. Operating in four-path mode when connected to a 3990 storage control unit, the system supports a second string for an aggregate maximum of sixty-four devices per subsystem.

Each Hard Disk Assembly (HDA) houses two actuator-head units along with platters. The initial Model 1 HDAs offered an unformatted capacity of 1.89 GB; Model 2 increased this figure to 3.78 GB per HDA. The Model 3 upgrade released in 1991 enhanced capacity by fifty percent to reach 5.67 GB per HDA, while the Model 9 introduced in 1993 tripled capacity to approximately 11.3 GB per HDA.

In contrast to earlier DASD designs that relied on large AC motors driving HDAs via belts, the IBM 3390 employed DC motors integrated directly within the drive enclosure. The Model 9 represented IBM’s final announcement of a Single Large Expensive Disk (SLED) drive.

IBM 9345

In November 1990, IBM launched the IBM 9345 hard disk drive as a Request Price Quotation (RPQ) tailored for its SuperComputing Systems Extensions (SCSE). Created at IBM's San Jose facility under the project name Sawmill, this drive offered a maximum capacity of 1.5 GB within a full-height 5¼-inch enclosure, utilizing eight 130 mm platters. It was groundbreaking as the first HDD to incorporate Magnetoresistive (MR) read/write heads.

IBM 9340

The IBM 9340 direct access storage device was introduced in October 1991 as a member of the 9340 channel-attached count key data (CKD) DASD subsystem family designed for IBM mainframe systems, including the ES/9000 series processors. The Model 1 configuration consisted of two 1.0 GB drives, whereas Model 2 comprised two 1.5 GB drives.

In terms of operation, the 9340/9345 series shared many features with the IBM 3990/3390 family but differed by lacking the non-volatile RAM cache present in the 3990 and offering a reduced maximum block length compared to the 3390. The operating system’s Input/Output Supervisor (IOS) detected these devices through the IECCINIT initializer, which accounted for their absence of non-volatile cache and assigned device types accordingly.

9330 family of disk drives

  1. The 9331 Diskette Unit models 1 and 11 were equipped with a single 8-inch floppy disk drive; models 2 and 12 utilized one 5-inch floppy disk drive.
  2. The 9332 Direct Access Storage Device incorporated the IBM 0667 hard disk drive.
  3. The 9333 High Performance Disk Drive Subsystem employed either IBM 0664 or IBM 0681 hard disks depending on the specific model.
  4. The 9334 Disk Expansion Unit connected between one and four SCSI hard drives to RS/6000 systems.
  5. The 9335 Direct Access Storage Subsystem featured the "Kestrel" hard disk drive developed at IBM Hursley in the UK—an 850 MB device consisting of three 14-inch platters and dual rotary actuators enabling access to multiple surfaces. This rack-mountable unit was introduced alongside the IBM 9370 Information System in October 1986. There are no known OEM versions of this product.
  6. The 9336 Disk Unit utilized the IBM 0681 hard disk drive, also known as Redwing.
  7. The 9337 Disk Array Subsystem incorporated IBM's IBM 0662 (Spitfire) or IBM 0663 (Corsair) hard drives.

IBM 2310

The IBM 2310 Removable Cartridge Drive debuted in 1964 with the IBM 1800 and was subsequently released in late 1965 with the IBM 1130, likely shipping first with the latter. It stored a total of 512,000 sixteen-bit words (equivalent to 1,024,000 bytes) on an IBM 2315 cartridge, which contained a single oxide-coated aluminum platter housed inside a plastic casing featuring openings for both the read/write arm and two heads.

IBM 5444

Introduced in September 1969 as part of System/3, the IBM 5444 was developed at IBM’s Hursley laboratory in England under the codename Dolphin. It utilized a single-disk cartridge (the IBM 5440) that contained one fourteen-inch platter. Three models were available:

  • Model 1: included one fixed and one removable disk, each with one hundred tracks per surface; cartridge capacity totaled approximately 1.23 MB
  • Model 2: featured one fixed and one removable disk, each having two hundred tracks per surface; capacity reached about 2.46 MB
  • Model 3: contained only one removable disk with two hundred tracks per surface; capacity was roughly 2.46 MB

IBM 62GV

First shipped in May of 1974 from IBM’s Hursley facility in the UK under the code name Gulliver, the IBM 62GV initially provided a storage capacity of five megabytes. Subsequent versions increased this to ten megabytes (designated as model 62TM) and later fourteen megabytes. It employed a Swinging Arm actuator mechanism paired with a single fourteen-inch platter. This actuator design, invented at Hursley, became IBM’s most widely licensed electro-mechanical innovation, gaining industry-wide adoption throughout the decade and remaining an industry standard nearly four decades later, with over ten billion units produced globally. Approximately one hundred seventy-seven thousand units of the IBM 62GV were shipped, making it the first hard disk drive to surpass one hundred thousand units sold.

