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IBM 3330

From Alfawiki
IBM Magnetic Disk Storage Division
Company typeDivision
IndustryComputer storage devices
Founded1956
Defunct2003
FateDivested hard disk drive division to Hitachi
ProductsHard disk drives, floppy disk drives
ParentIBM

IBM was a pioneer in producing magnetic disk storage devices from 1956 until 2003, at which point 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 driven by its engineers. The core mechanical principles of hard disk drives have remained largely unchanged since the introduction of the IBM 1301, and key performance benchmarks have adhered to longstanding industry norms established in the 1950s. Over time, the sector has witnessed dramatic reductions in cost and physical dimensions, alongside substantial improvements in storage capacity and operational speed.

From 1969 through the mid-1980s, IBM manufactured 8-inch floppy disk drives but did not become a major player in producing smaller 5.25- or 3.5-inch models. While IBM sold magnetic disk drives independently, it only began offering them under original equipment manufacturer (OEM) agreements starting in 1981. By 1996, IBM had discontinued manufacturing HDDs exclusive to its own systems, instead marketing all drives as OEM components.

Throughout its history, IBM has referred to magnetic disk drives using various terms such as direct-access storage device (DASD), disk file, and diskette file. This article adopts the widely accepted industry terminology of 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 on September 14, 1956, as part of the IBM 305 RAMAC computer system. A related model, the IBM 355, was launched for use with the IBM 650 RAMAC system. The initial prototype was delivered to Zellerbach Paper Company in June 1956, with full production shipments commencing in November 1957 to United Airlines.

Created to support real-time accounting applications, the IBM 350 offered storage for five million 6-bit characters (equivalent to 3.75 MB) across fifty-two disks each measuring 24 inches in diameter, utilizing a total of 100 recording surfaces. The disks rotated at a speed of 1200 rpm, enabling a data transfer rate of 8,800 characters per second. The read/write heads were maneuvered both vertically and radially over the tracks by an access mechanism. Several enhanced variants were released throughout the late 1950s. Leasing costs for the IBM RAMAC 305 system with the IBM 350 were set at $3,200 per month; production of this unit ceased in 1969.

The RAMAC program generated US Patent 3,503,060, which is regarded as a foundational patent for disk drive technology. Although initially rejected by IBM's board due to concerns about potential adverse effects on their punch card business, development persisted until it received approval from IBM's president.

The physical cabinet measured approximately 60 inches in length, stood 68 inches tall, and was 29 inches deep, weighing nearly one ton and necessitating forklift transport. Currie Munce from Hitachi Global Storage Technologies—successor to IBM’s storage division—has noted that while capacity could have been expanded beyond five million characters, IBM’s marketing department was cautious about market demand. Nevertheless, versions with double that capacity were announced in January 1959 and shipped later that year.

In recognition of its historical significance, the RAMAC 350 Disk File was designated an International Historic Landmark by The American Society of Mechanical Engineers in 1984. Restoration efforts commenced in 2002 under Al Hoagland's leadership in partnership with Santa Clara University; since 2005, this restored unit has been displayed at the Computer History Museum located in Mountain View, California.

IBM 353

The IBM 353, designed to operate alongside the IBM 7030, bore resemblance to the IBM 1301 but offered a higher data transfer speed. It provided storage for 2,097,152 (221) words of 64 bits each, totaling 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 employ a dedicated head per surface that floated on compressed air, akin to the IBM 350's approach. Production versions transitioned to self-flying heads similar to those utilized 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 incorporated the IBM 350 mechanism but featured up to three access arms instead of just one as in the IBM 350. Its storage capacity reached six million decimal digits plus an additional 600,000 sign characters. The device transferred entire tracks directly to and from the magnetic core memory found in the 653—an optional IBM 650 unit holding sixty signed ten-digit words, which matched the size of a single disk track or tape record.

