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IBM 0664

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Adapted from the English Wikipedia article IBM 0664, available under CC BY-SA 4.0Updated 9 August 2025
IBM Magnetic Disk Storage
Company typeDivision
IndustryComputer storage
Founded1956
Defunct2003
FateDivested hard disk drive operations to Hitachi
ProductsHard disk drives, floppy disk drives
ParentIBM

IBM was engaged in the production of magnetic disk storage units from 1956 until 2003, at which point it divested its hard disk drive operations to Hitachi. IBM pioneered both the hard disk drive (HDD) and floppy disk drive (FDD), with numerous technological advancements originating from its workforce. The core mechanical architecture of hard disk drives has remained largely unchanged since the introduction of the IBM 1301, and key performance benchmarks have adhered to consistent standards dating back to the 1950s. This product category has experienced significant decreases in cost and physical dimensions, alongside dramatic improvements in capacity and speed.

From 1969 through the mid-1980s, IBM produced 8-inch floppy disk drives, though it did not become a prominent manufacturer of the smaller 5.25- or 3.5-inch variants. While IBM consistently marketed its magnetic disk drives, it only began offering them under original equipment manufacturer (OEM) agreements starting in 1981. By 1996, IBM discontinued manufacturing hard drives exclusively for its own systems and transitioned to supplying all HDDs as OEM products.

IBM employed various designations for its magnetic disk storage devices, such as direct-access storage device (DASD), disk file, and diskette file. For clarity and alignment with industry usage, this article refers to them as hard disk drive (HDD) and floppy disk drive (FDD).

IBM 350

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

Engineered to support real-time accounting applications, the IBM 350 stored five million six-bit characters (equivalent to 3.75 MB) across fifty-two disks measuring 24 inches in diameter. It utilized a total of 100 recording surfaces and tracks that rotated at a speed of 1200 rpm. The data transfer rate achieved was approximately 8,800 characters per second. The read/write heads were moved both vertically and radially by an access mechanism to select specific data tracks. Throughout the late 1950s, several enhanced versions were released. The RAMAC 305 system with the IBM 350 was leased at $3,200 per month and remained available until its withdrawal in 1969.

The patent US 3,503,060 emerging from the RAMAC initiative is regarded as a seminal document for disk drive technology. Despite initial cancellation by IBM’s Board due to concerns about disrupting its punch card business, development proceeded under authorization from IBM’s president.

The physical dimensions of the unit were approximately 60 inches in length, 68 inches in height, and 29 inches in width, with a weight near one ton—necessitating forklifts and cargo aircraft for transportation. Hitachi Global Storage Technologies noted that although capacity could have been expanded beyond five million characters, IBM’s marketing hesitated to promote higher-capacity models at that time. Nevertheless, models with double capacity were announced in January 1959 and shipped later that year.

In recognition of its historical significance, the RAMAC 350 Disk File was designated an International Historic Landmark by The American Society of Mechanical Engineers in 1984. A restoration effort began in 2002 led by Al Hoagland in partnership with Santa Clara University. By 2005, the unit was relocated to the Computer History Museum in Mountain View, California, where it is showcased as part of the Revolution exhibition and demonstrated publicly.

IBM 353

The IBM 353, designed to work alongside the IBM 7030, resembled the IBM 1301 but offered a higher data transfer speed. It provided a storage capacity of 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 the first disk drive to implement one read/write head per surface, each hovering on a cushion of compressed air, similar to the IBM 350 disk storage (RAMAC). Production versions employed self-levitating heads comparable to those found 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 featured up to three access arms instead of a single one as in the IBM 350. The device stored six million decimal digits along with 600,000 sign indicators. Data transfer occurred by moving entire tracks between the magnetic core memory of the 653, an optional component for the IBM 650 that held sixty signed 10-digit words—adequate for a single disk track or tape record—and included two additional unrelated functions.

IBM 1405

Announced in 1961, the IBM 1405 Disk Storage Unit was tailored for the IBM 1400 series of mid-range business computers. Model 1 provided storage for ten million alphanumeric characters (60 million bits) across 25 disks; Model 2 doubled this capacity to twenty million characters (120 million bits) using fifty disks. The disks were stacked vertically on a spindle rotating at 1,200 revolutions per minute.

