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IBM 9330 Family

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Adapted from the English Wikipedia article IBM 9330 Family, available under CC BY-SA 4.0Updated 9 August 2025
IBM
Company typePublic
IndustryTechnology, Computer hardware
FoundedJune 16, 1911; 115 years ago (1911-06-16) in Endicott, New York, United States
FounderCharles Ranlett Flint (as Computing-Tabulating-Recording Company)
Headquarters
Armonk, New York
,
United States
ProductsMagnetic disk storage devices (historically), computer hardware, software, and services
Number of employees
350,000 (approximate, historical)
Websitewww.ibm.com

IBM was a pioneer in manufacturing magnetic disk storage devices from 1956 until 2003, when it divested its hard disk drive division to Hitachi. IBM employees were instrumental in inventing both the hard disk drive (HDD) and the floppy disk drive (FDD), contributing numerous technological advancements. The fundamental mechanical architecture of hard disk drives has largely persisted since the IBM 1301, with performance standards established in the 1950s still relevant today. Throughout the decades, these devices have experienced substantial declines in cost and physical dimensions, coupled with remarkable enhancements in storage capacity and operational efficiency.

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 formats. Although IBM consistently sold magnetic disk drives, it only started offering them under original equipment manufacturer (OEM) agreements beginning in 1981. By 1996, IBM discontinued producing hard disk drives exclusive to its own systems, instead marketing all HDDs solely as OEM products.

IBM has employed multiple terms to describe its magnetic disk drives over time, including direct-access storage device (DASD), disk file, and diskette file. For clarity, this article uses the widely accepted industry terminology: hard disk drive (HDD) and floppy disk drive (FDD).

IBM 350

The IBM 350 disk storage unit, recognized as the first-ever disk drive, was introduced by IBM on September 14, 1956, as part of the IBM 305 RAMAC system. A comparable model, the IBM 355, was launched for the IBM 650 RAMAC system. The acronym RAMAC stood for "Random Access Method of Accounting and Control". The initial prototype was delivered to Zellerbach Paper Company in June 1956, with mass shipments commencing in November 1957, including a unit sent to United Airlines in Denver.

Engineered for real-time business accounting applications, the IBM 350 could store five million 6-bit characters (equivalent to approximately 3.75 MB). It comprised fifty-two disks providing one hundred recording surfaces and tracks, rotating at a speed of 1200 revolutions per minute. The data transfer rate reached 8,800 characters per second. An access mechanism enabled selection of disk pairs and tracks through movable read/write heads. Several enhanced variants were released during the late 1950s. The IBM RAMAC 305 system with the IBM 350 was leased at a rate of $3,200 monthly. Production of this unit ceased in 1969.

The patent originating from the RAMAC initiative is regarded as foundational for modern disk drives. Although initially rejected by IBM's Board over concerns regarding its potential impact on punch card sales, development persisted at IBM’s San Jose facility until receiving approval from the company’s president.

Physically, the IBM 350 cabinet measured long by high by wide and weighed approximately one ton, necessitating forklifts and large cargo aircraft for transportation. According to Currie Munce from Hitachi Global Storage Technologies—which acquired IBM’s storage division—early marketing efforts hesitated to promote higher capacity drives due to uncertainty about sales prospects; nonetheless, 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. Beginning in 2002, a restoration team led by Al Hoagland undertook refurbishment of an IBM 350 RAMAC unit in partnership with Santa Clara University. This effort transitioned to the Computer History Museum in Mountain View, California in 2005, where it is now publicly displayed within the museum's Revolution exhibit.

IBM 353

The IBM 353, designed to operate alongside the IBM 7030, resembled the IBM 1301 but boasted a higher data transfer speed. It featured a storage capacity of 2,097,152 (221) words, each 64 bits in length (totaling 134,217,728 bits), and achieved a transfer rate of 125,000 words per second. A prototype delivered in late 1960 was pioneering as the first disk drive to utilize a dedicated head per surface that floated on compressed air, similar to the IBM 350 disk storage (RAMAC). Production versions adopted self-levitating heads akin to those found in the IBM 1301.

IBM 355

Introduced on September 14, 1956, the IBM 355 served as an enhancement to the widely used IBM 650. It incorporated the IBM 350 mechanism but improved upon it by employing up to three access arms instead of just one. The device could store six million decimal digits plus an additional 600,000 sign indicators. Data transfer involved moving entire tracks between the magnetic core memory of the 653—an optional module providing sixty signed 10-digit words sufficient for a single disk track or tape record—and other system components.

