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IBM 3380

From Alfawiki
Adapted from the English Wikipedia article IBM 3380, available under CC BY-SA 4.0Updated 9 August 2025
IBM Magnetic Disk Storage Division
Company typeDivision (former)
IndustryComputer storage hardware
Founded1956
Defunct2003
FateDivision divested to Hitachi
Headquarters
Armonk
,
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 was instrumental in inventing both the hard disk drive (HDD) and the floppy disk drive (FDD), contributing numerous technological advancements in these fields. The core mechanical architecture of modern hard disk drives traces back to the IBM 1301, with performance characteristics that have remained comparable since the 1950s. Over time, these devices have experienced dramatic decreases in cost and physical dimensions, accompanied by substantial improvements in storage capacity and operational speed.

Between 1969 and the mid-1980s, IBM manufactured 8-inch floppy disk drives but did not become a leading producer of the smaller 5.25- or 3.5-inch variants. Although IBM marketed its magnetic disk drives commercially, it only initiated OEM sales starting in 1981. By 1996, IBM had discontinued producing HDDs solely for its own systems, making all models available for OEM distribution.

IBM employed several designations for its magnetic disk drives, including direct-access storage device (DASD), disk file, and diskette file; however, this article uses the industry-standard terms hard disk drive (HDD) and floppy disk drive (FDD).

IBM 350

The IBM 350 disk storage unit holds the distinction of being the first-ever disk drive, introduced alongside the IBM 305 RAMAC computer system on September 14, 1956. A related model, the IBM 355, was released for the IBM 650 RAMAC system. The initial prototype was delivered to Zellerbach Paper Company in June 1956, with production units shipped from November 1957 to customers such as United Airlines.

Created to fulfill real-time business accounting requirements, the IBM 350 offered storage for five million 6-bit characters (equivalent to approximately 3.75 MB). It comprised fifty-two disks with a total of 100 recording surfaces, each containing 100 tracks, rotating at a speed of 1200 rpm. The data transfer rate reached 8,800 characters per second. A mechanical access system positioned read/write heads to select specific disk pairs and tracks. Throughout the late 1950s, several enhanced versions were introduced. The IBM RAMAC 305 system bundled with the 350 was leased at $3,200 monthly. Production of the IBM 350 ended in 1969.

The patent originating from the RAMAC initiative is acknowledged as the foundational patent for disk drives. Although initially rejected by IBM’s Board over concerns about its impact on punch card sales, development persisted at IBM San Jose until it received approval from IBM's president.

Measuring long, high, and wide, the cabinet housing the IBM 350 weighed approximately one ton and required forklifts for relocation; it was frequently transported via cargo aircraft. Currie Munce of Hitachi Global Storage Technologies noted that marketing constraints initially limited capacity expansion due to uncertainty about customer demand for higher-capacity drives; nevertheless, double-capacity models were announced in January 1959 and shipped later that year.

Acknowledging its historical importance, The American Society of Mechanical Engineers designated the RAMAC 350 Disk File as an International Historic Landmark in 1984. Restoration efforts commenced in 2002 under the leadership of Al Hoagland in collaboration with Santa Clara University. Since 2005, the refurbished unit has been on public display at the Computer History Museum located in Mountain View, California.

IBM 353

The IBM 353, paired with the IBM 7030, resembled the IBM 1301 but offered enhanced data transfer speeds. It provided storage for 2,097,152 (221) 64-bit words, equivalent to 134,217,728 bits, and could move data at a rate of 125,000 words per second. A prototype developed late in 1960 was pioneering in employing a dedicated head per disk surface that floated on compressed air, building upon the design principles established by the IBM 350 disk storage. Production versions featured self-levitating heads akin to those used in the IBM 1301.

IBM 355

Introduced on September 14, 1956, the IBM 355 broadened storage capabilities for the widely-used IBM 650. It incorporated the IBM 350's mechanism but upgraded with up to three access arms instead of just one. This unit stored six million decimal digits along with 600,000 sign indicators. Data transfer involved moving entire tracks between the magnetic core memory of the 653—an optional component for the IBM 650 offering sixty signed 10-digit words sufficient for a single disk track or tape record—and other functionalities.

