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IBM 0665

From Alfawiki
Adapted from the English Wikipedia article IBM 0665, available under CC BY-SA 4.0Updated 9 August 2025
IBM Magnetic Disk Storage Division
Company typeDivision
IndustryComputer storage devices
Founded1956
Defunct2003
FateDivested to Hitachi
Headquarters
San Jose
,
United States
ProductsHard disk drives, floppy disk drives
ParentIBM

IBM was a pioneer in manufacturing magnetic disk storage devices from 1956 until 2003, at which point it divested its hard disk drive division to Hitachi. IBM's workforce played a crucial role in inventing both the hard disk drive (HDD) and the floppy disk drive (FDD), contributing numerous advancements to these technologies. The core mechanical architecture of hard disk drives has largely remained unchanged since the introduction of the IBM 1301, with performance benchmarks established in the 1950s still relevant today. Throughout the years, these storage devices have experienced substantial decreases in cost and physical dimensions, alongside remarkable improvements in capacity and speed.

Between 1969 and the mid-1980s, IBM manufactured 8-inch floppy disk drives but did not become a leading producer of smaller form factors such as 5.25- or 3.5-inch drives. Although IBM consistently sold its magnetic disk drives, it only started offering them under original equipment manufacturer (OEM) agreements beginning in 1981. By 1996, IBM had discontinued producing hard disk drives exclusively for its own hardware, shifting entirely to marketing HDDs as OEM components.

IBM has employed multiple designations for its magnetic disk storage products, including direct-access storage device (DASD), disk file, and diskette file. In this article, the commonly accepted industry terms hard disk drive (HDD) and floppy disk drive (FDD) are used.

IBM 350

The IBM 350 disk storage unit, recognized as the first-ever disk drive, was introduced on September 14, 1956, as part of the IBM 305 RAMAC system. A related 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 production units first shipped to United Airlines in November 1957.

Created to fulfill real-time accounting requirements, the IBM 350 had a storage capacity of five million 6-bit characters (equivalent to 3.75 MB). It consisted of fifty-two disks providing 100 recording surfaces and tracks rotating at a speed of 1200 rpm. The data transfer rate reached 8,800 characters per second. The access mechanism enabled movement of read/write heads to select specific disk pairs and tracks. Several enhanced variants were introduced during the late 1950s. The IBM RAMAC 305 paired with the 350 was leased at $3,200 per month and was retired from service in 1969.

The patent originating from the RAMAC initiative is regarded as the foundational intellectual property for disk drive technology. Although initially rejected by IBM's board due to concerns about its potential negative impact on punch card sales, development persisted at IBM’s San Jose facility until receiving approval from IBM’s president.

The physical dimensions of the IBM 350 cabinet were approximately long, high, and wide. Weighing close to one ton, it required forklifts and sizable cargo aircraft for transportation. Currie Munce from Hitachi Global Storage Technologies—successor to IBM’s storage division—remarked that capacity could have been expanded beyond five million characters; however, IBM’s marketing team hesitated over uncertain demand. Despite this caution, double-capacity models were announced in January 1959 and delivered later that year.

In recognition of its engineering significance, the RAMAC 350 Disk File was named an International Historic Landmark by The American Society of Mechanical Engineers in 1984. A restoration effort led by Al Hoagland commenced in 2002 to refurbish an IBM 350 RAMAC unit in partnership with Santa Clara University. This project transitioned to the Computer History Museum, Mountain View, California in 2005 and is currently on public display.

IBM 353

The IBM 353, designed to operate alongside 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 supported a transfer rate of 125,000 words per second. A prototype delivered in late 1960 was notable as the first disk drive to implement one read/write head per surface flying on compressed air, similar to 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 served as a companion to the widely used IBM 650. It incorporated the IBM 350 mechanism but featured up to three access arms instead of just one. The device stored six million decimal digits along with 600,000 sign indicators. Data transfer involved moving complete tracks between the magnetic core memory of the 653, an optional IBM 650 storage unit capable of holding sixty signed 10-digit words—enough capacity for a single track or tape record.