IBM 1405

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

Each disk surface contained 200 tracks subdivided into five sectors, with sectors numbered 0–4 on the upper side and sectors 5–9 on the lower side. Sector capacity ranged from 178 to 200 characters. Up to three forked access arms, each equipped with two read/write heads (one for the top and one for the bottom), moved both vertically and horizontally under electronic control to access specific disks and tracks. Reading or writing a sector required approximately 10 milliseconds.

Access times varied from as low as 100 milliseconds up to a maximum of about 700 milliseconds for Model 1 and up to 800 milliseconds for Model 2. Model 2 supported up to 100,000 sectors that could contain either 200 characters in move mode or 178 characters in load mode, which included an additional word mark bit per character. Model 1 held half as many sectors at around 50,000.

IBM 7300

The IBM 7300 Disk Storage Unit was engineered specifically for use with the IBM 7070 system. Although IBM announced a second version in 1959, customers of the IBM 7070 and IBM 7074 systems preferred transitioning to the newer IBM 1301 after its release in 1961. The technology within the IBM 7300 shared similarities with that found in the IBM 350, IBM 355, and IBM 1405 disk drives.

IBM 1301

Unveiled on June 2, 1961, the IBM 1301 Disk Storage Unit was aimed at supporting IBM 7000 series mainframes and the IBM 1410. Each module could hold up to approximately 28 million characters (168 million bits), consisting of twenty-five large disks with forty user-accessible recording surfaces, each surface containing about two hundred fifty tracks. The Model 1 configuration included one module; Model 2 stacked two modules vertically. The 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 with this model was its design featuring an individual arm and read-write head dedicated to each disk surface, which moved simultaneously like a comb assembly—eliminating delays caused by repositioning heads between surfaces and reducing maximum access time to approximately one hundred eighty milliseconds. Additionally, it was the first drive to use aerodynamically shaped heads that flew on a thin cushion of air above the disk surfaces, improving performance.

Connection was facilitated through the IBM 7631 File Control unit, enabling integration with either IBM 1410 or IBM 7000 series systems or allowing sharing between two computers.

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 outright. The IBM 7631 controller cost an additional $1,185 monthly or $56,000 if bought upfront. All models were discontinued by the year 1970.

IBM 1302

Launched in September 1963, the IBM 1302 Disk Storage Unit increased storage capacity fourfold compared to the 1301, reaching 117 million 6-bit characters per module. It delivered an average access time of 165 milliseconds and a data transfer rate of 180,000 characters per second, more than doubling the speed of its predecessor. Each unit incorporated two separate access mechanisms dedicated to the inner and outer cylinder sets. The Model 2 version stacked two such modules to achieve twice the storage capacity. Leasing expenses were set at $5,600 per month for Model 1 and $7,900 per month for Model 2, with purchase prices of $252,000 and $355,500 respectively. The associated IBM 7631 controller was available for an additional $1,185 monthly lease or a one-time purchase of $56,000. Production of the IBM 1302 ceased in February 1965.

IBM 1311

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

The IBM 1316 Disk Pack measures about 4 inches in height and weighs approximately 10 pounds. It contains six disks each measuring 14 inches in diameter, providing ten usable recording surfaces. These disks rotate at a speed of 1500 revolutions per minute, with each surface divided into 100 tracks and each track segmented into 20 sectors; every sector holds 100 characters. The read/write heads are hydraulically actuated on a shared mechanism that is mechanically positioned before read/write operations commence. The disk pack is enclosed within a transparent plastic casing equipped with a locking handle to secure it during installation and removal.

The seven models consist of master drives equipped with controllers as well as slave drives without controllers:

  1. Master drive compatible with IBM 1440, 1460, or 1240 systems, capable of managing up to four Model 2 drives (1962–1971).
  2. Slave drive designed to work with master drives (1962–1975).
  3. Master drive for IBM 1620 or 1710 systems controlling up to three Model 2 drives (1962–1971).
  4. Master drive for IBM 1401 systems managing up to four Model 2 drives (1962–1971).
  5. Master drive for IBM 1410, 7010, or 7740 systems featuring standard Direct Seek capability, controlling up to four Model 2 drives (1963–1971).
  6. Presumed master drive introduced in March 1968 and retired by February 1971.
  7. Presumed slave drive introduced March 1968 and withdrawn in February 1971.

