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IBM 2319

From Alfawiki
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 division 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. Since the introduction of the IBM 1301, the core mechanical architecture of hard disk drives has remained largely unchanged, and performance benchmarks have adhered to consistent criteria established in the 1950s. Throughout the decades, the industry has witnessed substantial reductions in cost and physical dimensions, alongside marked enhancements in storage capacity and operational speed.

IBM manufactured 8-inch floppy disk drives beginning in 1969 and continued until the mid-1980s, though it did not emerge as a leading producer of smaller 5.25- or 3.5-inch floppy drives. While IBM marketed its magnetic disk drives commercially, it only started offering original equipment manufacturer (OEM) agreements in 1981. By 1996, IBM had discontinued manufacturing hard disk drives tailored exclusively for its systems, instead supplying all HDDs under OEM arrangements.

IBM employed various designations for its magnetic disk products, such as direct-access storage device (DASD), disk file, and diskette file. For clarity and consistency, this article adopts the widely accepted industry terms hard disk drive (HDD) and floppy disk drive (FDD).

IBM 350

The IBM 350 disk storage unit holds the distinction of being IBM’s inaugural disk drive, launched as an integral component of the IBM 305 RAMAC system on September 14, 1956. A related model, the IBM 355, was introduced for use with the IBM 650 computer system. The initial prototype was delivered to Zellerbach Paper Company in San Francisco in June 1956, with production units reaching customers such as United Airlines starting November 1957.

Engineered to support real-time business accounting processes, the IBM 350 had a storage capacity of five million 6-bit characters (equivalent to 3.75 MB), distributed over fifty-two disks each measuring 24 inches in diameter. This configuration provided one hundred recording surfaces and tracks rotating at a speed of 1200 revolutions per minute. Data transfer rates reached up to 8,800 characters per second. The read/write heads were maneuvered vertically and radially to access specific disk pairs and tracks. Several enhanced variants were introduced later in the decade. The IBM RAMAC 305 system bundled with the IBM 350 was leased at a rate of $3,200 monthly. Production ceased in 1969.

The patent US3,503,060, originating from the RAMAC development program, is acknowledged as a seminal invention underpinning modern disk drives. Although initially rejected by IBM’s board due to concerns over potential disruption to its punch card business, development persisted at IBM’s San Jose facility until receiving approval from company leadership.

Physically, the IBM 350’s cabinet measured roughly 60 inches in length, stood 68 inches tall, and was about 29 inches deep, weighing nearly one ton—necessitating forklifts and large cargo aircraft for transportation. Currie Munce, who served as research vice president at Hitachi Global Storage Technologies (the company that acquired IBM’s storage division), noted that while the capacity could have surpassed five million characters, marketing hesitated to advertise higher figures. Nevertheless, double-capacity models were announced and shipped during January 1959.

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

IBM 353

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

IBM 355

Introduced on September 14, 1956, the IBM 355 was an expansion for the widely used IBM 650 system. It incorporated the IBM 350 mechanism but featured up to three access arms instead of just one on the IBM 350. This device stored six million decimal digits along with 600,000 sign indicators. It transferred entire tracks to and from the magnetic core memory of the 653, an optional IBM 650 unit containing sixty signed ten-digit words—sufficient for a single disk track or tape record.

IBM 1405

Announced in 1961, the IBM 1405 Disk Storage Unit was designed for the IBM 1400 series of mid-range business computers. Model 1 offered storage capacity for ten million alphanumeric characters (60 million bits) across 25 vertically stacked disks rotating at 1200 rpm; Model 2 doubled this capacity to twenty million characters (120 million bits) using fifty disks.

Each side of a disk contained 200 tracks segmented into five sectors, numbered from 0 to 4 on the upper surfaces and from 5 to 9 on the lower ones. Each sector could hold either 178 or 200 characters. One to three forked access arms, each equipped with two read/write heads (top and bottom), moved both vertically and horizontally through electronic control to reach specific disks and tracks. The read/write time per sector was approximately ten milliseconds.

