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IBM 9340

From Alfawiki
Adapted from the English Wikipedia article IBM 9340, available under CC BY-SA 4.0Updated 9 August 2025
IBM Magnetic Disk Storage Division
Company typeDivision (historical)
IndustryComputer storage hardware
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 units from 1956 until 2003, when it divested its hard disk drive division to Hitachi. The company is credited with inventing both the hard disk drive (HDD) and the floppy disk drive (FDD), with numerous technological advancements originating from its workforce. While the fundamental mechanical architecture of hard disk drives has remained largely unchanged since the introduction of the IBM 1301, performance benchmarks have been consistent since the 1950s. Over time, these devices have experienced dramatic decreases in cost and physical dimensions, coupled with substantial gains in storage capacity and efficiency.

IBM's production of 8-inch floppy disk drives spanned from 1969 through the mid-1980s, although it did not become a leading supplier of the smaller 5.25- or 3.5-inch variants. Although IBM marketed its magnetic disk drives, it only began offering original equipment manufacturer (OEM) agreements starting in 1981. By 1996, IBM discontinued manufacturing hard disk drives tailored exclusively for its own systems, shifting entirely to OEM sales.

Throughout its history, IBM has referred to its magnetic disk products using various terms such as direct-access storage device (DASD), disk file, and diskette file. This article adheres to the industry-standard nomenclature: hard disk drive (HDD) and floppy disk drive (FDD).

IBM 350

The IBM 350 disk storage unit, recognized as the first commercial disk drive, was 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 engineering prototype was delivered to Zellerbach Paper Company in June 1956, with production units dispatched beginning November 1957 to United Airlines.

Created to support real-time business accounting tasks, the IBM 350 stored five million 6-bit characters (equivalent to 3.75 MB) across fifty-two disks employing one hundred recording surfaces. Each surface contained one hundred tracks and rotated at 1200 revolutions per minute, facilitating a data transfer rate of 8,800 characters per second. The read/write head assembly could select specific pairs of disks and tracks. Several enhanced versions were released during the late 1950s. Leasing the IBM RAMAC 305 system equipped with the 350 disk storage cost $3,200 monthly. The IBM 350 was retired from production in 1969.

The patent arising from the RAMAC project is regarded as foundational for disk drive technology. Although initially rejected by IBM’s Board due to concerns about its impact on punch card operations, development persisted at IBM's San Jose facility until receiving approval from IBM's president.

The physical dimensions of the IBM 350 cabinet are approximately long by high by wide. Weighing nearly one ton, transportation necessitated forklifts and large cargo aircraft. Currie Munce of Hitachi Global Storage Technologies noted that capacity could have exceeded five million characters; however, IBM’s marketing team was reluctant to promote drives with greater capacity at that time. Nevertheless, double-capacity models were announced in January 1959 and shipped later that year.

In recognition of its significance, the RAMAC 350 Disk File was designated an International Historic Landmark by The American Society of Mechanical Engineers in 1984. In 2002, a restoration initiative led by Al Hoagland commenced work on refurbishing an IBM 350 RAMAC unit in partnership with Santa Clara University. Since 2005, this restored device has been on display at the Computer History Museum located in Mountain View, California.

IBM 353

The IBM 353, utilized with the IBM 7030, bore resemblance to the IBM 1301 but offered a higher data transfer speed. It provided storage for 2,097,152 (221) 64-bit words, equating to 134,217,728 bits, and achieved a transfer rate of 125,000 words per second. A prototype delivered in late 1960 was notable as the first disk drive to feature one head per surface that hovered on compressed air, similar to the technology in the IBM 350 disk storage (RAMAC). Production units incorporated self-flying heads comparable to those found in the IBM 1301.

IBM 355

Introduced on September 14, 1956, the IBM 355 served as an enhancement for the widely used IBM 650. It employed the IBM 350 mechanism but included up to three access arms, unlike the single arm of the IBM 350, and could hold 6 million decimal digits along with 600,000 sign indicators. This device transferred entire tracks to and from the magnetic core memory of the 653, an optional storage unit for the IBM 650 that contained sixty signed 10-digit words—sufficient capacity for one disk track or tape record.

