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IBM 2310

From Alfawiki
IBM Magnetic Disk Storage Division
Company typeDivision
IndustryComputer storage devices
Founded1956
Defunct2003
FateDivested to Hitachi
Headquarters
United States
ProductsHard disk drives, floppy disk drives

IBM was a pioneer in the production of magnetic disk storage devices, manufacturing them from 1956 until 2003, when it divested its hard disk drive division to Hitachi. IBM is credited with inventing both the hard disk drive (HDD) and the floppy disk drive (FDD), with numerous advancements in these fields attributed to its engineers. The fundamental mechanical architecture of hard disk drives has remained largely unchanged since the introduction of the IBM 1301, and performance benchmarks continue to follow standards set during the 1950s. Over time, these storage devices have dramatically decreased in size and cost while achieving substantial gains in capacity and speed.

From 1969 through the mid-1980s, IBM manufactured 8-inch floppy disk drives but never became a dominant supplier of smaller 5.25- or 3.5-inch models. Although IBM sold magnetic disk drives directly, it only began offering them under original equipment manufacturer (OEM) agreements starting in 1981. By 1996, IBM had discontinued producing hard disk drives exclusive to its own systems, instead marketing all HDDs as OEM products.

IBM has used several names for its magnetic disk drives, including direct-access storage device (DASD), disk file, and diskette file. However, this article adopts the widely accepted industry terms hard disk drive (HDD) and floppy disk drive (FDD).

IBM 350

The IBM 350 disk storage unit was introduced as part of the IBM 305 RAMAC computer system on September 14, 1956, marking the debut of the first commercial disk drive. A related model, the IBM 355, was announced alongside the IBM 650 RAMAC system. The acronym RAMAC stands for "Random Access Method of Accounting and Control." The initial prototype was delivered to Zellerbach Paper Company in June 1956, with mass production shipments commencing in November 1957 to clients such as United Airlines.

Engineered for real-time business accounting applications, the IBM 350 stored five million 6-bit characters (equivalent to approximately 3.75 MB) across fifty-two disks featuring one hundred recording surfaces and one hundred tracks each. The disks rotated at a speed of 1200 rpm, enabling a data transfer rate of 8,800 characters per second. An access mechanism was responsible for selecting specific disk pairs and tracks for reading or writing data. Several enhanced versions were launched throughout the late 1950s. The rental price for an IBM RAMAC 305 system with the IBM 350 was $3,200 per month. Production of the IBM 350 ceased in 1969.

The patent originating from the RAMAC project is regarded as foundational for disk drive technology. Although initially rejected by IBM's Board over fears it might undermine punch card sales, development persisted at IBM’s San Jose facility until it received approval from IBM’s president.

The IBM 350's enclosure measured approximately long by high by wide and weighed nearly one ton, necessitating forklifts and large cargo aircraft for transportation. Currie Munce of Hitachi Global Storage Technologies noted that marketing teams were initially hesitant to increase storage capacity beyond five million characters due to market uncertainty; nevertheless, models with double this capacity were introduced later in 1959.

In recognition of its engineering significance, the RAMAC 350 Disk File was designated an International Historic Landmark by The American Society of Mechanical Engineers in 1984. A restoration effort led by Al Hoagland began in 2002 at Santa Clara University to refurbish an IBM 350 RAMAC unit. By 2005, this project had moved to the Computer History Museum in Mountain View, California, where the restored device is now on public display.

IBM 353

The IBM 353, designed to operate alongside the IBM 7030, resembled the IBM 1301 but featured a higher data transfer speed. It offered storage for 2,097,152 (221) words of 64 bits each, totaling 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 utilize a dedicated head per surface that hovered on compressed air, continuing the design evolution from the IBM 350 disk storage (RAMAC). Production versions incorporated self-flying heads akin to those found in the IBM 1301.

IBM 355

Introduced on September 14, 1956, the IBM 355 served as an accessory to the widely used IBM 650. It employed the IBM 350 mechanism but enhanced it by featuring up to three access arms instead of one, enabling storage of six million decimal digits plus an additional 600,000 signs. This unit transferred entire tracks to and from the magnetic core memory of the 653, an optional IBM 650 component containing sixty signed 10-digit words—enough to hold a single disk track or tape record—along with two supplementary features.

