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IBM 0680

From Alfawiki
Adapted from the English Wikipedia article IBM 0680, available under CC BY-SA 4.0Updated 9 August 2025
IBM magnetic disk storage division
Company typeDivision
IndustryComputer storage hardware
Founded1956
Defunct2003
FateDivested to Hitachi
ProductsHard disk drives, floppy disk drives
ParentIBM

IBM was a pioneer in producing magnetic disk storage hardware from 1956 until 2003, at which point it divested its hard disk drive operations to Hitachi. The company is credited with inventing both the hard disk drive (HDD) and the floppy disk drive (FDD), with numerous advancements in these technologies driven by IBM personnel. The essential mechanical structure of hard disk drives has remained largely unchanged since the introduction of the IBM 1301, and performance benchmarks have adhered to consistent standards established in the 1950s. This product range is distinguished by substantial decreases in cost and physical dimensions, coupled with notable enhancements in storage capacity and operational efficiency.

IBM manufactured 8-inch floppy disk drives starting in 1969 through the mid-1980s but did not become a leading producer of the smaller 5.25- or 3.5-inch floppy drives. Although IBM consistently marketed its magnetic disk drives, it began offering them under original equipment manufacturer (OEM) agreements only from 1981 onward. By 1996, IBM discontinued manufacturing HDDs exclusive to its own systems, transitioning entirely to OEM distribution for all models.

Within IBM, several terms have been used for magnetic disk drives, such as direct-access storage device (DASD), disk file, and diskette file; however, this article adopts the standard industry terminology hard disk drive (HDD) and floppy disk drive (FDD).

IBM 350

The IBM 350 disk storage system, recognized as the inaugural disk drive, was launched by IBM on September 14, 1956, as an integral component of the IBM 305 RAMAC system. A comparable model, the IBM 355, was introduced for the IBM 650 RAMAC system. The initial prototype was delivered to Zellerbach Paper Company in June 1956, with full production units shipped beginning November 1957 to customers including United Airlines.

Engineered to facilitate real-time business accounting processes, the IBM 350 held five million 6-bit characters (equivalent to 3.75 MB) across fifty-two disks measuring 24 inches each, utilizing a total of 100 recording surfaces and tracks. The disks rotated at a speed of 1,200 revolutions per minute, achieving a data transfer rate of approximately 8,800 characters per second. Its access mechanism operated by moving read/write heads over the disks' surfaces and tracks. Several enhanced versions were released throughout the late 1950s. The RAMAC 305 system equipped with the IBM 350 was leased at $3,200 monthly. Production of this unit ceased in 1969.

The key patent resulting from the RAMAC project is regarded as foundational within disk drive technology history. Initially halted by IBM’s board due to concerns about undermining punch card sales, development proceeded after receiving approval from IBM’s president.

The cabinet housing the IBM 350 measured 60 inches in length, stood 68 inches tall, and was 29 inches wide; it weighed roughly one ton and required forklift handling for relocation. Currie Munce from Hitachi Global Storage Technologies (which acquired IBM’s storage division) noted that IBM’s marketing team was reluctant to aggressively promote larger-capacity drives despite technical feasibility; nevertheless, models with doubled capacity were announced and delivered starting in 1959.

In recognition of its significance, the RAMAC 350 Disk File was declared an International Historic Landmark by The American Society of Mechanical Engineers in 1984. A restoration initiative began in 2002 under Al Hoagland’s leadership in partnership with Santa Clara University. By 2005, the refurbished unit was installed at the Computer History Museum located in Mountain View, California, where it remains on public display.

IBM 353

The IBM 353, designed to work alongside the IBM 7030, resembled the IBM 1301 but offered a superior data transfer speed. It provided storage for 2,097,152 (221) 64-bit words, equivalent to 134,217,728 bits, and could transfer data at a rate of 125,000 words per second. A prototype delivered in late 1960 was pioneering as the first disk drive to implement one head per disk surface that floated on compressed air, an advancement from the IBM 350's design. Production versions featured 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 for the widely used IBM 650. Utilizing the IBM 350 mechanism but equipped with up to three access arms (compared to one on the IBM 350), it stored six million decimal digits along with 600,000 sign indicators. This device transferred entire tracks between its magnetic storage and the IBM 650's 653 option core memory, which contained sixty signed ten-digit words—adequate for a single disk track or tape record—plus two additional unrelated functions.