IBM 1405

Announced in 1961, the IBM 1405 Disk Storage Unit was aimed at medium-sized business computers within the IBM 1400 series. Model 1 offered storage for 10 million alphanumeric characters (60 million bits) across 25 disks; Model 2 doubled this capacity with space for 20 million characters (120 million bits) on 50 disks. The disks rotated vertically on a shaft at a speed of 1200 rpm.

Each side of a disk contained 200 tracks segmented into five sectors (sectors numbered 0–4 on top surfaces and sectors 5–9 on bottom). Each sector could hold between 178 and 200 characters. One to three forked access arms were equipped with two read/write heads each (positioned on both sides of a disk) mounted on a carriage adjacent to the disk stack. During seek operations, these arms moved vertically to select among disks (0–49) and horizontally to choose tracks (0–199). Reading or writing a sector required approximately 10 milliseconds.

Access times varied from roughly 100 milliseconds up to a maximum of about 700 milliseconds for Model 1 and up 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 a word mark bit per character. Model 1 contained half as many sectors.

IBM 7300

The IBM 7300 Disk Storage Unit was developed for use with the IBM 7070 and saw its Model 2 announced in 1959. Despite this, following the launch of the IBM 1301 on June 5, 1961, customers preferred the newer IBM 1301 over the IBM 7300. The technology within the IBM 7300 shared similarities with that found in the IBM 350, IBM 355, and IBM 1405 units.

IBM 1301

Revealed on June 2, 1961, the IBM 1301 Disk Storage Unit targeted mainframes in the IBM 7000 series and also supported the IBM 1410. Each module stored up to 28 million characters (168 million bits), with slightly less capacity—25 million characters—when used with the IBM 1410. A module comprised of twenty-five large disks featuring forty user-accessible recording surfaces and two hundred fifty tracks per surface. The Model 1 consisted of a single module; Model 2 stacked two modules vertically. Disks rotated at a speed of eighteen hundred rpm while transferring data at ninety thousand characters per second.

A significant advancement was its design incorporating individual arms and read/write heads assigned to each recording surface, moving together like a comb. This arrangement eliminated delays caused by repositioning heads across disks and reduced maximum access time to approximately one hundred eighty milliseconds. Furthermore, it was pioneering as the first disk drive employing aerodynamically shaped heads that floated on a thin cushion of air above disk surfaces, enhancing overall performance.

Connection to systems was managed through the IBM 7631 File Control unit, which allowed operation either via a dedicated or shared interface between an IBM 1410 or an IBM 7000 series computer.

Pricing for the IBM 1301 Model 1 was set at $2,100 per month for leasing or $115,500 for purchase; Model 2 cost $3,500 monthly lease or $185,000 outright. The IBM 7631 controller leased at $1,185 monthly or could be purchased for $56,000. All versions were discontinued by the year 1970.

IBM 1302

Introduced in September 1963, the IBM 1302 Disk Storage Unit increased storage capacity to 117 million 6-bit characters per module, a fourfold improvement over the 1301. It offered an average access time of 165 milliseconds and a data transfer rate of 180,000 characters per second, more than double that of its predecessor. Each module was equipped with two separate access mechanisms dedicated to the inner and outer cylinders. The Model 2 variant doubled storage by stacking two modules together. Leasing fees were set at $5,600 per month for Model 1 and $7,900 per month for Model 2, while purchase prices were $252,000 and $355,500 respectively. Adding the IBM 7631 controller incurred an additional monthly lease cost of $1,185 or a one-time purchase expense of $56,000. Production of the 1302 ceased in February 1965.

IBM 1311

Announced on October 11, 1962, the IBM 1311 Disk Storage Drive was designed for mid-range business and scientific computing systems. It utilized a removable IBM 1316 disk pack capable of storing two million characters. Throughout the 1960s, seven different models were released before being phased out by the early 1970s.

The IBM 1316 Disk Pack measures approximately four inches in height and weighs about ten pounds. It contains six disks measuring fourteen inches each, with ten usable recording surfaces (the outer surfaces remain unused). The disks rotate at a speed of 1,500 revolutions per minute and feature ten read/write heads mounted on a hydraulically controlled arm. Each surface is divided into 100 tracks, each track further segmented into 20 sectors; every sector holds 100 characters. The disk pack is housed within a transparent plastic casing that includes a locking handle to facilitate easy removal and installation.