IBM 1405

Released in 1961 for the IBM 1400 series business computers, the IBM 1405 Disk Storage Unit was available in two variants: Model 1 stored 10 million alphanumeric characters (60 million bits) across 25 disks, while Model 2 held double that capacity with 20 million characters (120 million bits) on 50 disks. The disks were vertically arranged and rotated at a speed of 1200 rpm.

Each disk surface contained 200 tracks segmented into five sectors; sectors numbered 0 through 4 were located on top surfaces, whereas sectors 5 through 9 were on bottom surfaces. Each sector could accommodate between 178 and 200 characters. Between one and three forked access arms, each equipped with two read/write heads (one for the top and one for the bottom), moved vertically to select among disks (0–49) and horizontally to choose tracks (0–199). 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 as much as 800 milliseconds for Model 2. The latter model contained around 100,000 sectors that could store either 200 characters in move mode or 178 characters in load mode, which included an additional word mark bit per character. Model 1 featured half this number of sectors.

IBM 7300

The IBM 7300 Disk Storage Unit was engineered specifically for use with the IBM 7070 system. Despite IBM announcing a second model in 1959, the debut of the IBM 1301 on June 5, 1961, shifted customer preference toward the newer drive among users of both the IBM 7070 and IBM 7074 systems. The technology underpinning the IBM 7300 bore similarities to 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 designed for deployment with IBM 7000 series mainframes and the IBM 1410. Each module could store up to twenty-eight million characters (168 million bits), or twenty-five million characters when paired with the IBM 1410. The unit comprised twenty-five large disks featuring forty user-accessible recording surfaces with two hundred fifty tracks apiece. Model 1 included a single module; Model 2 stacked two modules together. Disks rotated at a speed of eighteen hundred rpm and transferred data at ninety thousand characters per second.

A significant advancement was its architecture featuring an independent arm and read/write head for every surface that moved simultaneously in a comb-like fashion. This innovation eliminated delays caused by repositioning heads between disks and reduced maximum access time to just one hundred eighty milliseconds. Additionally, it was the first disk drive to employ aerodynamically shaped heads that floated on a thin cushion of air above the disk surfaces, improving overall performance.

Connection was established through the IBM 7631 File Control unit, which allowed compatibility with either IBM 1410 or IBM 7000 series systems or enabled sharing between two computers. Leasing fees for Model 1 were $2,100 monthly or $115,500 for purchase; Model 2 leased at $3,500 per month or $185,000 to acquire. The IBM 7631 controller itself cost $1,185 per month or $56,000 outright. All models were phased out by the year 1970.

IBM 1302

Launched in September 1963, the IBM 1302 Disk Storage Unit offered a fourfold increase in capacity compared to the 1301, storing up to 117 million 6-bit characters per module. It delivered an average access time of 165 milliseconds and achieved data transfer rates of 180,000 characters per second, more than doubling the throughput of its predecessor. Each module incorporated two separate access mechanisms to service the inner and outer cylinder regions. The Model 2 version increased storage by stacking two modules together. Leasing fees were set at $5,600 per month for Model 1 and $7,900 per month for Model 2, while purchase prices stood at $252,000 and $355,500 respectively. The IBM 7631 controller was available for an additional $1,185 monthly or $56,000 as a one-time purchase. Production of the 1302 ceased in February 1965.

IBM 1311

Introduced on October 11, 1962, the IBM 1311 Disk Storage Drive was designed for medium-sized business and scientific computing systems. Comparable in size to a top-loading washing machine, it utilized removable IBM 1316 disk packs capable of storing two million characters. Throughout the 1960s, seven different models were released before being phased out by the early 1970s.

Each IBM 1316 disk pack measures approximately four inches in height and weighs about ten pounds. It contains six disks with a diameter of fourteen inches each, providing ten recording surfaces since the outermost surfaces remain unused. The read/write heads—ten in total—are hydraulically positioned across tracks while the disks rotate at 1500 revolutions per minute. Each surface features one hundred tracks divided into twenty sectors per track; every sector holds one hundred characters. The disk pack is enclosed within a transparent plastic casing equipped with a locking handle that facilitates easy insertion and removal.

