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IBM 3340

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

IBM was engaged in the production of magnetic disk storage devices from 1956 until 2003, at which point it divested its hard disk drive division to Hitachi. IBM’s workforce was instrumental in pioneering both the hard disk drive (HDD) and floppy disk drive (FDD) technologies. The core mechanical framework of hard disk drives has largely remained unchanged since the introduction of the IBM 1301, and performance benchmarks have adhered to consistent standards dating back to the 1950s. Throughout this period, these storage solutions experienced dramatic decreases in cost and physical dimensions, coupled with substantial enhancements in capacity and speed.

From 1969 through the mid-1980s, IBM manufactured 8-inch floppy disk drives but did not become a significant producer of the smaller 5.25- or 3.5-inch formats. Although IBM sold its magnetic disk drives directly, it only started supplying them under original equipment manufacturer (OEM) agreements beginning in 1981. By 1996, IBM had discontinued manufacturing hard disk drives specifically for its own systems, instead offering all HDDs exclusively as OEM products.

IBM employed various names for its magnetic disk drives, including direct-access storage device (DASD), disk file, and diskette file. For clarity and consistency, this article uses the industry-standard terminology hard disk drive (HDD) and floppy disk drive (FDD).

IBM 350

The IBM 350 disk storage unit holds the distinction of being the first hard disk drive, introduced by IBM as part of the IBM 305 RAMAC system on September 14, 1956. Alongside it, a comparable model—the IBM 355—was launched for the IBM 650 RAMAC system. The initial prototype was delivered to Zellerbach Paper Company in June 1956, with mass production shipments commencing in November 1957 to United Airlines.

Designed to support real-time business accounting processes, the IBM 350 stored five million characters encoded in 6-bit format (equivalent to 3.75 MB) across fifty-two disks measuring 24 inches each, utilizing a total of 100 recording surfaces. The disks rotated at a speed of 1200 revolutions per minute, achieving a data transfer rate of 8,800 characters per second. Its access mechanism employed movable heads capable of selecting specific pairs of disks and tracks. Several enhanced versions were introduced during the late 1950s. The system was leased at a rate of $3,200 monthly and remained in service until its retirement in 1969.

A key patent from the RAMAC project, US3,503,060, is regarded as foundational for disk drive technology. Although initially rejected by IBM’s board over concerns that it might undermine the punch card business, development persisted at IBM’s San Jose laboratory until receiving approval from IBM’s president.

The physical dimensions of the unit were substantial: it measured 60 inches in length, stood 68 inches tall, and was 29 inches wide, weighing approximately one ton—necessitating forklifts and cargo aircraft for transportation. A research vice president from Hitachi Global Storage Technologies later noted that while capacity could have been expanded further, IBM’s marketing team was reluctant to promote larger storage sizes at that time. Nevertheless, versions with double the original capacity were announced in January 1959 and shipped within that year.

In recognition of its historical significance, the RAMAC 350 was declared an International Historic Landmark by The American Society of Mechanical Engineers in 1984. Restoration efforts began in 2002 under the leadership of Al Hoagland at Santa Clara University; since 2005, the refurbished unit has been on display at the Computer History Museum located in Mountain View, California.

IBM 353

The IBM 353, employed with the IBM 7030, resembled 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 marked the first disk drive to feature one head per disk surface flying on compressed air, continuing the innovation lineage from the IBM 350 disk storage (RAMAC). Production versions utilized self-flying heads akin to those found in the IBM 1301.

IBM 355

Introduced on September 14, 1956, the IBM 355 enhanced the functionality of the well-known IBM 650. It incorporated the IBM 350 mechanism but included up to three access arms instead of one on the IBM 350, enabling storage of six million decimal digits plus an additional 600,000 sign characters. This device transferred entire tracks to and from the magnetic core memory of the 653, an optional IBM 650 storage unit that held sixty signed 10-digit words—adequate for a single disk track or tape record—alongside two other unrelated features.

IBM 1405

Launched in 1961 for the IBM 1400 series business computers, the IBM 1405 Disk Storage Unit was available in two variants: Model 1 with a capacity of ten million alphanumeric characters (60 million bits) across 25 disks, and Model 2 offering twenty million characters (120 million bits) on fifty disks. The disks were arranged vertically on a shaft rotating at 1200 revolutions per minute.