The seven IBM 1311 models included:

  1. A master drive supporting IBM 1440, 1460, or 1240 systems; capable of managing up to four Model 2 slave drives; introduced in 1962 and retired in 1971.
  2. A slave drive compatible with master units; released in 1962 and withdrawn in 1975.
  3. A master drive for IBM 1620 or 1710 systems; controls up to three slaves without special features; launched in 1962 and discontinued in 1971.
  4. A master drive designed for IBM 1401 systems; supports up to four slaves; introduced in 1962 and phased out in 1971.
  5. A master drive compatible with IBM 1410, 7010, or 7740 systems; controls as many as four slaves; includes standard Direct Seek functionality; released in 1963 and withdrawn in 1971.
  6. & #7: Presumed master and slave drives introduced in March 1968; both decommissioned by February 1971.

Several optional enhancements were available to improve performance and capacity:

  • Direct Seek: Removes the need to return to zero track during seeking operations.
  • Scan Disk: Facilitates rapid automatic searching.
  • Seek Overlap: Permits concurrent seeks and read/write operations across multiple drives.
  • Track Record: Boosts capacity by recording one large continuous record per track instead of multiple sectors—allowing up to approximately 18.7 million bits depending on configuration.

Master drives (Models 1,3,4,5) are equipped with additional power supplies and control circuitry and are roughly one foot wider than Model 2 slave drives.

IBM 2302

The IBM 2302 represents the System/360 adaptation of the 1302, tailored for S/360 direct access storage device architecture. It employs a fixed module containing twenty-five platters with forty-six recording surfaces. The Model 3 features a single module while Model 4 incorporates two modules. Each module contains two independent access mechanisms—referred to as access groups—covering inner and outer sets of approximately two hundred fifty cylinders each, with one read/write head assigned per track. Average rotational latency is measured at seventeen milliseconds with a maximum delay of thirty-four milliseconds; maximum seek time within each access group is up to one hundred eighty milliseconds. Tracks hold approximately four thousand nine hundred eighty-five bytes each, resulting in a formatted capacity of about one hundred twelve megabytes per module. Connection to IBM mainframes is facilitated 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 interfaced with System/360 models 85 and 195 via the IBM 2880 Block Multiplexor Channel. Its popularity surged with the advent of Virtual Storage on System/370, frequently functioning as a paging storage on systems such as the 3155, 3165, 3158, 3168, 3033, 4341, and 3081 (the latter utilizing specialized microcode). The 2305 was also well-suited for managing small, high-transaction data sets including catalogs and job queues.

The smaller variant, the 2305-1, delivers a capacity of 5.4 MB with a data transfer rate of 3.0 MB/s and an average access time of 2.5 ms. In contrast, the larger 2305-2 offers 11.2 MB capacity at a transfer speed of 1.5 MB/s and an average access latency of 5 ms. This blend of storage size and rapid data throughput made it optimal for system-resident tasks, work files, job queues, indices, and frequently accessed datasets. Its swift response characteristics rendered it particularly effective as a paging device in environments handling more than 1.5 transactions per second under heavy load.

IBM 2311

The IBM 2311 Disk Storage Drive debuted in 1964 alongside the 2841 Control Unit, servicing the IBM System/360 series as well as compatibility with the IBM 1130 and IBM 1800 systems. It also connected directly to the IBM System/360 Model 20 and Model 25 computers. All units utilized the removable IBM 1316 Disk Pack, originally introduced with the IBM 1311.

The Model 1 connects to most IBM mainframes through the 2841 Control Unit; however, for the System/360 Model 25, this connection is managed by a Disk Attachment Control. Disk packs employ IBM's count key data format allowing variable record lengths. Models designated as 11 or 12—used with the integrated control of Model 20—feature a fixed sector format; these disk packs are not interchangeable with those used by Model 1.

While mechanically akin to the IBM 1311, the 2311 incorporated enhanced recording technology and provided storage capacity of approximately 7.25 megabytes across six removable platters. It uses ten read/write heads mounted on a hydraulically actuated arm, with each platter surface containing 200 tracks plus three optional spare tracks to compensate for defects. The average seek time is about 85 milliseconds, and it supports data transfer rates up to 156 kilobytes per second.