The seven IBM 1311 models include various master and slave configurations customized for different IBM systems:

  1. Master drive compatible with IBM 1440, 1460, or 1240 systems; capable of managing up to four Model 2 slave units (1962–1971).
  2. Slave drive supporting master drive functions (1962–1975).
  3. Master drive designed for IBM 1620 or 1710 systems; controls up to three slaves (1962–1971).
  4. Master drive intended for IBM 1401 systems; manages up to four slaves (1962–1971).
  5. Master drive suited for IBM 1410, 7010, or 7740 systems; includes standard Direct Seek capability; controls up to four slaves (1963–1971).
  6. & #7 Presumed master and slave drives introduced in March 1968 and retired in February 1971.

Several optional enhancements were available to improve functionality and storage:

  • Direct Seek: Removes the need to return to zero position before seeking.
  • Scan Disk: Facilitates fast automatic scanning for specific identifiers or conditions.
  • Seek Overlap: Permits concurrent seek operations during read/write processes across multiple drives.
  • Track Record: Boosts capacity by recording a single large record per track instead of multiple sectors, increasing total storage to roughly 17.9 million bits in Move Mode and nearly 18.8 million bits in Load Mode.

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

IBM 2302

The IBM 2302 serves as the System/360 counterpart to the 1302, featuring track formatting tailored to S/360 DASD standards rather than those used in the IBM 7000 series.

This unit employs a fixed module containing twenty-five platters with forty-six recording surfaces. The Model 3 version includes one such module; Model 4 incorporates two modules. Each module is equipped with two independent access mechanisms—referred to as access groups—serving respectively the innermost and outermost sets of 250 cylinders. Each access mechanism utilizes one read/write head per track. Rotational latency averages seventeen milliseconds with a maximum of thirty-four milliseconds; maximum seek time within each access group is up to one hundred eighty milliseconds. Tracks are formatted with a size of 4,985 bytes each, resulting in an approximate formatted capacity of one hundred twelve megabytes per module. Connectivity to IBM mainframes is facilitated through the IBM 2841 Storage Control Unit.

IBM 2305

Launched in 1970, the IBM 2305 fixed-head disk drive along with the IBM 2835 Storage Control initially interfaced with System/360 models 85 and 195 through the IBM 2880 Block Multiplexor Channel.

Throughout the System/370 period, particularly with Virtual Storage, the 2305 became a popular paging device on systems such as the 3155, 3165, 3158, 3168, 3033, 4341, and 3081 (the latter utilizing specialized microcode). It was also well-suited for managing high-transaction small data sets including catalogs and job queues.

The 2305-1 variant provides a storage capacity of 5.4 MB and supports data transfer rates of up to 3.0 MB/s via a 2-byte channel interface, featuring an average access latency of 2.5 milliseconds. In contrast, the larger-capacity 2305-2 offers 11.2 MB at a transfer speed of 1.5 MB/s with an average access time of around 5 milliseconds.

Engineered for rapid and continuous access to smaller data volumes, the 2305’s speed and storage size made it optimal for system-resident tasks such as work files, job queues, indices, and frequently accessed datasets. Its swift response time was particularly beneficial in heavily utilized systems demanding paging throughput exceeding 1.5 transactions per second.

IBM 2311

The IBM 2311 Disk Storage Drive debuted in 1964 alongside the 2841 Control Unit, designed to operate across the IBM System/360 series as well as the IBM 1130 and IBM 1800 systems. Additionally, it connects directly to the IBM System/360 Model 20 and Model 25. All units employ the removable IBM 1316 Disk Pack, which originated with the IBM 1311.

For most IBM mainframes, the Model 1 version of the 2311 interfaces through the 2841 Control Unit; meanwhile, the System/360 Model 25 utilizes a Disk Attachment Control that provides comparable functionality. Disk packs on these systems are formatted using IBM's count key data variable record length structure.

Models 11 and 12 connect to the System/360 Model 20’s integrated control unit and utilize a fixed sector format. Disk packs formatted for Model 1 are incompatible with those used by Models 11 or 12.

While mechanically akin to the IBM 1311, the IBM 2311 enhanced recording density, storing up to 7.25 megabytes on a six-platter removable IBM 1316 disk pack. It is equipped with ten read/write heads mounted on a hydraulically actuated arm featuring mechanical detents to ensure precise track alignment. Each disk surface contains 200 tracks plus three reserved for defect management. The average seek time is approximately 85 milliseconds with a data transfer rate of around 156 kB/s.