Several optional enhancements were available to improve functionality:

  • Direct Seek: Removes the need to return to zero position during each seek operation.
  • Scan Disk: Facilitates rapid automatic searching.
  • Seek Overlap: Permits concurrent seek operations and input/output across multiple drives.
  • Track Record: Increases capacity by writing a single large record per track instead of multiple sectors; this can raise total storage up to approximately 18.7 million bits under Load Mode.

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

IBM 2302

The IBM 2302 serves as the System/360 counterpart to the IBM 1302, incorporating track formatting consistent with System/360 DASD standards. It employs a fixed module containing twenty-five platters with forty-six recording surfaces. The Model 3 configuration includes one such module; Model 4 contains two modules. Each module is equipped with two independent access mechanisms—referred to as access groups—which separately handle the innermost and outermost sets of approximately 250 cylinders each. Each access group features one read/write head per track. The average rotational latency is approximately 17 milliseconds with a maximum of about 34 milliseconds; maximum seek time per access group is up to 180 milliseconds. Each track holds around 4,985 bytes of data; consequently, formatted capacity per module is roughly equivalent to 112 megabytes. Connectivity to IBM mainframe systems is provided via 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 360/85 and 360/195 through the IBM 2880 Block Multiplexor Channel. Its popularity grew with the advent of System/370's Virtual Storage, frequently functioning as a paging device on systems such as the 3155, 3165, 3158, 3168, 3033, 4341, and 3081 (the latter utilizing specialized microcode). The 2305 was also well-suited for managing small, high-activity data sets like catalogs and job queues.

The 2305-1 model provides a capacity of 5.4 MB and delivers data at a rate of 3.0 MB/s, with an average access time of approximately 2.5 milliseconds. In contrast, the larger 2305-2 offers an 11.2 MB capacity with a data transfer speed of 1.5 MB/s and an average access time around 5 milliseconds. Its rapid response time and high throughput made it particularly effective for system-resident tasks, work files, job queues, indices, and frequently accessed data—especially when used as a paging device in systems handling more than 1.5 transactions per second.

IBM 2311

The IBM 2311 Disk Storage Drive was introduced in 1964 alongside the 2841 Control Unit and was designed primarily for the IBM System/360 series but also found use with the IBM 1130 and IBM 1800. It connects directly to the System/360 Model 20 and Model 25. All units utilize removable IBM 1316 Disk Packs, which were originally developed for the IBM 1311.

The Model 1 version of the 2311 connects to most IBM mainframe systems via the 2841 Control Unit; however, for the System/360 Model 25, a Disk Attachment Control performs this role. Disk packs are formatted using IBM's count key data variable-length record format. Models 11 and 12, which are integrated with the Model 20's control system, use a fixed-sector format; disk packs formatted under one scheme are not compatible with the other.

Mechanically akin to the IBM 1311 but offering enhanced recording density, the 2311 stores up to 7.25 megabytes on a six-platter removable disk pack. It employs ten read/write heads mounted on a hydraulically actuated arm featuring mechanical detents for accurate track positioning. Each platter surface contains 200 tracks plus three spare tracks reserved for defect management. The average seek time is approximately 85 milliseconds, while data transfer rates reach up to 156 kB/s.

Standardized electrical interfaces across System/360 models allowed for broad compatibility, which encouraged third-party manufacturers to produce plug compatible disk drives and contributed to a growing market for IBM-compatible storage devices.

IBM 2314 Disk Access Storage Facility Model 1

Released in April 1965, the IBM 2314 Disk Access Storage Facility Model 1 supported both System/360 and System/370 platforms. Equipped with a Two Channel Switch feature, it could connect simultaneously to two separate channels. The disk drive mechanism resembled that of the IBM 2311 but featured substantially increased data density.

This model stored roughly 29 million characters on a removable IBM 2316 disk pack that expanded from six to eleven disks (totaling twenty recording surfaces). The read/write head assembly consisted of twenty heads mounted on a hydraulically actuated arm with mechanical detents ensuring precise positioning. Each surface contained 200 tracks. Initial access times were comparable to those of the IBM 2311 but improved in later versions due to actuator enhancements. Data transfer rates doubled to approximately 310 kB/s.