Each disk surface contained 200 tracks divided into five sectors; sectors numbered 0 through 4 were located on the upper side, while sectors 5 through 9 were on the lower side. Each sector accommodated between 178 and 200 characters. One to three fork-shaped access arms, each equipped with two read/write heads (one on top and one on bottom), moved vertically across disks and horizontally across tracks under electronic control. 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 up to 800 milliseconds for Model 2. Model 2 contained about 100,000 sectors capable of holding either 200 characters in move mode or 178 characters in load mode, which included an additional word mark bit per character. Model 1 had roughly half that number of sectors.

IBM 7300

The IBM 7300 Disk Storage Unit was engineered for use with the IBM 7070 system; a second model was announced in 1959. Nevertheless, the arrival of the IBM 1301 in 1961 diminished its appeal among customers of both the IBM 7070 and IBM 7074. The technology incorporated in the IBM 7300 shared similarities with that found in the IBM 350, IBM 355, and IBM 1405 units.

IBM 1301

Unveiled on June 2, 1961, the IBM 1301 Disk Storage Unit was intended for use with mainframe computers in the IBM 7000 series as well as the IBM 1410. Each module stored approximately twenty-eight million characters (168 million bits), or twenty-five million characters when paired with the IBM 1410. A module contained twenty-five large disks providing forty user-accessible recording surfaces and two hundred fifty tracks per surface. The Model 1 featured a single module; Model 2 stacked two modules vertically. Disks rotated at a speed of eighteen hundred revolutions per minute, delivering data at ninety thousand characters per second.

A significant innovation was the use of an individual arm and read/write head for each disk surface, moving collectively like a comb assembly. This design eliminated delays caused by repositioning heads between disks and reduced maximum access time to approximately one hundred eighty milliseconds. Additionally, the IBM 1301 was pioneering in employing aerodynamically shaped heads that floated on a thin air cushion above disk surfaces, enabling closer proximity and enhanced performance.

The unit interfaced through the IBM 7631 File Control, allowing it to operate with both IBM 1410 and IBM 7000 series systems or be shared between two computers.

Reflecting its advanced design, pricing for Model 1 was $2,100 per month for leasing or $115,500 for purchase; Model 2 leased at $3,500 monthly or could be bought for $185,000. The IBM 7631 controller carried an additional cost of $1,185 per month lease or $56,000 purchase price. All versions were phased out by around 1970.

IBM 1302

Released in September 1963, the IBM 1302 Disk Storage Unit enhanced the IBM 1301 by increasing its capacity fourfold, achieving storage of 117 million 6-bit characters per module through advanced recording methods. Each module incorporated two separate access mechanisms dedicated to the inner and outer cylinders, improving data retrieval speed. The Model 2 variant 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, with purchase prices of $252,000 and $355,500 respectively; the IBM 7631 controller was available for an additional lease cost of $1,185 per month or a purchase price of $56,000. The IBM 1302 was discontinued in February 1965.

IBM 1311

Introduced on October 11, 1962, the IBM 1311 Disk Storage Drive catered to medium-sized business and scientific computing needs. It utilized a removable IBM 1316 disk pack containing six 14-inch disks with ten recording surfaces, capable of storing 2 million characters. These disks rotated at 1500 rpm and featured read/write heads mounted on hydraulic actuators. Each surface was divided into 100 tracks with 20 sectors per track; each sector held 100 characters.

Throughout the 1960s, seven different models were launched and eventually phased out by the early 1970s. The initial drive functioned as a "master" unit housing the controller and could manage several Model 2 "slave" drives across various IBM systems such as the IBM 1401, IBM 1440, and IBM 1410. Master units differed in capabilities including Direct Seek functionality and control capacity.

Available optional features included:

  • Direct Seek: Removes the need to return to track zero before seeking a new track.
  • Scan Disk: Facilitates rapid automated searching.
  • Seek Overlap: Permits simultaneous seek and read/write operations across multiple drives.
  • Track Record: Enhances capacity by recording one large record per track rather than multiple sectors, increasing total storage to about 18 million bits.

Master drives (Models 1,3,4,5) contained extra power supplies and control circuitry and were physically wider than Model 2 slave units.

IBM 2302

The IBM 2302 serves as the System/360 counterpart to the 1302, featuring track formatting adapted for S/360 DASD architecture instead of that used in the IBM 7000 series.