Standardized electrical interfaces allowed third-party manufacturers to develop plug compatible disk drives compatible with IBM systems, promoting competition within compatible storage device markets.

IBM 2314 Disk Access Storage Facility Model 1

Unveiled in April 1965, the IBM 2314 Disk Access Storage Facility Model 1 supported both System/360 and System/370 architectures and incorporated a Two Channel Switch enabling simultaneous connection to two channels. Its disk mechanism resembled that of the IBM 2311 but featured increased data density.

This drive stored roughly 29 million characters on a removable IBM 2316 disk pack, which expanded from six to eleven disks (providing twenty recording surfaces). The IBM 2316 disks measured in diameter. It employed twenty read/write heads mounted on a hydraulically actuated arm with mechanical detents for accurate track positioning; each surface contained about 200 tracks. Initial access times were comparable to those of the IBM 2311 but improved in subsequent models due to actuator enhancements. Data transfer speeds doubled to approximately 310 kB/s.

The Model 1 was sold as a package containing nine disk drives at a single price point, including a storage control unit, one single-drive module, and two four-drive modules totaling nine drives. These drives were installed in individual drawers for straightforward disk pack access, earning them the nickname "Pizza Ovens." Although nine drives were included physically, only eight could be accessed by the system simultaneously; the ninth functioned as an offline spare to facilitate maintenance without disrupting operations. Drive system addresses were configured via user-swappable plugs, allowing physical reassignment of addresses as well as designation of spare drives.

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

Additional versions of the IBM 2314 were released subsequently.

IBM 2314 Direct Access Storage Series

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

  • 2312 Disk Storage, featuring a single-drive unit.
  • 2313 Disk Storage, comprising a module with four drives.
  • 2318 Disk Storage, containing two drives per module.

IBM 2319

To address competition from plug-compatible manufacturers producing subsystems comparable to the 2314, IBM launched the cost-effective three-drive 2319 module in 1970. This was achieved by removing one drive from the four-drive 2313, rebranding it as the 2319 A1, and offering it at a significantly lower rental rate. This strategy reduced expenses for new customers while maintaining higher charges for existing users. 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 2319 B series includes three-disk modules that support configurations of three, six, or nine drives connected to a newly introduced 2314 Model B Storage Control Unit.

IBM 3310

Released on January 30, 1979, the IBM 3310 Direct Access Storage Device was developed specifically for IBM 4331 midrange computer systems. Each drive provided a storage capacity of 64.5 MB. This fixed-block architecture device was primarily utilized with DOS/VSE and VM, which were the only S/370 operating systems compatible with FBA devices.

IBM 3330

The IBM 3330 Direct Access Storage Facility, known by its code name Merlin, was introduced in June 1970 for IBM System/370 and System/360/195 platforms. The initial offerings included the two-drive Model 1 and the single-drive Model 2. Each removable disk pack had a capacity of 100 MB. Notable features included a 30 ms access time and a data transfer speed of 806 kB/s. A key advancement was the implementation of fire code error correction, which enhanced reliability and lowered costs by allowing tolerance for imperfections on disk surfaces.

The original configuration consisted of one storage control unit (3830 Model 1) directly mounted to a single 3330 drive, with the option to connect up to three additional drives in series, supporting as many as eight drives per string.

In August 1972, IBM introduced the 3830 Model 2 Storage Control along with the 3333 Disk Storage and Control, which decoupled control functions from the drive string. The upgraded 3830 acted as a director-style controller capable of managing multiple strings. The first device in each string, called the 3333, combined controller functions with two drives and could support up to three additional attached 3330 units (totaling eight drives per string). Two such 3333 units could be connected to one 3830 Model 2 controller, enabling up to sixteen drives per controller; an optional string switch allowed connection to two separate controllers.

In 1973, IBM announced double-density (-11) variants: models 3333–11, 3330-11, and 3336–11 featuring disk packs with capacities up to 200 MB. Mixing single-density and double-density drives within the same string was not supported. Field upgrades from original models to -11 versions were feasible but required both drive conversion and data migration.

The IBM 3330 product line 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 string; there are no A model versions of the IBM 3344. Therefore, an IBM 3344 must be connected behind an IBM 3340 A model acting as head of string.