IBM 1405

Announced in 1961 for the IBM 1400 series of business computers, the IBM 1405 Disk Storage Unit was available in two variants: Model 1 held ten million alphanumeric characters (60 million bits) across 25 disks; Model 2 doubled this capacity to twenty million characters (120 million bits) on fifty disks. The disks were arranged vertically and rotated at a speed of 1200 revolutions per minute.

Each disk surface contained 200 tracks segmented into five sectors; sectors numbered 0 through 4 were on the upper surfaces, while sectors 5 through 9 were on the lower sides. Each sector accommodated between 178 and 200 characters. Access arms ranged from one to three forked units, each fitted with two read/write heads (one for the top and one for the bottom), which moved vertically to select among disks (0–49) and horizontally to access tracks (0–199). Seek times varied from approximately 100 milliseconds up to a maximum of 700 milliseconds for Model 1 and extended to 800 milliseconds for Model 2. Model 2 contained a total of 100,000 sectors, double that of Model 1. Sectors operated in either "move mode," transferring all 200 characters, or "load mode," which included 178 characters plus an additional word mark bit per character.

IBM 7300

The IBM 7300 Disk Storage Unit was engineered for use with the IBM 7070 system; a second model was announced in 1959. Nevertheless, when IBM launched the 1301 in 1961, it became a more appealing choice for customers using the IBM 7070 and IBM 7074. The technology employed by the IBM 7300 shared similarities with that of the IBM 350, IBM 355, and IBM 1405 units.

IBM 1301

Unveiled on June 2, 1961, the IBM 1301 Disk Storage Unit was aimed at supporting mainframe computers within the 7000 series as well as the IBM 1410. Each module could store up to twenty-eight million characters (168 million bits), or twenty-five million characters when paired with the IBM 1410. The modules consisted of twenty-five large disks providing forty user-accessible recording surfaces, each containing two hundred fifty tracks. The Model 1 configuration included a single module; Model 2 stacked two modules vertically. Disks rotated at a speed of eighteen hundred revolutions per minute, enabling data transfer rates of ninety thousand characters per second.

A significant innovation was the implementation of individual arms and heads dedicated to each recording surface that moved collectively in a comb-like fashion. This arrangement eliminated delays caused by repositioning heads between disks and reduced maximum access time to approximately one hundred eighty milliseconds. Furthermore, the IBM 1301 was pioneering as the first disk drive utilizing aerodynamically engineered heads that floated on a thin cushion of air above the disk surface, allowing closer proximity and enhanced performance.

Connection was facilitated through the IBM 7631 File Control unit, which supported operation with either an IBM 1410 or a system from the IBM 7000 series, including shared use between two computers.

Pricing for leasing the IBM 1301 Model 1 was $2,100 per month or $115,500 if purchased outright; Model 2 cost $3,500 monthly or $185,000 purchased. The IBM 7631 controller was priced at $1,185 per month leased or $56,000 purchased. All variants were phased out by approximately 1970.

IBM 1302

Introduced in September 1963, the IBM 1302 Disk Storage Unit offered a fourfold increase in capacity compared to the 1301, reaching 117 million 6-bit characters per module. It delivered an average access time of 165 milliseconds and data transfer speeds of 180,000 characters per second, more than twice as fast as its predecessor. Each module was equipped with two independent access mechanisms dedicated to the inner and outer cylinders respectively. The Model 2 version doubled storage by stacking two such modules. Leasing fees were set at $5,600 monthly for Model 1 and $7,900 monthly for Model 2, while purchase prices stood at $252,000 and $355,500 correspondingly. Additionally, the IBM 7631 controller could be leased for $1,185 per month or purchased for $56,000. Production of the 1302 ceased in February 1965.

IBM 1311

The IBM 1311 Disk Storage Drive was unveiled on October 11, 1962, designed primarily 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.

Each IBM 1316 Disk Pack measures approximately four inches in height and weighs around ten pounds. It contains six disks measuring fourteen inches each, providing ten recording surfaces—the outermost surfaces remain unused. A single actuator with ten read/write heads moves hydraulically to access tracks while the disks rotate at 1,500 revolutions per minute. Every surface consists of 100 tracks, each subdivided into 20 sectors holding 100 characters apiece. To protect the disks during handling, the pack is encased in a clear plastic shell with a bottom cover.