The standardized electrical interfaces across System/360 enabled third-party vendors to manufacture plug-compatible disk drives, fostering competition within IBM-compatible storage markets.

IBM 2314 Disk Access Storage Facility Model 1

Released on April 22, 1965, the IBM 2314 Disk Access Storage Facility Model 1 was designed for use with both System/360 and System/370 systems. Featuring a Two Channel Switch capability, it allowed simultaneous attachment to two separate channels. Building upon the foundational design of the IBM 2311, it incorporated recording improvements that increased data density.

The IBM 2314 housed approximately 29 million characters on a removable IBM 2316 disk pack that expanded from six to eleven disks, providing twenty recording surfaces in total. It employed twenty individual read/write heads mounted on a hydraulically actuated arm equipped with mechanical detents. Each surface contained around 200 tracks. While initial access times were comparable to those of the IBM 2311, enhancements to the actuator mechanism eventually reduced these times; meanwhile, data transfer rates doubled to reach approximately 310 kilobytes per second.

Originally sold as a package including nine disk drives at one price point—with drives shipped separately from their control unit and additional drive modules—the drives were installed in individual drawers for convenient disk pack access. This design earned them the nickname "Pizza Ovens." Only eight drives could be accessed concurrently; the ninth served as an offline spare allowing maintenance without interrupting ongoing operations. Drive system addresses were configured via user-swappable plugs, enabling flexible reassignment including designation of spares.

An optional addition—the IBM 2844 Control Unit—provided simultaneous dual-channel access to two distinct drives within the storage facility.

Later iterations of the IBM 2314 further enhanced these features:

IBM 2314 Direct Access Storage Series

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

  • 2312 Disk Storage, designed as a single-drive unit.
  • 2313 Disk Storage, configured with four drives.
  • 2318 Disk Storage, featuring two drives.

IBM 2319

To address competition from plug-compatible vendors producing devices comparable to the 2314, IBM launched the cost-effective three-drive 2319 series in 1970. The 2319 A1 model was created by eliminating one drive from the four-drive 2313, offered at a lower leasing rate to attract new clients while maintaining premium pricing for existing customers. The 2319-A1 connects exclusively to integrated controllers on System/370 Models 135 and 145; it supports traditional 2314 DASD units such as the 2312 or 2318. The 2319 B series accommodates configurations of three, six, or nine drives linked to a newly introduced 2314 Model B Storage Control Unit.

IBM 3310

Released on January 30, 1979, the IBM 3310 Direct Access Storage Device was designed for IBM 4331 midrange computer systems, providing a capacity of 64.5 MB per disk drive. It utilized fixed-block architecture and was compatible with DOS/VSE and VM, the only S/370 operating systems supporting FBA devices.

IBM 3330

The IBM 3330 (code-named Merlin) debuted in June 1970 for IBM System/370 and System/360/195 platforms. It featured removable disk packs with a capacity of 100 MB each, an average access time of 30 ms, and a data transfer speed of 806 kB/s. This model introduced sophisticated error correction via fire codes capable of correcting burst errors up to 11 bits long, improving data integrity and reducing costs by tolerating flaws on disk surfaces.

Initially, the system comprised a single storage control unit (3830 Model 1) connected to up to four physically linked drives, with a maximum of eight drives permitted per string. In August 1972, IBM unveiled the 3830 Model 2 Storage Control alongside the 3333 Disk Storage and Control, which separated control units from drives. The Model 2 controller functioned as a director-type unit overseeing multiple drive strings; within each string, the first unit was a 3333 combining controller and two drives, capable of managing up to three additional attached 3330 drives—allowing up to eight drives per string. Two such 3333 units could be connected to one controller, enabling up to sixteen drives with optional string switching between controllers.

In 1973, IBM introduced double-density (-11) variants: the 3333–11, 3330-11, and higher-capacity 3336–11 Disk Packs offering up to 200 MB storage. Mixing single- and double-density drives within the same string was not supported. Although field upgrades from Model 1 to Model -11 were feasible, they were complex due to necessary drive conversions and data migration processes.

The IBM 3330 product line was discontinued in 1983.