Each disk surface contained 200 tracks segmented into five sectors; sectors numbered 0–4 were located on top surfaces while sectors 5–9 were on bottom surfaces. Each sector stored between 178 and 200 characters. One to three forked access arms, each equipped with two read/write heads for both sides of a disk, moved vertically to select among disks (0–49) and horizontally to choose tracks (0–199). Reading or writing data from 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 one hundred thousand sectors that could hold either two hundred characters in move mode or one hundred seventy-eight characters in load mode, which included an additional word mark bit per character. Model 1 had fifty thousand sectors.

IBM 7300

The IBM 7300 Disk Storage Unit was developed for use with the IBM 7070, with IBM announcing a second model in 1959. Nevertheless, upon introduction of the 1301 on June 5, 1961, many customers of both the IBM 7070 and IBM 7074 found it more appealing. The technology within the IBM 7300 shares common elements with the IBM 350, IBM 355, and IBM 1405 units.

IBM 1301

Released on June 2, 1961, the IBM 1301 Disk Storage Unit was designed for mainframe computers in the 7000 series as well as for the IBM 1410. Each module stored twenty-eight million characters (168 million bits), or twenty-five million characters when used with the IBM 1410. A module comprised twenty-five large disks providing forty user-accessible recording surfaces, each containing two hundred fifty tracks. The Model 1 configuration included one 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 notable advancement was having an individual arm and head dedicated to each surface that moved collectively like a comb mechanism. This eliminated repositioning delays between disks and reduced maximum access time to one hundred eighty milliseconds. The design also enhanced seek performance by positioning heads closer to the disk center rather than starting from the outer edge.

The IBM 1301 was pioneering as the first disk drive employing aerodynamically shaped heads that fly on a thin air cushion above disk surfaces, improving operational efficiency.

Connection to host systems was managed through the IBM 7631 File Control unit, with models supporting use by either IBM 1410 or IBM 7000 series computers or sharing access between two machines.

Leasing costs for the IBM 1301 Model 1 were $2,100 monthly or $115,500 for purchase; Model 2 cost $3,500 per month or $185,000 to buy. The IBM 7631 controller rental was $1,185 monthly or $56,000 if purchased. All versions were retired by around 1970.

IBM 1302

Released 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 delivered an average access time of 165 milliseconds and a data transfer speed of 180,000 characters per second, more than twice that of its predecessor. Each module incorporated two separate access mechanisms—one dedicated to the inner 250 cylinders and another for the outer 250 cylinders. The Model 2 version combined two modules to double the overall storage capacity. Leasing fees were set at $5,600 monthly for Model 1 and $7,900 for Model 2, while purchase prices stood at $252,000 and $355,500 respectively. Additionally, the IBM 7631 controller could be leased for $1,185 per month or purchased outright for $56,000. The IBM 1302 was discontinued in February 1965.

IBM 1311

Announced on October 11, 1962, the IBM 1311 Disk Storage Drive was designed for medium-sized business and scientific computer systems. Roughly comparable in size to a top-loading washing machine, it stored up to 2 million characters on a removable IBM 1316 disk pack. Throughout the 1960s, seven different models were introduced before being phased out by the early 1970s.

Each IBM 1316 Disk Pack measures about four inches in height, weighs approximately ten pounds, and consists of six fourteen-inch disks providing ten usable recording surfaces. The disks rotate at 1,500 revolutions per minute with each surface divided into 100 tracks containing twenty sectors each; every sector holds 100 characters. A hydraulic actuator moves ten read/write heads across the tracks. The disk pack is encased in a transparent plastic shell equipped with a locking handle to facilitate easy insertion and removal.