The seven IBM 1311 models include master drives equipped with controllers capable of managing multiple Model 2 slave drives. These master units were customized for various systems such as the IBM 1440, IBM 1620, IBM 1401, and IBM 1410 series, offering differing control features and capabilities. Introduced between 1962 and 1968, these models were withdrawn by the mid-1970s.

Available options included:

  • Direct Seek: Allows direct movement to a target track without returning to track zero first.
  • Scan Disk: Facilitates rapid automatic searching.
  • Seek Overlap: Permits overlapping seek operations with simultaneous reads or writes across multiple drives.
  • Track Record: Enhances storage capacity by writing one large record per track instead of multiple sectors, increasing total storage to roughly eighteen million bits depending on character encoding.

Master drives (Models 1,3,4,5) are approximately one foot wider than Model 2 slave drives due to additional power supplies and control electronics.

IBM 2302

The IBM 2302 serves as the System/360 counterpart to the 1302, adapted for S/360's DASD architecture rather than that of the IBM 7000 series.

It comprises a fixed module containing twenty-five platters with forty-six usable recording surfaces. The Model 3 includes a single module; the Model 4 incorporates two modules. Each module features two separate access mechanisms—one dedicated to the innermost 250 cylinders and another for the outermost 250 cylinders—referred to as access groups. Each access group has one read/write head per track. The average rotational latency is approximately seventeen milliseconds with a maximum of thirty-four milliseconds; maximum seek time per access group reaches up to one hundred eighty milliseconds. Tracks hold up to 4,985 bytes; after formatting and inclusion of alternate tracks, each module offers about 112 megabytes of storage. 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 the 360/85 and 360/195 models through the IBM 2880 Block Multiplexor Channel.

This drive gained prominence during the rollout 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 requiring specialized microcode). Additionally, it was favored for managing small, high-transaction data sets like catalogs and job queues.

The 2305-1 model delivers a capacity of 5.4 MB with a throughput of 3.0 MB/s and an average access latency of 2.5 ms; in contrast, the larger 2305-2 offers an 11.2 MB capacity at a data rate of 1.5 MB/s and an average access time of 5 ms.

Engineered for rapid and continuous retrieval of modest data volumes, the IBM 2305’s combination of speed and storage size made it well-suited for system-resident tasks, work files, job queues, indices, and frequently accessed data collections. Its swift response times proved especially beneficial as a paging device in heavily utilized environments processing more than 1.5 transactions per second.

IBM 2311

Introduced in 1964 alongside the 2841 Control Unit, the IBM 2311 Disk Storage Drive supported the IBM System/360 series as well as the IBM 1130 and IBM 1800 systems. It also connected directly to the IBM System/360 Model 20 and Model 25. All units utilized the removable IBM 1316 Disk Pack, which was initially designed for the IBM 1311.

The Model 1 version of the 2311 connects to most IBM mainframes through the 2841 Control Unit; however, on the System/360 Model 25, it interfaces via a Disk Attachment Control functioning as its control unit. The disk packs employ IBM’s count key data variable-length record format.

Models 11 and 12 are integrated with the System/360 Model 20’s built-in control unit and utilize fixed-sector formatting. Due to differing formats, disk packs are not interchangeable between Model 1 drives and Models 11 or 12.

While mechanically similar to the IBM 1311, the IBM 2311 enhanced recording density to store up to 7.25 megabytes on a six-platter IBM 1316 disk pack. It includes ten read/write heads mounted on a hydraulically actuated arm; each surface contains 200 tracks plus three spare tracks reserved for defects. The average seek time is approximately 85 ms with a data transfer speed of about 156 kB/s.

Standardized electrical interfaces enabled third-party manufacturers to produce plug compatible disk drives suitable for IBM systems, fostering competition in storage hardware offerings.

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, it allowed simultaneous connection to two channels. Its mechanical design resembled that of the IBM 2311 but featured increased data density.

This drive stored roughly 29 million characters on a removable IBM 2316 disk pack that expanded platters from six to eleven (14-inch diameter), providing twenty recording surfaces. It utilized twenty individual read/write heads mounted on a hydraulically actuated arm with mechanical detents. Each surface contained around 200 tracks. Subsequent versions improved upon the original average seek time of approximately 85 ms, while doubling data transfer rates to about 310 kB/s.