IBM 3340

Introduced in March 1973 for the IBM System/370, the IBM 3340 Direct Access Storage Facility, known internally as Winchester, came in three configurations: the 3340-A2 featuring two drives and a controller, and the B2 (two drives) and B1 (single drive) models. The B-units could be connected to an A2 controller, supporting up to eight drives in total.

This system utilized removable data modules that incorporated both the head and arm assembly; during mechanical load and unload operations, the module’s access door opened automatically, eliminating the need to remove external covers as was necessary with earlier disk pack designs. It offered an average access time of 25 milliseconds and data transfer speeds reaching 885 kB/s. There were three variants of the IBM 3348 Data Module available: a 35 MB version and two 70 MB versions, one of which included 500 KB of fixed heads designed for quicker access. The 3340 implemented error correction technology and remained in production until its withdrawal in 1984.

Developed under Ken Haughton’s leadership in San Jose, the original concept centered on two removable modules each with a capacity of 30 MB—giving rise to the code name Winchester, inspired by the Winchester .30-30 rifle. Although storage capacities grew over time, this nickname endured.

A significant breakthrough was its cost-effective head design that permitted heads to land on and lift from the disk surface without unloading, thereby simplifying and reducing the expense of the actuator mechanism. This innovation, termed "Winchester technology," became widely adopted throughout the disk drive industry.

The designation Winchester or colloquially Winnie remained popular when referring to hard drives well into the early 1990s but has since largely disappeared from global usage.

IBM 3344

The IBM 3344 shares a close resemblance with the 3340 but differs by employing fixed media rather than removable 3348 data modules. Each spindle contains four logical drives, each matching the capacity of a single 3348–70 module. This model is only offered in dual drive configurations without an A (head-of-string) variant. The 3344-B2F distinguishes itself from the 3344-B2 by having fixed heads over certain cylinders on both drives. Both require a 3340-A2 or 3340-A2F unit to serve as head of string. Internally, the IBM 3344 is essentially identical to the IBM 3350; distinctions are limited to microcode differences within their control units.

IBM 3350

Released in 1975 for IBM System/370 systems, the IBM 3350 Direct Access Storage Facility carried the code name Madrid. It introduced sealed head-disk assemblies (HDAs) with integrated head and arm components, establishing a design standard for subsequent IBM DASD products. Each HDA contained 555 cylinders, utilized 30 heads, and stored approximately 19,069 bytes per track, resulting in roughly 317 MB of storage capacity.

Available models included A2, A2F, B2, B2F, C2, and C2F—each equipped with two HDAs. The A2 and A2F models incorporated an additional electronic board that enabled connection to storage control units (controllers), frequently functioning as head-of-string units. Storage strings were arranged beginning with an A2 or A2F unit followed by up to three B2 units or combinations that included C2 models. The A2 typically featured a string switch allowing concurrent I/O operations through two separate control units such as the Model 2 of the IBM 3830 or Integrated Storage Control (ISC) embedded in CPUs like the IBM 3148, 3158, or 3168. Later controllers such as the IBM 3880 maintained backward compatibility with these configurations.

The C2 variant also contained a controller providing a secondary communication path but was primarily used as a spare activated only if the A unit’s controller failed; it connected exclusively to one control unit and did not include a string switch.

Valid string configurations for IBM 3350 units encompassed combinations such as -A, -AB, -ABB, -ABBB, -AC-, -ABC-, and -ABBC-.

Models designated with "x2F" (for example, A2F) incorporated fixed head regions covering the first five cylinders on both HDAs to eliminate seek times within those cylinders entirely. This design enhanced performance for frequently accessed datasets like HASP or JES2 checkpoint areas and optimized system swap processes under TSO and MVS environments by minimizing head movement during task context switches.

The IBM 3350 series was officially discontinued in September of 1994.

IBM 3370

Released in January 1979, the IBM 3370 Direct Access Storage Device was designed for IBM 4331, 4341, and System/38 midrange systems. It incorporated seven fixed 14-inch platters, delivering a storage capacity of 571 MB per unit. This model was pioneering as the first hard disk drive to utilize thin-film head technology, which originated at the Thomas J. Watson Research Center during the late 1960s. The 3370 employed a fixed-block architecture and was compatible with DOS/VSE and VM operating systems running on S/370 platforms.

IBM 3375

Serving as a counterpart to the 3370, the IBM 3375 adopted count key data architecture, which was essential for supporting OS/360 and its subsequent versions.