IBM 3340 and IBM 3344

While sharing many characteristics, only the IBM 3340 could serve as a head-of-string device; the 3344 required attachment to a IBM 3340 A model functioning as the head controller unit.

IBM 3340

Introduced in March 1973 for the IBM System/370, the IBM 3340 Direct Access Storage Facility—known internally as Winchester—offered three variants: the 3340-A2 (comprising two drives and a controller), and the B2 (two drives) and B1 (single drive) models, which could be connected to an A2 unit to support up to eight drives.

This system utilized removable data modules that housed both the head and arm assemblies. A mechanical load/unload mechanism operated an access door, enabling connection of the module without removing any external covers. It delivered an average access time of 25 milliseconds and data transfer speeds up to 885 kilobytes per second. Three types of IBM 3348 Data Modules were produced: one with a 35 MB capacity and two with 70 MB capacity, one of which incorporated a fixed-head section of 500 KB for accelerated access. The system incorporated error correction features and remained in production until 1984.

Developed under Ken Haughton at IBM's San Jose facility, the initial concept centered on dual removable modules each holding 30 MB. The Winchester codename derived from this "30/30" capacity configuration, a nod to the Winchester .30-30 rifle; although storage sizes increased over time, the nickname persisted.

A significant breakthrough was the economical head design that eliminated the need for unloading heads from the disk surface. This "Winchester technology" enabled heads to land on and lift off from spinning platters, simplifying the head and arm assembly while reducing costs. This approach set a precedent that became widely adopted across the storage industry.

The term Winchester or Winnie continued as a colloquial reference to hard disk drives into the early 1990s but has since fallen out of common usage worldwide.

IBM 3344

The IBM 3344 shares similarities with the 3340 but differs by employing fixed media rather than removable IBM 3348 data modules. Each spindle accommodates four logical drives, each matching the capacity of a single 3348–70 module. Available exclusively as dual-drive configurations, it does not include an A model (head-of-string). The 3344-B2F variant incorporates fixed heads positioned over certain cylinders on both drives. Both the 3344-B2 and 3344-B2F require connection to a 3340-A2 or 3340-A2F unit serving as head-of-string. Internally, the IBM 3344 is functionally identical to the IBM 3350; distinctions arise only in microcode within the control unit.

IBM 3350

The IBM 3350 Direct Access Storage Facility, codenamed Madrid, debuted in 1975 targeting IBM System/370 environments. It featured sealed head-disk assemblies (HDAs) integrating both head and arm components within a non-removable enclosure. Disk geometry consisted of 555 cylinders, 30 heads per cylinder, and track sizes of 19,069 bytes, providing approximately 317 MB of storage per HDA. The adoption of sealed HDAs marked a standard practice in all subsequent IBM DASD offerings.

Available models included A2, A2F, B2, B2F, C2, and C2F—all configured with two HDAs each. The A2 and A2F models incorporated an additional electronic board enabling connection to storage control units—referred to as controllers or head-of-string units. These devices were organized into strings beginning with an A2 or A2F unit followed by up to three B2 units or various combinations involving B2 and C2 units. Typically, the A2 unit contained a string switch facilitating connectivity to two separate storage control units, allowing concurrent I/O operations on different HDAs. Compatible storage controllers encompassed the IBM 3830 Model 2, Integrated Storage Control (ISC) embedded in CPUs such as the IBM 3148, and later backward-compatible controllers like the IBM 3880.

The C2 model also housed a controller offering an alternate access path to itself and other units; however, its primary role was serving as a backup controller engaged if the A unit’s controller failed. Its connectivity capabilities were more limited compared to those of the A unit.

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

Models designated with "x2F" suffixes (such as A2F) featured fixed-head areas covering the initial five cylinders on both HDAs. This design effectively reduced seek times within this zone to zero by eliminating head movement during access. Such zones were intended for frequently used data segments like HASP or JES checkpoint information to minimize mechanical delays on spool devices. Additionally, these fixed-head sections supported TSO swap areas and system swap spaces used by OS/360 successors—including MVT, SVS, and MVS—by efficiently managing non-contiguous page blocks during user or batch job context switches.

The IBM 3350 product line was officially retired in September 1994.