IBM 1405

Released in 1961 for the IBM 1400 series business computers, the IBM 1405 Disk Storage Unit provided scalable capacity options. Model 1 stored ten million alphanumeric characters (60 million bits) across 25 disks, while Model 2 doubled this to twenty million characters (120 million bits) using fifty disks. The disks were vertically stacked and rotated at a speed of 1200 rpm.

Each disk surface contained 200 tracks segmented into five sectors; sectors numbered 0 to 4 were on the top side and sectors 5 to 9 on the bottom. Each sector held between 178 and 200 characters. One to three forked access arms, each equipped with two read/write heads covering both surfaces of a disk, moved vertically to select among disks (0–49) and horizontally to choose tracks (0–199). Reading or writing a sector took 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 800 milliseconds for Model 2. The latter model featured 100,000 sectors capable of storing 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 that number of sectors.

IBM 7300

The IBM 7300 Disk Storage Unit was engineered for compatibility with the IBM 7070. Although IBM announced a second model in 1959, the launch of the IBM 1301 on June 5, 1961, shifted customer preference toward the latter among users of both the IBM 7070 and IBM 7074. The technology underpinning the IBM 7300 shared similarities with that employed 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 primarily for use with mainframe computers from the IBM 7000 series as well as the IBM 1410. Each module could hold up to twenty-eight million characters (168 million bits), or twenty-five million characters when connected to an IBM 1410. Modules contained twenty-five large disks providing forty user-accessible recording surfaces with two hundred fifty tracks per surface. Disks rotated at a speed of eighteen hundred rpm, enabling data transfer rates of ninety thousand characters per second.

A notable advancement was its use of individual arms and read/write heads dedicated to each recording surface, which moved collectively like a comb. This configuration eliminated delays caused by repositioning heads across disks and reduced maximum access time to one hundred eighty milliseconds. The heads were aerodynamically shaped to fly on a thin cushion of air above disk surfaces, enhancing performance reliability.

Connection was achieved through the IBM 7631 File Control unit, which allowed operation either with the IBM 1410 or IBM’s mainframe series or facilitated sharing between two systems.

Leasing fees for Model 1 were set at $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 carried an additional lease cost of $1,185 monthly or $56,000 if bought outright. All versions were discontinued by 1970.

IBM 1302

Released in September 1963, the IBM 1302 Disk Storage Unit offered a fourfold increase in capacity compared to the IBM 1301, reaching 117 million 6-bit characters per module. It delivered an average access time of 165 milliseconds and achieved data transfer speeds of 180,000 characters per second, which was more than double that of its predecessor. Each module was equipped with two separate access mechanisms designed for the inner and outer cylinder ranges. The Model 2 variant enhanced capacity further 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 were $252,000 and $355,500 respectively. Adding the IBM 7631 controller increased monthly leasing by $1,185 or added $56,000 to the purchase cost. The IBM 1302 was discontinued in February 1965.

IBM 1311

Introduced on October 11, 1962, the IBM 1311 Disk Storage Drive was designed for medium-scale business and scientific computing environments. Similar in size to a top-loading washing machine, it stored up to two million characters on a removable IBM 1316 disk pack. Throughout the 1960s, seven different models were produced before being phased out by the early 1970s.

Each IBM 1316 disk pack consisted of six disks measuring 14 inches in diameter, with ten usable recording surfaces (the outer surfaces remained unused), rotating at 1500 revolutions per minute. The drive employed a hydraulic actuator to position ten read/write heads over 100 tracks per surface. Each track contained twenty sectors capable of holding 100 characters each. For protection during handling, the disk pack was encased in a plastic shell.