The Model 1 package included nine disk drives sold together; separately available components included a storage control unit, one single-drive module, and two four-drive modules summing to nine drives total. Drives were installed in drawers for convenient disk pack access, earning them the nickname "Pizza Ovens." Of these nine drives, only eight operated concurrently; one served as an online spare or could be taken offline for maintenance without interrupting system operation. Drive system addresses were configured using user-swappable plugs that facilitated physical reassignment.

An optional IBM 2844 Control Unit permitted two System/360 channels to access separate disk drives within the facility simultaneously.

Subsequent models of the IBM 2314 further enhanced these features:

IBM 2314 Direct Access Storage System - Variants

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

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

IBM 2319

To rival plug-compatible manufacturers offering storage subsystems comparable to the 2314, IBM launched the cost-effective three-drive 2319 series in 1970. This was developed by removing one drive from the four-drive 2313 unit and rebranding it as the 2319 A1, marketed at a significantly reduced rental fee—aimed at attracting new customers while preserving higher charges for existing clients. The 2319-A1 interfaces with integrated controllers designed for System/370 Models 135 and 145. Traditional 2314 DASD devices such as the 2312 or 2318 can also be connected to the 2319-A1. The 2319 B series supports 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. Each unit provided a storage capacity of 64.5 MB and utilized fixed-block architecture, compatible with DOS/VSE and VM operating systems running on S/370 platforms.

IBM 3330

The IBM 3330 Direct Access Storage Facility, codenamed Merlin, debuted in June 1970 targeting IBM System/370 and System/360/195 machines. Initial offerings included a two-drive Model 1 and a single-drive Model 2. These devices used removable disk packs with a capacity of 100 MB each, delivering an access time of 30 ms and data transfer speeds up to 806 kB/s. A notable advancement was integrated error correction, enhancing dependability and cutting costs by accommodating disk surface flaws via fire codes capable of correcting burst errors up to eleven bits.

Early setups combined one storage control unit (3830 Model 1) managing up to four attached drive "strings," allowing a maximum of eight drives. In August 1972, IBM introduced the 3830 Model 2 Storage Control along with the 3333 Disk Storage and Control, separating control units from drive strings. The updated 3830 acted as a director-style controller overseeing multiple strings. The first device in each string, the 3333, incorporated both controller functions and two drives, with the ability to manage up to three additional attached 3330 drives for a total of eight per string. Two such strings could be connected to one 3830 Model 2 controller, enabling support for as many as sixteen drives; the optional string switch on the 3333 allowed connection to two separate controllers.

In 1973, IBM launched double-density (-11) variants: the 3333–11, 3330-11, along with higher-capacity (200 MB) disk packs labeled as the 3336–11. It was not possible to mix single- and double-density drives within the same string; upgrading required conversion procedures and data migration.

The IBM 3330 series was discontinued in 1983.

IBM 3340 and IBM 3344

The IBM models 3340 and 3344 share many characteristics; however, only the 3340 model is qualified to serve as head of string. No A model versions exist for the 3344, which must be connected under a head-of-string role provided by a 3340 A model device.

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 and a controller, along with the B2 model (two drives) and B1 model (single drive). The B-series units could be linked to an A2 controller, supporting up to eight drives in total.

This system utilized removable data modules that incorporated both the head and arm assembly. During mechanical load and unload operations, the module’s access door would open to interface with the drive, eliminating the necessity of removing an external cover. It delivered an access time of 25 milliseconds and achieved data transfer speeds of 885 kB/s. Three versions of the IBM 3348 Data Module were available: one with a 35 MB capacity and two offering 70 MB, one of which included a 500 KB fixed-head area for quicker access. The 3340 implemented error correction technology and remained in production until its discontinuation in 1984.

Developed at IBM’s San Jose facility under Ken Haughton's leadership, the initial concept centered on two removable 30 MB modules. This design inspired the Winchester nickname, referencing the Winchester .30-30 rifle. Despite increases in storage capacity over time, the codename persisted throughout its lifecycle.