Access durations varied between 100 milliseconds and up to a maximum of 700 milliseconds for Model 1 and 800 milliseconds for Model 2. The latter model included one hundred thousand sectors containing either two hundred characters in move mode or one hundred seventy-eight characters in load mode (which added a word mark bit per character). Model 1 comprised fifty thousand sectors.

IBM 7300

The IBM 7300 Disk Storage Unit was created for use with the IBM 7070, with a second model announced in 1959. Nevertheless, following the debut of the IBM 1301 on June 5, 1961, users of both the IBM 7070 and IBM 7074 preferred the IBM 1301 over the IBM 7300. The technology within the IBM 7300 shared commonalities with that found in the IBM 350, IBM 355, and IBM 1405 units.

IBM 1301

Unveiled on June 2, 1961, the IBM 1301 Disk Storage Unit was intended for use with IBM 7000 series mainframes and the IBM 1410. It stored twenty-eight million characters per module (twenty-five million when paired with the IBM 1410), featuring twenty-five large disks and forty user-accessible recording surfaces, each containing two hundred fifty tracks. The Model 1 consisted of a single module; Model 2 stacked two modules vertically. Disks rotated at eighteen hundred revolutions per minute and transferred data at ninety thousand characters per second.

A significant advancement was its design where each surface had its own dedicated arm and head moving simultaneously like a comb assembly. This eliminated delays caused by moving heads between disks and reduced maximum access time to one hundred eighty milliseconds. The heads were aerodynamically engineered to fly over a thin air cushion above the disk surface, allowing closer spacing and improved performance.

The IBM 1301 connected through the IBM 7631 File Control unit, enabling compatibility with either an IBM 1410 or an IBM 7000 series computer, or allowing sharing between two systems.

Lease pricing for the IBM 1301 Model 1 was $2,100 monthly or $115,500 for purchase; Model 2 cost $3,500 per month or $185,000 outright. The IBM 7631 controller leased at $1,185 monthly or was available for $56,000 to buy. All versions were retired by approximately 1970.

IBM 1302

Launched in September 1963, the IBM 1302 Disk Storage Unit significantly enhanced recording capabilities, offering four times the storage capacity of the IBM 1301 by holding 117 million 6-bit characters per module. It delivered an average access time of 165 milliseconds and achieved data transfer speeds of 180,000 characters per second, more than doubling the throughput of its predecessor. Each module was equipped with two separate access mechanisms dedicated to the inner and outer cylinder sets. A Model 2 variant increased capacity further by stacking two such modules together. Leasing fees for Model 1 were set at $5,600 per month, with a purchase price of $252,000; Model 2's leasing cost was $7,900 monthly or $355,500 to buy outright. Adding the IBM 7631 controller incurred an additional monthly lease of $1,185 or $56,000 to own. 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 computer systems. It utilized a removable IBM 1316 disk pack roughly comparable in size to a top-loading washing machine, capable of storing two million characters. Throughout the 1960s, seven different models were produced before being phased out in the early 1970s.

The IBM 1316 disk pack comprises six disks measuring 14 inches each, providing ten recording surfaces as the outer disk faces remained unused; the total weight is approximately ten pounds. Operating at 1500 revolutions per minute, it features ten read/write heads mounted on a hydraulically controlled actuator arm. Each surface includes 100 tracks subdivided into twenty sectors per track, with each sector holding one hundred characters. The disk pack is encased in a transparent plastic shell with a locking mechanism to facilitate easy removal and installation.

The seven IBM 1311 models can be categorized into master drives containing controllers and slave drives lacking them. Master drives are capable of managing multiple slave units depending on system compatibility:

  1. Master drive for IBM 1440/1460/1240 systems; can manage up to four Model 2 slave drives (1962–1971).
  2. Slave drive compatible with master units; supports master's advanced functions (1962–1975).
  3. Master drive designed for IBM 1620/1710 systems; controls up to three slaves without enhanced features (1962–1971).
  4. Master drive for IBM 1401 systems; manages up to four slaves (1962–1971).
  5. Master drive compatible with IBM 1410/7010/7740 systems; includes standard Direct Seek capability; controls up to four slaves (1963–1971).
  6. & #7 Presumed master and slave drives introduced in 1968 and withdrawn by early 1971.