The Model 1 was marketed as a package including nine drives plus a storage control unit; drives were installed in drawers allowing easy disk pack access. Due to their appearance, these units earned the nickname "Pizza Ovens." Although nine drives were included, only eight could be accessed at any time—the ninth served as an offline spare for maintenance or replacement purposes. Drive system addresses were configured through user-swappable plugs providing flexible setup options.

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

Later models built upon these foundational features:

IBM 2314 Direct Access Storage System - Model Variants

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

  • 2312 Disk Storage: a single-drive unit.
  • 2313 Disk Storage: a configuration with four drives.
  • 2318 Disk Storage: comprised of two drives.

IBM 2319

To address competition from plug compatible manufacturers offering storage devices comparable to the 2314, IBM launched the cost-effective three-drive 2319 series in 1970. The 2319-A1 model was derived by removing one drive from the four-drive 2313, enabling a significantly lower rental fee for new clients while preserving higher charges for existing customers. This model interfaces with integrated controllers on System/370 Models 135 and 145. Additionally, traditional 2314 DASD units such as the 2312 or 2318 can be connected to the 2319-A1. The 2319 B series accommodates configurations of three, six, or nine drives linked to a newly designed 2314 Model B Storage Control Unit.

IBM 3310

Released on January 30, 1979, the IBM 3310 Direct Access Storage Device was designed specifically for IBM 4331 midrange computer systems. Each drive provided a storage capacity of 64.5 MB and utilized fixed-block architecture, ensuring compatibility with DOS/VSE and VM operating systems that support FBA devices.

IBM 3330

The IBM 3330 Direct Access Storage Facility, known internally as Merlin, debuted in June 1970 targeting IBM System/370 and System/360 Model 195 systems. The initial offerings were a two-drive Model 1 and a single-drive Model 2. Each removable disk pack stored 100 MB, featured a 30 ms access time, and supported data transfer speeds up to 806 kB/s. A notable advancement was the incorporation of fire code error correction technology, which improved reliability and reduced expenses by accommodating imperfections on the disk surface.

The standard setup included one storage control unit (3830 Model 1) connected to a chain of up to four drives (with a maximum of eight drives per chain). In August 1972, IBM introduced separate components: the 3830 Model 2 Storage Control and the 3333 Disk Storage and Control. The upgraded 3830 functioned as a director-style controller managing multiple chains. The first unit in each chain—the 3333—combined controller functions with two disk drives and could manage up to three additional attached 3330 units, allowing up to eight drives per chain. Two separate 3333 units could be linked to a single controller for a total of sixteen drives; optional string switches enabled connectivity to two controllers.

In 1973, IBM rolled out double-density (-11) variants including the 3333–11, 3330-11, and high-capacity 3336–11 Disk Packs capable of storing up to 200 MB. Mixing original single-density and double-density drives within one chain was not supported. Upgrading existing models to the -11 versions involved significant drive modifications and data transfer operations.

The IBM 3330 series was discontinued in 1983.

IBM 3340 and IBM 3344

Both the IBM 3340 and IBM 3344 models share many characteristics; however, only the IBM 3340 can serve as the primary unit in a chain. There are no A model versions of the IBM 3344; thus, any IBM 3344 must be connected under an IBM 3340 A model acting as the head of the chain.

IBM 3340

Introduced in March 1973 for the IBM System/370, the IBM 3340 Direct Access Storage Facility, internally named Winchester, came in three configurations: the 3340-A2 featuring two drives with a controller, and the B2 (two drives) and B1 (single drive) units designed to connect to the A2, supporting up to eight drives in total.

This system utilized removable data modules that housed both the head and arm assembly; its access door opened mechanically during load and unload operations, removing the necessity to detach covers as was required by earlier disk pack designs. The device delivered a 25 ms average access time and a data throughput of 885 kB/s. The IBM 3348 Data Modules were available in three variants: one with 35 MB capacity and two with 70 MB, one of which included a 500 KB fixed-head section for accelerated access. Equipped with error correction capabilities, the 3340 was discontinued in 1984.

Conceived under Ken Haughton’s leadership in San Jose, the original concept revolved around two removable modules each holding 30 MB—giving rise to its Winchester codename, a nod to the Winchester .30-30 rifle. Despite later capacity expansions, the nickname endured.