The system architecture featured a "master drive" equipped with controller functions that managed multiple Model 2 "slave drives." Master drives were tailored for compatibility with different systems:

  1. Designed for IBM 1440, 1460, or 1240 systems; capable of controlling up to four slave units. (1962–1971)
  2. Slave drive compatible with master drive functionality. (1962–1975)
  3. Intended for IBM 1620 or 1710 systems; managed up to three slaves; lacked special features. (1962–1971)
  4. Compatible with IBM 1401 systems; controlled as many as four slaves. (1962–1971)
  5. Suited for IBM 1410, 7010, or 7740 systems; controlled up to four slaves and included standard Direct Seek capability. (1963–1971)
  6. & #7 Models believed to represent master and slave drives respectively but not fully documented. (1968–1971)

Available optional enhancements included:

  • Direct Seek—removes the need to return to track zero before initiating a seek.
  • Scan Disk—enables rapid automatic searches for specific identifiers or conditions.
  • Seek Overlap—allows simultaneous seeking and reading/writing across several drives.
  • Track Record—increases storage capacity by allowing one large record per track instead of multiple sectors, raising total storage to roughly 18.8 million bits.

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

IBM 2302

The IBM 2302 represents the System/360 adaptation of the 1302 unit, specifically configured for S/360 DASD architecture. It utilizes a fixed module containing twenty-five platters with forty-six recording surfaces each. Model 3 consists of one module; Model 4 includes two modules. Each module is equipped with two independent access mechanisms—referred to as access groups—serving the innermost and outermost sets of 250 cylinders respectively. Each access group features one read/write head per track. The average rotational latency is approximately 17 milliseconds with a maximum of 34 milliseconds; maximum seek time per access group reaches up to 180 milliseconds. Each track holds about 4,985 bytes; after formatting and reserved alternates are accounted for, total capacity sums to approximately 112 megabytes. Connectivity to IBM mainframes is facilitated through the IBM 2841 Storage Control Unit.

IBM 2305

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

During the System/370 period, the 2305 gained prominence as a paging device for Virtual Storage environments. It was extensively utilized across systems such as the 3155, 3165, 3158, 3168, 3033, 4341, and the 3081 (the latter employing specialized microcode). Beyond paging, it efficiently handled frequently accessed small data sets including catalogs and job queues.

The smaller variant, the 2305-1, provided a storage capacity of 5.4 MB with a data transfer rate of 3.0 MB/s via a two-byte channel interface and featured an average access latency of 2.5 milliseconds. In contrast, the larger 2305-2 model offered an 11.2 MB capacity at a throughput of 1.5 MB/s and had an average access time of approximately 5 milliseconds.

Engineered for rapid and continuous retrieval of limited data volumes, the 2305’s combination of speed and capacity made it well-suited for system-resident functions such as work files, job queues, indices, and other frequently referenced datasets. Its swift response times were particularly advantageous in high-demand systems requiring transaction rates exceeding 1.5 per second, especially when deployed as a paging device.

IBM 2311

Introduced in 1964 alongside the 2841 Control Unit, the IBM 2311 Disk Storage Drive served multiple platforms including IBM System/360, IBM 1130, and IBM 1800. It also connected directly to the IBM System/360 Model 20 and Model 25 systems. All units utilized removable IBM 1316 Disk Packs, which were originally created for use with the IBM 1311.

The Model 1 version of the 2311 connects to most IBM mainframes via the 2841 Control Unit; however, for the System/360 Model 25, a Disk Attachment Control Unit performs this role. These disk packs employ IBM’s count key data variable-length record format. In contrast, Models 11 and 12 interface with the integrated control of the System/360 Model 20 and utilize a fixed-sector format. Notably, disk packs are not interchangeable between Model 1 and Models 11/12 drives.

Mechanically akin to the IBM 1311 but featuring enhanced recording technology for increased data density, the IBM 2311 stores up to 7.25 megabytes on a six-platter removable disk pack. It uses ten read/write heads mounted on a hydraulically actuated arm, with each surface containing approximately 200 tracks plus three spare tracks. The average seek time is around 85 milliseconds, while its data transfer speed reaches up to 156 kB/s.

The uniform electrical interface across System/360 models allowed third-party manufacturers to develop plug compatible disk drives, encouraging competition within the IBM-compatible storage market.