It employs a fixed module consisting of 25 platters with recording surfaces on 46 sides. The Model 3 includes one such module; Model 4 incorporates two. Each module is equipped with two independent access mechanisms—one dedicated to the innermost 250 cylinders and another to the outermost 250—referred to as access groups. Every access mechanism provides a single read/write head per track. Average rotational latency is approximately 17 milliseconds with a maximum of 34 milliseconds; maximum seek time per access group is around 180 milliseconds. Each track holds about 4,985 bytes; after formatting and accounting for alternate tracks, each module offers roughly 112 MB of storage. The IBM 2302 interfaces with IBM mainframes through the IBM 2841 Storage Control Unit.

IBM 2305

Introduced in 1970 alongside the IBM 2835 Storage Control Unit, the IBM 2305 fixed-head storage device initially connected to System/360 models such as the 360/85 and 360/195 via the IBM 2880 Block Multiplexor Channel.

During the System/370 period with Virtual Storage, demand for the IBM 2305 surged as it was often employed as a paging device on systems including the IBM models 3155, 3165, 3158, 3168, 3033, 4341, and even the specially microcoded 3081. It was also well-suited for high-activity small data sets like catalogs and job queues.

The smaller model, the IBM 2305-1, provides a capacity of 5.4 MB with a data transfer rate of up to 3.0 MB/s over a two-byte channel interface and an average access time of approximately 2.5 milliseconds. The larger IBM 2305-2 doubles capacity to about 11.2 MB but offers a lower data rate of around 1.5 MB/s and an average access time near five milliseconds.

Designed for rapid continuous access to small volumes of data, the IBM 2305’s capacity and performance made it ideal for system-resident functions such as work files, job queues, indices, and frequently accessed data sets. Its swift response time rendered it particularly valuable as a paging device in heavily loaded environments processing more than one and a half transactions per second.

IBM 2311

The IBM 2311 Disk Storage Drive, introduced in 1964 alongside the 2841 Control Unit, was developed primarily for the IBM System/360 series but also compatible with the IBM 1130 and IBM 1800. It connected directly to the System/360 Model 20 and Model 25 systems. All units utilized the removable IBM 1316 Disk Pack, which had its origins with the IBM 1311.

The Model 1 attaches to most IBM mainframe systems via the 2841 Control Unit; for the System/360 Model 25, connection is established through a Disk Attachment Control offering similar capabilities. Disk packs employ IBM’s count key data format, which supports variable record lengths.

Models 11 and 12, designed for use with the System/360 Model 20’s built-in control, utilize fixed sector formatting. Due to these format differences, disk packs cannot be interchanged between Model 1 and Models 11 or 12.

While mechanically akin to the IBM 1311, the 2311 features enhanced recording technology and stores 7.25 megabytes on a removable disk pack comprising six platters. It incorporates ten read/write heads mounted on a hydraulically actuated arm that is mechanically positioned with detents for precise track alignment. Each disk surface contains 200 tracks plus three additional spare tracks for defect management. The average seek time is approximately 85 ms, with a data transfer rate of 156 kB/s.

The uniform electrical interface across System/360 models facilitated third-party production of plug compatible disk drives, encouraging a competitive market in IBM-compatible storage devices.

IBM 2314 Disk Access Storage Facility Model 1

Released in April 1965, roughly one year after the System/360 launch, the IBM 2314 supported both System/360 and System/370 platforms. Equipped with a Two Channel Switch, it allowed simultaneous connection to two channels. Although its disk mechanism resembled that of the 2311, it provided increased data density.

The device stored around 29 million characters on a removable IBM 2316 disk pack consisting of eleven disks measuring in diameter, offering twenty recording surfaces in total. It utilized twenty read/write heads mounted on a hydraulically actuated arm with mechanical detents. Each surface contained 200 tracks. Initial access times were comparable to those of the 2311 but improved over time due to actuator refinements. Data transfer speeds reached up to 310 kB/s, doubling that of its predecessor.

The original Model 1 configuration bundled nine drives under a single price point and included a storage control unit along with one single-drive module and two four-drive modules, totaling nine drives. These drives were installed in pull-out drawers for convenient disk pack handling and earned the nickname "Pizza Ovens" because of their distinctive appearance. Only eight drives could be accessed simultaneously; the ninth served as an offline spare for maintenance or replacement purposes. Each drive’s system address was determined by user-swappable plugs, enabling flexible address assignments and spare drive designation.

An optional 2844 Control Unit permitted two System/360 channels to access separate drives within the facility concurrently.