A significant breakthrough was the economical design of its read/write heads that allowed them to land on and lift off from the disk surface during spin-up and spin-down without unloading. This "Winchester technology" minimized mechanical complexity and costs dramatically, setting a new standard for disk drive manufacturing.

The terms Winchester or Winnie persisted as informal industry references for hard disk drives into the early 1990s but have since largely disappeared from common usage worldwide.

IBM 3344

The IBM 3344 shares similarities with the 3340 but employs fixed media rather than removable IBM 3348 data modules. Each spindle accommodates four logical drives, matching the capacity of a single 3348–70 module. Offered exclusively as dual-drive units, it does not include an A model (head of string). The 3344-B2F variant differs from the 3344-B2 by incorporating fixed heads over certain cylinders on both drives. Both variants require a 3340-A2 or 3340-A2F unit as the head of string controller. Internally, the architecture of the 3344 closely mirrors that of the IBM 3350, with differences confined primarily to microcode within its control unit.

IBM 3350

Released in 1975 for IBM System/370, the IBM 3350 Direct Access Storage Facility bore the code name Madrid. It introduced sealed head-disk assemblies (HDAs) integrating both heads and arms into a single non-removable unit, setting a precedent for sealed HDAs in subsequent IBM DASD products. The disk geometry comprised 555 cylinders, 30 heads per cylinder, and tracks containing 19,069 bytes each, resulting in approximately 317.5 MB storage per HDA.

Available models included A2, A2F, B2, B2F, C2, and C2F configurations; each housed two HDAs. The A2 and A2F units incorporated an additional electronics board to interface with storage control units—commonly known as controllers or head-of-string devices. These units could be arranged in strings starting with an A2/A2F followed by up to three B2 units or two B2s plus one C2. Typically, the A2 unit featured a string switch enabling connection to two storage control units concurrently, facilitating simultaneous I/O operations across different HDAs. Compatible controllers encompassed the Model 2 version of the IBM 3830, Integrated Storage Control (ISC) embedded within CPUs such as models 3148/3158/3168, along with later backward-compatible controllers like the IBM 3880.

The C2 model also contained a controller functioning as an alternative path for itself and other units; it served as a backup controller if the primary controller on an A unit failed but offered more limited connectivity options compared to that on an A unit. Valid string configurations for IBM 3350 included combinations such as -A, -AB, -ABB, -ABBB, -AC-, -ABC-, and -ABBC-.

Models suffixed with "x2F" (for example, A2F) featured fixed-head regions spanning the first five cylinders on both HDAs. This design eliminated seek time within this reserved area and was optimized for frequently accessed datasets like HASP or JES checkpoint files to reduce head movement on spool devices. Additionally, it supported TSO swap data as well as system swap data under OS/360 successors such as MVT and SVS, along with MVS environments—enhancing context switch efficiency between TSO users or batch processing regions.

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

IBM 3370

Debuting in January 1979, the IBM 3370 Direct Access Storage Device was designed for IBM 4331, 4341, and System/38 midrange computer systems. It comprised seven fixed 14-inch platters, delivering a total capacity of 571 MB per unit. Notably, it was the pioneer in employing thin-film head technology, which was developed at the Thomas J. Watson Research Center. The 3370 utilized a fixed-block architecture compatible with DOS/VSE and VM operating systems running on S/370 platforms.

IBM 3375

Serving as a counterpart to the 3370, the IBM 3375 implemented count key data architecture and supported OS/360 along with its subsequent versions.

IBM 3380

Released on June 11, 1980, the IBM 3380 Direct Access Storage Device incorporated film head technology and provided a capacity of 2.52 GB per unit. Each unit contained two hard disk assemblies equipped with dual actuators, each actuator accessing 630 MB. It achieved a data transfer speed of 3 MB/s and had an average access time of approximately 16 milliseconds. Initial pricing ranged between $81,000 and $142,200. Due to challenges related to tribology between heads and media, shipments were delayed until October 1981.

Typical configurations consisted of one A unit paired with as many as three B units; with four devices per unit, strings could include up to sixteen devices. These units were generally connected to a 3880 storage control unit featuring dual paths, enabling two concurrent I/O operations targeting separate hard disk assemblies.