IBM 2314 Disk Access Storage Facility Model 1

The IBM 2314 Disk Access Storage Facility Model 1, introduced in April of 1965, was designed to support both System/360 and System/370 architectures. Equipped with a Two Channel Switch feature, it could simultaneously connect to two separate channels. Its disk mechanism resembled that of the IBM 2311 but was optimized for higher storage density, accommodating over twenty-nine million characters on a removable IBM 2316 disk pack composed of eleven disks providing twenty recording surfaces.

This drive utilized twenty read/write heads positioned on a hydraulically actuated arm featuring mechanical detents aligned with each track. Each disk surface contained approximately two hundred tracks. While initial access times were comparable to those of the IBM 2311, actuator improvements in later versions led to reduced latency. The data transfer rate doubled relative to its predecessor, reaching approximately 310 kB/s.

The Model 1 was marketed as a set of nine disk drives bundled together; separately shipped components included a storage control unit plus one single-drive module and two four-drive modules summing to nine drives total. Each drive was mounted within individual drawers facilitating easy removal and insertion of disk packs—earning them the nickname "Pizza Ovens." At any given time, only eight drives were active; the ninth served either as a standby spare or could be taken offline for maintenance without interrupting ongoing operations. Drive system addresses were configured using user-replaceable plugs that allowed dynamic reassignment including designating spares.

By incorporating a separate IBM 2844 Control Unit, two System/360 channels could concurrently access distinct drives within this facility.

Subsequent models introduced expanded features and configurations:

IBM 2314 Direct Access Storage System - Model Variants

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

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

IBM 2319

To address competition from plug compatible manufacturers offering alternatives to the 2314 storage, IBM launched in 1970 an affordable three-drive unit called the 2319. This model was developed by removing one drive from the four-drive 2313 and rebranding the resulting module as the 2319 A1. This approach enabled IBM to reduce leasing costs for new clients while keeping existing customers on higher rates. The 2319-A1 interfaces exclusively with integrated controllers on System/370 Models 135 and 145; it can also connect to standard 2314 DASD devices such as the 2312 or 2318. The 2319 B series supports configurations of three, six, or nine drives linked to a redesigned 2314 Model B Storage Control Unit.

IBM 3310

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

IBM 3330

The IBM 3330 Direct Access Storage Facility, known internally as Merlin, debuted in June 1970 for use with IBM System/370 and System/360/195 computers. Initial offerings included a two-drive Model 1 and a single-drive Model 2. Each removable disk pack stored up to 100 MB. With an access time of approximately 30 ms and a data transfer rate of 806 kB/s, this model introduced fire code error correction technology, enhancing dependability and reducing expenses by allowing for minor disk surface flaws.

The original architecture consisted of one storage control unit (the 3830 Model 1) paired with a single 3330 drive, expandable by adding up to three more drives in a "string," supporting up to eight drives per string.

In August 1972, IBM unveiled the 3830 Model 2 Storage Control alongside the 3333 Disk Storage and Control, which separated control functions from drive arrays. The upgraded 3830 functioned as a director-style controller overseeing multiple strings. The initial unit in each string, the 3333, combined a controller with two drives and could manage up to three additional connected 3330 drives (totaling eight). The Model 2 controller supported two such strings simultaneously for up to sixteen drives per controller; optionally, the 3333 included a string switch enabling dual-controller attachment.

In 1973, IBM introduced double-density (-11) variants: the models named 3333–11, 3330-11, along with the higher-capacity (200 MB) disk packs labeled as 3336–11. Mixing single-density and double-density drives within the same string was not permitted. Field upgrades to Model -11 were feasible but complex, requiring both drive conversion and complete data transfer.

The IBM 3330 series was discontinued in 1983.

IBM 3340 and IBM 3344

Although sharing many characteristics, only the IBM 3340 could function as the head of a drive string; no A model was produced for the IBM 3344, which must be connected under a 3340 A model acting as the string head.

IBM 3340

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

This system utilized detachable data modules that housed both the head and arm assemblies; a mechanical load/unload mechanism operated an access door to engage or disengage the module. Unlike prior disk packs, it did not require removal of a cover. The device offered an access time of 25 milliseconds and a data transfer rate of 885 kilobytes per second. Three types of IBM 3348 Data Modules were marketed: one with a 35 MB capacity and two with 70 MB capacities, one of which included 500 KB of fixed heads for accelerated access. The 3340 featured error correction capabilities and remained in production until 1984.