Further models expanded upon these foundational features:

IBM 2314 direct access storage facility - A series

In 1969, IBM segmented the storage system into distinct configurations that allowed connection of up to nine drives (with eight accessible online) to a 2314 Storage Control. These configurations included:

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

IBM 2319

To address competition from plug-compatible vendors offering alternatives to the 2314 storage subsystems, IBM launched the more affordable three-drive 2319 series in 1970. This was achieved by removing one drive from the four-drive 2313 module, rebranding it as the 2319 A1, and providing it at a significantly lower rental cost. This approach reduced expenses for new customers while preserving higher fees for existing clients. The 2319-A1 connects to integrated controllers designed for System/370 Models 135 and 145; it is also compatible with traditional 2314 DASD units such as the 2312 or 2318. The 2319 B series supports configurations of three, six, or nine drives linked to a newly introduced 2314 Model B Storage Control Unit.

IBM 3310

Unveiled on January 30, 1979, the IBM 3310 Direct Access Storage Device was aimed at IBM 4331 midrange computer systems. Each unit provided a 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, known internally as Merlin, debuted in June 1970 for IBM System/370 and System/360/195 environments. Initial offerings included the two-drive Model 1 and single-drive Model 2 variants. Removable disk packs stored 100 MB each, featuring access times of approximately 30 ms and data transfer speeds of 806 kB/s. A notable advancement was the integration of error correction utilizing fire codes to compensate for disk defects, thereby improving reliability and lowering operational costs.

Originally, one storage control unit (the 3830 Model 1) managed up to four physically connected drives arranged in a "string," with a maximum capacity of eight drives per string.

In August 1972, IBM released the 3830 Model 2 Storage Control alongside the 3333 Disk Storage and Control, which decoupled control units from drive strings. The upgraded 3830 functioned as a director-type controller overseeing multiple strings. The initial unit in each string, the 3333, combined a controller with two drives and could support up to three additional connected 3330 drives, allowing up to eight drives per string. The Model 2 controller could handle two such strings (up to sixteen drives total) and offered an optional string switch enabling dual control attachments.

In 1973, double-density (-11) models were introduced: the 3333–11, 3330-11, and 3336–11 Disk Packs doubled storage capacity to 200 MB. Mixing single- and double-density drives within the same string was not permitted. Upgrades from standard to -11 models were feasible in the field but required conversion of drives and data transfer.

The IBM 3330 was discontinued in 1983.

IBM 3340 and 3344

While the IBM 3340 and IBM 3344 share many characteristics, only the IBM 3340 can act as the head of a string; there are no A model versions of the IBM 3344, which must connect through an IBM 3340 A model serving as string head.

IBM 3340

Introduced in March 1973 for the IBM System/370, the IBM 3340 Direct Access Storage Facility—known by its code name Winchester—came in three variants: 3340-A2 (which included two drives and a controller), B2 (two drives), and B1 (a single drive). Up to eight B-units could be connected to one A2 controller.

This system utilized removable data modules that incorporated the head and arm assemblies; uniquely, the data module’s access door allowed mechanical loading and unloading without requiring cover removal, a departure from earlier disk pack designs. It offered an average access time of 25 milliseconds and data transfer rates reaching 885 kB/s. Three versions of the IBM 3348 Data Module were marketed: one with 35 MB capacity and two with 70 MB, one of which featured 500 KB of fixed heads for enhanced access speed. The design included error correction capabilities and remained in production until its discontinuation in 1984.

Engineered in San Jose under the leadership of Ken Haughton, the initial concept centered on two removable 30 MB modules, inspiring the Winchester nickname after the Winchester .30-30 rifle. Although storage capacities increased over time, this moniker endured.

A significant advancement was the economical head design permitting heads to land on and lift off from the disk surface during spin-up and spin-down without unloading. This "Winchester technology" simplified head and arm mechanisms, reducing manufacturing costs and complexity, and it soon became an industry standard for disk drives.

The term Winchester or colloquially Winnie remained widely used to describe hard drives well into the early 1990s but has since largely fallen out of favor.

IBM 3344

The IBM 3344 shares similarities with the 3340 but differentiates itself by employing fixed media rather than removable 3348 data modules. Each spindle accommodates four logical drives, each matching the capacity of a 3348–70 module. Available exclusively as dual-drive models, it lacks an A (head of string) variant. The 3344-B2F model varies from the 3344-B2 by incorporating fixed heads over certain cylinders on both drives. Both versions require a 3340-A2 or 3340-A2F unit to serve as head of string. Internally, the IBM 3344 mirrors the IBM 3350 architecture; distinctions are confined to microcode differences within the control unit.