IBM 1405

Released in 1961 for the IBM 1400 series computers, the IBM 1405 Disk Storage Unit was available in two variants: Model 1 accommodated 10 million alphanumeric characters (60 million bits) across 25 disks; Model 2 doubled this capacity to 20 million characters (120 million bits) using 50 disks. The disks rotated vertically at a speed of 1200 revolutions per minute.

Each disk surface contained 200 tracks subdivided into five sectors. The access arms—ranging from one to three forked designs—each carried two read/write heads servicing both the top and bottom surfaces. These arms were mounted on a carriage adjacent to the disk stack and moved vertically to select among disks (0–49) and horizontally to choose tracks (0–199). Each track comprised ten sectors that stored either 178 or 200 characters. Reading or writing a sector took approximately ten milliseconds.

Access times varied between 100 milliseconds and up to a maximum of 700 milliseconds for Model 1 and 800 milliseconds for Model 2. Model 2 included 100,000 sectors holding either 200 characters in move mode or 178 characters in load mode, which incorporated an additional word mark bit per character; Model 1 contained half as many sectors.

IBM 7300

The IBM 7300 Disk Storage Unit was created for use with the IBM 7070, with a second model announced in 1959. Nonetheless, following the debut of the IBM 1301 on June 5, 1961, customers showed greater preference for the latter. The technology employed in the IBM 7300 was comparable 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 aimed at supporting the IBM 7000 series mainframe computers as well as the IBM 1410. Each module provided storage for approximately 28 million characters (168 million bits), or about 25 million characters when used with the IBM 1410. Modules consisted of twenty-five large disks offering forty user-accessible recording surfaces and featuring two hundred fifty tracks per surface. The Model 1 configuration included a single module; Model 2 stacked two modules vertically. Disks rotated at a speed of eighteen hundred revolutions per minute and transferred data at a rate of ninety thousand characters per second.

A significant advancement was the use of an individual arm and read/write head for each disk surface, arranged together like a comb. This architecture eliminated delays caused by moving heads between disks and reduced maximum access time to one hundred eighty milliseconds. Additionally, the IBM 1301 was pioneering in employing aerodynamically designed heads that flew on a thin cushion of air above each disk surface, enhancing overall performance.

Connection was facilitated through the IBM 7631 File Control unit, allowing operation with either the IBM 1410 or IBM 7000 series systems—or simultaneous use by both.

Lease pricing for the IBM 1301 Model 1 was $2,100 monthly or $115,500 for purchase; Model 2 leased at $3,500 monthly or purchased for $185,000. The IBM 7631 controller added $1,185 per month or $56,000 if bought outright. All versions were discontinued by 1970.

IBM 1302

Launched in September 1963, the IBM 1302 Disk Storage Unit introduced advanced recording technology that increased capacity to four times that of the 1301, achieving storage of 117 million 6-bit characters per module. It delivered an average access time of 165 milliseconds and data transfer speeds of 180,000 characters per second, exceeding twice the throughput of its predecessor. Each module incorporated two access arms to service both inner and outer cylinder regions. The Model 2 configuration stacked two such modules together, effectively doubling the storage capacity. Leasing fees were set at $5,600 per month for Model 1 and $7,900 per month for Model 2, with purchase prices at $252,000 and $355,500 respectively; the IBM 7631 controller was available separately for $1,185 monthly or $56,000 outright. The IBM 1302 was discontinued in February 1965.

IBM 1311

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

Each IBM 1316 disk pack measures high and weighs , containing six disks with ten usable recording surfaces (the outermost surfaces remain unused). The pack’s ten read/write heads are hydraulically positioned across tracks on disks rotating at 1500 revolutions per minute. Every surface holds 100 tracks divided into 20 sectors each; every sector accommodates 100 characters. Encased within a plastic shell featuring a locking handle for secure installation and removal, this design became widely adopted in subsequent storage devices.