Available optional enhancements included:

  • Direct Seek: Removes the need to return to zero position prior to seeking.
  • Scan Disk: Enables rapid automated searching for specific identifiers or conditions.
  • Seek Overlap: Permits simultaneous seek and read/write operations across multiple drives.
  • Track Record: Maximizes storage by writing one large record per track instead of multiple sectors; this can increase total capacity up to approximately 18.7 million bits depending on configuration.

Master drives (Models 1,3,4,5) incorporate extra power supplies and control circuitry, resulting in a width roughly one foot greater than that of Model 2 slave drives.

IBM 2302

The IBM 2302 represents the System/360 adaptation of the earlier 1302 model, featuring track formatting aligned with System/360 DASD architecture rather than that of the IBM 7000 series. It employs a fixed module containing twenty-five platters with forty-six recording surfaces. Model 3 configurations include one such module; Model 4 units comprise two modules. Each module is equipped with two independent access mechanisms—referred to as access groups—serving the innermost and outermost sets of 250 cylinders respectively. Each access mechanism carries one read/write head per track. The average rotational latency is about seventeen milliseconds, with a maximum delay reaching thirty-four milliseconds; maximum seek time within each access group is approximately one hundred eighty milliseconds. Tracks hold up to 4,985 bytes each; after formatting and accounting for alternate tracks, each module offers around 112 megabytes of storage capacity. Connection to IBM mainframes is facilitated through the IBM 2841 Storage Control Unit.

IBM 2305

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

With the advent of Virtual Storage on System/370, the 2305 became highly sought after, frequently employed as a paging device across various models such as the 3155, 3165, 3158, 3168, 3033, 4341, and 3081 (the latter utilizing specialized microcode). Its design made it particularly effective for handling small but frequently accessed data sets like catalogs and job queues.

The 2305-1 variant provides a storage capacity of 5.4 MB and a data transfer rate of 3.0 MB/s, featuring an average access latency of approximately 2.5 milliseconds. In contrast, the larger 2305-2 offers an expanded capacity of 11.2 MB at a transfer speed of 1.5 MB/s with an average access time around 5 milliseconds.

Optimized for rapid and continuous access to limited data volumes, the 2305’s balance of speed and capacity suited it well for system-resident functions, including work files, job queues, indices, and frequently used datasets. Its swift response times proved advantageous as a paging resource in high-demand environments processing 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 to support the IBM System/360, while also compatible with systems like the IBM 1130 and IBM 1800. It connected directly to System/360 Models 20 and 25. All units utilized removable IBM 1316 Disk Packs, which were originally developed for the IBM 1311.

The Model 1 version of the 2311 connects through the 2841 Control Unit to a majority of IBM mainframes; on the Model 25 system, connectivity is provided via a Disk Attachment Control that integrates control unit functionality. The disk packs employ IBM’s count key data format supporting variable-length records.

Models designated as 11 or 12 operate with fixed-sector formatting when used with the System/360 Model 20’s integrated control. Due to differing formatting methods, disk packs are not interchangeable between Model 1 drives and Models 11 or 12.

Though mechanically akin to the IBM 1311, the IBM 2311 features enhanced recording capabilities. It stores up to 7.25 megabytes on a removable six-platter disk pack and uses ten read/write heads mounted on a hydraulically actuated mechanism. Each disk surface contains approximately 200 tracks plus three additional spares. The average seek time is around 85 milliseconds, and it supports data transfer rates up to 156 kB/s.

Uniform electrical interface standards across System/360 computers allowed third-party vendors to manufacture plug compatible disk drives, encouraging competition within the IBM-compatible storage market.

IBM 2314 Disk Access Storage Facility Model 1

Debuting in April of 1965, the IBM 2314 Disk Access Storage Facility Model 1 was compatible with both System/360 and System/370 mainframe lines. It featured a Two Channel Switch capability enabling simultaneous connection to two channels. While its storage mechanism was similar to that of the IBM 2311, it delivered greater data density.

This drive housed roughly 29 million characters on a removable IBM 2316 disk pack composed of eleven disks (yielding twenty recording surfaces). It employed twenty read/write heads on a hydraulically actuated assembly, with each surface containing about 200 tracks. Subsequent models enhanced access times beyond those of the original IBM 2311 and doubled data transfer speeds to approximately 310 kB/s.