The seven IBM 1311 models include:

  1. Master drive used with IBM 1440, 1460, or 1240 systems; capable of controlling up to four Model 2 drives. Introduced in 1962 and retired in 1971.
  2. Slave drive supporting master drive functionality. Introduced in 1962 and withdrawn in 1975.
  3. Master drive compatible with IBM 1620 or IBM 1710 systems; controls up to three Model 2 drives without additional features. Introduced in 1962 and discontinued in 1971.
  4. Master drive designed for IBM 1401 systems; manages up to four Model 2 drives. Introduced in 1962 and phased out in 1971.
  5. Master drive for IBM 1410, IBM 7010, or IBM 7740 systems; controls up to four Model 2 drives and includes Direct Seek as standard. Released in January 1963 and withdrawn by May 1971.
  6. Presumed master drive introduced in March 1968; retired February 1971.
  7. Presumed slave drive corresponding to Model 6 introduced March 1968; withdrawn February1971.

Available optional features were:

  • Direct Seek: Allows direct access to tracks without returning to track zero first.
  • Scan Disk: Provides automated fast searching for specific identifiers or conditions.
  • Seek Overlap: Permits concurrent seek operations alongside read/write functions across multiple drives.
  • Track Record: Enhances storage capacity by writing a single large record per track instead of multiple sectors—yielding up to around eighteen million bits depending on configuration.

Master drives (Models 1,3,4,5) include additional power supplies and control circuitry, resulting in a width roughly one foot greater than that of Model 2 slave drives.

IBM 2302

The IBM 2302 represents the System/360 adaptation of the 1302, formatted specifically for S/360 DASD architecture. It utilizes a fixed module containing twenty-five platters with forty-six recording surfaces. The Model 3 incorporates one such module; Model 4 contains two modules. Each module is equipped with two independent access mechanisms—termed access groups—covering the innermost and outermost sets of 250 cylinders respectively, each featuring one read/write head per track. Average rotational latency is approximately seventeen milliseconds with a maximum delay of thirty-four milliseconds; maximum seek time per group reaches up to one hundred eighty milliseconds. Tracks hold about four thousand nine hundred eighty-five bytes each, yielding a total module capacity of approximately one hundred twelve megabytes. Connectivity to IBM mainframes is achieved through the IBM 2841 Storage Control Unit.

IBM 2305

Launched in 1970 alongside the IBM 2835 Storage Control, the IBM 2305 fixed-head storage device initially interfaced with System/360 models 85 and 195 through the IBM 2880 Block Multiplexor Channel. It gained significant popularity with the advent of System/370's Virtual Storage, frequently functioning as a paging device on systems such as the 3155, 3165, 3158, 3168, 3033, 4341, and 3081 (the latter utilizing specialized microcode). Additionally, the 2305 was widely employed for managing small, high-transaction data sets like catalogs and job queues.

The 2305-1 model provides a storage capacity of 5.4 MB with a data transfer rate of 3.0 MB/s and an average access time of 2.5 milliseconds via a 2-byte channel interface. In contrast, the larger 2305-2 variant offers an 11.2 MB capacity at a throughput of 1.5 MB/s and an average access latency of 5 milliseconds. Its blend of substantial capacity and rapid data rates made it well-suited for system-resident tasks, work files, job queues, indices, and frequently accessed datasets. The device’s swift response time rendered it ideal for paging operations in heavily loaded environments processing more than 1.5 transactions per second.

IBM 2311

The IBM 2311 Disk Storage Drive was introduced in 1964 alongside the 2841 Control Unit to serve the IBM System/360 series and was also compatible with the IBM 1130 and IBM 1800. It connected directly to the IBM System/360 Model 20 and Model 25 systems. 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; however, on the System/360 Model 25, it interfaces through a Disk Attachment Control that provides similar functionality. The disk packs employ IBM’s count key data variable-length record format.

Models 11 and 12 were tailored for the System/360 Model 20’s integrated control architecture and utilize fixed-sector formatting. Disk packs are not interchangeable between Model 1 and Models 11 or 12.

While mechanically resembling the IBM 1311, the IBM 2311 incorporated enhanced recording technology and stored up to 7.25 megabytes on a six-platter removable disk pack. It featured ten read/write heads mounted on a hydraulically actuated arm with each platter surface containing 200 tracks plus three spare tracks reserved for defects. The average seek time was approximately 85 milliseconds with a data transfer rate reaching up to 156 kB/s.

A uniform electrical interface across System/360 models allowed third-party vendors to manufacture plug compatible disk drives, promoting competition within the IBM-compatible storage market.