The seven IBM 1311 models consist of master drives equipped with controllers and slave drives managed by these masters:

  1. Master drive tailored for IBM 1440, 1460, or 1240 systems; capable of controlling up to four Model 2 slave units. Released October 11, 1962; withdrawn February 8, 1971.
  2. Slave drive compatible with master drive specifications. Released October 11, 1962; withdrawn January 6, 1975.
  3. Master drive intended for IBM 1620 or IBM 1710 systems; manages up to three Model 2 slaves; lacks special features. Released October 11, 1962; withdrawn May 12, 1971.
  4. Master drive compatible with IBM 1401 systems; controls up to four Model 2 slaves. Released October 11, 1962; withdrawn February8,1971.
  5. Master drive designed for IBM1410, IBM7010, or IBM7740 systems; supports up to four Model2 slaves; includes Direct Seek functionality as standard. Released January7,1963; withdrawn May12,1971.
  6. Presumed master drive introduced March5,1968; withdrawn February2,1971.
  7. Presumed slave drive complementing Model6 introduced March5,1968; withdrawn February2,1971.

Several optional features were available to boost performance:

  • Direct Seek: Removes the requirement to return to track zero before seeking a new track.
  • Scan Disk: Facilitates rapid automatic searching for specific identifiers or conditions.
  • Seek Overlap: Permits concurrent seek and read/write operations across multiple drives.
  • Track Record: Enhances storage by writing one large record per track instead of multiple sectors—achieving up to roughly18 million bits depending on configuration.

Master drives (Models1,3,4,and5) incorporate additional power supplies and control circuitry and are approximately one foot wider than the Model2 slave units.

IBM 2302

The IBM 2302 represents the System/360 adaptation of the IBM 1302, tailored to fit the S/360 direct access storage device architecture. It incorporates a fixed module containing 25 platters, amounting to 46 recording surfaces. Model 3 is equipped with a single module, whereas Model 4 includes two modules. Each module features two separate access mechanisms that cover the 250 innermost and 250 outermost cylinders, referred to as access groups, each having one read/write head per track. The average rotational latency is approximately 17 milliseconds, with a maximum delay of 34 milliseconds; the highest seek time within each access group reaches up to 180 milliseconds. Each track holds 4,985 bytes, resulting in an overall module capacity near 112 megabytes. The 2302 interfaces with IBM mainframe systems through the IBM 2841 Storage Control Unit.

IBM 2305

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

During the System/370 period, particularly for virtual storage environments such as OS/VS2, the 2305 was extensively utilized as a paging device on systems including the 3155, 3165, and 3081 (with specialized microcode). It also served high-transaction small data sets like catalogs and job queues effectively.

The smaller model, 2305-1, offers a capacity of 5.4 megabytes with a data transfer rate of 3.0 megabytes per second and an average access time of approximately 2.5 milliseconds. The larger variant, 2305-2, provides an 11.2-megabyte capacity at a transfer speed of 1.5 megabytes per second and an average access time of about 5 milliseconds.

Engineered for rapid and continuous access to modest-sized data volumes, the 2305 proved ideal for system-resident files, work files, job queues, indices, and frequently accessed datasets. Its swift response times made it particularly valuable as a paging device in heavily loaded environments processing more than 1.5 transactions per second.

IBM 2311

Launched in 1964 alongside the 2841 Control Unit, the IBM 2311 Disk Storage Drive was designed primarily for the IBM System/360 but also supported the IBM 1130 and IBM 1800. It connects directly to the IBM System/360 Model 20 and Model 25 models. All units employ removable IBM 1316 Disk Packs, identical to those used in the IBM 1311.

The Model 1 is compatible with most IBM mainframes via the IBM 2841 Control Unit and attaches to the System/360 Model 25 through a Disk Attachment Control. Disk packs utilize IBM's count key data variable-length record format. Models 11 and 12, which work with Model 20's integrated control unit, use a fixed-sector format; disk packs between these two formatting schemes are not interchangeable.

While mechanically similar to the IBM 1311, the IBM 2311 benefits from enhanced recording technology and stores approximately 7.25 megabytes on a six-platter removable disk pack. It employs ten read/write heads mounted on hydraulically actuated arms, with each surface containing about 200 tracks plus three spare tracks reserved for defect management. The average seek time is around 85 milliseconds, and it achieves a data transfer rate of roughly 156 kilobytes per second.

Uniform electrical interfaces across all System/360 models allowed third-party vendors to manufacture plug compatible disk drives, thereby encouraging competition within the IBM-compatible storage market.