The initial Model 1 configuration consisted of nine disk drives sold as a single package, with storage control units and drive modules shipped separately. Drives were installed in pull-out drawer assemblies colloquially known as "Pizza Ovens." Of these nine drives, eight could be active simultaneously while one served as an offline user-accessible spare for maintenance purposes. Drive system addresses were configured via user-interchangeable plugs that allowed easy reassignment by swapping plugs.

An optional IBM 2844 Control Unit permitted two concurrent System/360 channel accesses directed at separate drives within this storage facility.

Additional variants of the IBM 2314 were introduced in later releases:

IBM 2314 Direct Access Storage Facility - Model Variants

In 1969, IBM segmented the 2314 storage system into distinct models, each supporting up to nine drives (with eight accessible online) connected to a 2314 Storage Control unit:

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

IBM 2319

To address competition from plug compatible manufacturers producing storage subsystems comparable to the 2314, IBM introduced the 2319 series in 1970—a cost-effective three-drive module. This series was developed by removing one drive from the four-drive 2313 and rebranding it as the 2319 A1, which was then offered at a significantly reduced rental fee. This approach lowered the entry cost for new customers while preserving higher rental charges for existing ones. The 2319-A1 connects with integrated controllers designed for System/370 Models 135 and 145. Additionally, traditional 2314 DASD units such as the 2312 or 2318 can be linked to the 2319-A1. The 2319 B series accommodates three, six, or nine drives attached to the updated 2314 Model B Storage Control Unit.

IBM 3310

Launched 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. Utilizing fixed-block architecture, the device operated under DOS/VSE and VM, the only S/370 operating systems that supported FBA devices.

IBM 3330

The IBM 3330 Direct Access Storage Facility, internally codenamed Merlin, debuted in June 1970 targeting IBM System/370 and IBM System/360/195 machines. Initial versions included a two-drive Model 1 and a single-drive Model 2. Removable disk packs offered a capacity of 100 MB each, with access times of approximately 30 ms and data transfer speeds reaching 806 kB/s. A significant advancement was the integration of error correction via fire codes, which improved reliability and lowered costs by accommodating minor disk surface defects.

Originally, one storage control unit (3830 Model 1) managed a single 3330 drive, with up to three additional drives physically connected to form strings containing as many as eight drives.

In August 1972, IBM released the 3830 Model 2 Storage Control along with the 3333 Disk Storage and Control, which separated control units from drive strings. The upgraded 3830 functioned as a director-type controller overseeing multiple strings. The first device in each string, the 3333, incorporated both controller functionality and two drives and could manage up to three attached 3330 drives, allowing up to eight drives per string. The enhanced 3830 Model 2 supported two such strings simultaneously (up to sixteen drives total), with optional string switches enabling connection to two distinct control units.

In 1973, IBM announced double-density (-11) models: the 3333–11, the 3330-11, and larger-capacity (200 MB) disk packs designated as the 3336–11. Mixing single-density and double-density drives within a single string was not permitted. Upgrading from standard models to Model-11 versions in the field was feasible but required extensive conversion processes and data migration.

The IBM 3330 was discontinued in 1983.

IBM 3340 and 3344

While the IBM 3340 and 3344 share many characteristics, only the 3340 models can function as the head of a device string. The 3344 lacks an A model drive, requiring it to be connected to a 3340 A model drive serving as the string leader.

IBM 3340

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

This system utilized removable data modules that incorporated both the head and arm assemblies; during loading or unloading, the module’s access door would open, eliminating the need to remove covers as was necessary with earlier disk packs. It delivered an average access time of 25 milliseconds and supported data transfer rates up to 885 kilobytes per second. The IBM 3348 Data Module came in three variants: one with a capacity of 35 MB and two versions offering 70 MB, one of which included a 500 KB fixed-head area for faster access. The 3340 featured built-in error correction capabilities and was phased out in 1984.

Designed under Ken Haughton in San Jose, the initial concept revolved around two removable modules each holding 30 MB—hence the Winchester nickname referencing the Winchester .30-30 rifle. Although storage capacities grew over time, this codename remained associated with the product.