IBM 2314 Disk Access Storage Facility Model 1

Released in April of 1965, the IBM 2314 Disk Access Storage Facility Model 1 supported both System/360 and System/370 platforms. It featured a Two Channel Switch capability that enabled simultaneous connections to two channels. Building upon the foundational design of the IBM 2311, it offered increased data density.

This drive stored roughly twenty-nine million characters on a removable IBM 2316 disk pack—similar in design to the IBM 1316 but taller due to its eleven platters providing twenty recording surfaces. The actuator assembly hydraulically positioned twenty read/write heads over each surface containing two hundred tracks. Subsequent enhancements improved access times beyond those of its predecessor (the IBM 2311) and doubled data transfer speeds to approximately 310 kB/s.

The Model 1 was delivered as a package containing nine disk drives; separately shipped components included a storage control unit, one single-drive module, and two four-drive modules. The drives were installed in pull-out drawers colloquially known as "Pizza Ovens." Although nine drives were included in total, only eight were accessible simultaneously—the ninth served as an offline spare to facilitate maintenance without interrupting ongoing operations. Drive system addresses were configured using user-swappable plugs, allowing flexible reassignment of drives within the system.

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

Subsequent iterations of the IBM 2314 followed these initial developments:

IBM 2314 Direct Access Storage Series

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

  • The 2312 Disk Storage, which housed a single drive.
  • The 2313 Disk Storage, featuring four drives.
  • The 2318 Disk Storage, containing two drives.

IBM 2319

To address the challenge posed by plug-compatible manufacturers offering alternatives to the 2314 storage subsystems, IBM introduced the cost-effective three-drive 2319 series in 1970. This model was derived by removing one drive from the four-drive 2313 and rebranding it as the 2319 A1, which was offered at a significantly lower rental rate. This approach reduced expenses for new customers while preserving higher charges for existing users. The 2319-A1 interfaces with integrated controllers designed for System/370 Models 135 and 145. Additionally, traditional 2314 DASD units such as the 2312 or 2318 can connect to the 2319-A1. The 2319 B series supports configurations of three, six, or nine drives connected to a new 2314 Model B Storage Control Unit.

IBM 3310

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

IBM 3330

The IBM 3330 Direct Access Storage Facility, codenamed Merlin, was introduced in June 1970 for use with IBM System/370 and System/360/195 computers. Initially available as Model 1 (two drives) and Model 2 (one drive), it featured removable disk packs with a capacity of 100 MB each. Boasting a 30 ms access time and an 806 kB/s data transfer rate, it incorporated error correction through fire codes, which improved reliability and lowered costs by accommodating imperfections on disk surfaces.

The setup consisted of one storage control unit (the 3830 Model 1) connected to up to four drives arranged in a "string" with a maximum of eight drives. In August 1972, IBM announced the 3830 Model 2 Storage Control alongside the 3333 Disk Storage and Control, which separated control functions from the drive string. The 3830 evolved into a director-style controller capable of managing multiple strings. Each string started with a 3333 unit containing both a controller and two drives; this unit could support up to three additional attached 3330 drives, allowing eight drives per string. The upgraded 3830 Model 2 could link two such strings together, enabling control of up to sixteen drives per storage control unit. The 3333 also optionally supported dual-controller connections via a string switch.

In 1973, IBM released double-density (-11) variants such as the 3333–11, 3330-11, and larger-capacity 3336–11 Disk Packs offering up to 200 MB. Mixing single- and double-density drives within the same string was not supported. Field upgrades from original models to -11 versions were feasible but complex, requiring drive conversions and data transfers.

The IBM 3330 series was discontinued in 1983.

IBM 3340 and IBM 3344

While the IBM 3340 and 3344 models share many characteristics, only the 3340 can function as the head of a string. There are no A model versions of the 3344, so it must be connected under a 3340 A model acting as the string’s head unit.

IBM 3340

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

This system utilized removable data modules that incorporated both the head and arm assembly; during load or unload operations, the module's access door opened to engage with the drive, eliminating the need to remove covers as with earlier disk packs. It provided an access time of 25 milliseconds and a data transfer rate of 885 kB/s. Three versions of the IBM 3348 Data Module were available, with capacities of 35 MB and two at 70 MB, one of which included a fixed-head section of 500 KB for accelerated access. The 3340 incorporated error correction capabilities and was discontinued in 1984.