IBM 2314 Disk Access Storage Facility Model 1

Debuting in April 1965, the IBM 2314 Disk Access Storage Facility Model 1 was compatible with both the System/360 and System/370 families. Equipped with a Two Channel Switch, it allowed simultaneous connection to two channels. Building upon the earlier 2311 model, it increased data density by utilizing the IBM 2316 disk pack—resembling the 1316 but taller and containing eleven platters, thus offering twenty recording surfaces.

The device featured twenty read/write heads mounted on a hydraulically driven arm with mechanical detents to ensure accurate track alignment. Each surface consisted of 200 tracks. Initial access times were comparable to those of the 2311, but subsequent enhancements improved speed. The data transfer rate was doubled, reaching 310 kB/s.

The Model 1 was sold as a set of nine disk drives under a single price; however, shipments included a storage control unit, one standalone drive module, and two four-drive modules totaling nine drives. These drives were housed in drawers for straightforward disk pack handling, earning them the nickname "Pizza Ovens." Only eight drives operated simultaneously; the ninth functioned as an offline spare, enabling maintenance without interrupting system operation. System addresses could be configured via user-exchangeable plugs, permitting physical reassignment of drives.

An optional 2844 Control Unit allowed two System/360 channels to access different drives concurrently within the same storage facility.

Subsequent versions of the IBM 2314 were released later:

IBM 2314 Direct Access Storage Facility - A Series

In 1969, IBM separated the 2314 facility into distinct models supporting up to nine drives (eight active) connected to a 2314 Storage Control:

  • 2312 Disk Storage, consisting of a single-drive module.
  • 2313 Disk Storage, comprising a four-drive module.
  • 2318 Disk Storage, featuring a two-drive module.

IBM 2319

To compete with plug compatible manufacturers offering similar storage subsystems to the 2314, IBM launched in 1970 the budget-friendly three-drive module series known as 2319. This was derived by removing one drive from the four-drive 2313 and marketing it as the 2319 A1 at a significantly reduced rental cost. This approach lowered expenses for new clients while preserving higher fees for existing customers. The 2319-A1 connects to integrated controllers designed for System/370 Models 135 and 145. Traditional 2314 DASD units such as the 2312 or 2318 could also be attached to the 2319-A1. The 2319 B series supported configurations with three, six, or nine drives linked to a new 2314 Model B Storage Control Unit.

IBM 3310

Unveiled on January 30, 1979, the IBM 3310 Direct Access Storage Device targeted IBM 4331 midrange computer systems. Each drive provided a capacity of 64.5 MB. The device utilized fixed-block architecture and was compatible exclusively with S/370 operating systems DOS/VSE and VM.

IBM 3330

Introduced in June 1970 for IBM System/370 and System/360/195 platforms, the IBM 3330 Direct Access Storage Facility—codenamed Merlin—initially came as Model 1 with two drives and Model 2 with one drive. It featured removable disk packs with a capacity of 100 MB each. The system offered a typical access time of 30 ms and sustained data transfer rates of up to 806 kB/s. A notable advancement was its use of error correction through fire codes, which improved reliability and lowered costs by accommodating disk defects.

The original configuration included one storage control unit (3830 Model 1) connected to between one and four physically linked 3330 drives ("string"), supporting up to eight drives per string.

In August 1972, IBM introduced the 3830 Model 2 Storage Control along with 3333 Disk Storage and Control, separating control functions from drive units. The new controller acted as a director-type device managing multiple strings, while each string's first unit—the 3333—included both controller functions and two drives and could manage up to three attached additional 3330s (maximum eight drives per string). Two such units could connect to one controller for a total of sixteen drives; optionally, the 3333 incorporated a string switch allowing attachment to two controllers.

By 1973, IBM released double-density (-11) variants: the models named 3333–11, 3330-11, and larger-capacity (200 MB) disk packs called the 3336–11. Mixing single- and double-density devices within one string was unsupported; upgrading required converting existing drives and migrating all data.

The IBM 3330 series was discontinued in 1983.

IBM 3340 and 3344

While the IBM 3340 and 3344 share many characteristics, only the 3340 can function as the head of string. The 3344 does not have an A model variant; therefore, it must be connected to a 3340 A model drive to serve as the head of string.