A major breakthrough was its economical head design permitting heads to land on and lift off from spinning disks without requiring unloading. This "Winchester technology" significantly simplified and lowered costs for head and arm mechanisms, setting a new industry benchmark. The term Winchester or Winnie was widely used for hard drives into the early 1990s but has since become obsolete worldwide.

IBM 3344

The IBM 3344 shares similarities with the 3340 but differs by using fixed media instead of removable IBM 3348 data modules. Each spindle supports four logical drives, each matching the capacity of a single 70 MB module from the 3348 line. Available solely as dual-drive units, the 3344 does not have an A model variant; consequently, it must connect to a 3340-A2 or A2F unit acting as the string head. The 3344-B2F model is distinguished from the B2 by having fixed heads positioned over certain cylinders on both drives. Internally, the architecture of the IBM 3344 is identical to that of the IBM 3350; their distinction lies exclusively in differences within control unit microcode.

IBM 3350

The IBM 3350 Direct Access Storage Facility, codenamed Madrid, debuted in 1975 targeting IBM System/370 environments. It introduced sealed head-disk assemblies (HDAs) combining both head and arm mechanisms into a non-removable unit. Each HDA contained 555 cylinders with 30 heads, providing roughly 19 KB per track and totaling approximately 317 MB per assembly. This sealed HDA design became standard for subsequent IBM DASD products.

Available models included A2, A2F, B2, B2F, C2, and C2F, each equipped with two HDAs. The A2 and A2F variants incorporated an additional electronics board enabling connection to storage control units (SCUs), also referred to as controllers or heads of string. Drives were arranged into strings beginning with an A2 or A2F unit followed by up to three B2 units or combinations such as two B2s plus one C2. The A2 model typically featured a string switch allowing dual SCU connections; this facilitated simultaneous input/output operations on separate HDAs. Compatible SCUs included the IBM 3830 Model 2, Integrated Storage Controllers (ISC) embedded within CPUs like models 3148, 3158, and 3168, as well as later backward-compatible controllers such as the IBM 3880.

The C2 unit contained its own controller providing a secondary path to itself and preceding devices in the string but acted only as a backup controller when the primary controller on an A unit was offline. Unlike A units that connected to two SCUs simultaneously, C units were limited to a single SCU connection. Valid string configurations for IBM 3350 included patterns such as -A-, -AB-, -ABB-, -ABBB-, -AC-, -ABC-, and -ABBC-.

Models designated "x2F" (for example, A2F) featured fixed-head areas covering the first five cylinders on each HDA. This design reduced seek times within those cylinders effectively to zero and targeted frequently accessed checkpoint regions used by HASP or JES2 spooling systems. It also enhanced performance for Time Sharing Option (TSO) swap areas under MVT, SVS, and MVS operating systems by minimizing head movement during context switches.

The IBM 3350 series was officially discontinued in September of 1994.

IBM 3370

In January 1979, IBM launched the IBM 3370 Direct Access Storage Device, designed for use with IBM 4331, 4341, and System/38 midrange systems. This device contained seven fixed 14-inch platters, delivering a storage capacity of 571 MB per unit. Notably, the 3370 was the pioneer in employing thin-film head technology, a development originating from the Thomas J. Watson Research Center in the late 1960s. It utilized a fixed-block architecture and was compatible exclusively with DOS/VSE and VM operating systems.

IBM 3375

The IBM 3375 served as a complementary model implementing count key data architecture, a requirement for operating systems such as OS/360 and its successors.

IBM 3380

Introduced on June 11, 1980, the IBM 3380 Direct Access Storage Device incorporated film head technology and offered a capacity of 2.52 GB per unit. Each unit consisted of two hard disk assemblies, each equipped 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 16 milliseconds. Initial pricing ranged between $81,000 and $142,200. Due to tribological challenges involving the interaction between heads and media, shipments commenced only in October 1981.

Typical configurations included one A unit accompanied by up to three B units; each IBM 3380 comprised four devices, enabling strings of up to sixteen devices. These were commonly connected to IBM 3880 storage control units featuring dual paths to facilitate simultaneous I/O operations targeting distinct hard disk assemblies.