Developed under Ken Haughton’s leadership in San Jose, the initial design centered on two removable 30 MB modules—giving rise to its "Winchester" nickname, inspired by the Winchester .30-30 rifle cartridge. Although storage sizes increased later on, the codename endured.

A major breakthrough was its economical head design that enabled heads to land on and lift off from spinning disks without unloading, dramatically simplifying mechanics and lowering manufacturing costs. This innovation, known as "Winchester technology," became widely adopted across disk drive production.

While the term Winchester was commonly used to describe hard drives into the early 1990s, its usage has since diminished significantly.

IBM 3344

Similar in design to the 3340, the IBM 3344 differs by employing fixed media rather than removable 3348 modules. Each spindle supports four logical drives equivalent in capacity to a single 3348–70 module. Available exclusively as dual-drive systems, the 3344 lacks an A-model (head of string). The variant 3344-B2F incorporates fixed heads over select cylinders on both drives. Both the 3344-B2 and 3344-B2F models require connection to a 3340-A2 or 3340-A2F unit acting as head of string. Internally, the architecture of the 3344 aligns closely with that of the IBM 3350, differing primarily in control unit microcode.

IBM 3350

Released in 1975 for IBM System/370, the IBM 3350 Direct Access Storage Facility bore the codename Madrid. It introduced sealed, non-removable head-disk assemblies (HDAs) integrating both head and arm components—a design that set a precedent for IBM DASD devices. Its disk geometry consisted of 555 cylinders, each with 30 heads and tracks containing approximately 19,069 bytes, resulting in about 317 MB per HDA.

The product line included models A2, A2F, B2, B2F, C2, and C2F, all equipped with two HDAs per unit. The A2 and A2F models featured an additional controller board allowing connection to storage control units such as the IBM 3830 Model 2 or Integrated Storage Control (ISC) embedded within IBM mainframes like the 3148, 3158, and 3168. Subsequent controllers like the IBM 3880 maintained backward compatibility. Units were organized into strings headed by an A2 or A2F controller followed by up to three B2 units or various combinations including C2 units. Typically, the A2 unit incorporated a string switch enabling simultaneous I/O operations via dual control unit connections to separate HDAs.

The C2 model contained a secondary backup controller with limited connectivity that activated only if the primary A unit’s controller failed and shut down. Permissible string configurations included -A, -AB, -ABB, -ABBB, -AC-, -ABC-, and -ABBC-.

Models designated with "x2F" (such as A2F) featured fixed head sections covering the initial five cylinders on both HDAs, effectively eliminating seek time within this region. This zone was optimized for frequently accessed data like HASP or JES checkpoint files to enhance spool device performance. Additionally, it supported TSO swap space as well as system swap areas for OS/360 successors (MVT, SVS) and MVS by improving context switching efficiency among users or batch jobs.

The IBM 3350 series was discontinued in September 1994.

IBM 3370

In January 1979, IBM launched the IBM 3370 Direct Access Storage Device tailored for IBM 4331, 4341, and System/38 midrange systems. This unit housed seven fixed 14-inch platters, delivering a storage capacity of 571 MB per device. Notably, it was the pioneering hard disk drive to incorporate thin-film head technology, developed at the Thomas J. Watson Research Center. The 3370 utilized a fixed-block architecture and was compatible with DOS/VSE and VM operating systems running on S/370 hardware.

IBM 3375

The IBM 3375 served as a complementary model employing count key data architecture, designed for compatibility with OS/360 and its subsequent versions.

IBM 3380

Unveiled on June 11, 1980, the IBM 3380 Direct Access Storage Device featured thin-film head technology and offered a capacity of 2.52 GB per unit. Each unit contained two hard disk assemblies, each equipped with two actuators accessing 630 MB. It supported a data transfer speed of 3 MB/s with an average access latency of 16 milliseconds. Initial pricing ranged between $81,000 and $142,200. Due to challenges related to tribology between the heads and media surfaces, commercial shipments commenced in October 1981.