IBM 1405

Launched in 1961 for the IBM 1400 series business computers, the IBM 1405 Disk Storage Unit was available in two variants. Model 1 stored ten million alphanumeric characters (equivalent to sixty million bits) across twenty-five disks; Model 2 doubled this capacity with twenty million characters (one hundred twenty million bits) on fifty disks. The disks rotated vertically at a speed of 1200 revolutions per minute.

Each disk surface contained two hundred tracks segmented into five sectors (numbered 0–4 on top sides and 5–9 on bottom sides), each sector holding between 178 and 200 characters. From one to three forked access arms equipped with dual read/write heads moved both vertically and horizontally under electronic control to access specific disks and tracks. Sector read/write operations took approximately ten milliseconds.

Access times varied from around one hundred milliseconds up to a maximum of seven hundred milliseconds for Model 1 and eight hundred milliseconds for Model 2. Model 2 included one hundred thousand sectors capable of storing either two hundred characters in move mode or one hundred seventy-eight characters in load mode, which incorporated a word mark bit. Model 1 contained half that number of sectors.

IBM 7300

The IBM 7300 Disk Storage Unit was engineered for use with the IBM 7070, with a second model announced in 1959. Nevertheless, when IBM unveiled the 1301 on June 5, 1961, it became more appealing to users of both the IBM 7070 and IBM 7074 systems. The technology within the IBM 7300 shared roots with earlier models such as the IBM 350, IBM 355, and IBM 1405.

IBM 1301

Officially announced on June 2, 1961, the IBM 1301 Disk Storage Unit targeted the 7000 series mainframe computers and the IBM 1410. Each module stored twenty-eight million characters (one hundred sixty-eight million bits), or twenty-five million characters when used with the IBM 1410, spread across twenty-five large disks featuring forty user-accessible recording surfaces with two hundred fifty tracks each. The Model 1 comprised a single module; Model 2 stacked two modules vertically. Disks rotated at eighteen hundred revolutions per minute, enabling data transfer rates of ninety thousand characters per second.

A significant advancement was its use of individual arms and heads dedicated to each recording surface that moved together like a comb. This architecture eliminated delays caused by repositioning heads across disks and reduced maximum access time to one hundred eighty milliseconds. Furthermore, the IBM 1301 pioneered aerodynamically designed flying heads that floated on a thin air cushion above disk surfaces, allowing closer spacing and enhanced performance.

Connectivity was provided through the IBM 7631 File Control unit, facilitating compatibility with either IBM 1410 or IBM 7000 series computers, or permitting shared use between two systems.

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

IBM 1302

Introduced in September 1963, the IBM 1302 Disk Storage Unit provided 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 a data transfer speed of 180,000 characters per second, more than doubling the throughput of its predecessor. Each module was equipped with two separate access mechanisms designated for the inner and outer cylinders. Similar to the 1301, the Model 2 configuration stacked two modules to achieve twice the storage capacity. Leasing fees were set at $5,600 per month for Model 1 and $7,900 per month for Model 2, with purchase prices of $252,000 and $355,500 respectively; additionally, the IBM 7631 controller cost $1,185 monthly or $56,000 to buy. The IBM 1302 was discontinued in February 1965.

IBM 1311

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

Each IBM 1316 disk pack stands approximately four inches tall, weighs about ten pounds, and contains six disks measuring fourteen inches in diameter with ten active recording surfaces. The drive employs ten read/write heads mounted on a hydraulically actuated mechanism that moves radially across tracks. Disks spin at a speed of 1500 revolutions per minute; each surface includes 100 tracks subdivided into 20 sectors per track, with each sector capable of storing 100 characters. The disk pack is enclosed in a protective plastic casing that facilitates straightforward insertion and removal.

The seven IBM 1311 models encompassed master drives—which incorporated controllers and power supplies—and slave drives. Master units managed several slave drives across various IBM systems such as the IBM 1440, IBM 1460, IBM 1401, IBM 1410, and IBM 7010. These models were retired between the early and mid-1970s.