IBM 3340

Introduced in March 1973 for the IBM System/370, the IBM 3340 Direct Access Storage Facility—known by its codename Winchester—was available in three configurations: the 3340-A2 (two drives with controller), B2 (two drives without controller), and B1 (single drive). Up to eight B units could be linked to one A2 unit.

A distinctive feature was its removable data modules that housed the head and arm assembly. The access door of these modules opened mechanically during loading and unloading, eliminating the need to remove protective covers as was common with earlier disk packs. Performance included a 25 ms access time and a data transfer rate of 885 kB/s. Three variants of the IBM 3348 Data Module offered storage capacities of 35 MB, 70 MB, and a specialized 70 MB version equipped with fixed heads for accelerated access. The system incorporated error correction capabilities and was phased out by 1984.

Engineered in San Jose under Ken Haughton’s leadership, the initial design targeted two removable modules each with 30 MB capacity—hence the nickname Winchester, inspired by the Winchester .30-30 rifle. Although storage sizes grew over time, this codename remained.

A major breakthrough was its economical head design that did not require unloading from the disk media. This "Winchester technology" enabled the heads to land on and lift off spinning disks directly, simplifying actuator mechanisms and reducing costs. This approach became widely adopted across the disk drive industry.

Throughout the early 1990s, "Winchester" or "Winnie" became generic terms for hard drives but have since become less common.

IBM 3344

The IBM 3344 closely resembles the 3340 but utilizes fixed media instead of removable IBM 3348 data modules. Each spindle contains four logical drives, each matching the capacity of a single 70 MB 3348 module. The model is only produced in dual-drive formats and lacks an A (head of string) variant. The 3344-B2F model includes fixed heads positioned over several cylinders on both drives. Both the 3344-B2 and B2F require connection to a 3340-A2 or A2F acting as head of string. Internally, the IBM 3344 shares its design with the IBM 3350; differences are limited exclusively to variations in control unit microcode.

IBM 3350

The IBM 3350 Direct Access Storage Facility, bearing the codename Madrid, was introduced in 1975 for IBM System/370. It featured sealed, non-removable head-disk assemblies (HDAs) that integrated both head and arm components—a design that established sealed HDAs as standard in IBM DASD products thereafter. Its disk geometry comprised 555 cylinders, 30 heads, and tracks containing 19,069 bytes each, resulting in roughly 317 MB of storage per HDA.

Available models included A2, A2F, B2, B2F, C2, and C2F configurations, each housing two HDAs. The A2 and A2F models contained an additional electronics board enabling connection to a storage control unit (controller), often serving as the string’s head unit. Drives were arranged in strings beginning with an A2 or A2F followed by up to three B2 units or combinations including C2 units. Typically, the A2 unit featured a string switch allowing simultaneous I/O operations through two storage control units on separate HDAs. Compatible controllers comprised the 3830 Model 2, ISC units embedded in CPUs such as models 3148/3158/3168, as well as later backward-compatible controllers like the IBM 3880. The C2 model incorporated a spare controller designed to take over if an A unit’s controller failed; however, it had restricted connectivity capabilities.

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

Models suffixed with "x2F" (e.g., A2F) featured fixed head zones covering the first five cylinders on both HDAs, effectively eliminating seek time within this area. This region was optimized for frequently accessed data such as HASP or JES2 checkpoint files to improve spool device performance. Additionally, it supported swap data for TSO and system swap tasks (MVT, SVS, MVS), enhancing context switching efficiency between TSO sessions or batch jobs.

The IBM 3350 series was officially retired in September 1994.

IBM 3370

In January 1979, IBM introduced the IBM 3370 Direct Access Storage Device designed for IBM 4331, 4341, and System/38 midrange systems. This device consisted of seven fixed 14-inch platters, providing a storage capacity of 571 MB per unit. It was pioneering as the first hard disk drive to incorporate thin-film head technology, developed at the Thomas J. Watson Research Center. The 3370 utilized fixed-block architecture and supported DOS/VSE and VM operating systems on the System/370 platform.