In February 1985, IBM introduced the Extended Capability Models (3380 E) with double density, doubling capacity to 5.04 GB per unit by incorporating two actuators per hard disk assembly, each managing 1.26 GB.

The triple-capacity variant, known as the 3380 K and announced in August 1987, provided 7.562 GB per unit through two actuators of 1.89 GB each. Models J and K offered an optional four-path mode which doubled the number of devices per string to thirty-two when connected to an IBM 3990 storage control unit, allowing four concurrent I/O operations.

The IBM 3380 series encompassed twelve different models: six A-units serving as string heads with controller logic interfacing with storage control units; five B-units connecting to either A- or C-units; and one C-unit designed for direct connection to an IBM channel.

Manufacturing continued until May 1996, marking an unusually long market duration of fifteen years—significantly exceeding the typical lifespan of disk drives.

IBM 3390

Debuting in November 1989, the IBM 3390 Direct Access Storage Device family provided storage capacities reaching up to twenty-two gigabytes spread across multiple drives. The system costs varied widely from $90,000 to $795,000 depending on configuration and total capacity.

A typical IBM 3390 string consisted of a central A unit containing four or eight devices, optionally accompanied by one or two B units capable of housing up to twelve devices each. Operating in four-path mode through connection to an IBM 3990 storage control unit, the setup could support a second string for a maximum of sixty-four devices within a single subsystem.

Each Hard Disk Assembly (HDA) contained two actuator-head units along with platters: Model 1 offered a capacity of 1.89 GB per HDA; Model 2 doubled this to 3.78 GB per HDA. In 1991, Model 3 increased capacity by fifty percent to reach 5.67 GB per HDA; later in 1993, Model 9 tripled it further to achieve 11.3 GB per HDA.

Unlike earlier DASD models that relied on large AC motors coupled with belts for platter rotation, the IBM 3390 HDAs incorporated directly driven DC motors enclosed within the assembly.

The Model 9 represented IBM’s final iteration of Single Large Expensive Disk (SLED) drives.

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 project name Sawmill. This full-height 5¼-inch HDD incorporated up to eight 130 mm platters, delivering a maximum storage capacity of 1.5 GB. Significantly, it was the pioneer HDD to implement magnetoresistive (MR) read/write heads.

IBM 9340

The IBM 9340 DASD was launched in October 1991 as part of the 9340 channel-attached count key data (CKD) DASD subsystem family designed for IBM mainframe systems, including ES/9000 processors. The Model 1 variant housed two HDDs with 1.0 GB each, whereas Model 2 contained two drives with 1.5 GB capacity apiece.

From an operational perspective, the 9340/9345 resembled the IBM 3990/3390 series but differed by lacking the non-volatile RAM cache found in the 3990 and supporting a shorter maximum block size than the 3390. The operating system’s Input/Output Supervisor (IOS) utilized the IECCINIT initializer to detect device characteristics, recognizing the absence of non-volatile cache in the 9340 and the reduced track length in the 9345, thus assigning distinct device types accordingly.

9330 family of disk drives

  1. The 9331 Diskette Unit models 1 and 11 featured a single 8-inch floppy disk drive; models 2 and 12 included one 5¼-inch floppy disk drive.
  2. The IBM 0667 HDD powered 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 disks to RS/6000 systems.
  5. The IBM-designed "Kestrel" hard drive with an 850 MB capacity, consisting of three 14-inch platters and dual rotary actuators accessing multiple surfaces, was utilized in the rack-mountable 9335 Direct Access Storage Subsystem. Announced in October 1986 as part of the IBM 9370 Information System, it had no known OEM counterparts.
  6. The IBM 0681 HDD (Redwing) was employed in the 9336 Disk Unit.
  7. The IBM 0662 (Spitfire) or IBM 0663 (Corsair) HDDs were used within the 9337 Disk Array Subsystem.