Several optional features were available to enhance performance and storage capacity:

  • Direct Seek: Removed the need for returning to zero during seek operations.
  • Scan Disk: Provided fast automatic search capabilities.
  • Seek Overlap: Enabled simultaneous seeking alongside reading or writing on multiple drives.
  • Track Record: Increased capacity by recording one large record per track instead of multiple smaller sectors; this allowed storage of up to roughly eighteen million bits depending on operational mode.

Master drives were roughly one foot wider than slave drives due to additional control components.

IBM 2302

The IBM 2302 represents the System/360 version of the earlier 1302 drive but is formatted specifically for compatibility with System/360's DASD architecture rather than the Series/7000 systems. It utilizes a fixed module composed of twenty-five platters with data recorded on forty-six surfaces. The Model 3 contains a single module while Model 4 includes two modules. Each module incorporates two independent access mechanisms—one servicing the inner set of 250 cylinders and another handling the outer set of 250 cylinders—referred to as access groups. Each access mechanism is equipped with one read/write head per track. The average rotational latency is approximately seventeen milliseconds with a maximum of thirty-four milliseconds; maximum seek time within each access group is up to one hundred eighty milliseconds. Tracks hold about 4,985 bytes each, resulting in a formatted capacity of approximately one hundred twelve megabytes per module. Connection to IBM mainframes is established through the IBM 2841 Storage Control Unit.

IBM 2305

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

During the Virtual Storage period of System/370, the 2305 gained prominence as a paging storage unit on systems such as the 3155, 3165, 3158, 3168, 3033, 4341, and 3081 (the latter utilizing specialized microcode). It was also employed for managing frequently accessed small datasets like catalogs and job queues.

The 2305-1 model delivers a capacity of 5.4 MB and supports data transfer rates up to 3.0 MB/s via a 2-byte channel interface, with an average access time of approximately 2.5 milliseconds. In contrast, the larger 2305-2 offers an 11.2 MB storage size at a transfer speed of 1.5 MB/s and an average seek time of 5 milliseconds.

Engineered for rapid, continuous retrieval of compact data volumes, the IBM 2305's storage size and performance characteristics make it well-suited for system-resident functions such as work files, job queues, indices, and datasets accessed frequently. Its swift response times render it particularly effective as a paging device in high-demand environments processing over 1.5 transactions per second.

IBM 2311

The IBM 2311 Disk Storage Drive debuted in 1964 with the 2841 Control Unit and was compatible with IBM System/360, IBM 1130, and IBM 1800 systems. Direct connection to System/360 Models 20 and 25 was also supported. It utilized removable IBM 1316 Disk Packs originally designed for the IBM 1311.

The Model 1 version connects to most IBM mainframes through the 2841 Control Unit; however, for Model 25 systems, a Disk Attachment Control unit fulfills this role. Disk packs are formatted using IBM's count key data variable-length record format. Models 11 and 12—used with System/360 Model 20’s built-in control—employ a fixed-sector format, making disk packs incompatible between these two formatting schemes.

While mechanically akin to the IBM 1311, the IBM 2311 enhanced recording technology to achieve higher data density, accommodating up to 7.25 megabytes on a six-platter removable disk pack. The drive contains ten read/write heads mounted on a hydraulically actuated mechanism featuring mechanical detents for precise track positioning. Each disk surface holds 200 tracks plus three optional spare tracks. The average seek time is approximately 85 milliseconds with a data transfer rate of around 156 kilobytes per second.

A standardized electrical interface across System/360 models allowed third-party vendors to manufacture plug-compatible disk drives, promoting a competitive market for IBM-compatible storage hardware.

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. Featuring a Two Channel Switch capability, it could connect simultaneously to two channels. Building upon the foundation of the IBM 2311 design, it increased storage density and overall capacity by housing approximately twenty-nine million characters on an IBM 2316 disk pack composed of eleven disks (20 recording surfaces). The drive uses twenty read/write heads controlled hydraulically with mechanical detents; each surface contains 200 tracks.

Initial access times were comparable to those of the IBM 2311 but improved with actuator advancements over time. The data transfer rate doubled to approximately 310 kilobytes per second.