A notable breakthrough was its economical head design allowing heads to land on and lift off from spinning disk media during spin-up and spin-down phases, removing the requirement to physically unload heads from the media. This innovation reduced mechanical complexity and cost significantly and became a foundational approach in subsequent disk drive engineering.

The term Winchester remained closely associated with hard disk drives into the early 1990s but has since largely fallen out of use worldwide.

IBM 3344

The IBM 3344 shares similarities with the 3340 but replaces removable 3348 data modules with fixed media. Each spindle contains four logical drives, each matching the capacity of a single 3348–70 module. Available exclusively as dual-drive models, it does not include an A-series (head-of-string) version. The 3344-B2F variant incorporates fixed heads over certain cylinders on both drives. Both models, 3344-B2 and 3344-B2F, require connection to a 3340-A2 or 3340-A2F unit acting as head-of-string. Internally, the IBM 3344 is essentially identical to the IBM 3350; their primary difference lies in control unit microcode.

IBM 3350

Released in 1975 for IBM System/370 under the codename Madrid, the IBM 3350 featured sealed head-disk assemblies (HDAs) that integrated heads and arms within a non-removable enclosure. Its disk geometry consisted of 555 cylinders, with 30 heads accessing tracks containing approximately 19,069 bytes each, resulting in around 317 MB storage per HDA. This sealed HDA design set a new standard for IBM DASD products thereafter.

Models such as A2, A2F, B2, B2F, C2, and C2F each housed two HDAs. The A2 and A2F models included an extra electronics board that enabled connection to storage control units—often referred to as controllers or head-of-string units. These models were organized into strings starting with an A2 or A2F unit followed by up to three B2 units or combinations including two B2s plus a C2 unit. Typically, the A2 unit contained a string switch allowing simultaneous connections to two storage control units for parallel I/O operations. Compatible 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 unit contained a secondary controller serving as a failover path; however, it had limited connectivity options—it could connect only to one control unit and was intended for use if the primary A-unit controller malfunctioned. Valid configurations for IBM 3350 strings included -A, -AB, -ABB, -ABBB, -AC-, -ABC-, and -ABBC- arrangements.

The "x2F" variants (for example, A2F) incorporated fixed-head zones covering the first five cylinders on both HDAs. This feature eliminated seek time within these areas and targeted frequently accessed data locations such as HASP or JES checkpoint information to reduce head movement on spool devices. Additionally, these fixed-head regions supported TSO swap data as well as system swap data under MVT, SVS, and MVS operating systems by optimizing context switching between user sessions or batch jobs.

The IBM 3350 series was withdrawn from production 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, delivering a storage capacity of 571 MB per unit. Notably, the 3370 was the pioneer HDD to implement thin-film head technology, a development originating at the Thomas J. Watson Research Center during the late 1960s. It utilized a fixed-block architecture and was compatible with DOS/VSE and VM operating systems running on S/370 platforms.

IBM 3375

The IBM 3375 functioned as a complementary model featuring count key data (CKD) architecture. It was compatible with OS/360 and its subsequent iterations.

IBM 3380

Unveiled on June 11, 1980, the IBM 3380 Direct Access Storage Device employed thin-film head technology and provided a capacity of 2.52 GB per unit, consisting of two hard disk assemblies each equipped with two actuators accessing 630 MB. Its data transfer rate reached up to 3 MB/s, with an average access latency of 16 milliseconds. Initial pricing ranged between $81,000 and $142,200. Due to tribological challenges involving the interaction of heads and media surfaces, commercial shipments commenced in October 1981.

The typical setup combined a single A unit with as many as three B units; each IBM 3380 housed four devices, enabling configurations of up to sixteen devices in a string. These units generally connected to a 3880 storage control unit featuring dual paths, which allowed for two concurrent I/O operations directed at separate HDAs.

In February 1985, IBM introduced the Extended Capability Models (3380 E) featuring double-density storage with capacities of 5.04 GB per unit (two actuators each holding 1.26 GB). Later, in August 1987, the triple-capacity Model K was launched, offering 7.562 GB per unit through two actuators of 1.89 GB each. Both Models J and K supported an optional four-path configuration when linked to a 3990 storage control unit, facilitating up to four simultaneous I/O operations across device strings extending to thirty-two devices.

The IBM 3380 series consisted of twelve distinct models: six A-units that served as string heads containing controller logic interfacing with IBM storage control units; five B-units that connected either to A- or C-units; and one C-unit designed for direct connection to an IBM channel.