IBM 3350

Released in 1975 for IBM System/370, the IBM 3350—code-named Madrid—featured sealed head-disk assemblies (HDAs) that integrated heads and arms into a non-removable unit. Its disk geometry comprised 555 cylinders, 30 heads, and 19,069 bytes per track, resulting in approximately 317 MB capacity per HDA. This sealed HDA design set a precedent for subsequent IBM DASD products.

The product line included models A2, A2F, B2, B2F, C2, and C2F, each containing two HDAs. Models A2 and A2F incorporated an additional electronic board enabling connection to the control unit; these often functioned as controllers or head-of-string devices. Typical configurations involved an A2 or A2F unit followed by up to three B2 units or combinations including C2 units. The A2 model frequently featured a string switch allowing connection to two storage control units simultaneously, facilitating concurrent I/O operations on separate HDAs.

Compatible storage control units encompassed the 3830 Model 2 and Integrated Storage Control (ISC) embedded in CPUs such as the IBM 3148, 3158, or 3168; later controllers like the IBM 3880 maintained backward compatibility. The C2 model contained a controller that served as a secondary path for itself and other units but was limited to connection with only one control unit; it primarily acted as a backup if the A unit's controller failed.

Permissible IBM 3350 configurations included strings designated -A, -AB, -ABB, -ABBB, -AC-, -ABC-, and -ABBC-.

Variants marked "x2F" (e.g., A2F) combined standard x2 features with fixed head sections spanning the first five cylinders to eliminate seek time within that range. This design enhanced performance for frequently accessed data areas such as HASP or JES2 checkpoints and improved system swap efficiency under TSO and MVS by reducing head movement during context switching.

The IBM 3350 series was officially retired from the market in September 1994.

IBM 3370

In January 1979, IBM launched the IBM 3370 Direct Access Storage Device tailored for IBM 4331, 4341, and System/38 midrange systems. This model incorporated seven stationary 14-inch platters, delivering a storage capacity of 571 MB per unit. Notably, the 3370 was the pioneer HDD to implement thin-film head technology, a development originating from the Thomas J. Watson Research Center during the late 1960s. It utilized a fixed-block design and was compatible with DOS/VSE and VM operating environments.

IBM 3375

The IBM 3375 served as a complementary device employing count key data architecture, which was essential for operating systems such as OS/360 and its subsequent versions.

IBM 3380

Debuting on June 11, 1980, the IBM 3380 adopted film head technology and offered a capacity of 2.52 GB per unit, composed of two hard disk assemblies each containing two actuators accessing 630 MB. It featured a data transfer rate of 3 MB/s alongside an average access latency of 16 milliseconds. Initial pricing spanned from $81,000 to $142,200. Due to tribological challenges between the heads and media surfaces, actual shipments commenced in October 1981.

A typical setup included one A unit plus up to three B units; each 3380 housed four devices allowing strings of up to sixteen devices. Generally connected through a 3880 storage control unit with dual paths, this configuration supported two concurrent I/O operations targeting separate HDAs.

In February 1985, IBM introduced the Extended Capability Models (3380 E) featuring double density and a capacity of 5.04 GB per unit (two actuators at 1.26 GB each). Later, in August 1987, the triple-capacity variant named the 3380 K was released with a total of 7.562 GB per unit (two actuators at 1.89 GB each). Models J and K supported four-path operation with up to thirty-two devices per string when connected to a 3990 storage control unit, enabling four simultaneous I/O operations.

The entire IBM 3380 lineup consisted of twelve models: six A-units (string heads equipped with additional logic for storage control unit connection), five B-units (linking to A- or C-units), and one C-unit (which connected directly to an IBM channel).

Manufacture continued until May 1996, resulting in an impressive fifteen-year production span—exceeding typical disk drive lifecycles.

IBM 3390

The IBM 3390 Direct Access Storage Device series was introduced in November 1989, providing storage capacities up to 22 gigabytes distributed over multiple drives. Pricing varied from $90,000 to $795,000 based on configuration and capacity.

A standard 3390 string comprises a central A unit containing four or eight devices and optionally one or two B units accommodating up to twelve devices each. Operating in four-path mode when connected to a 3990 storage control unit, this setup supports an additional second string of 3390 devices, allowing up to sixty-four devices within one subsystem.