Developed in San Jose under Ken Haughton's leadership, the original design targeted two removable 30 MB modules. This concept inspired the Winchester nickname, drawn from the Winchester .30-30 rifle. Although storage capacities expanded over time, the codename endured.

A significant breakthrough was the economical head design that eliminated the need to unload heads from the media. This "Winchester technology" enabled heads to land on and lift off from spinning disks, simplifying the head and arm mechanism while reducing costs. This approach became a foundational standard in disk drive production.

The terms Winchester or Winnie continued as informal references to hard disk drives into the early 1990s but have since fallen out of common use worldwide.

IBM 3344

The IBM 3344 shares similarities with the 3340 but distinguishes itself by employing fixed media rather than removable 3348 data modules. Each spindle supports four logical drives, each matching the capacity of a single 3348–70 module. Available exclusively as dual-drive models, it does not include an A (head of string) variant. The 3344-B2F model differs from the 3344-B2 by featuring fixed heads over certain cylinders on both drives. Both variants require a 3340-A2 or 3340-A2F unit as the head-of-string controller. Internally, the IBM 3344 mirrors the IBM 3350 architecture, with variations limited to microcode within the control unit.

IBM 3350

Released in 1975 for IBM System/370 systems, the IBM 3350 Direct Access Storage Facility bore the codename Madrid. It introduced sealed, non-removable head-disk assemblies (HDAs) that combined head and arm components—a design that became standard for sealed HDAs in IBM DASD products thereafter. Each HDA contained 555 cylinders, 30 heads, and stored 19,069 bytes per track, yielding roughly 317 MB of storage capacity.

The product line included models A2, A2F, B2, B2F, C2, and C2F, each housing two HDAs. Models A2 and A2F incorporated an extra electronic board that connected to the storage control unit and functioned as controllers or head-of-string units. Typical configurations consisted of an A2 or A2F unit followed by up to three B2 units or combinations involving C2 units. The A2 model often featured a string switch enabling connections to two control units simultaneously, permitting concurrent I/O operations on different HDAs. Compatible storage control units encompassed the 3830 Model 2, Integrated Storage Controller (ISC) within CPUs such as the 3148/3158/3168 series, as well as later backward-compatible units like the IBM 3880.

The C2 model included a secondary controller acting as a failover if an A unit’s controller malfunctioned; however, it lacked full connectivity capabilities compared to the A unit’s string switch. Valid IBM 3350 configurations included strings such as -A, -AB, -ABB, -ABBB, -AC-, -ABC-, and -ABBC-.

Models designated with "x2F" suffixes (for example, A2F) featured fixed-head sections spanning the first five cylinders on both HDAs, effectively reducing seek times within these zones to zero. This optimized performance for frequently accessed data areas like HASP or JES2 checkpoints and enhanced system swap data handling during TSO and MVS context switches by minimizing head movement.

The IBM 3350 series was officially withdrawn from sale in September 1994.

IBM 3370

Debuting in January 1979 for use with IBM 4331, 4341, and System/38 midrange systems, the IBM 3370 incorporated seven fixed 14-inch platters, delivering a storage capacity of 571 MB. This model was pioneering as the first hard disk drive to implement thin-film head technology, which was developed during the late 1960s at the Thomas J. Watson Research Center. The device utilized fixed-block architecture and was compatible with DOS/VSE and VM operating systems running on System/370 platforms.

IBM 3375

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

IBM 3380

Released on June 11, 1980, the IBM 3380 provided a storage capacity of 2.52 GB per unit by combining two hard disk assemblies, each equipped with dual actuators accessing 630 MB. It supported a data transfer speed of 3 MB per second and had an average access latency of 16 milliseconds. Initial prices ranged between $81,000 and $142,200. However, early deliveries were postponed until October 1981 due to tribological challenges involving the interaction between read/write heads and disk media.

A typical setup featured one A unit accompanied by up to three B units; each IBM 3380 housed four devices, enabling configurations with up to 16 devices in a string. These drives were generally connected via a dual-path interface to a 3880 storage control unit, allowing two concurrent I/O operations directed at separate hard disk assemblies.