The Model 1 configuration included nine drives bundled together with a separate storage control unit; drives were installed in drawers allowing straightforward disk pack replacement and earned the nickname "Pizza Ovens" due to their distinctive appearance. Although nine drives were present, only eight could be accessed simultaneously; the ninth served as a hot spare or could be taken offline for maintenance. Drive addresses were assigned using user-swappable plugs to facilitate easy reconfiguration.

An optional 2844 Control Unit could be added to permit two System/360 channels simultaneous access to different drives within the storage facility.

Later models expanded upon these features:

IBM 2314 Direct Access Storage Series

In 1969, IBM divided the storage facility into various models capable of supporting up to nine drives (with eight accessible online) connected through a 2314 Storage Control. These included:

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

IBM 2319

To compete with plug-compatible manufacturers producing subsystems equivalent to the 2314, IBM launched the budget-friendly three-drive 2319 series in 1970. This was accomplished by removing one drive from the four-drive 2313 model, renaming it the 2319 A1, and offering it at a substantially lower rental cost. This approach reduced expenses for new clients while retaining higher charges for existing customers. The 2319-A1 connects to integrated controllers found on System/370 Models 135 and 145, and it also supports conventional 2314 DASD devices like the 2312 or 2318. The 2319 B series accommodates three, six, or nine drives linked to the updated 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 employed fixed-block architecture compatible with DOS/VSE and VM, the only S/370 operating systems supporting FBA devices.

IBM 3330

The IBM 3330 Direct Access Storage Facility, codenamed Merlin, debuted in June 1970 targeting IBM System/370 and System/360/195 platforms. Initial offerings included a two-drive Model 1 and a single-drive Model 2. The removable disk packs stored up to 100 MB each, featured a 30 ms access time, and delivered data transfer speeds of 806 kB/s. A significant advancement was built-in error correction, which improved reliability and reduced expenses by allowing tolerance for disk surface flaws through fire code error correction.

Originally, one storage control unit (3830 Model 1) connected up to four drives arranged in a "string," with a maximum of eight drives per string.

In August 1972, IBM introduced the 3830 Model 2 Storage Control along with the 3333 Disk Storage and Control, which separated control functions from the drives. The 3830 Model 2 acted as a director-type controller managing multiple strings. Each string's first unit, the 3333, contained a controller with two drives and could handle up to three additional attached 3330 units, allowing for eight drives per string. Two such 3333 units could be linked to one controller for a total of sixteen drives; optional string switches enabled connections to two separate controllers.

In 1973, IBM released double-density (-11) variants: the models 3333–11, 3330-11, and 3336–11 featured disk packs with capacities up to 200 MB. Mixing single-density and double-density drives within the same string was not supported. Upgrading existing drives to Model 11 required conversion procedures and data migration.

The IBM 3330 product line was phased out in 1983.

IBM 3340 and IBM 3344

The IBM models 3340 and 3344 possess similar characteristics; however, only the IBM 3340 is capable of functioning as the head of a string. Models from the IBM 3344 series must connect to a Model A version of the IBM 3340 serving as the string’s head unit.

IBM 3340

Introduced in March 1973 for the IBM System/370, the IBM 3340 Direct Access Storage Facility, known by the codename Winchester, came in three variants: the 3340-A2 featuring two drives plus a controller, and the B2 (two drives) and B1 (single drive) models, which could be linked to an A2 unit to expand up to eight drives.

This system employed removable data modules that incorporated both the head and arm assemblies; rather than removing a cover as with earlier disk packs, a mechanical load/unload mechanism opened or closed the module’s access door to engage it with the drive. The device offered a 25 ms access latency and supported data transfer speeds of 885 kB/s. Three versions of the IBM 3348 Data Module were available: one with 35 MB capacity and two with 70 MB, one of which included a 500 KB fixed-head section designed for quicker access. Featuring error correction capabilities, the IBM 3340 was discontinued in 1984.

Developed under Ken Haughton in San Jose, the initial concept centered on two removable modules each holding 30 MB—this inspired the Winchester nickname, referencing the Winchester .30-30 rifle. Although storage capacities increased over time, the name persisted.