IBM 3370

Released in January 1979, the IBM 3370 Direct Access Storage Device was designed for IBM 4331, 4341, and System/38 midrange systems. It incorporated seven fixed 14-inch disks, providing a total storage capacity of 571 MB per unit. Notably, it was the first hard disk drive to implement thin-film head technology developed at the Thomas J. Watson Research Center. The 3370 utilized fixed-block architecture and was compatible with DOS/VSE and VM operating systems running on S/370 platforms.

IBM 3375

The IBM 3375 served as a complementary device employing count key data architecture, supporting OS/360 and its subsequent operating systems.

IBM 3380

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

The typical setup consisted of one A unit and up to three B units; each 3380 housed four devices, permitting strings of up to sixteen devices. Generally connected via dual paths to a 3880 storage control unit, the system supported two concurrent I/O operations targeting separate hard disk assemblies.

In February 1985, IBM released the Extended Capability Models (3380 E), which doubled the capacity to 5.04 GB per unit by employing two actuators of 1.26 GB on two assemblies. Later, in August 1987, the triple-capacity variant (3380 K) became available, offering 7.562 GB per unit with two actuators of 1.89 GB each. Models J and K could function in four-path mode through a 3990 storage control unit, enabling support for up to thirty-two devices per string and four simultaneous I/O operations.

The IBM 3380 series encompassed twelve models: six A-units (which included string heads with controller logic interfacing with IBM storage control units), five B-units (connected to A or C units), and one C-unit (linked directly to an IBM channel).

Manufacturing continued until May 1996, resulting in an impressive fifteen-year lifecycle that surpassed typical disk drive longevity.

IBM 3390

Debuted in November 1989, the IBM 3390 Direct Access Storage Device line delivered storage capacities reaching up to twenty-two gigabytes across multiple drives. System pricing varied between $90,000 and $795,000 depending on configuration and capacity.

A standard 3390 configuration featured a central A unit containing four or eight devices, optionally accompanied by one or two B units holding up to twelve devices each. The system operated in four-path mode connected to a 3990 storage control unit capable of supporting a second 3390 string, allowing up to sixty-four devices within a single subsystem.

Each Hard Disk Assembly (HDA) incorporated two actuator-head units along with platters; Model 1 provided an unformatted capacity of 1.89 GB per HDA, while 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; subsequently, the Model 9 introduced in 1993 tripled this figure to achieve an unformatted capacity of 11.3 GB per HDA.

Contrasting earlier DASD designs that employed large AC motors driving HDAs via belts, the IBM 3390 HDAs utilized enclosed DC motors for direct drive.

The Model 9 marked IBM's last announcement 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 engineered at IBM’s San Jose facility under the project name Sawmill. This full-height 5¼-inch HDD supported capacities up to 1.5 GB by utilizing as many as eight 130 mm platters. It was distinguished as the first hard drive to incorporate magnetoresistive (MR) head technology.

IBM 9340

In October 1991, IBM released the 9345 Direct Access Storage Device (DASD) within the 9340 series— a channel-attached count key data (CKD) DASD subsystem designed for IBM mainframes such as the ES/9000 processor family. The Model 1 of the 9345 housed two HDDs with 1.0 GB each, whereas Model 2 contained two drives of 1.5 GB capacity.

From an operational standpoint, the 9340/9345 shared similarities with the IBM 3990/3390 series but did not include the non-volatile RAM cache found on the 3990 and supported a shorter maximum block length compared to the 3390. The operating system’s Input/Output Supervisor (IOS) detected this hardware through a specialized initializer named IECCINIT, which also handled other DASD types. During initialization, the OS recognized that the 9340 lacked non-volatile cache and that the 9345 had fewer tracks per surface, resulting in assignment of a distinct device type separate from the 3990/3390 family.

9330 Series Disk Drives

  1. The 9331 Diskette Unit models 1 and 11 incorporated a single 8-inch floppy disk drive; models 2 and 12 featured one 5-inch floppy disk drive.
  2. The 9332 Direct Access Storage Device utilized the IBM 0667 hard disk drive.
  3. The 9333 High Performance Disk Drive Subsystem employed either IBM 0664 or IBM 0681 HDDs depending on specific model variations.
  4. The 9334 Disk Expansion Unit enabled connection of one to four SCSI hard drives to RS/6000 systems.
  5. The 9335 Direct Access Storage Subsystem was equipped with an IBM-developed "Kestrel" hard drive—an 850 MB unit containing three large, 14-inch disks and dual rotary actuators capable of accessing multiple surfaces simultaneously. This rack-mountable device was introduced in October 1986 as part of the IBM 9370 Information System lineup. No original equipment manufacturer (OEM) versions are documented.
  6. The 9336 Disk Unit incorporated the IBM 0681 HDD, also known as Redwing.
  7. The 9337 Disk Array Subsystem included either IBM’s 0662 (Spitfire) or 0663 (Corsair) hard disk drives.