IBM 3380

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

The typical setup included one A unit accompanied by up to three B units; each IBM 3380 contained four devices, enabling configurations of up to sixteen devices connected in series—commonly linked to a 3880 storage control unit that supported two concurrent I/O operations across different HDAs.

In February 1985, IBM launched the Extended Capability Models (3380 E), which doubled storage capacity to 5.04 GB per unit by utilizing two actuators with capacities of 1.26 GB each. Later, in August 1987, the triple-capacity variant known as the 3380 K was introduced, offering 7.562 GB per unit via two actuators holding 1.89 GB each. Both Models J and K included an optional four-path mode that allowed up to thirty-two devices per string when connected to a 3990 storage control unit, supporting four simultaneous I/O operations.

The IBM 3380 series consisted of twelve distinct models: six A-units (which functioned as string leaders incorporating controller logic for connection to IBM storage control units), five B-units (designed to attach to A or C units), and one C-unit (offering direct channel connectivity).

Production continued until May 1996, marking an exceptional fifteen-year period on the market—surpassing the typical lifespan of most disk drives.

IBM 3390

Unveiled in November 1989, the IBM 3390 Direct Access Storage Device family provided storage capacities reaching up to twenty-two gigabytes distributed across multiple drives. Pricing for these systems varied from $90,000 to $795,000 based on configuration and capacity requirements.

A typical IBM 3390 configuration includes a central A unit containing four or eight devices, optionally flanked by one or two B units that can house as many as twelve devices each. Operating in four-path mode when connected to a 3990 storage control unit, this setup can support a second string of IBM 3390 devices—allowing up to sixty-four devices within the subsystem.

Each Hard Disk Assembly (HDA) comprises two actuator-head assemblies and platters: Model 1 delivers a capacity of 1.89 GB per HDA; Model 2 doubles this to 3.78 GB per HDA. Announced in September 1991, Model 3 increased capacity by fifty percent to reach 5.67 GB per HDA; while Model 9, introduced in May 1993, tripled capacity again up to 11.3 GB per HDA.

Distinct from earlier DASD models that relied on large alternating current motors with belt drives, the IBM 3390 HDAs utilized enclosed direct current motors for direct drive operation. The Model 9 represented IBM’s final iteration of Single Large Expensive Disk (SLED) technology.

IBM 9345

Introduced in November 1990 as a Request Price Quotation (RPQ) option for IBM’s SCSE (SuperComputing Systems Extensions), the IBM 9345 hard disk drive was developed at IBM’s San Jose facility under the project name Sawmill. This full-height 5¼-inch HDD housed up to eight 130 mm platters and offered a maximum storage capacity of 1.5 GB. It was distinguished as the first hard drive to utilize Magnetoresistive (MR) read/write heads.

IBM 9340

In October 1991, IBM released the 9345 DASD within the 9340 channel-attached Count Key Data (CKD) DASD subsystem series tailored for IBM mainframe systems, including the ES/9000 processor line. The 9345 Model 1 contained two HDDs each with 1.0 GB capacity, while Model 2 featured two HDDs with 1.5 GB each.

From an operational standpoint, the 9340/9345 resembled the 3990/3390 series but lacked the non-volatile RAM cache found in the 3990 and had a shorter maximum block length compared to the 3390. The OS Input/Output Supervisor (IOS) recognized these devices through a dedicated initializer named IECCINIT, which also managed other DASD types. During initialization, the system detected that the 9340 did not include non-volatile cache and that the 9345 had fewer tracks per cylinder, resulting in a unique device classification distinct from the 3990/3390 series.

9330 Family of Disk Drives

  1. Models 1 and 11 of the 9331 Diskette Unit incorporated 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 employed the IBM 0667 hard disk drive.
  3. The High Performance Disk Drive Subsystem, designated as model 9333, used either IBM 0664 or IBM 0681 HDDs, depending on configuration.
  4. The 9334 Disk Expansion Unit connected between one and four SCSI hard drives to RS/6000 systems.
  5. The Direct Access Storage Subsystem model 9335 featured an IBM-designed "Kestrel" hard disk—an 850 MB unit composed of three large (14-inch) platters and dual rotary actuators enabling access to multiple surfaces. Announced in October 1986 alongside the IBM 9370 Information System, this rack-mountable device has no documented OEM equivalents.
  6. The IBM 0681 HDD (Redwing) powered the model 9336 Disk Unit.
  7. The Disk Array Subsystem model 9337 integrated either IBM’s 0662 (Spitfire) or 0663 (Corsair) hard drives.