A notable breakthrough was its economical head design that eliminated the need to unload heads from media. Known as "Winchester technology," this innovation allowed heads to land on and lift off spinning disks, simplifying head and arm mechanisms while reducing costs. This approach set a precedent that became standard in disk drive production.

While the term Winchester was prevalent for hard drives through the early 1990s, it has since largely disappeared from common usage worldwide.

IBM 3344

The IBM 3344 closely resembles the 3340 but distinguishes itself by utilizing fixed media instead of removable IBM 3348 data modules. Each spindle hosts four logical drives, each matching the capacity of a 3348–70 module. Available solely as dual-drive configurations, it lacks an A (head of string) model. The 3344-B2F variant differs from the B2 by incorporating fixed heads over certain cylinders. Both models require connection to a 3340-A2 or 3340-A2F unit acting as head of string. Internally, the IBM 3344 shares its architecture with the IBM 3350, differing primarily in control unit microcode.

IBM 3350

Released in 1975 for IBM System/370 and codenamed Madrid, the IBM 3350 introduced sealed head-disk assemblies (HDAs) that integrated heads and arms into a single non-removable unit. Its disk configuration consists of 555 cylinders, 30 heads, and approximately 19,069 bytes per track, resulting in around 317 MB capacity per HDA. This sealed HDA design became standard practice for IBM DASD units thereafter.

Units labeled A2, A2F, B2, B2F, C2, and C2F each contain two HDAs. The A2 and A2F models include an additional electronic board enabling connection to control units—often called controllers or head-of-string units. Typical setups begin with an A2 or A2F unit followed by up to three B2 units or combinations including C2 units. The A2 unit generally incorporates a string switch permitting attachment to two storage control units simultaneously, facilitating concurrent I/O operations across different HDAs. Compatible control units encompass the 3830 Model 2, ISC in systems such as the 3148/3158/3168 CPUs, and later backward-compatible devices like the 3880.

The C2 unit also contains a controller providing a secondary path for itself and other units but is mainly reserved as a backup if the A unit’s controller fails; its connectivity is more limited compared to that of the A unit. Valid IBM 3350 configurations include strings designated -A, -AB, -ABB, -ABBB, -AC-, -ABC-, and -ABBC-.

Models with an "x2F" suffix (for example, A2F) feature fixed-head regions spanning the first five cylinders on each HDA. This eliminates seek time within these cylinders by providing immediate access. These fixed-head areas are typically allocated for frequently used functions such as HASP or JES checkpoint data, greatly enhancing performance by minimizing head movement on spool devices. Additionally, they support TSO swap data and system swap data in OS/360 successors (MVT, SVS) as well as MVS environments, thereby improving context switch efficiency among TSO users or batch processes.

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

IBM 3370

In January 1979, IBM launched the IBM 3370 Direct Access Storage Device designed for IBM 4331, 4341, and System/38 midrange systems. This device incorporated seven fixed 14-inch platters, offering a storage capacity of 571 MB per unit. Notably, the 3370 was the pioneer in utilizing thin-film head technology, a development originating from the Thomas J. Watson Research Center. It operated on a fixed-block architecture and was compatible with DOS/VSE and VM operating systems running on the S/370 platform.

IBM 3375

The IBM 3375 served as a counterpart to the 3370 but utilized count key data architecture, which was necessary for operating systems such as OS/360 and its successors.

IBM 3380

Unveiled on June 11, 1980, the IBM 3380 Direct Access Storage Device employed thin-film head technology and delivered a capacity of 2.52 GB per unit. Each unit consisted of two hard disk assemblies, each with two independent actuators accessing 630 MB. The device supported 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 tribological challenges between the heads and media surfaces, shipments commenced only in October 1981.

Configurations allowed one A unit combined with up to three B units; each IBM 3380 contained four devices, enabling strings of up to sixteen devices. The system typically interfaced with a 3880 storage control unit featuring two paths for concurrent I/O operations directed at different hard disk assemblies.