In February 1985, IBM launched the Extended Capability Model (3380 E) with double density, offering a capacity of 5.04 GB per unit (two actuators at 1.26 GB each). Later, in August 1987, the Model K expanded capacity further to 7.562 GB per unit (two actuators at 1.89 GB each). Both Models J and K supported four-path operation when linked to a 3990 storage control unit, facilitating up to four simultaneous I/O processes across as many as 32 devices within a string.

The IBM 3380 series encompassed twelve distinct models: six A-units functioning as string leaders with controller logic interfacing with IBM storage controllers; five B-units connecting to A- or C-units; and one C-unit designed for direct connection to an IBM channel.

Manufacturing concluded in May 1996 after an impressive production span of fifteen years, surpassing the longevity typical of most disk drives.

IBM 3390

Introduced in November 1989, the IBM 3390 Direct Access Storage Device lineup delivered storage capacities reaching up to 22 gigabytes distributed across multiple drives. Depending on configuration and size, system prices varied from $90,000 to $795,000.

A standard IBM 3390 string consists of a central A unit containing four or eight devices and may include one or two B units housing up to twelve devices each. Operating in four-path mode when connected to a 3990 storage control unit, this setup can accommodate a second string of IBM 3390 drives, supporting up to sixty-four devices within the subsystem.

Each Hard Disk Assembly (HDA) contains two actuator-head units along with platters; Model 1 HDAs offered capacities of 1.89 GB, Model 2 increased this to 3.78 GB, Model 3 (introduced in 1991) further expanded capacity to 5.67 GB, and Model 9 (released in 1993) reached up to 11.3 GB per HDA.

Contrasting with earlier DASD designs that employed large AC motors and belts for platter rotation, the IBM 3390 HDAs utilized direct-drive DC motors enclosed within the drive housing. The Model 9 represented IBM’s final release of Single Large Expensive Disk (SLED) technology.

IBM 9345

Launched in November 1990 as a Request Price Quotation (RPQ) option for IBM’s SuperComputing Systems Extensions (SCSE), the IBM 9345 hard disk drive was engineered at IBM’s San Jose laboratory under the project name Sawmill. This full-height 5¼-inch drive housed up to eight 130 mm platters, providing a maximum storage capacity of 1.5 GB. It was pioneering as the first HDD to incorporate magnetoresistive (MR) heads, which significantly improved data read efficiency.

IBM 9340

The IBM 9340 DASD was introduced in October 1991 as part of the IBM 9340 channel-attached CKD DASD subsystem series for mainframe systems, including the ES/9000 family. The 9345 Model 1 included two drives each with 1.0 GB capacity, whereas Model 2 consisted of two drives with 1.5 GB each.

In terms of operation, the 9340/9345 series paralleled the capabilities of the 3990/3390 models but did not feature the non-volatile RAM cache found in the 3990 and supported a shorter maximum block length compared to the 3390. During initialization, the OS Input/Output Supervisor (IOS) identified device attributes via IECCINIT, recognizing the absence of non-volatile cache on the 9340 and noting the reduced track count on the 9345, thereby assigning distinct device types accordingly.

9330 family of disk drives

  1. The 9331 Diskette Unit models 1 and 11 contained a single 8-inch floppy disk drive; models 2 and 12 were equipped with a single 5-inch floppy disk drive.
  2. The IBM 0667 HDD powered the 9332 Direct Access Storage Device.
  3. The IBM 0664 or IBM 0681 HDDs were utilized by the high-performance disk drive subsystem, model-dependent, designated as the 9333.
  4. The 9334 Disk Expansion Unit connected between one and four SCSI hard drives to RS/6000 systems.
  5. The "Kestrel" HDD, developed at IBM Hursley in the UK, was featured in the 9335 Direct Access Storage Subsystem. This rack-mountable unit included three large 14-inch disks totaling an 850 MB capacity and employed dual rotary actuators for multi-surface access. It debuted alongside the IBM 9370 Information System in October 1986. There are no records of OEM variants.
  6. The IBM Redwing HDD (model 0681) was used within the 9336 Disk Unit.
  7. The Disk Array Subsystem model 9337 incorporated either IBM's Spitfire (0662) or Corsair (0663) HDDs.