IBM 2310

The IBM 2310 Removable Cartridge Drive made its debut in 1964 alongside the IBM 1800 and later with the IBM 1130 in 1965, with initial shipments likely coinciding with the latter in late that year. It stored up to 512,000 words of sixteen bits each (equivalent to approximately one million bytes) on an IBM 2315 cartridge. This cartridge housed a single oxide-coated aluminum platter enclosed within a plastic casing featuring openings for both the read/write arm and two read/write heads.

IBM 5444

Introduced in September of 1969 as part of System/3 and developed at IBM’s Hursley laboratory in England under the codename Dolphin, the IBM 5444 employed a disk cartridge known as the IBM 5440 containing one fourteen-inch disk. Three configurations were available:

  • Model 1: included one fixed disk and one removable disk, each providing one hundred tracks per surface; cartridge capacity was approximately 1.23 MB
  • Model 2: featured one fixed and one removable disk with two hundred tracks per surface; cartridge capacity increased to about 2.46 MB
  • Model 3: consisted of a single removable disk with two hundred tracks per surface; capacity matched Model 2 at roughly 2.46 MB

IBM 62GV

Introduced in May 1974, the IBM 62GV was created at IBM's Hursley laboratory in the United Kingdom under the project name Gulliver. The initial model provided a storage capacity of 5 MB, while subsequent versions (such as the 62TM) expanded this to 10 MB and 14 MB. Utilizing a Swinging Arm actuator paired with a single 14-inch disk, this design became IBM's most widely licensed electro-mechanical innovation. Both the actuator mechanism and filtration system gained broad adoption in hard disk drives throughout the 1980s and continue to be industry standards nearly forty years later. Over its production lifespan, approximately 177,000 units of the IBM 62GV were sold, making it the first hard disk drive to surpass 100,000 units shipped.

OEM and Small Systems HDDs

This segment addresses hard disk drives produced by IBM for OEM distribution and small IBM systems such as the System/3, System/32, /34, /36, and AS/400. Drives are cataloged by their OEM model designations and organized by their initial customer shipment dates.

IBM 0680

Released in 1979 for most IBM small systems and lower-tier System/370 models as the 3310 direct access storage device, the 0680 was officially announced as an OEM product in September 1981. Developed at IBM’s Hursley facility in the UK under the codename Piccolo, it incorporated six 8-inch (210 mm) disks and initially offered up to 65 MB capacity with an enhanced rotary actuator design.

A higher-capacity variant known as the 62SW was introduced in June 1984, doubling storage space; however, its market penetration was limited due to a cost per megabyte comparable to that of the 62GV.

IBM 0676

The 0676 was launched in November 1982 as a 5247 Disk Storage Unit intended for the IBM System/23 Datamaster. Developed at IBM Rochester, Minnesota under the designation 21ED, this model featured an 8-inch hard drive with capacities of either 15 or 30 MB achieved through two or four 210 mm disks. In 1983, it was incorporated into the System/36’s 5360 System Unit. Capacity enhancements were made in 1984 by increasing tracks per surface, after which it became part of the System/36’s upgraded 5362 System Unit.

IBM 0665

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

IBM 0667

The 0667 began shipping in August 1986. Created at IBM Rochester under the codename "Grant," it was a full-height ESDI hard disk drive measuring 5¼ inches with up to four disks of 130 mm diameter and a maximum capacity of 70 MB. This drive was offered as an optional component on certain PC RT models (6150, 6151, and 6152) as well as System/36 Model System Units (5363 and 5364).