The typical setup consisted of one A unit accompanied by up to three B units; each 3380 assembly incorporated four devices, enabling configurations up to sixteen devices in a string. These units were commonly connected to IBM 3880 storage control units featuring dual-path architecture that allowed simultaneous I/O operations targeting different hard disk assemblies.

In February 1985, IBM introduced the Extended Capability Model (3380 E), doubling storage density to 5.04 GB per unit by utilizing two actuators at 1.26 GB each. Later, in August 1987, the triple-capacity variant named the 3380 K was announced with a capacity of 7.562 GB per unit (two actuators at 1.89 GB each). Both Models J and K offered an optional four-path mode when linked to an IBM 3990 storage control unit, supporting up to thirty-two devices per string and enabling four concurrent I/O processes.

The IBM 3380 series comprised twelve distinct models: six A-units acting as string leaders with controller logic interfacing with storage control units; five B-units connected to either A- or C-units; and one C-unit designed for direct connection to IBM channels.

Manufacturing continued until May 1996, marking an impressive fifteen-year tenure in the marketplace—an unusually long lifecycle for disk drives.

IBM 3390

Released in November 1989, the IBM 3390 series of Direct Access Storage Devices provided capacities reaching up to 22 gigabytes distributed across multiple drives. System pricing varied from $90,000 to $795,000 depending on configuration and capacity levels.

A typical IBM 3390 string consisted of a central A unit containing four or eight devices, optionally flanked by one or two B units supporting up to twelve devices each. Operating in four-path mode when connected to a 3990 storage control unit, this configuration could accommodate a second string of IBM 3390s for a total of up to sixty-four devices within a subsystem.

Each Hard Disk Assembly (HDA) incorporated two actuator-head mechanisms along with platters: Model 1 offered an unformatted capacity of 1.89 GB; Model 2 doubled this to 3.78 GB per HDA. The Model 3 upgrade released in 1991 increased capacity by fifty percent to reach 5.67 GB per HDA, while Model 9 introduced in 1993 tripled that figure to achieve an unformatted capacity of 11.3 GB per HDA.

In contrast to earlier DASD units which relied on large AC motors coupled via belts, the IBM 3390 HDAs were powered directly by enclosed DC motors. The Model 9 represented IBM’s final iteration of the Single Large Expensive Disk (SLED) drive design.

IBM 9345

Introduced in November 1990 as a Request for Price Quotation (RPQ) tailored for IBM's SuperComputing Systems Extensions (SCSE), the IBM 9345 hard disk drive was engineered 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 as many as eight 130 mm platters. Notably, it was the pioneer in implementing magnetoresistive (MR) read/write heads.

IBM 9340

In October 1991, IBM unveiled the 9345 DASD within the broader 9340 series—a collection of channel-attached count key data (CKD) direct access storage devices designed for IBM mainframe systems, including the ES/9000 processor line. The first model of the 9345 incorporated two hard drives each with a capacity of 1.0 GB, while the second model doubled this to two drives of 1.5 GB each.

From a functional perspective, the 9340/9345 closely resembled the earlier 3990/3390 series; however, it lacked the non-volatile RAM cache found in the 3990 and featured a shorter maximum block length compared to the 3390.

The operating system’s Input/Output Supervisor (IOS) detected these devices through a specialized initializer named IECCINIT, which also supported various other DASD types. During initialization, the OS discerned that the 9340 did not include non-volatile cache and that the 9345 had a diminished track capacity, thereby assigning a unique device type distinct from the 3990/3390 models.