OEM and Small Systems Hard Drives

This segment details HDDs produced by IBM intended for OEM distribution and use in IBM’s smaller systems, including the System/3, System/32, /34, /36, and AS/400 series. Drives are cataloged by their OEM model designations and organized according to their initial shipment dates.

IBM 0680

Introduced in 1979, the 0680 served as the 3310 direct access storage device for most IBM small systems and entry-level System/370 models. Officially announced as the 0680 OEM variant in September 1981, it was developed at IBM’s Hursley facility in the UK under the project name Piccolo. This model incorporated six 8-inch (210 mm) platters, providing a starting capacity of up to 65MB, and featured an enhanced rotary actuator.

A higher-capacity version known as the 62SW appeared in June 1984; however, its sales were limited since its cost per megabyte was comparable to that of the 62GV.

IBM 0676

The 0676 became available in November 1982 as part of the 5247 Disk Storage Unit for the IBM System/23 Datamaster. Developed at IBM Rochester, Minnesota under the designation 21ED, this 8-inch HDD initially offered capacities of either 15 or 30 MB using two or four 210 mm platters. In 1983, it was incorporated into the S/36’s 5360 System Unit. Capacity was doubled in 1984 by increasing track density per surface, and this enhanced drive was subsequently included in the System/36’s 5362 System Unit.

IBM 0665

Released in October 1985 within the PC AT (5170) system unit, the 0665 was developed at IBM Rochester with the internal codename "Pixie." This 5-inch hard drive came in capacities of 20, 30, and 44 MB.

IBM 0667

The 0667 appeared in August 1986. Created at IBM Rochester under the codename "Grant," this full-height, 5-inch ESDI hard drive offered a maximum capacity of 70 MB across up to four 130 mm platters. It was available as an optional component for select PC RT models (6150, 6151, 6152) and System/36 Model System Units (5363, 5364).

IBM 0669

Shipping in 1987, the 0669 was developed at IBM Rochester, Minnesota under the project name "Grant-Prime." This full-height, 5-inch HDD supported capacities up to 115 MB on four 130 mm platters and functioned as the internal storage device for both the System/36 5363 and Series 1 4956 System Units.

IBM 0671

Also introduced in 1987, the 0671 was developed at IBM Rochester with the codename "Lee." It featured an ESDI full-height, 5-inch form factor with up to eight 130 mm disks and a maximum capacity of up to 316 MB. This model represented IBM’s first implementation of a thin metal film recording surface. By 1988, it was incorporated into the IBM AS/400’s 9404 System Unit, which could house two or optionally three of these drives.

IBM 0661

Launched in 1989 as model number 371, the 0661 was designed collaboratively by IBM Rochester and Hursley under the codename "Lightning." It was a SCSI hard drive featuring up to eight 95 mm platters (14 heads) with an initial capacity of 320 MB. A subsequent "Turbo" version with a capacity of approximately 400 MB followed in 1990. This drive became a standard component across prominent IBM systems such as the AS/400 System Unit Model CXX.

IBM 0681

The 0681 began shipping from IBM Hursley, UK in April 1990 under the project name Redwing—marking the final hard drive developed at that site. This full-height, five-inch HDD contained twelve 130 mm platters and offered a top capacity of up to approximately 857 MB. It was also IBM’s inaugural HDD employing PRML data decoding technology. The drive powered the release of the 9333 Disk Drive Subsystem in early 1992; later that year by May, a higher-density variant with a capacity of around 1.07 GB became available.

IBM 0663

Introduced in late 1991 under the codename "Corsair," the 0663 was a compact 3-inch hard disk drive with a half-height profile measuring 1.6 inches. It delivered up to 1 GB of storage across eight 95 mm platters. This drive appeared in select PS/2 and RS/6000 systems and marked IBM's first OEM HDD to utilize Magnetoresistance (MR) head technology.