IBM 2310

The IBM 2310 Removable Cartridge Drive debuted in 1964 with the IBM 1800 and was introduced to the IBM 1130 line in 1965, likely shipping first with the latter in late that year. It stored up to 512,000 sixteen-bit words (equivalent to just over one million bytes) on an IBM 2315 cartridge containing a single fourteen-inch oxide-coated aluminum platter enclosed within a plastic casing featuring openings for read/write heads and arm access.

IBM 5444

Launched in September of 1969 as part of the System/3 family, the IBM 5444 was engineered at IBM’s Hursley laboratory under the codename Dolphin. This device utilized a removable disk cartridge known as the IBM 5440, which contained one fourteen-inch platter. It was offered in three variants:

  • Model 1: equipped with one fixed and one removable disk, each having one hundred tracks per surface; cartridge capacity stood at approximately 1.23 MB
  • Model 2: featured one fixed plus one removable disk with two hundred tracks per surface; cartridge capacity doubled to about 2.46 MB
  • Model 3: contained only one removable disk with two hundred tracks per surface; capacity matched Model 2 at roughly 2.46 MB

IBM 62GV

The IBM 62GV, first shipped in May of 1974 from IBM’s Hursley facility in the UK under the codename Gulliver, initially offered a storage capacity of five megabytes. Subsequent variants expanded this to ten megabytes (62TM) and ultimately fourteen megabytes. It incorporated a Swinging Arm actuator design paired with a single fourteen-inch platter. This actuator mechanism became IBM’s most widely licensed electromechanical innovation, adopted broadly throughout the industry during the early eighties and remaining in use nearly four decades later across more than ten billion units worldwide. 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 hard disk drives manufactured by IBM, provided as OEM products and designed for IBM's smaller systems, including the System/3, System/32, /34, /36, and AS/400 series. These HDDs are cataloged by their OEM model numbers and arranged according to their initial customer shipment dates.

IBM 0680

Initially introduced in 1979, the 0680 was utilized across many IBM small systems and entry-level System/370 models as the 3310 direct access storage device. Officially announced as the 0680 OEM variant in September 1981, its development took place at IBM's Hursley facility in the UK under the project name Piccolo. This model incorporated six 8-inch (210 mm) platters with a starting capacity of up to 65MB and featured an enhanced rotary actuator mechanism.

A higher-capacity iteration, designated the 62SW, became available in June 1984 but experienced limited market success due to pricing similar to that of the 62GV.

IBM 0676

The 0676 was first released in November 1982 as part of the 5247 Disk Storage Unit for the IBM System/23 Datamaster. Engineered at IBM Rochester, Minnesota under the internal code 21ED, it was an 8-inch HDD offering initial storage options of either 15 or 30 MB through configurations of two or four 210 mm platters. By 1983, it had been incorporated into the System/36’s 5360 System Unit. In 1984, its capacity was doubled by increasing the number of tracks per surface, subsequently being used in the System/36’s 5362 System Unit.

IBM 0665

Released in October 1985 alongside the PC AT (5170) system unit, the 0665 was developed at IBM Rochester under the codename "Pixie." This model featured a 5¼-inch form factor and offered storage capacities of 20, 30, and 44 MB.

IBM 0667

Debuting in August 1986, the 0667 was created at IBM Rochester with the project name "Grant." It was a full-height ESDI hard drive measuring 5¼ inches, delivering up to 70 MB capacity distributed over as many as four 130 mm platters. This HDD was offered as an optional component on select PC RT models (6150, 6151, and 6152) as well as on System/36 Model System Units (5363 and 5364).

IBM 0669

Introduced in 1987, the 0669 originated from IBM Rochester under the codename "Grant-Prime." It was a full-height hard disk with a 5-inch form factor capable of storing up to 115 MB across four 130 mm platters. This drive served as the internal storage solution for both the 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 name "Lee." It featured a full-height ESDI design with a 5-inch form factor and supported capacities reaching up to 316 MB using eight 130 mm platters. Notably, this model represented IBM’s inaugural implementation of a thin metal film recording surface. In 1988, it was integrated into the IBM AS/400’s 9404 System Unit, supporting configurations of two or three drives.