9330 family of disk drives

  1. The 9331 Diskette Unit models 1 and 11 were equipped with a single 8-inch floppy disk drive; models 2 and 12 featured one 5-inch floppy disk drive.
  2. The IBM 0667 hard disk drive powered the 9332 Direct Access Storage Device.
  3. The High Performance Disk Drive Subsystem, designated as model 9333, employed either IBM’s 0664 or 0681 HDDs depending on configuration.
  4. The 9334 Disk Expansion Unit connected from one up to four SCSI hard disks to RS/6000 systems.
  5. The Direct Access Storage Subsystem model 9335 incorporated an IBM-designed "Kestrel" HDD offering an 850 MB capacity through three large 14-inch platters and dual rotary actuators enabling access to multiple surfaces; it was designed for rack mounting and launched alongside the October 1986 IBM 9370 Information System. No known OEM variants exist.
  6. The IBM 0681 HDD (Redwing) was utilized in the 9336 Disk Unit.
  7. The Disk Array Subsystem model 9337 employed either IBM’s 0662 (Spitfire) or 0663 (Corsair) hard disk drives.

IBM 2310

The IBM 2310 Removable Cartridge Drive made its debut in 1964 with the IBM 1800 system and subsequently appeared in late 1965 with the IBM 1130. It stored a total of 512,000 sixteen-bit words — equivalent to just over one million bytes — on an IBM 2315 cartridge. This cartridge consisted of a single oxide-coated aluminum platter housed within a plastic casing featuring openings that allowed a read/write arm and two heads to operate.

IBM 5444

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

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

IBM 62GV

Released in May of 1974 from IBM’s Hursley facility under the codename Gulliver, the IBM 62GV initially provided a storage capacity of five megabytes. Subsequent versions—identified as model 62TM—increased capacity first to ten megabytes and then to fourteen megabytes. This device employed a Swinging Arm actuator mechanism paired with a single fourteen-inch platter. This actuator design became IBM’s most widely licensed electromechanical invention, gaining broad industry adoption throughout the 1980s and remaining an industry standard nearly forty years later. Approximately one hundred seventy-seven thousand units of the IBM 62GV were shipped, marking it 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 utilized in IBM small systems such as the System/3, System/32, /34, /36, and AS/400. Drives are identified by their OEM model designations and arranged in order of their initial shipment to customers.

IBM 0680

Initially released in 1979 for many IBM small systems and entry-level System/370 models as the 3310 direct access storage device, the OEM variant was introduced under the model number 0680 in September 1981. Created at IBM’s Hursley laboratory in the UK with the project name Piccolo, it featured a maximum capacity of 65MB via six 8-inch (210 mm) platters and incorporated an enhanced rotary actuator design.

A double-capacity variant known as the 62SW was launched in June 1984; however, its market penetration was limited because its cost per megabyte was comparable to that of the 62GV.

IBM 0676

The 0676 made its debut 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 storage options of either 15 or 30 MB utilizing two or four platters. By 1983, it was incorporated into the S/36’s 5360 System Unit. In 1984, capacity was doubled through increased track density per platter surface, leading to its adoption in the System/36’s 5362 System Unit.

IBM 0665

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

IBM 0667

The 0667 entered the market in August 1986. Created at IBM Rochester with the project title "Grant," this full-height 5-inch ESDI hard drive supported up to four platters measuring 130 mm each and offered a capacity of 70 MB. It was available as an optional feature on select PC RT models (6150, 6151, 6152) and on System/36 Model System Units (5363, 5364).

IBM 0669

Launched in 1987 from IBM Rochester under the codename "Grant-Prime," the 0669 was a full-height 5-inch hard drive delivering up to 115 MB across four 130 mm platters. It served as the internal storage solution for both the System/36’s 5363 and Series 1’s 4956 System Units.

IBM 0671

Also released in 1987 by IBM Rochester and designated internally as "Lee," the 0671 was a full-height ESDI hard drive with eight platters measuring 130 mm each, providing up to 316 MB of storage. This model represented IBM’s initial implementation of a thin metal film recording surface. In 1988, it was integrated into the AS/400’s 9404 System Unit, supporting configurations with two or three drives.

IBM 0661

Introduced in 1989 as model number 371, the 0661 was developed collaboratively by IBM Rochester and Hursley under the codename "Lightning." This SCSI hard disk drive featured eight platters of 95 mm diameter with fourteen read/write heads and offered a capacity of 320 MB. A subsequent "Turbo" version with a capacity of 400 MB appeared in 1990. The drive became standard equipment across multiple IBM platforms, including various AS/400 System Unit Model CXX configurations.