IBM 3375

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

IBM 3380

Released on June 11, 1980, the IBM 3380 employed thin-film head technology and delivered a storage capacity of 2.52 GB per unit, consisting of two hard disk assemblies each with two independent actuators accessing 630 MB. It achieved a data transfer speed of 3 MB/s and an average seek time of 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 with up to sixteen devices in a string. Generally connected to a 3880 storage control unit via two channels, it allowed two concurrent I/O operations targeting separate hard disk assemblies.

In February 1985, IBM launched the Extended Capability Models (3380 E) featuring double-density storage with capacities of 5.04 GB per unit (two actuators at 1.26 GB each). Later, in August 1987, the Model K offered triple the original capacity at 7.562 GB per unit (two actuators of 1.89 GB each) and supported four-path connectivity when paired with a 3990 storage control unit. This configuration permitted up to thirty-two devices per string and four simultaneous I/O processes.

The IBM 3380 lineup comprised twelve distinct models: six A-units functioning as string controllers interfacing with IBM storage control units; five B-units designed to connect to either A or C units; and one C-unit capable of direct connection to IBM channels.

Production continued until May 1996, marking an impressive fifteen-year tenure that surpassed the typical lifespan of most disk drives.

IBM 3390

Introduced in November 1989, the IBM 3390 Direct Access Storage Device series provided storage capacities reaching up to 22 gigabytes across multiple drives. Pricing for these systems varied widely from $90,000 to $795,000 based on configuration and total capacity.

A standard IBM 3390 string includes a central A unit containing four or eight devices, optionally accompanied by 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 supports a second string for a maximum of sixty-four devices within the subsystem.

Each Hard Disk Assembly (HDA) incorporates two actuator-head assemblies along with platters: Model 1 delivers an unformatted capacity of 1.89 GB; Model 2 doubles this to approximately 3.78 GB per HDA. The Model 3, released in September 1991, enhanced capacity by fifty percent to reach around 5.67 GB per HDA. Subsequently, Model 9, unveiled in May 1993, tripled the capacity further to approximately 11.3 GB per HDA.

Departing from earlier DASD designs that used large AC motors driving HDAs via belts, the IBM 3390 employed integrated DC motors housed within the enclosure itself. Notably, Model 9 represented IBM's final iteration of a Single Large Expensive Disk (SLED) drive.

IBM 9345

Launched in November 1990 as a Request Price Quotation (RPQ) for IBM’s SuperComputing Systems Extensions (SCSE), the IBM 9345 hard disk drive was developed at IBM’s San Jose facility under the project name Sawmill. This full-height 5¼-inch drive supported capacities up to 1.5 GB by utilizing up to eight 130 mm platters. Notably, it was the pioneering HDD to incorporate 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 lineup designed for IBM mainframe platforms such as the ES/9000 series. The 9345 Model 1 included two HDDs each with a capacity of 1.0 GB, whereas Model 2 contained two drives of 1.5 GB each.

From an operational standpoint, the 9340/9345 units bore similarity to the 3990/3390 subsystems but did not feature the non-volatile RAM cache found in the 3990 and had a shorter maximum block length compared to the 3390. The operating system’s Input/Output Supervisor (IOS) identified these devices through the IECCINIT initializer, which detected the lack of non-volatile cache on the 9340 and the reduced track count on the 9345, assigning device types accordingly.

9330 family of disk drives

  1. Models 1 and 11 of the 9331 Diskette Unit each contained a single 8-inch floppy disk drive (FDD), while models 2 and 12 were equipped with one 5¼-inch FDD.
  2. The IBM 0667 HDD was utilized in the 9332 Direct Access Storage Device.
  3. The high-performance disk drive subsystem, model 9333, incorporated either IBM 0664 or IBM 0681 HDDs depending on its variant.
  4. The 9334 Disk Expansion Unit connected between one and four SCSI hard drives to RS/6000 systems.
  5. Featuring an IBM Hursley-developed "Kestrel" HDD, the 9335 Direct Access Storage Subsystem housed an 850 MB drive composed of three 14-inch platters with dual rotary actuators enabling access to multiple surfaces. This rack-mountable device debuted alongside the IBM 9370 Information System in October 1986; no original equipment manufacturer (OEM) versions have been documented.
  6. The IBM 0681 HDD (Redwing) was implemented in the 9336 Disk Unit.
  7. The disk array subsystem model 9337 employed either IBM’s 0662 (Spitfire) or 0663 (Corsair) hard drives.