IBM 0661

The 0661, identified as model 371 upon its introduction in 1989, was developed jointly at IBM Rochester and Hursley under the codename "Lightning." This SCSI hard disk featured up to eight platters measuring 95 mm each with a total capacity of approximately 320 MB and included fourteen read/write heads. A subsequent "Turbo" version with a capacity of around 400 MB followed in 1990. The drive became standard equipment on multiple IBM platforms such as the AS/400 System Unit Model CXX.

IBM 0681

Unveiled in April 1990 from IBM Hursley under the project name Redwing—the final HDD developed at that site—the 0681 offered maximum storage of up to approximately 857 MB utilizing twelve platters sized at 130 mm within a full-height five-inch enclosure. This unit was pioneering as the first HDD to implement PRML data decoding technology. It powered the IBM 9333 Disk Drive Subsystem introduced in early 1992, with an enhanced higher-density variant reaching about 1.07 GB released by May of that year.

IBM 0663

Introduced at the end of 1991 under the name "Corsair," the 0663 was a compact 3-inch hard disk drive featuring a half-height (1.6-inch) form factor and a maximum capacity of 1 GB distributed over eight 95 mm platters. It was utilized in select PS/2 and RS/6000 systems and marked the first OEM drive to integrate Magnetoresistance (MR) head technology.

IBM 0664

Released in November 1992 and developed at IBM Rochester, Minnesota, the 0664—codenamed "Allicat"—was a full-height 5-inch HDD (measuring 3.25 inches tall) that effectively combined two 3-inch drives. This device offered up to 2.013 GB storage using as many as eight 95 mm platters.

IBM 0662

The 0662 debuted in June 1993, also developed at IBM Rochester under the codename "Spitfire." This full-height (1-inch tall) 3-inch hard drive delivered 1.05 GB capacity across three disks or five recording surfaces. It found application internally within the 9336 Disk Unit and 9337 Disk Array.

Floppy disk drive

IBM pioneered floppy disk technology by launching the first 8-inch floppy disk drive in 1971, initially designed as a read-only medium for program loading. The company followed up with its first read/write floppy drive in 1973 as part of the 3740 Data Entry System. Although IBM established foundational standards for 8-inch floppy drives, it did not market these drives independently, allowing other industry players to develop their own solutions.

At one time, IBM was the largest original equipment manufacturer (OEM) buyer of 5-inch floppy drives. Its preference for two-sided drives with a density of 48 tracks per inch helped set this configuration as an industry norm. Despite plans to produce these and smaller formats internally, IBM discontinued all such manufacturing efforts by 1985. Notably, its attempt in 1983 to OEM the smaller 4-inch DemiDisk did not achieve commercial success.

"Star" series of HDDs

On October 17, 1994, IBM Storage Systems unveiled three new families of hard disk drives: the Travelstar series featuring 2-inch drives tailored for notebook computers; the Deskstar line comprising 3-inch desktop drives; and the Ultrastar range of high-performance 3-inch drives aimed at demanding applications.

IBM's first HDD versus its last HDDs

The following table compares IBM's original hard disk drive, the RAMAC 350, with the final trio of models from its "Star" series of OEM HDDs. This comparison underscores significant advancements in cost-efficiency and miniaturization alongside remarkable improvements in storage capacity and operational performance.

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 (millimeters) 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) Approx. 2374 watts (8100 BTUs/hour), peaking at around 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
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 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 Distinct from HDDs and FDDs

In certain IBM operating systems, hard disk drives (HDDs) and floppy disk drives (FDDs) are categorized under DASDs (direct access storage devices). This classification also encompasses several other storage technologies, including:

IBM 7320 Drum

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

IBM 2301 Drum

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

IBM 2303 Drum

The IBM 2303, launched in 1964, is a magnetic drum-based storage unit.

IBM 2321 Data Cell

Debuting in 1964, the IBM 2321 Data Cell employs short strips of magnetic tape for data retention. It accommodates ten detachable cells, each with a capacity of 40 MB, resulting in a total storage capability of 400 MB.

IBM 3850 Mass Storage System

The IBM 3850 Mass Storage System, which came out in 1974, functions as a tape cartridge library. It stages data onto IBM 3330 or 3350 disk drives and presents these as virtual drives to the host system.

See also

External links

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