IBM 2310

Introduced in conjunction with the IBM 1800 in 1964 and later with the IBM 1130 in 1965—most likely first delivered with the latter in late that year—the IBM 2310 Removable Cartridge Drive stored up to 512,000 sixteen-bit words (equivalent to approximately one million bytes) on an IBM 2315 cartridge. This cartridge contained a single oxide-coated aluminum platter enclosed within a plastic shell featuring openings for both read/write heads and arm access.

IBM 5444

Announced in September 1969 as part of System/3, the IBM 5444 was developed at IBM’s Hursley facility in England under the codename Dolphin. It utilized a disk cartridge known as the IBM 5440 that contained one fourteen-inch platter. Three model variations were available:

  • Model 1: equipped with one fixed and one removable disk, each offering 100 tracks per surface, yielding a cartridge capacity of approximately 1.23 MB
  • Model 2: featured one fixed and one removable disk with doubled tracks at 200 per surface, doubling cartridge capacity to roughly 2.46 MB
  • Model 3: included a single removable disk with 200 tracks per surface, also providing about 2.46 MB capacity

IBM 62GV

The IBM 62GV, which began shipping in May of 1974 from IBM’s Hursley UK laboratory under project name Gulliver, initially offered a storage size of five megabytes. Subsequent versions included a ten megabyte model labeled as the '62TM' and an expanded fourteen megabyte variant. This drive employed a Swinging Arm actuator design paired with one fourteen-inch disk. The Swinging Arm actuator became IBM’s most widely licensed electro-mechanical innovation, ultimately being adopted broadly across HDDs industry-wide throughout the following decades. With approximately 177,000 units shipped, it was also notable as 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 components and designed for IBM’s smaller systems such as the System/3, System/32, /34, /36, and AS/400. These drives are referenced by their OEM model identifiers and organized according to their initial customer shipment dates.

IBM 0680

The 0680 was initially delivered in 1979, primarily supporting IBM small systems and entry-level System/370 models as the 3310 direct access storage device. Officially introduced as the 0680 OEM variant in September 1981, it was engineered at IBM’s Hursley laboratory in the UK under the project name Piccolo. This drive offered a maximum capacity of 65MB utilizing six 8-inch (210 mm) platters and incorporated an enhanced rotary actuator mechanism.

A higher-capacity iteration known as the 62SW appeared in June 1984; however, its adoption was limited due to a cost per megabyte comparable to the more premium 62GV model.

IBM 0676

The 0676 arrived in November 1982 as a 5247 Disk Storage Unit tailored for the IBM System/23 Datamaster. Developed at IBM Rochester, Minnesota under the designation 21ED, this 8-inch hard drive provided storage options of either 15 or 30 MB through configurations of two or four platters. By 1983, it had been integrated into the S/36’s 5360 System Unit. In 1984, its capacity doubled by increasing track density per surface and was subsequently utilized within the S/36’s 5362 System Unit.

IBM 0665

Introduced in October 1985 within the PC AT (5170) chassis, the 0665 was created under the codename "Pixie" at IBM Rochester. This hard drive featured a 5¼-inch form factor with storage capacities ranging from 20 to 44 MB.

IBM 0667

The 0667, launched in August 1986 and developed at IBM Rochester under the project name "Grant," was a full-height, 5¼-inch ESDI hard disk drive. It supported up to four platters measuring 130 mm each and offered a maximum capacity of 70 MB. This model was available on select PC RT systems (6150, 6151, 6152) as well as System/36 Model System Units (5363, 5364).

IBM 0669

Released in 1987 and developed at IBM Rochester, Minnesota with the codename "Grant-Prime," the 0669 was a full-height, 5-inch hard disk drive featuring four 130 mm platters that provided up to 115 MB of storage. It served as the internal drive for System/36’s 5363 and Series 1’s 4956 System Units.

IBM 0671

Also appearing in 1987, the 0671 was developed at IBM Rochester under the codename "Lee." This full-height, five-inch ESDI hard drive delivered up to 316 MB across eight platters measuring 130 mm each. It represented IBM’s initial implementation of thin metal film recording surfaces and was incorporated into the AS/400’s 9404 System Unit released in 1988, supporting configurations of two or three drives.