IBM 2310

Introduced in 1964 with the IBM 1800 and subsequently in late 1965 with the IBM 1130, the IBM 2310 Removable Cartridge Drive stored data on an IBM 2315 cartridge capable of holding 512,000 sixteen-bit words (equivalent to 1,024,000 bytes). The cartridge contained a single oxide-coated aluminum platter encased within a plastic shell featuring openings for both the read/write arm and dual heads.

IBM 5444

Unveiled in September 1969 as part of System/3, the IBM 5444 was engineered at IBM’s Hursley laboratory in England under the codename Dolphin. It utilized a cartridge—model 5440—that housed one fourteen-inch disk. There were three variants:

  • Model 1: included one fixed and one removable disk, each supporting one hundred tracks per surface; cartridge capacity was approximately 1.23 MB
  • Model 2: comprised one fixed and one removable disk with two hundred tracks per surface; cartridge capacity reached about 2.46 MB
  • Model 3: featured solely a removable disk with two hundred tracks per surface; cartridge capacity also measured roughly at 2.46 MB

IBM 62GV

The IBM 62GV, first delivered in May of 1974, originated from IBM’s Hursley facility in the United Kingdom under the project name Gulliver. Initially offering a storage capacity of five megabytes, subsequent versions expanded this to ten megabytes (62TM model) and fourteen megabytes. It employed a Swinging Arm actuator design incorporating a single fourteen-inch platter. This actuator mechanism—conceived at Hursley—became IBM’s most broadly licensed electro-mechanical invention and dominated hard drive designs throughout the decade of the eighties, remaining a standard nearly four decades later. Over its production span, approximately one hundred seventy-seven thousand units of the IBM 62GV were shipped, marking it as the first hard disk drive to surpass one hundred thousand units sold.

OEM and Small Systems Hard Drives

This segment details hard disk drives produced by IBM for OEM distribution and use in IBM small systems such as the System/3, System/32, /34, /36, and AS/400. Drives are listed by their OEM model numbers and organized according to their initial shipment dates.

IBM 0680

Introduced in 1979, the 0680 was deployed primarily on IBM small systems and entry-level System/370 models as the 3310 direct access storage device. The OEM variant was released in September 1981. Created at IBM Hursley in the UK under the project name Piccolo, it incorporated six 8-inch (210 mm) platters with an initial storage capacity reaching 65MB and featured an enhanced rotary actuator design.

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

IBM 0676

The 0676 became available in November 1982 as a 5247 Disk Storage Unit designed for the IBM System/23 Datamaster. Developed at IBM Rochester, Minnesota, under the internal name 21ED, this 8-inch hard drive initially offered capacities of either 15 or 30 MB by utilizing two or four 210 mm platters. In 1983, it was incorporated into the System/36’s 5360 System Unit. By 1984, its capacity was doubled by increasing the number of tracks per surface and it was also employed in the System/36’s 5362 System Unit.

IBM 0665

Launched in October 1985 within the PC AT (5170) system unit, the 0665 was developed at IBM Rochester under the codename "Pixie." This model was a 5¼-inch hard drive providing storage options of 20, 30, and 44 MB.

IBM 0667

The 0667 entered the market in August 1986. Created at IBM Rochester with the codename "Grant," it was a full-height ESDI hard disk drive measuring 5¼ inches and offering up to 70 MB capacity across as many as four 130 mm platters. It was available on select PC RT models (6150, 6151, 6152) as well as System/36 Model System Units (5363, 5364).

IBM 0669

Released in 1987, the 0669 was developed at IBM Rochester, Minnesota under the codename "Grant-Prime." This full-height, five-inch hard drive supported up to four 130 mm disks with a maximum capacity of approximately 115 MB. It served as the internal storage solution for both the System/36 5363 and Series 1 4956 System Units.