In February 1985, IBM launched the Extended Capability Models (3380 E) offering double density with a capacity of 5.04 GB per unit—two actuators each providing 1.26 GB. Later, in August 1987, the triple-capacity Model K was introduced with a storage size of 7.562 GB per unit (two actuators at 1.89 GB each) and included an optional four-path mode. This enhancement allowed strings to support up to thirty-two devices when connected to a 3990 storage control unit and enabled four simultaneous I/O operations.

The IBM 3380 product line consisted of twelve models: six A-units which acted as string leaders containing controller logic for attachment to IBM storage controls; five B-units that connected to A- or C-units; and one C-unit designed for direct channel connection.

Production of the IBM 3380 series continued until May 1996, resulting in an impressive fifteen-year production span.

IBM 3390

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

A typical 3390 configuration featured a central A unit housing four or eight devices, optionally flanked by one or two B units capable of holding up to twelve devices each. The system operated in four-path mode when connected to a 3990 storage control unit, which could support an additional second string of 3390 devices—allowing up to sixty-four devices within a single subsystem.

The Hard Disk Assemblies (HDAs) incorporated two actuator-head assemblies along with platters: Model 1 offered an unformatted capacity of 1.89 GB; Model 2 doubled this capacity to 3.78 GB per HDA. An upgrade introduced in 1991 (Model 3) increased capacity further to 5.67 GB per HDA, followed by the Model 9 in 1993 which tripled it again to reach approximately 11.3 GB per HDA.

Unlike prior DASD designs that used large AC motors driving platters via belts, the IBM 3390 employed a DC motor integrated directly within the HDA enclosure. The Model 9 marked IBM’s final iteration of the Single Large Expensive Disk (SLED) drive design.

IBM 9345

Introduced in November 1990 as a Request Price Quotation (RPQ) option for IBM's SuperComputing Systems Extensions (SCSE), the IBM 9345 hard disk drive was engineered at IBM’s San Jose facility under the project name Sawmill. This full-height 5¼-inch HDD supported up to eight 130 mm platters, delivering a maximum storage capacity of 1.5 GB. It notably marked the first use of Magneto Resistive (MR) heads in a hard disk drive.

IBM 9340

The IBM 9340 DASD was launched in October 1991 as part of the 9340 series of channel-attached count key data (CKD) DASD subsystems tailored for IBM mainframe environments, including the ES/9000 processor line. The Model 1 configuration housed two 1.0 GB HDDs, whereas Model 2 contained two drives each with 1.5 GB capacity.

From an operational perspective, the 9340/9345 shared similarities with the 3990/3390 series but lacked the non-volatile RAM cache found in the 3990 and supported a shorter maximum block length than the 3390. The device characteristics were identified by the OS Input/Output Supervisor (IOS) through a specialized initializer known as IECCINIT, responsible for managing various DASD types. During system initialization, the OS detected that the 9340 did not include non-volatile cache and acknowledged the reduced track count on the 9345, assigning unique device type identifiers accordingly.

9330 family of disk drives

  1. The 9331 Diskette Unit models 1 and 11 incorporated a single 8-inch floppy disk drive (FDD), while models 2 and 12 featured one 5-inch FDD.
  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 variants.
  4. The 9334 Disk Expansion Unit connected between one and four SCSI HDDs to RS/6000 systems.
  5. The 9335 Direct Access Storage Subsystem contained an IBM-developed "Kestrel" HDD with an 850 MB capacity, consisting of three 14-inch platters and dual rotary actuators enabling access to multiple surfaces. This rack-mountable device was announced in October 1986 alongside the IBM 9370 Information System. No original equipment manufacturer (OEM) versions have been documented.
  6. The 9336 Disk Unit used the IBM 0681 HDD, also known as Redwing.
  7. The 9337 Disk Array Subsystem integrated either IBM’s 0662 (Spitfire) or 0663 (Corsair) hard drives.

IBM 2310

The IBM 2310 Removable Cartridge Drive was introduced in 1964 with the IBM 1800 system and later appeared in the IBM 1130 in 1965, most likely shipping initially with the latter in late that year. It stored up to 512,000 words of 16 bits each (equivalent to 1,024,000 bytes) on an IBM 2315 cartridge. This cartridge contained a single oxide-coated aluminum platter enclosed within a plastic shell, designed with openings for both the read/write arm and two read/write heads.