IBM 0669

Released in 1987 and developed at IBM Rochester, Minnesota under the codename "Grant-Prime," the 0669 was a full-height HDD featuring a five-inch form factor with up to four disks measuring 130 mm each, delivering storage capacities up to 115 MB. This model served as the internal hard drive for both System/36’s 5363 and Series/1’s 4956 System Units.

IBM 0671

Also debuting in 1987, the 0671 was developed at IBM Rochester under the codename "Lee." It was an ESDI full-height five-inch hard drive capable of housing up to eight disks of 130 mm diameter for a maximum capacity of up to 316 MB. This model represented IBM's initial implementation of thin metal film recording technology. In 1988, it was integrated into the IBM AS/400’s 9404 System Unit configuration supporting two or three drives.

IBM 0661

Introduced in 1989 as model 371, the 0661 was initially developed under the codename "Lightning" at IBM facilities in Rochester and Hursley, UK. This SCSI hard drive featured a capacity of 320 MB, utilizing up to eight 95 mm platters with 14 read/write heads. A subsequent enhancement, the 400 MB "Turbo" version, was released in 1990. The drive became a common component within various IBM systems, notably the AS/400 System Unit Model CXX.

IBM 0681

Debuting in April 1990 from IBM Hursley’s laboratory, the 0681—known internally as Redwing—was the final hard disk developed there. It provided storage up to 857 MB in a full-height 5-inch form factor, employing twelve 130 mm platters. This model was pioneering as the first to implement PRML data decoding technology. It was integrated into the 9333 Disk Drive Subsystem launched in early 1992, with an upgraded 1.07 GB high-density variant introduced in May of that year.

IBM 0663

Released toward the end of 1991 and nicknamed "Corsair," the 0663 was a compact hard disk featuring a half-height (1.6-inch) profile and a 3-inch form factor. It offered up to 1 GB storage across eight 95 mm platters. This drive appeared in select PS/2 and RS/6000 systems and was notable as the first OEM disk to incorporate Magnetoresistance (MR) heads, which improved both read accuracy and durability.

IBM 0664

Launched in November 1992 and developed at IBM Rochester under the codename "Allicat," the 0664 was a full-height (3.25-inch) 5-inch hard disk that combined two separate 3-inch drives. It delivered a maximum capacity of 2.013 GB using up to eight 95 mm platters.

IBM 0662

The 0662, introduced in June 1993 as "Spitfire" from IBM Rochester, was a full-height (1-inch) hard disk with a compact 3-inch form factor. It offered up to 1.05 GB capacity distributed over three platters or five recording surfaces. This model served as the internal storage device for both the IBM 9336 Disk Unit and the IBM 9337 Disk Array.

Floppy disk drive

IBM pioneered floppy disk technology by releasing the first read-only 8-inch floppy disk drive in 1971, followed by its initial read/write version in 1973 with the introduction of the 3740 Data Entry System. Although IBM established early standards for 8-inch floppy drives, it chose not to market these drives separately, allowing industry-wide standards to develop independently.

At one time, IBM was the largest OEM buyer of 5-inch floppy disk drives, adopting a two-sided design with a track density of 48 tracks per inch that eventually became an industry benchmark. Despite plans to manufacture these and smaller formats internally, IBM abandoned such initiatives by 1985. Additionally, its attempt in 1983 to OEM the smaller 4-inch DemiDiskette did not succeed.

"Star" series of HDDs

On October 17, 1994, IBM’s Storage Systems division introduced three distinct families of hard drives: the Travelstar series featuring compact 2-inch drives for notebook computers; the Deskstar line comprising 3-inch drives designed for desktop systems; and the Ultrastar series of high-performance 3-inch drives aimed at demanding computing environments.

IBM's first HDD versus its last HDDs

The following table contrasts IBM’s original hard drive—the RAMAC 350—with its final trio of "Star" series OEM hard drives, illustrating significant advancements through dramatic reductions in physical size and cost alongside substantial gains in capacity and 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 (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 (~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 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:

IBM 7320 Drum

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

IBM 2301 Drum

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

IBM 2303 Drum

Introduced in 1964, the IBM 2303 is 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 retention. It accommodates ten removable cells, each with a capacity of 40 MB, summing to an overall storage 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 provides the system with virtualized access to these 3330 drives.

See also

External links

Related profiles

IIBM 1311IIBM 0661IIBM 353IIBM 355
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