IBM 2310

Released initially with the IBM 1800 in 1964 and subsequently with the IBM 1130 in 1965—most likely shipping first alongside the latter—the IBM 2310 Removable Cartridge Drive stored data on an IBM 2315 cartridge containing a single oxide-coated aluminum disk enclosed within a plastic casing featuring openings for the read/write arm and dual heads. It held a total of 512,000 sixteen-bit words, equivalent to approximately one megabyte (1,024,000 bytes).

IBM 5444

The IBM 5444, introduced in September of 1969 as part of System/3, was developed at IBM’s Hursley laboratory in England under the codename Dolphin. It operated using a removable disk cartridge (5440) that contained one fourteen-inch platter. This series comprised three models:

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

IBM 62GV

Initially delivered in May of 1974, the IBM 62GV emerged from development at IBM’s Hursley facility under the codename Gulliver, originally offering a storage capacity of five megabytes. Subsequent models expanded capacity to ten megabytes (62TM) and later fourteen megabytes. It utilized a Swinging Arm actuator paired with a single fourteen-inch disk—a mechanism invented at Hursley that became IBM’s most widely licensed electromechanical innovation. This actuator design, combined with its filtration system, set an industry standard by the early eighties and continues to be extensively used nearly forty years later. With approximately 177,000 units shipped, the IBM 62GV was notably the first hard drive to surpass sales of one hundred thousand units.

OEM and Small Systems Hard Drives

This segment focuses on IBM-produced hard disk drives supplied as OEM components and designed for IBM's smaller systems such as the System/3, System/32, /34, /36, and AS/400. Drives are categorized by their OEM model numbers and arranged according to the date they were first delivered to customers.

IBM 0680

Beginning in 1979, the 0680 was utilized in numerous IBM small systems and entry-level System/370 units as the 3310 direct access storage device. Officially announced as the 0680 OEM variant in September 1981, it was engineered at IBM's Hursley laboratory in the United Kingdom under the project name Piccolo. This model incorporated six 8-inch (210 mm) platters and initially offered a storage capacity of up to 65MB, featuring an enhanced rotary actuator mechanism.

A double-capacity iteration called the 62SW was introduced in June 1984; however, its commercial success was limited due to a cost per megabyte comparable to that of the 62GV.

IBM 0676

The 0676 made its debut in November 1982 as a 5247 Disk Storage Unit tailored for the IBM System/23 Datamaster. Developed at IBM’s Rochester facility in Minnesota under the designation 21ED, this hard drive used 8-inch platters and initially provided either 15 or 30 MB of storage across two or four disks. By 1983, it was incorporated into the System/36’s 5360 System Unit. In 1984, capacity was doubled by increasing the number of tracks per surface, after which it was integrated into the S/36’s 5362 System Unit.

IBM 0665

Released in October 1985 within the PC AT (5170) system unit, the 0665 was created at IBM Rochester under the codename "Pixie." It was a 5¼-inch hard drive available with capacities of 20, 30, and 44 MB.

IBM 0667

Introduced in August 1986 and developed at IBM Rochester under the project name "Grant," the 0667 was a full-height 5¼-inch ESDI hard drive featuring up to four 130 mm platters and a maximum capacity of 70 MB. This drive was supplied on select PC RT models (6150, 6151, 6152) as well as System/36 Model System Units (5363, 5364).

IBM 0669

The 0669, launched in 1987 and developed at IBM Rochester under the codename "Grant-Prime," was a full-height 5-inch hard disk drive offering up to 115 MB of storage across four 130 mm platters. It served as an internal drive for both the System/36 5363 and Series 1 (4956) System Units.

IBM 0671

Also introduced in 1987 from IBM Rochester’s development team under the codename "Lee," the 0671 was an ESDI full-height 5-inch drive with a maximum capacity of 316 MB spread over eight 130 mm platters. This model represented IBM’s initial use of a thin metal film recording surface. In 1988, it became part of the IBM AS/400 9404 System Unit configuration, supporting installations of two or three drives.

IBM 0661

The 0661, released in 1989 as model number 371, originated from collaborative development efforts at IBM Rochester and Hursley (UK) under the codename "Lightning." It featured a SCSI interface with up to eight disks measuring 95 mm each (14 read/write heads), providing a base capacity of 320 MB. A subsequent "Turbo" variant with a capacity of 400 MB followed in 1990. This hard drive became standard equipment across multiple IBM platforms including various AS/400 System Unit Model CXX configurations.