Production of the IBM 3380 continued until May 1996, marking an impressive fifteen-year lifespan well beyond standard disk drive market durations.

IBM 3390

Introduced in November 1989, the IBM 3390 Direct Access Storage Device family offered storage capacities up to 22 gigabytes distributed across multiple drives. Depending on configuration and capacity levels, system prices varied from $90,000 to $795,000.

A typical IBM 3390 string included a central A unit containing four or eight devices and was optionally flanked by one or two B units housing up to twelve devices each. Operating in four-path mode via connection to a 3990 storage control unit, this setup could support an additional 3390 string for a total of up to sixty-four devices within the subsystem.

Each Hard Disk Assembly (HDA) comprised two actuator-head units along with platters: Model 1 offered an unformatted capacity of 1.89 GB; Model 2 doubled this to provide 3.78 GB per HDA. The Model 3 released in 1991 increased capacity by fifty percent to reach 5.67 GB per HDA, while Model 9 in 1993 tripled it further to deliver up to 11.3 GB per HDA.

Diverging from earlier DASD designs that used large AC motors coupled with belts for spindle rotation, the IBM 3390 HDAs were powered directly by enclosed DC motors. The Model 9 represented IBM’s final iteration of Single Large Expensive Disk (SLED) technology.

IBM 9345

Introduced in November 1990 as a Request Price Quotation (RPQ) for IBM's SuperComputing Systems Extensions (SCSE), the IBM 9345 hard disk drive was developed at IBM's San Jose facility under the codename Sawmill. This full-height 5¼-inch drive accommodated up to eight 130 mm platters, delivering a maximum capacity of 1.5 GB. Notably, it was the first HDD to utilize Magnetoresistive (MR) head technology.

IBM 9340

In October 1991, IBM unveiled the 9345 DASD within the 9340 series of channel-attached count key data (CKD) DASD subsystems, designed for compatibility with IBM mainframes such as the ES/9000 processor family. The 9345 Model 1 included two drives each with 1.0 GB capacity, whereas Model 2 comprised two drives with 1.5 GB each.

From a functional perspective, the 9340/9345 resembled the 3990/3390 series but differed by lacking the non-volatile RAM cache found in the 3990 and by having a shorter maximum block length compared to the 3390.

The OS Input/Output Supervisor (IOS) recognized these devices through a specialized initializer named IECCINIT, which also managed other DASD hardware. During initialization, the operating system detected the absence of non-volatile cache in the 9340 and noted the reduced track count on the 9345, resulting in assignment of device types distinct from those of the 3990/3390 units.

9330 family of disk drives

  1. The 9331 Diskette Unit came in models 1 and 11 equipped with an 8-inch floppy disk drive; models 2 and 12 featured a 5-inch floppy disk drive.
  2. The IBM 0667 hard disk was employed in the 9332 Direct Access Storage Device.
  3. The 9333 High Performance Disk Drive Subsystem incorporated either IBM 0664 or IBM 0681 hard drives depending on the specific model.
  4. The 9334 Disk Expansion Unit allowed connection of one to four SCSI hard disk drives to RS/6000 systems.
  5. Announced in October 1986 alongside the IBM 9370 Information System, the rack-mountable 9335 Direct Access Storage Subsystem housed an IBM-developed "Kestrel" hard drive with an 850 MB capacity. This drive contained three 14-inch platters and featured dual rotary actuators enabling access to multiple heads per surface. No OEM versions of this unit are known.
  6. The IBM 0681 hard disk was utilized within the 9336 Disk Unit (Redwing).
  7. The IBM 0662 (Spitfire) or IBM 0663 (Corsair) hard disks were integrated into the 9337 Disk Array Subsystem.

IBM 2310

The IBM 2310 Removable Cartridge Drive debuted in 1964 alongside the IBM 1800 and was subsequently introduced with the IBM 1130 in 1965, most likely shipping initially with the latter toward late that year. It stored up to 512,000 sixteen-bit words (equivalent to one million twenty-four thousand bytes) on an IBM 2315 cartridge. This cartridge contained a single oxide-coated aluminum platter enclosed within a plastic casing featuring openings for both the read/write arm and two heads.