IBM 0661

The 0661, first shipped in 1989 as model number 371, originated from collaborative development between IBM Rochester and Hursley. It was a SCSI hard disk drive with capacities up to 320 MB utilizing eight platters sized at 95 mm (with fourteen heads). In 1990, an enhanced "Turbo" version offering a capacity of up to 400 MB was introduced. This drive became a standard component on key IBM platforms including the AS/400 System Unit Model CXX.

IBM 0681

Introduced in April of 1990, the 0681 represented IBM Hursley’s final hard disk development effort under the codename Redwing. It featured twelve platters measuring 130 mm each within a full-height five-inch enclosure and offered storage capacities reaching up to 857 MB. Notably, it was IBM’s first hard drive employing PRML data decoding technology. This model powered the early-1992 release of the 9333 Disk Drive Subsystem, with a higher-density variant providing up to 1.07 GB becoming available in May of that year.

IBM 0663

Introduced in late 1991 under the codename "Corsair," the 0663 was a compact 3-inch hard disk drive featuring a half-height (1.6-inch) form factor. It provided storage capacity up to 1 GB utilizing eight 95 mm platters. This model was available on select PS/2 and RS/6000 systems and marked IBM’s inaugural OEM HDD to incorporate Magnetoresistance (MR) read heads.

IBM 0664

Released in November 1992 and developed at IBM Rochester, Minnesota, under the codename "Allicat," the 0664 was a full-height 5-inch hard disk drive with a height of 3.25 inches. It effectively combined two 3-inch drives, delivering up to 2.013 GB capacity across as many as eight 95 mm disks.

IBM 0662

The 0662, launched in June 1993 and created at IBM Rochester with the codename "Spitfire," was a full-height (1-inch) 3-inch hard disk drive providing 1.05 GB of storage on three platters or five recording surfaces. This drive functioned as the internal HDD for both the 9336 Disk Unit and the 9337 Disk Array.

Floppy disk drive

IBM was instrumental in the development of the floppy disk drive, debuting the 8-inch FDD in 1971 initially as a read-only program loading device, followed by its first read/write version in 1973 integrated into the 3740 Data Entry System. Although IBM established early standards for 8-inch floppy drives, it never marketed these drives independently, allowing the broader industry to progress autonomously.

At one time, IBM was the largest original equipment manufacturer (OEM) buyer of 5-inch floppy disk drives, with its selection of two-sided models operating at 48 tracks per inch helping to set this as an industry norm. Despite initiating plans to produce smaller form factors, IBM discontinued these projects by 1985. Its attempt in 1983 to OEM a 4-inch DemiDiskette did not succeed.

"Star" series of HDDs

On October 17, 1994, IBM's Storage Systems division unveiled three distinct families of hard disk drives: the Travelstar series featuring 2-inch drives for notebook computers, the Deskstar lineup with 3-inch drives aimed at desktop PCs, and the Ultrastar series of high-performance 3-inch drives designed for demanding computing environments.

IBM's first HDD versus its last HDDs

The table below contrasts IBM's initial 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 reduction and miniaturization alongside enhancements in storage capacity and operational performance.

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 (gigabytes) 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) (8100 BTUs/hour = approximately 2374 watts), up to 5500 VA depending on unit model 16 10.3 1.85 ×1,283
Power efficiency (megabytes per watt) 0.0016 9,125 17,476 43,243 ×27,375,856
Manufacturer's list 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
Rotational 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

In certain IBM operating systems, both hard disk drives (HDDs) and floppy disk drives (FDDs) are categorized as DASDs (direct access storage devices). Additional forms of DASD technology encompass:

IBM 7320 Drum

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

IBM 2301 Drum

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

IBM 2303 Drum

Another magnetic drum storage device, the IBM 2303, became available in 1964.

IBM 2321 Data Cell

Debuted in 1964, the IBM 2321 Data Cell stores data on short strips of magnetic tape. It features ten removable 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, launched in 1974, functions as a tape cartridge library that stages data onto IBM 3330 or 3350 disk drives. It presents these as virtual drives to the host system.

See also

External links

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