IBM 5444

Released in September 1969 as part of System/3, the IBM 5444 was developed at IBM’s Hursley laboratory in England under the codename Dolphin. It employed the IBM 5440 disk cartridge, which housed a single 14-inch platter. Three models were offered:

  • Model 1: one fixed disk plus one removable disk, each featuring 100 tracks per surface; cartridge capacity was approximately 1.23 MB
  • Model 2: one fixed disk and one removable disk, each with an increased track density of 200 tracks per surface; cartridge capacity doubled to about 2.46 MB
  • Model 3: included only one removable disk with 200 tracks per surface; cartridge capacity remained at approximately 2.46 MB

IBM 62GV

The IBM 62GV, introduced in May 1974, was engineered at IBM's Hursley laboratory in the UK and was internally known as Gulliver. Its original storage capacity was 5 MB, which was later expanded in subsequent versions to 10 MB (62TM) and eventually 14 MB. This model incorporated a Swinging Arm actuator paired with a single 14-inch disk—a mechanism pioneered at Hursley that became IBM's most extensively licensed electromechanical innovation. The actuator and its filtration system gained widespread acceptance across the hard disk drive industry throughout the 1980s and continue to be industry standards nearly four decades later. Approximately 177,000 units of the IBM 62GV were sold, making it the first hard drive to surpass 100,000 units shipped.

OEM and Small Systems HDDs

This section details IBM hard drives provided as OEM products and those designed for IBM’s smaller systems such as the System/3, System/32, /34, /36, and AS/400. The drives are listed by their OEM model numbers along with their initial shipment dates.

IBM 0680

First delivered in 1979 for most IBM small systems and entry-level System/370 models as the 3310 direct access storage device, the 0680 was formally announced as an OEM variant in September 1981. Developed at IBM’s Hursley facility under the codename Piccolo, it featured six 8-inch (210 mm) disks and initially offered up to 65 MB of capacity with an enhanced rotary actuator design.

A double-capacity version known as the 62SW was released in June 1984; however, it experienced limited market success due to its cost per megabyte being comparable to that of the 62GV.

IBM 0676

Released in November 1982 as a 5247 Disk Storage Unit for the IBM System/23 Datamaster, the 0676 was developed at IBM Rochester, Minnesota, under the designation 21ED. It was an 8-inch HDD available with capacities of either 15 or 30 MB, utilizing two or four disks measuring 210 mm each. In 1983, it was integrated into the System/36 through the 5360 System Unit. By 1984, its capacity was doubled by increasing track density per surface and it was subsequently incorporated into the System/36’s 5362 System Unit.

IBM 0665

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

IBM 0667

The 0667, which first became available in August 1986, originated from IBM Rochester under the codename "Grant." It was a full-height ESDI hard disk of size 5¼ inches with a maximum capacity of 70 MB spread across up to four disks measuring 130 mm each. This drive was supplied on selected PC RT models (6150, 6151, and 6152) as well as System/36 Model System Units (5363 and 5364).

IBM 0669

Launched in 1987 and developed at IBM Rochester under the codename "Grant-Prime," the 0669 was a full-height hard drive sized at five inches. It offered capacities up to 115 MB using four disks of 130 mm diameter. This model 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 and created at IBM Rochester with the codename "Lee," the 0671 was a full-height five-inch ESDI hard disk capable of storing up to 316 MB across eight disks sized at 130 mm each. It represented IBM’s inaugural implementation of thin metal film recording surfaces and was incorporated in early 1988 into the AS/400’s 9404 System Unit, which accommodated two or three such drives.

IBM 0661

The 0661, introduced in 1989 as model number 371, was developed under the codename "Lightning" at both IBM Rochester and Hursley UK. It featured a SCSI interface with a capacity of up to 320 MB using eight disks of size 95 mm (with fourteen heads). A higher-capacity "Turbo" version offering up to 400 MB followed in 1990. This drive became a standard component for prominent IBM systems including variants of the AS/400 System Unit Model CXX.

IBM 0681

Released in April 1990, the 0681 was engineered at IBM Hursley under the project name Redwing, marking the final hard drive developed at this facility. This full-height 5-inch HDD utilized twelve 130 mm platters to deliver a maximum capacity of 857 MB and introduced PRML data decoding technology. It was incorporated into the 9333 Disk Drive Subsystem, which debuted in early 1992, followed by an enhanced 1.07 GB high-density variant launched in May of the same year.