IBM 5444

Launched in September 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 designated as the IBM 5440 that contained one fourteen-inch platter. It was available in three variants:

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

IBM 62GV

The 62GV was initially released in May 1974 from IBM's Hursley facility in the United Kingdom, where it was developed under the codename Gulliver. It originally provided 5 MB of storage capacity, with subsequent versions expanding this to 10 MB (designated 62TM) and eventually to 14 MB. This model utilized a Swinging Arm actuator paired with a single 14-inch disk. The straightforward design of this actuator became IBM's most widely licensed electromechanical innovation, gaining widespread adoption across the industry throughout the 1980s and remaining in use within hard disk drives for many years afterward. Approximately 177,000 units of the IBM 62GV were produced, marking it as the first hard drive to surpass 100,000 units sold.

OEM and Small Systems HDDs

This segment details IBM-produced hard disk drives marketed as OEM components and for use in IBM’s smaller system lines such as System/3, System/32, /34, /36, and AS/400. Drives are identified by their OEM model numbers and organized by their initial shipment dates.

IBM 0680

Introduced in 1979, the 0680 was deployed across many IBM small systems and entry-level System/370 models as the 3310 direct access storage device. It was officially announced as the 0680 OEM variant in September 1981 and developed at IBM’s Hursley laboratory under the codename Piccolo. This drive offered an initial capacity of up to 65 MB through six 8-inch (210 mm) disks and incorporated an enhanced rotary actuator mechanism.

A higher-capacity version known as the 62SW was released in June 1984 but experienced limited commercial success due to pricing that was comparable to the 62GV model.

IBM 0676

The 0676 debuted in November 1982 as a component of the 5247 Disk Storage Unit designed for the IBM System/23 Datamaster. Created at IBM Rochester, Minnesota under the internal code name 21ED, it featured an 8-inch form factor with capacities of either 15 or 30 MB achieved via two or four disks. In 1983, this drive was incorporated into the System/36’s 5360 System Unit. Its capacity was doubled in 1984 by increasing the number of tracks per disk surface, subsequently being integrated into the S/36’s upgraded 5362 System Unit.

IBM 0665

The 0665 made its debut in October 1985 as part of the PC AT (5170) system chassis. Developed at IBM Rochester under the codename "Pixie," this hard drive measured 5 inches and was available in storage options of 20, 30, and 44 MB.

IBM 0667

Released in August 1986, the 0667 was developed at IBM Rochester with the codename "Grant." This full-height, five-inch ESDI hard drive supported capacities up to 70 MB using up to four disks measuring 130 mm each. It was offered as an optional feature on select PC RT models (6150, 6151, and 6152) as well as on System/36 Model System Units (5363 and 5364).

IBM 0669

The 0669, which shipped in 1987 from IBM Rochester under the codename "Grant-Prime," was a full-height five-inch hard disk capable of reaching up to 115 MB using four disks sized at 130 mm. This unit served as the internal storage device for both the System/36 model 5363 and Series 1 model 4956 system units.

IBM 0671

Also introduced in 1987 from IBM Rochester and codenamed "Lee," the 0671 was a full-height five-inch ESDI HDD offering capacities up to 316 MB across eight disks measuring 130 mm each. This model marked IBM's first implementation of a thin metal film recording surface technology. It was included within the IBM AS/400’s 9404 System Unit released in 1988, which accommodated two or three such drives.

IBM 0661

First appearing in shipments during 1989 under model number 371, the 0661 was jointly developed by teams at IBM Rochester and Hursley, UK (codenamed "Lightning"). This SCSI hard drive provided up to 320 MB capacity using as many as eight disks sized at 95 mm with fourteen read/write heads. A higher-performance "Turbo" variant offering up to 400 MB followed in 1990. The drive became a standard component across multiple IBM platforms including various AS/400 system units.

IBM 0681

Introduced in April 1990, the 0681 was created at IBM Hursley, UK (known as "Redwing") and represented the laboratory’s final hard disk drive offering. This full-height 5-inch drive provided a maximum capacity of 857 MB utilizing twelve 130 mm platters and was IBM's inaugural HDD to incorporate PRML data decoding technology. It served as the core component for the 9333 Disk Drive Subsystem launched in early 1992, with an enhanced version offering 1.07 GB becoming available by May that year.