In February 1985, IBM released the Extended Capability Models (3380 E), doubling density to achieve 5.04 GB per unit by employing two actuators of 1.26 GB each across two disk assemblies.

August 1987 saw the introduction of the Model K with triple capacity at 7.562 GB per unit (two actuators of 1.89 GB). Models J and K offered an optional four-path mode that doubled devices per string to thirty-two when connected to a 3990 storage control unit, enabling four simultaneous I/O channels.

The IBM 3380 series comprised twelve variants: six A-units featuring controller logic for connection to IBM storage control units; five B-units designed to connect to A- or C-units; and one C-unit capable of direct attachment to an IBM channel.

Production of these models ceased in May 1996 after more than fifteen years on the market—surpassing the typical lifespan of disk drives from that period.

IBM 3390

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

A typical IBM 3390 string consists of a central A unit containing four or eight devices, accompanied by one or two optional B units holding up to twelve devices each. Operating in four-path mode, it connects to a 3990 storage control unit capable of supporting an additional string, allowing up to sixty-four devices within a subsystem.

Hard Disk Assemblies (HDAs) in this series incorporate two actuator-head units along with platters. Model 1 HDAs provided an unformatted capacity of 1.89 GB; Model 2 increased this to 3.78 GB per HDA. The Model 3 introduced in 1991 expanded capacity by fifty percent to reach 5.67 GB per HDA, while Model 9 launched in 1993 tripled it further to approximately 11.3 GB per HDA.

Unlike earlier DASD devices that relied on large AC motors coupled with belts, the IBM 3390 HDAs utilized enclosed DC motors with direct drive mechanisms. The Model 9 represented IBM’s final release within their Single Large Expensive Disk (SLED) drive line.

IBM 9345

Launched in November 1990 as a Request for 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 drive offered capacities up to 1.5 GB within a full-height 5¼-inch enclosure, utilizing eight 130 mm platters. It was distinguished as the first HDD to incorporate magnetoresistive (MR) read/write heads, significantly improving data access performance.

IBM 9340

The IBM 9340 DASD was introduced in October 1991 as part of the 9340 series, a channel-attached count key data (CKD) DASD subsystem designed for IBM mainframes, including the ES/9000 line. The 9345 Model 1 configuration included two HDDs of 1.0 GB each, while Model 2 comprised two HDDs with 1.5 GB capacity each.

In terms of operation, the 9340/9345 series paralleled the capabilities of the 3990/3390 drives but differed by lacking the non-volatile RAM cache found in the 3990 and featuring a shorter maximum block size compared to the 3390.

The operating system’s Input/Output Supervisor (IOS) detected these devices using a specialized initializer, IECCINIT, which also managed other DASD types. During initialization, the OS identified the absence of non-volatile cache on the 9340 and the reduced track size on the 9345, assigning device types distinct from those used by the 3990/3390 family.

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 contained one 5-inch floppy disk drive.
  2. The IBM 0667 hard disk was utilized in the 9332 Direct Access Storage Device.
  3. The High Performance Disk Drive Subsystem, modelled as the 9333, employed either IBM 0664 or IBM 0681 hard disks depending on configuration.
  4. The 9334 Disk Expansion Unit connected between one and four SCSI hard drives to RS/6000 systems.
  5. The Direct Access Storage Subsystem designated as the 9335 incorporated an IBM "Kestrel" hard disk developed at IBM Hursley, UK. This drive featured an 850 MB capacity with three large 14-inch platters and dual rotary actuators enabling multiple surface access. Announced in October 1986 alongside the IBM 9370 Information System, this rack-mountable unit has no known OEM variants.
  6. The IBM 0681 hard disk (codenamed Redwing) was implemented in the 9336 Disk Unit.
  7. The Disk Array Subsystem modelled as the 9337 utilized IBM's IBM 0662 (Spitfire) or IBM 0663 (Corsair) hard disks.