IBM 0681

Launched in April of 1990 and developed at IBM Hursley with the codename Redwing, the 0681 represented the final hard drive developed at that site. It delivered up to an impressive capacity of 857 MB within a full-height, five-inch form factor utilizing as many as twelve 130 mm platters. Notably, this model introduced PRML data decoding technology. The drive played a key role in the release of the IBM 9333 Disk Drive Subsystem in early 1992, with an enhanced high-density version offering up to 1.07 GB becoming available by May that year.

IBM 0663

Released toward the end of 1991 and internally known as "Corsair," the 0663 was a compact 3-inch hard disk drive with a half-height profile measuring 1.6 inches. It offered a maximum storage capacity of 1 GB distributed over eight 95 mm platters. This model was incorporated into select PS/2 and RS/6000 systems, marking IBM's initial use of Magnetoresistance (MR) heads in an OEM drive.

IBM 0664

Introduced in November 1992, the 0664—developed under the codename "Allicat" at IBM's Rochester facility in Minnesota—was a full-height hard drive standing 3.25 inches tall and sized at 5 inches. It combined two 3-inch drives internally, delivering up to 2.013 GB of capacity across eight 95 mm platters.

IBM 0662

The 0662, codenamed "Spitfire" and also developed at IBM Rochester, became available in June 1993. This full-height (1-inch tall) 3-inch HDD provided 1.05 GB of storage across three platters or five data surfaces. It was utilized within IBM’s own 9336 Disk Unit and the 9337 Disk Array.

Floppy disk drive

IBM pioneered floppy disk technology by launching the first 8-inch floppy disk drive in 1971, initially as a read-only program loader. The company followed this with its first read/write version in 1973, integrated into the 3740 Data Entry System. Although IBM set early standards for 8-inch floppy drives, it refrained from marketing standalone units, thereby allowing broader industry development to proceed independently.

At one point, IBM was the largest original equipment manufacturer (OEM) buyer of 5-inch floppy disk drives. Its preference for two-sided drives featuring a track density of 48 tracks per inch helped define industry benchmarks. Despite plans to produce smaller form factor drives, IBM discontinued these projects in 1985. Its attempt to OEM the smaller 4-inch DemiDiskette in 1983 did not succeed.

"Star" series of HDDs

On October 17, 1994, IBM’s Storage Systems division unveiled three distinct hard drive product lines: the Travelstar series targeting notebook computers with 2-inch drives; the Deskstar series designed for desktop systems featuring 3-inch drives; and the Ultrastar line aimed at high-performance computing environments, also using 3-inch drives.

IBM's first HDD versus its last HDDs

The following table contrasts IBM’s inaugural hard disk drive, the RAMAC 350, with the final trio of models from its "Star" series of OEM HDDs. This comparison highlights significant advancements in storage capacity and performance alongside drastic reductions in physical size and cost.

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 (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 (pounds) 2,140 1.7 1.4 0.2 1,244×
Weight (kilograms) 971 0.8 0.64 0.095
Power consumption (watts) 8100 BTUs/hour (2374 watts), 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 27,375,856×
List price (Template:US$) $34,500 ($234,000 adjusted to 2002 dollars) 1,200 360 420
Price per megabyte (Template:US$) $9,200 ($68,000 adjusted to 2002 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 Beyond HDDs and FDDs

In certain IBM operating systems, both hard disk drives (HDDs) and floppy disk drives (FDDs) fall under the category of DASDs (direct access storage devices). Additional DASD variants encompass:

IBM 7320 Drum

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

IBM 2301 Drum

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

IBM 2303 Drum

The IBM 2303, debuted in 1964, is another example of a magnetic drum storage system.

IBM 2321 Data Cell

Revealed 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, resulting in an aggregate of 400 MB.

IBM 3850 Mass Storage System

Unveiled in 1974, the IBM 3850 Mass Storage System functions as a tape cartridge library that stages data onto IBM 3330 or 3350 disk drives. This system emulates virtual 3330 drives to the host environment.

See also

External links

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