IBM 0663

Released in late 1991 under the codename "Corsair," the 0663 was a compact 3-inch hard disk drive featuring a half-height (1.6-inch) profile and delivering up to 1 GB capacity across eight 95 mm platters. This model was implemented in select PS/2 and RS/6000 systems and was notable as the first OEM drive to utilize Magnetoresistance (MR) head technology.

IBM 0664

The 0664, developed at IBM Rochester, Minnesota under the codename "Allicat," debuted in November 1992. It was a full-height 5-inch HDD (3.25 inches tall) that effectively combined two 3-inch drives, offering storage capacity up to 2.013 GB across 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 high) 3-inch hard disk drive providing 1.05 GB of storage distributed over three platters or five surfaces. This drive was utilized internally within the IBM 9336 Disk Unit and the IBM 9337 Disk Array.

Floppy disk drive

IBM was a pioneer in floppy disk technology, launching its first 8-inch floppy disk drive in 1971 as a read-only program loading device, followed by its initial read/write model in 1973 with the introduction of the 3740 Data Entry System. Although IBM established early benchmarks for 8-inch floppy drives, it did not market these drives separately, allowing other industry players to develop independently.

At one point, IBM stood as the largest buyer of OEM 5-inch floppy disk drives; its preference for double-sided units with 48 tracks per inch helped solidify this configuration as an industry norm. Despite intentions to produce these and smaller formats internally, IBM discontinued all such manufacturing efforts by 1985. Its attempt to launch a commercial OEM version of the smaller 4-inch DemiDiskette in 1983 did not succeed.

"Star" series of HDDs

On October 17, 1994, IBM Storage Systems unveiled three distinct families of hard disk drives: Travelstar, featuring compact 2-inch drives tailored for notebook computers; Deskstar, comprising 3-inch drives designed for desktop use; and Ultrastar, also utilizing a 3-inch format but optimized for high-performance computing environments.

Comparison of IBM's Initial HDD and Final "Star" Series Models

The following table contrasts IBM's pioneering hard disk drive, the RAMAC 350, with later models from its "Star" series of OEM HDDs. The comparison illustrates significant advancements including drastic reductions in physical size and cost alongside substantial gains in storage capacity and operational efficiency.

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 (GB) 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 (mm) 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 (lbs) 2,140 1.7 1.4 0.2 ~1,244×
Weight (kg) 971 0.8 0.64 0.095
Power consumption (watts) Approx.2374 watts (8100 BTUs/hour), varying up to ~5500 VA depending on model 16 10.3 1.85 ~1,283×
Power efficiency (megabytes/watt) 0.0016 9,125 17,476 43,243 ~27 million ×
List price (Template:US$) $34,500 ($234,000 adjusted to 2002 dollars) $1,200 $360 $420 -
Cost per megabyte (Template:US$) $9,200 ($68,000 in adjusted dollars) $0.0082 $0.0020 $0.0053 -
Areal density (megabits/in²) 0.002 26,263 46,300 70,000 -
Areal density (kilobits/mm²) 0.003 40,708 71,765 108,500 -
Volume density (gigabytes/in³) 0.00000003 6 8 20 -
Volume density (megabytes/cm³) 0.000002 388 478 1,203 -
Average latency (ms) 25 3 4 7 -
Average seek time (ms) 600 5.9 10.2 12 -
Data transfer rate (MB/s) 0.001 103 29.4 43.75


DASD Devices Distinct from HDDs and FDDs

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

IBM 7320 Drum

The IBM 7320 represents a magnetic drum storage system that was launched in 1962.

IBM 2301 Drum

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

IBM 2303 Drum

The IBM 2303, released in 1964, is a magnetic drum storage unit similar in design to its predecessors.

IBM 2321 Data Cell

Unveiled in 1964, the IBM 2321 Data Cell utilizes short strips of magnetic tape for data retention. It accommodates ten removable cells, each with a capacity of 40 MB, summing up to a total of 400 MB.

IBM 3850 Mass Storage System

The IBM 3850 Mass Storage System, introduced in 1974, functions as a tape cartridge library that stages data onto IBM 3330 or 3350 disk drives. It offers virtual drive access to the host system.

See also

External links

Related profiles

PPunched cardDDeskstarTTravelstarMMicrodrive
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