IBM 2310

Introduced in conjunction with the IBM 1800 in 1964 and later with the IBM 1130 in 1965—most likely shipping first with the latter by late that year—the IBM 2310 Removable Cartridge Drive stored data on an IBM 2315 cartridge. This cartridge contained a single oxide-coated aluminum platter measuring fourteen inches in diameter housed within a plastic casing featuring openings for the read/write arm and two heads. It held a capacity of approximately 512,000 sixteen-bit words (equivalent to about one million bytes).

IBM 5444

Released 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 utilized a removable disk cartridge known as the IBM 5440 containing one fourteen-inch platter. Three models were available:

  • Model 1: comprised 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 disk and one removable disk with two hundred tracks per surface; cartridge capacity doubled to about 2.46 MB
  • Model 3: included only one removable disk with two hundred tracks per surface; capacity matched Model 2 at approximately 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. Its initial storage capacity was 5 MB, which was later expanded in subsequent versions to 10 MB (62TM) and eventually 14 MB. The device incorporated a Swinging Arm actuator paired with a single 14-inch platter—a mechanism developed at Hursley that became IBM’s most extensively licensed electromechanical innovation. This actuator design, along with its filtration system, became a widespread standard in hard disk drives throughout the 1980s and has remained influential for nearly forty years. Approximately 177,000 units of the IBM 62GV were sold, making it the first hard disk drive to surpass the milestone of 100,000 units shipped.

OEM and Small Systems HDDs

This segment focuses on IBM-produced hard drives marketed as OEM components and those intended for IBM’s smaller systems such as System/3, System/32, /34, /36, and AS/400. Drives are cataloged by their OEM model number and arranged according to their initial shipment dates.

IBM 0680

The 0680 model began shipping in 1979, supporting most IBM small systems and entry-level System/370 models as the 3310 direct access storage device. Officially announced in September 1981 as the OEM variant 0680, it was engineered at IBM’s Hursley facility under the codename Piccolo. This drive offered an initial capacity of up to 65 MB using six 8-inch (210 mm) platters and incorporated an enhanced rotary actuator design.

A higher-capacity version named the 62SW was released in June 1984; however, it experienced limited sales due to its cost per megabyte being comparable to that of the 62GV.

IBM 0676

Released in November 1982, the 0676 was introduced as a 5247 Disk Storage Unit for the IBM System/23 Datamaster. Developed at IBM Rochester, Minnesota (project name 21ED), this hard disk featured two or four 8-inch (210 mm) platters providing storage options of either 15 or 30 MB. In 1983, it was integrated into the S/36’s 5360 System Unit. By 1984, its capacity was doubled through increased track density per surface and it became part of the System/36’s 5362 System Unit.

IBM 0665

The 0665 debuted in October 1985 within the PC AT (5170) system unit. Created under the codename "Pixie" at IBM Rochester, this model was a compact 5-inch hard drive offering capacities of 20, 30, and 44 MB.

IBM 0667

First available in August 1986, the 0667 was developed at IBM Rochester with the project name "Grant." This full-height ESDI hard disk measured five inches and supported up to four platters sized at 130 mm, delivering a capacity of up to 70 MB. It was offered as an optional storage solution for certain PC RT models (6150, 6151, 6152) as well as System/36 Model System Units (5363, 5364).

IBM 0669

Introduced in 1987 and developed at IBM Rochester under the codename "Grant-Prime," the 0669 was a full-height five-inch hard drive capable of holding up to 115 MB across four platters measuring 130 mm each. It served as the internal storage device for both the System/36 Model 5363 and Series/1 Model 4956 System Units.

IBM 0671

Also launched in 1987 from IBM Rochester with the codename "Lee," the 0671 represented an ESDI full-height five-inch hard disk that could store up to 316 MB using eight platters sized at 130 mm. This model introduced IBM’s first implementation of a thin metal film recording surface. By 1988, it was incorporated into the IBM AS/400 Model 9404 System Unit configurations supporting two or three drives.