Each Hard Disk Assembly (HDA) includes two actuator-head units along with platters: Model 1 offered an unformatted capacity of 1.89 GB; Model 2 doubled this to 3.78 GB per HDA. The Model 3 upgrade released in September 1991 increased capacity by fifty percent to reach 5.67 GB per HDA; subsequently, Model 9 launched in May 1993 tripled capacity again to provide 11.3 GB per HDA.

Differing from previous DASD models that used large AC motors driving HDAs via belts, the IBM 3390 incorporated a DC motor directly coupled within the enclosure to power the HDA.

The Model 9 represented IBM’s final iteration of the Single Large Expensive Disk (SLED) drive design.

IBM 9345

Released in November 1990 as a Request for Price Quotation (RPQ) for IBM's SuperComputing Systems Extensions (SCSE), the IBM 9345 hard disk drive originated from IBM's San Jose laboratory under the project name Sawmill. This full-height 5¼-inch drive housed up to eight 130 mm platters, delivering a maximum storage capacity of 1.5 GB. Notably, it was the pioneering HDD to incorporate Magnetoresistive (MR) read/write heads.

IBM 9340

In October 1991, IBM unveiled the 9345 DASD within the 9340 series—a channel-attached count key data (CKD) direct access storage subsystem designed for IBM mainframe systems, including the ES/9000 processor lineup. The Model 1 of the 9345 contained two HDDs each offering 1.0 GB, whereas Model 2 featured two drives with 1.5 GB capacity each.

From a functional standpoint, the 9340/9345 series resembled the capabilities of the 3990/3390 models but lacked certain features such as the non-volatile RAM cache found in the 3990 and supported a smaller maximum block size compared to the 3390.

The Input/Output Supervisor (IOS) component of the operating system employed a specialized initializer named IECCINIT to detect device-specific attributes, recognizing that the 9340 did not include non-volatile cache and that the 9345 had a reduced track count. Consequently, these devices were assigned unique device types during system initialization, differing from those of the 3990/3390 series.

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 contained one 5-inch floppy disk drive.
  2. The 9332 Direct Access Storage Device utilized the IBM 0667 hard disk drive.
  3. The 9333 High Performance Disk Drive Subsystem incorporated either IBM 0664 or IBM 0681 HDDs 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 IBM Hursley-developed "Kestrel" HDD—an 850 MB device consisting of three 14-inch platters with dual rotary actuators enabling access to multiple surfaces. Designed for rack mounting, it debuted alongside the October 1986 IBM 9370 Information System. No original equipment manufacturer (OEM) variants are documented.
  6. The 9336 Disk Unit employed the IBM 0681 HDD, also known as Redwing.
  7. The 9337 Disk Array Subsystem integrated IBM's 0662 (Spitfire) or 0663 (Corsair) hard disk drives.

IBM 2310

Introduced in conjunction with the IBM 1800 in 1964 and later with the IBM 1130 in 1965—most likely first shipped with the latter in late that year—the IBM 2310 Removable Cartridge Drive stored data on an IBM 2315 cartridge containing a single oxide-coated aluminum platter protected within a plastic casing. It held up to 512,000 sixteen-bit words (equivalent to 1,024,000 bytes) and provided read/write capabilities.

IBM 5444

The IBM 5444, launched in September 1969 as part of System/3 and developed at IBM’s Hursley facility in the United Kingdom under the codename Dolphin, utilized a single-disk cartridge designated as model 5440 featuring one fourteen-inch platter. Its three configurations included:

  • Model 1: comprised one fixed and one removable disk, each with one hundred tracks per surface; cartridge capacity was approximately 1.23 MB
  • Model 2: contained one fixed plus one removable disk, each with two hundred tracks per surface; cartridge capacity reached around 2.46 MB
  • Model 3: featured only one removable disk with two hundred tracks per surface; cartridge capacity matched Model 2 at about 2.46 MB

IBM 62GV

First delivered in May of 1974 from IBM’s Hursley laboratory under the internal name Gulliver, the IBM 62GV initially offered a storage size of five megabytes. Subsequent versions increased capacity to ten megabytes (62TM) and eventually fourteen megabytes. This model incorporated a Swinging Arm actuator paired with a single fourteen-inch disk—a design that became one of IBM’s most widely licensed electromechanical innovations. Its actuator mechanism and filtration approach were extensively adopted throughout hard disk drives during the decade of the eighties and continue to be industry standards today. With over 177,000 units sold, the IBM 62GV was also notable for being the first hard drive to surpass sales of one hundred thousand units.