IBM 0663

The 0663, codenamed "Corsair," arrived in late 1991 as a compact 3-inch hard drive featuring a half-height (1.6-inch) form factor. It provided up to 1 GB storage across eight 95 mm disks. Implemented in select PS/2 and RS/6000 systems, this model represented IBM's initial use of Magnetoresistance (MR) heads in an OEM disk drive.

IBM 0664

Shipping in November 1992, the 0664 was created under the "Allicat" codename at IBM Rochester, Minnesota. This full-height 5-inch HDD (3.25 inches tall) combined two 3-inch drives and offered capacities reaching up to 2.013 GB using eight 95 mm platters.

IBM 0662

Introduced in June 1993 with the codename "Spitfire" at IBM Rochester, the 0662 was a full-height (1-inch) 3-inch hard disk drive delivering 1.05 GB storage across three disks or five recording surfaces. This drive played a key role in the operation of both the 9336 Disk Unit and the 9337 Disk Array.

Floppy disk drive

IBM was a pioneer in floppy disk technology, launching the original 8-inch floppy disk drive in 1971 as a read-only device for program loading. Its first read/write model followed in 1973 with the introduction of the 3740 Data Entry System. Although IBM helped establish early standards for 8-inch FDDs, it refrained from selling these drives independently, allowing other manufacturers to develop the market further.

At one time, IBM ranked as the largest OEM buyer of 5-inch floppy drives; its selection of two-sided units with a density of 48 tracks per inch contributed to setting this configuration as an industry benchmark. While IBM had intentions to produce smaller form factors, these initiatives were discontinued by 1985. Additionally, an attempt in 1983 to OEM a 4-inch DemiDiskette was unsuccessful.

"Star" series of HDDs

On October 17, 1994, IBM's Storage Systems division unveiled three new hard drive product lines: the Travelstar series featuring 2-inch drives tailored for laptops, the Deskstar line with 3-inch drives designed for desktop computers, and the Ultrastar range of high-performance 3-inch drives aimed at enterprise systems.

IBM's first HDD versus its last HDDs

The following table contrasts IBM’s inaugural hard disk drive, the RAMAC 350, with three final models from its "Star" series of OEM hard drives. The comparison highlights substantial advancements including drastic reductions in physical size and cost alongside significant gains 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-fold
Physical dimensions (inches) 60×68×29 4×1×5.75 4×1×5.75 2.75×0.38×3.95
Dimensions (millimeters) 1500×1700×700 102×25×146 102×25×146 70×9.5×100
Volume (cubic inches) 118,320 23 23 4 29,161-fold
Volume (liters) 1,939 0.4 0.4 0.1
Weight (pounds) 2,140 1.7 1.4 0.2 1,244-fold reduction
Weight (kilograms) 971 0.8 0.64 0.095
Power consumption (watts) Approximately 2374 watts (8100 BTUs/hour), up to a peak of around 5500 VA depending on configuration 16 10.3 1.85 1,283-fold improvement
Power efficiency (megabytes per watt) 0.0016 9,125 17,476 43,243 \+27 million times
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 year-2002 value) \$0.0082 \$0.0020 \$0.0053
Areal density (megabits per square inch) 0.002 26,263 46,300 70,000
Areal density (kilobits per square millimeter) 0.003 40,708 71,765 108,500
Volumetric density (gigabytes per cubic inch) 0.00000003 6 8 20
Volumetric density (megabytes per cubic centimeter) 0.000002 388 478 1,203
Rotational latency (milliseconds) 25 3 4 7
Average seek time (milliseconds) 600 5.9 10.2 12
Data transfer rate (megabytes per second) 0.001 103 29.4 43.75

DASD Devices Beyond HDDs and FDDs

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 system that debuted in 1962.

IBM 2301 Drum

Introduced in the late 1960s, the IBM 2301 is a magnetic drum-based storage apparatus.

IBM 2303 Drum

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

IBM 2321 Data Cell

Announced in 1964, the IBM 2321 Data Cell utilizes short strips of magnetic tape for data retention. It accommodates ten detachable cells, each with a capacity of 40 MB, culminating in a total storage size of 400 MB.

IBM 3850 Mass Storage System

Released in 1974, the IBM 3850 Mass Storage System is a tape cartridge library that stages information onto IBM 3330 or 3350 disk drives. This system presents these drives as virtual devices to the host environment.

See also

External links

Related profiles

IIBM 1311IIBM 0661IIBM 353IIBM 355
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