IBM 0664

The 0664 debuted in November 1992, developed at IBM Rochester, Minnesota, under the codename "Allicat." This full-height 5-inch HDD (3.25 inches tall) combined two 3-inch drives to provide a maximum capacity of 2.013 GB using up to eight 95 mm platters.

IBM 0662

Released in June 1993 and known internally as "Spitfire," the 0662 was a full-height (1 inch) 3-inch HDD developed at IBM Rochester. It offered 1.05 GB of storage on three disks or five disk surfaces and served as the internal hard drive for the 9336 Disk Unit and the 9337 Disk Array.

Floppy disk drive

IBM was a pioneer in floppy disk technology, launching the first 8-inch floppy disk drive in 1971 as a read-only device for program loading, followed by its initial read/write model in 1973 with the introduction of the 3740 Data Entry System. Although IBM set early benchmarks for 8-inch floppy drives, it never marketed these drives independently, allowing the broader industry to develop freely.

At one time, IBM was the largest original equipment manufacturer (OEM) buyer of 5-inch floppy disk drives. Its selection of two-sided, 48 tracks-per-inch models helped establish this standard format across the industry. Despite preparing to produce these and smaller floppy formats, IBM ceased all such manufacturing efforts by 1985. Notably, its 1983 initiative to OEM the 4-inch DemiDiskette did not succeed.

"Star" series of HDDs

On October 17, 1994, IBM Storage Systems unveiled three new hard disk drive families: the Travelstar series featuring 2-inch drives for laptops, the Deskstar lineup with 3-inch drives designed for desktop computers, and the Ultrastar series of high-performance 3-inch drives aimed at demanding systems.

IBM's first HDD versus its last HDDs

The following table compares IBM's very first hard disk drive, the RAMAC 350, with three final models from its "Star" series of OEM HDDs. It illustrates substantial improvements in storage capacity and performance alongside significant reductions in physical size and cost over a span of nearly five decades.

Parameter (units) RAMAC 350 Ultrastar 146Z10 Deskstar 180GXP Travelstar 80GN Maximum improvement over 46 years
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 consumption (watts) Approx. 2374 watts (8100 BTUs/hour), up to 5500 VA depending on model 16 10.3 1.85 1,283
Power efficiency (megabytes/watt) 0.0016 9,125 17,476 43,243 27,375,856
List price (Template:US$) \$34,500 (\$234,000 adjusted to 2002 dollars) \$1200 \$360 \$420
Cost per megabyte (Template:US$) \$9,200 (\$68,000 adjusted to 2002 dollars) \$0.0082 \$0.0020 \$0.0053
Areal density (megabits/in²) 0.002 26,263 46,300 70,000
Areal density (kilobits/mm²) 0.003 40,708 71,765 108,500
Volumetric density (gigabytes/in³) 0.00000003 6 8 20
Volumetric density (megabytes/cm³) 0.000002 388 478 1,203
Rotational latency (ms) 25 3 4 7
Average seek time (ms) 600 5.9 10.2 12
Data transfer rate (megabytes/s) 0.001 103 29.4 43.75

DASD Devices Distinct from HDDs and FDDs

Within certain IBM operating systems, hard disk drives (HDDs) and floppy disk drives (FDDs) are categorized under the umbrella of DASDs (direct access storage devices). Additional storage technologies classified as DASDs encompass:

IBM 7320 Drum

The IBM 7320, launched in 1962, represents a magnetic drum storage unit.

IBM 2301 Drum

Introduced in the late 1960s, the IBM 2301 is another example of a magnetic drum-based storage device.

IBM 2303 Drum

Debuted in 1964, the IBM 2303 also utilizes magnetic drum technology for data storage.

IBM 2321 Data Cell

The IBM 2321 Data Cell, revealed in 1964, employs short strips of magnetic tape to retain information. It accommodates ten removable cells, each with a capacity of 40 MB, resulting in a total storage capability of 400 MB.

IBM 3850 Mass Storage System

Announced in 1974, the IBM 3850 Mass Storage System is a tape cartridge library system that stages data onto IBM 3330 or 3350 disk drives, presenting these as virtual drives to the host system.

See also

External links

Related profiles

IIBM 1311IIBM 0661IIBM 353IIBM 355
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