OEM and Small Systems Hard Drives

This segment details IBM-produced hard disk drives marketed as OEM units and designed for IBM’s smaller platforms such as the System/3, System/32, /34, /36, and AS/400 series. The drives are cataloged by their OEM model identifiers and organized according to their initial shipment dates.

IBM 0680

Introduced in 1979, the 0680 served as the 3310 direct access storage device for many IBM small systems and entry-level System/370 models. Officially announced in September 1981 as the 0680 OEM variant, it was engineered at IBM Hursley in the United Kingdom under the project name Piccolo. This drive incorporated six 8-inch (210 mm) platters and initially offered a capacity up to 65MB, featuring an enhanced rotary actuator mechanism.

A double-capacity iteration called the 62SW was released in June 1984; however, its sales were limited due to its cost per megabyte being comparable to the more expensive 62GV model.

IBM 0676

The 0676 was delivered starting November 1982 as a 5247 Disk Storage Unit tailored for the IBM System/23 Datamaster. Created at IBM Rochester, Minnesota under the designation 21ED, this 8-inch hard disk offered initial storage options of either 15 or 30 MB, utilizing two or four 210 mm disks respectively. By 1983, it was incorporated into the System/36’s 5360 System Unit. In 1984, its capacity was doubled through increased tracks per surface, and it became part of the S/36’s upgraded 5362 System Unit.

IBM 0665

Released in October 1985 for use within the PC AT (5170) system unit, the 0665 was developed under the codename "Pixie" at IBM Rochester. It was a 5-inch hard disk drive available in capacities of 20, 30, and 44 MB.

IBM 0667

The 0667 appeared on the market in August 1986. Developed at IBM Rochester with the project name "Grant," this full-height ESDI 5-inch hard drive contained up to four 130 mm platters and provided a maximum capacity of 70 MB. It was supplied for specific PC RT models (6150, 6151, 6152) as well as System/36 Model System Units (5363, 5364).

IBM 0669

Introduced in 1987, the 0669 was another product of IBM Rochester's development efforts under the codename "Grant-Prime." This full-height, five-inch HDD supported up to four 130 mm disks with a total capacity reaching 115 MB. It served as the internal storage solution for both System/36’s 5363 and Series 1’s 4956 System Units.

IBM 0671

Also launched in 1987, the 0671 was developed at IBM Rochester under the codename "Lee." This full-height ESDI five-inch hard drive featured eight 130 mm platters delivering up to a maximum of 316 MB capacity. Notably, it marked IBM’s initial introduction of a thin metal film recording surface technology. In 1988, it was integrated into the IBM AS/400’s 9404 System Unit configurations that housed two or three such drives.

IBM 0661

The 0661 made its debut in 1989 as model number 371. Developed jointly at IBM Rochester and Hursley, UK under the codename "Lightning," this SCSI hard drive accommodated up to eight 95 mm disks with fourteen heads and initially offered a capacity of 320 MB. A subsequent "Turbo" variant with a capacity of 400 MB followed in 1990. It became a standard component across various IBM systems including the AS/400 System Unit Model CXX.

IBM 0681

Launched in April of 1990 from IBM Hursley’s laboratories under the codename Redwing—representing their final HDD development effort—this full-height five-inch hard drive provided up to twelve 130 mm disks supporting an overall capacity of up to 857 MB. It was also IBM’s first HDD to implement PRML data decoding technology. The drive powered the newly introduced 9333 Disk Drive Subsystem released in early 1992, with an enhanced higher-density version offering a capacity of approximately 1.07 GB added to this subsystem by May that year.

IBM 0663

Released in late 1991 under the project name "Corsair," the 0663 was a compact half-height (1.6-inch) 3-inch hard drive. It provided a maximum capacity of 1 GB utilizing eight 95 mm platters. This model was incorporated into select PS/2 and RS/6000 systems and marked IBM’s inaugural OEM hard disk drive to feature Magnetoresistance (MR) read/write heads.

IBM 0664

The 0664 debuted in November 1992, originating from IBM Rochester, Minnesota, where it was known as "Allicat." This full-height 5-inch hard disk drive (measuring 3.25 inches in height) combined two 3-inch drives to deliver up to 2.013 GB of storage across as many as eight 95 mm disks.