IBM 0681

The 0681, unveiled in April 1990 from IBM Hursley under project name "Redwing," was the final hard drive developed at that facility. This full-height, five-inch HDD provided up to 857 MB storage using twelve platters sized at 130 mm each and introduced PRML data decoding technology for the first time at IBM. It powered the launch of the 9333 Disk Drive Subsystem in early 1992, followed by a higher-density variant offering up to 1.07 GB that became 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 delivered a maximum storage capacity of 1 GB across eight 95 mm platters and incorporated magnetoresistive (MR) heads, marking it as the first OEM drive to utilize this technology. This model was integrated into selected PS/2 and RS/6000 systems.

IBM 0664

The 0664, launched in November 1992, was developed at IBM Rochester, Minnesota, under the project name "Allicat." This full-height 5-inch HDD (measuring 3.25 inches in height) effectively combined two 3-inch drives and offered up to 2.013 GB capacity using as many as eight 95 mm platters.

IBM 0662

Released in June 1993 and known internally as "Spitfire," the 0662 was a full-height (1-inch high) 3-inch hard drive providing 1.05 GB storage on three disks or five surfaces. It found application inside IBM’s 9336 Disk Unit and the 9337 Disk Array.

Floppy disk drive

IBM was instrumental in developing the floppy disk drive, debuting the 8-inch FDD in 1971 primarily as a read-only device for program loading. The company followed this with its first read/write version in 1973 as part of the 3740 Data Entry System. While IBM established early standards for 8-inch floppy drives, it did not market these units independently, allowing the broader industry to develop autonomously.

At one point, IBM was the largest consumer of OEM 5-inch floppy drives, and its preference for double-sided models with a density of 48 tracks per inch helped set this as an industry benchmark. Although IBM intended to produce these and smaller-sized drives internally, all such manufacturing plans were terminated by 1985. Additionally, IBM’s 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 revealed three new families of hard disk drives: the Travelstar, a 2-inch model designed for laptops; the Deskstar, a 3-inch desktop drive; and the Ultrastar, a high-performance 3-inch HDD targeted at demanding applications.

IBM's first HDD versus its last HDDs

The following table contrasts IBM’s inaugural hard disk drive, the RAMAC 350, with its final three "Star" series OEM models. It highlights remarkable advancements in cost reduction and miniaturization alongside substantial improvements in storage capacity and operational efficiency.

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 times
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 times
Volume (liters) 1,939 0.4 0.4 0.1
Weight (pounds) 2,140 1.7 1.4 0.2 1,244 times lighter
Weight (kilograms) 971 0.8 0.64 0.095
Power consumption (watts) ~2374 (8100 BTUs/hour) 16 10.3 1.85 1,283 times more efficient power use
Power efficiency (megabytes per watt) 0.0016 9,125 17,476 43,243 27 million times increase
Retail price (Template:US$) \$34,500
(equivalent to \$234,000 in 2002 dollars) 		\$1,200 \$360 \$420
Cost per megabyte (Template:US$) \$9,200
(equivalent to \$68,000 in 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

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

IBM 7320 Drum

The IBM 7320, unveiled in 1962, represents a magnetic drum storage apparatus.

IBM 2301 Drum

Introduced during the late 1960s, the IBM 2301 is a type of magnetic drum storage device.

IBM 2303 Drum

The IBM 2303, released in 1964, is another example of magnetic drum storage technology.

IBM 2321 Data Cell

Announced in 1964, the IBM 2321 Data Cell stores information using short strips of magnetic tape. It accommodates ten removable cells, each with a capacity of 40 MB, resulting in a total storage of 400 MB.

IBM 3850 Mass Storage System

Launched in 1974, the IBM 3850 Mass Storage System is a tape cartridge library that stages data onto IBM 3330 or 3350 disk drives, offering virtual disk drive functionality to the host system.

See also

External links

Related profiles

IIBM 1311IIBM 0661IIBM 353IIBM 355
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