IBM 0671

Also introduced in 1987, the 0671—known internally as "Lee" at IBM Rochester—was a full-height five-inch ESDI hard disk drive capable of holding up to 316 MB across as many as eight 130 mm platters. This model represented IBM’s first implementation of thin metal film recording surfaces. In 1988, it was incorporated into the IBM AS/400 9404 System Unit, supporting configurations with two or three drives per unit.

IBM 0661

The 0661, identified as model 371, debuted in 1989. Initially developed under the codename "Lightning" at IBM Rochester and Hursley, UK, this SCSI hard drive featured up to eight 95 mm disks (14 heads) delivering a capacity of around 320 MB. A subsequent "Turbo" version with a capacity of approximately 400 MB followed in 1990. This drive became standard equipment on various IBM platforms including the AS/400 System Unit Model CXX.

IBM 0681

Shipped from IBM Hursley in April 1990 and developed under the codename Redwing—the final HDD project at that facility—the 0681 was a full-height five-inch hard disk drive offering capacities up to about 857 MB using up to twelve 130 mm platters. It was also notable for being IBM’s first HDD to utilize PRML data decoding technology. This drive powered the launch of the 9333 Disk Drive Subsystem in early 1992, with an enhanced higher-density variant reaching approximately 1.07 GB introduced by May of that year.

IBM 0663

Introduced in late 1991, the 0663, also known as "Corsair," was a compact 3-inch hard disk drive featuring a half-height (1.6-inch) form factor. It offered up to 1 GB storage across eight 95 mm platters and was incorporated into select PS/2 and RS/6000 systems. Notably, it was the first OEM HDD to utilize Magnetoresistance (MR) head technology.

IBM 0664

Released in November 1992, the 0664—codenamed "Allicat" and developed at IBM Rochester, Minnesota—was a full-height 5-inch hard drive standing 3.25 inches tall. It essentially combined two 3-inch drives and provided a maximum capacity of 2.013 GB using up to eight 95 mm disks.

IBM 0662

The 0662, launched in June 1993 under the codename "Spitfire" at IBM Rochester, was a full-height (1-inch) 3-inch hard disk drive. It delivered 1.05 GB of storage spread over three platters or five surfaces and served as the internal drive for both the 9336 Disk Unit and the 9337 Disk Array.

Floppy disk drive

IBM played a pioneering role in floppy disk technology, debuting the 8-inch floppy disk drive in 1971 as a read-only program loader and subsequently introducing its first read/write model in 1973 with the 3740 Data Entry System. Although IBM established early standards for 8-inch FDDs, it refrained from selling these drives independently, allowing the broader industry to evolve on its own.

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 specification as an industry benchmark. Despite intentions to produce these and smaller formats internally, IBM abandoned such plans in 1985. Additionally, its 1983 initiative to OEM the smaller 4-inch DemiDiskette did not succeed.

"Star" series of HDDs

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

IBM's first HDD versus its last HDDs

The following table contrasts IBM's inaugural HDD, the RAMAC 350, with its final three "Star" series OEM models, illustrating remarkable advancements in cost-efficiency and size reduction alongside substantial improvements in capacity and performance.

Parameter (units) RAMAC 350 Ultrastar 146Z10 Deskstar 180GXP Travelstar 80GN Maximum improvement over 46 years
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 (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) ~2374 watts (8100 BTUs/hour), up to 5500 VA depending on model 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

In certain IBM operating systems, hard disk drives (HDDs) and floppy disk drives (FDDs) are categorized under DASDs (direct access storage devices). Additional DASD types encompass:

IBM 7320 Drum

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

IBM 2301 Drum

The IBM 2301 is a magnetic drum device that debuted in the late 1960s.

IBM 2303 Drum

Released in 1964, the IBM 2303 is another example of a magnetic drum storage unit.

IBM 2321 Data Cell

Announced in 1964, the IBM 2321 Data Cell employs short strips of magnetic tape for data storage. It contains ten removable cells, each with a capacity of 40 MB, amounting to a total of 400 MB.

IBM 3850 Mass Storage System

The IBM 3850 Mass Storage System, unveiled in 1974, functions as a tape cartridge library that stages data onto IBM 3330 or 3350 disk drives. This system presents these disks as virtual drives to the host.

See also

External links

Related profiles

IIBM 1311IIBM 0661IIBM 353IIBM 355
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