IBM 0662

Introduced in June 1993 and developed at IBM Rochester under the codename "Spitfire," the 0662 was a full-height (1-inch tall) 3-inch hard drive. It offered a capacity of 1.05 GB using three platters or five recording surfaces. This drive was utilized internally within 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 medium for program loading. Its inaugural read/write floppy disk drive appeared in 1973 with the release of the 3740 Data Entry System. Although IBM established early standards for the 8" floppy drives, it refrained from selling them as standalone products, allowing industry-wide standards to develop autonomously.

At one stage, IBM ranked as the largest buyer of OEM 5-inch floppy disk drives. Its preference for two-sided models with a track density of 48 tracks per inch played a key role in setting this format as an industry benchmark. Despite intentions to produce these drives and smaller variants internally, IBM discontinued such plans by 1985. Additionally, its attempt in 1983 to OEM the smaller 4-inch DemiDiskette did not succeed.

"Star" series of HDDs

On October 17, 1994, IBM's Storage Systems division unveiled three new families of hard drives: the Travelstar series featuring 2-inch drives tailored for notebook computers; the Deskstar line with 3-inch drives designed for desktop use; and the Ultrastar series of high-performance 3-inch drives aimed at enterprise systems.

Comparison: IBM's first HDD versus its final HDD models

The following table contrasts IBM’s pioneering RAMAC 350 hard drive with three of its latest "Star" series OEM HDDs. The comparison underscores remarkable advancements including drastic reductions in physical size and cost alongside substantial gains in storage capacity and operational efficiency.

Parameter (units) RAMAC 350 Ultrastar 146Z10 Deskstar 180GXP Travelstar 80GN Improvement over 46 years (maximum)
Announcement date Sep 1956 Jul 2002 Oct 2002 Nov 2002
Storage capacity (GB) 0.004 146 180 80 ×48,000
Physical dimensions (inches) 60×68×29 4×1×5.75 4×1×5.75 2.75×0.38×3.95
Physical dimensions (mm) 1500×1700×700 102×25×146 102×25×146 70×9.5×100
Volume (cubic inches) 118,320 23 23 4 ×29,161
Volume (liters) 1,939 0.4 0.4 0.1
Weight (pounds) 2,140 1.7 1.4 0.2 ×1,244
Weight (kilograms) 971 0.8 0.64 0.095
Power consumption (watts) ~2,374 watts (~8100 BTUs/hour), up to 5500 VA depending on configuration 16 10.3 1.85 ×1,283
Power efficiency (megabytes per watt) 0.0016 9,125 17,476 43,243 ×27,375,856
Retail price (Template:US$) \$34,500 (\$234,000 adjusted to 2002 dollars) \$1,200 \$360 \$420
Cost per megabyte (Template:US$) \$9,200 (\$68,000 adjusted to 2002 dollars) 0.0082 0.0020 0.0053
Areal density (megabits per square inch) 0.002 26,263 46,300 70,000
Areal density (kilobits per square millimeter) 0.003 40,708 71,765 108,500
Volumetric density (gigabytes per cubic inch) 0.00000003 6 8 20
Volumetric density (megabytes per cubic centimeter) 0.000002 388 478 1,203
Average latency (milliseconds) 25 3 4 7
Average seek time (milliseconds) 600 5.9 10.2 12
Data transfer rate (megabytes per second) 0.001 103 29.4 43.75


DASD Devices Beyond HDDs and FDDs

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

IBM 7320 Drum

The IBM 7320 represents a magnetic drum storage system that was introduced in 1962.

IBM 2301 Drum

Launched in the late 1960s, the IBM 2301 is a magnetic drum-based storage unit.

IBM 2303 Drum

The IBM 2303, introduced in 1964, is another example of a magnetic drum storage device.

IBM 2321 Data Cell

Announced in 1964, the IBM 2321 Data Cell utilizes short strips of magnetic tape for data storage. It features ten removable cells, each with a capacity of 40 MB, resulting in a combined total of 400 MB.

IBM 3850 Mass Storage System

The IBM 3850 Mass Storage System, debuted in 1974, is a tape cartridge library that manages data by staging it onto IBM 3330 or 3350 disk drives, thereby presenting the system with virtual disk drive functionality.

See also

External links

Related profiles

PPunched cardDDeskstarTTravelstarMMicrodrive
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