IBM 0661

The 0661, which appeared in 1989 as model number 371, was developed jointly by IBM Rochester and Hursley laboratories. It featured a SCSI interface with up to eight platters measuring 95 mm each (equipped with fourteen heads) and provided a capacity of approximately 320 MB. A higher-performance "Turbo" variant with a capacity of around 400 MB followed in 1990. This drive became a standard component across multiple IBM platforms including various AS/400 System Unit Model CXX configurations.

IBM 0681

Unveiled in April 1990 at IBM Hursley and internally referred to as Redwing, the 0681 marked the final hard disk drive designed at that facility. This full-height 5-inch model utilized twelve 130 mm platters to provide a maximum capacity of 857 MB and was notable for introducing PRML (Partial Response Maximum Likelihood) data decoding technology. It was integrated into the 9333 Disk Drive Subsystem released in early 1992, which later featured an upgraded version with increased storage reaching 1.07 GB.

IBM 0663

Launched towards the end of 1991 under the project name "Corsair," the 0663 was a compact half-height (approximately 1.6 inches) hard disk drive with a 3-inch form factor. Equipped with eight 95 mm disks, it offered up to 1 GB of storage. This drive appeared in select PS/2 and RS/6000 systems and represented IBM's initial OEM implementation of Magnetoresistive (MR) head technology.

IBM 0664

Introduced 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 drive that effectively combined two 3-inch drives. It delivered a capacity of up to 2.013 GB using eight 95 mm platters.

IBM 0662

The 0662, released in June 1993 and known internally as "Spitfire" at IBM Rochester, was a full-height (approximately 1 inch) hard disk drive with a 3-inch form factor. It provided 1.05 GB storage across three disks or five recording surfaces and was utilized as the internal drive for both the 9336 Disk Unit and the 9337 Disk Array.

Floppy disk drive

IBM was a pioneer in floppy disk drive technology, introducing the first 8-inch floppy disk drive in 1971 primarily as a read-only medium for program loading. This was followed by IBM's initial read/write floppy model in 1973 as part of the 3740 Data Entry System. Although IBM established early standards for these 8-inch drives, it did not market them independently, allowing industry-wide standards to develop autonomously.

As a significant original equipment manufacturer (OEM) buyer of 5-inch floppy drives, IBM’s preference for two-sided drives with a track density of 48 tracks per inch helped cement this configuration as an industry norm. Despite intentions to manufacture these drives alongside smaller variants, IBM ceased production efforts by 1985. An earlier 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 launched three distinct hard disk drive product lines: the Travelstar series featuring compact 2-inch drives designed for notebook computers; the Deskstar line consisting of 3-inch drives aimed at desktop applications; and the Ultrastar series of high-performance 3-inch drives intended for demanding enterprise environments.

Comparing IBM's First HDD to Its Final HDD Models

The following table presents a comparison between IBM’s inaugural hard disk drive, the RAMAC 350, and the last three models from its "Star" series of OEM HDDs. The data underscores substantial advancements over a span of nearly five decades, showing remarkable decreases in physical size and cost alongside substantial enhancements 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
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) Approximately 2374 watts (8100 BTUs/hour), up to 5500 VA depending on configuration 16 10.3 1.85 ×1,283
Power efficiency (megabytes per watt) 0.0016 9,125 17,476 43,243
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, both hard disk drives (HDDs) and floppy disk drives (FDDs) are categorized under the umbrella of DASDs (direct access storage devices). Additional types of DASD technologies include:

IBM 7320 Drum

Launched in 1962, the IBM 7320 represents a magnetic drum storage unit.

IBM 2301 Drum

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

IBM 2303 Drum

The IBM 2303, a magnetic drum device, was brought to market in 1964.

IBM 2321 Data Cell

Announced in 1964, the IBM 2321 Data Cell utilizes short strips of magnetic tape for data storage. It contains ten removable cells, each with 40 MB capacity, totaling an overall storage of 400 MB.

IBM 3850 Mass Storage System

Debuting in 1974, the IBM 3850 Mass Storage System is a tape cartridge library designed to stage data onto IBM 3330 or 3350 disk drives, effectively presenting virtualized drives to the host system.

See also

External links

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