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IBM 353

From Alfawiki
IBM
IndustryComputer hardware, data storage
FoundedJune 16, 1911; 115 years ago (1911-06-16) (as Computing-Tabulating-Recording Company) in Endicott, New York, United States
Headquarters
Armonk
,
United States
ProductsHard disk drives, floppy disk drives, computer hardware

IBM was a pioneer in manufacturing magnetic disk storage devices from 1956 until 2003, when it divested its hard disk drive division to Hitachi. The company is credited with inventing both the hard disk drive (HDD) and the floppy disk drive (FDD), with numerous technological advancements driven by its workforce. Since the introduction of the IBM 1301, the essential mechanical architecture of hard disk drives has largely remained unchanged, and performance benchmarks have adhered to standards established in the 1950s. Over time, this product category saw dramatic decreases in cost and physical dimensions while simultaneously achieving substantial improvements in storage capacity and operational efficiency.

IBM produced 8-inch floppy disk drives from 1969 through the mid-1980s but did not become a leading manufacturer for the smaller 5.25- or 3.5-inch formats. Although IBM consistently marketed its magnetic disk drives, it only started offering them under original equipment manufacturer (OEM) arrangements beginning in 1981. By 1996, IBM discontinued manufacturing HDDs exclusive to its own systems, instead supplying all drives as OEM components.

Throughout its history, IBM has used various designations for its magnetic disk products, such as direct-access storage device (DASD), disk file, and diskette file. For clarity and alignment with industry terminology, this article employs the terms hard disk drive (HDD) and floppy disk drive (FDD).

IBM 350

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

Created to fulfill real-time business accounting requirements, the IBM 350 provided storage for five million 6-bit characters (equivalent to 3.75 MB) distributed over fifty-two disks measuring 24 inches each, utilizing one hundred recording surfaces and tracks. The disks rotated at a speed of 1200 rpm and supported a data transfer rate of 8,800 characters per second. Its access mechanism operated by moving read/write heads vertically and horizontally to select specific surfaces and tracks on the disks. Several enhanced versions were introduced during the late 1950s. The complete RAMAC 305 system with the IBM 350 was leased at $3,200 monthly. Official production ceased in 1969.

Patent US3,503,060 arising from the RAMAC development is regarded as a foundational patent for disk drive technology. Despite initial cancellation by IBM’s Board due to concerns about its potential impact on punch card revenues, development continued at IBM San Jose until receiving endorsement from IBM’s president.

The physical cabinet housing the IBM 350 measured roughly 60 inches in length, stood 68 inches tall, and was 29 inches wide. Weighing close to one ton, it required forklifts and cargo aircraft for transportation. According to Currie Munce of Hitachi Global Storage Technologies—which acquired IBM’s storage business—marketing initially hesitated to promote higher capacity models due to uncertain demand; however, double-capacity units were shipped starting in 1959.

Acknowledging its groundbreaking nature, the RAMAC 350 Disk File was named 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 and later relocated to the Computer History Museum in Mountain View, California in 2005, where it remains on public display.

IBM 353

The IBM 353, designed for use 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, with a transfer rate of 125,000 words per second. A prototype delivered in late 1960 was the first disk drive to employ one head per surface that floated on compressed air, continuing the concept introduced by the IBM 350 (RAMAC). Production versions incorporated self-levitating heads similar to those found in the IBM 1301.

IBM 355

Introduced on September 14, 1956, the IBM 355 enhanced storage capabilities for the widely used IBM 650. Utilizing the IBM 350 mechanism as its foundation, it featured up to three access arms—compared to a single arm on the IBM 350—and could hold six million decimal digits along with 600,000 sign characters. The device transferred entire tracks to and from the magnetic core memory of the 653 option, which provided sixty signed ten-digit words—sufficient for one disk track or tape record.

IBM 1405

Announced in 1961 for the IBM 1400 series business computers, the IBM 1405 Disk Storage Unit was available in two variants: Model 1 offering storage for 10 million alphanumeric characters (equivalent to 60 million bits) across 25 disks, and Model 2 doubling that capacity with 50 disks. The disks revolved vertically at a speed of 1200 rpm.

Each disk surface contained 200 tracks subdivided into five sectors; sectors were numbered from 0 to 4 on the upper side and from 5 to 9 on the lower side. Each sector accommodated either 178 or 200 characters. One to three forked access arms, each equipped with two read/write heads (one on top and one underneath), moved vertically to select among disks numbered from 0 to 49 and horizontally to choose tracks numbered from 0 to 199. Each track provided ten sectors. The time required to read or write a sector was approximately 10 milliseconds.

Access times varied between 100 milliseconds and a maximum of up to 700 milliseconds for Model 1 and up to 800 milliseconds for Model 2. Model 2 contained a total of 100,000 sectors with either 200 characters in move mode or reduced to 178 characters in load mode, which added a word mark bit per character. Model 1 had half as many sectors at 50,000.

IBM 7300

The IBM 7300 Disk Storage Unit was developed specifically for use with the IBM 7070. IBM introduced a Model 2 version in 1959. Nevertheless, following the launch of the 1301 in 1961, many customers using the IBM 7070 and IBM 7074 favored that newer model. The technology employed by the IBM 7300 was related to that used in earlier models such as the IBM 350, IBM 355, and IBM 1405.

IBM 1301

Unveiled on June 2, 1961, the IBM 1301 Disk Storage Unit targeted mainframe computers within the 7000 series as well as the IBM 1410. It stored approximately twenty-eight million characters (168 million bits) per module—25 million characters when paired with the IBM 1410. Each module consisted of twenty-five large disks providing forty user recording surfaces and two hundred fifty tracks per surface. The Model 1 included one module; Model 2 stacked two modules vertically. Disks rotated at a speed of eighteen hundred rpm and transferred data at ninety thousand characters per second.

A major advancement was its design featuring an individual arm and read/write head dedicated to each surface, moving collectively like a comb assembly. This arrangement eliminated delays caused by switching heads between disks and reduced maximum access time down to one hundred eighty milliseconds. The heads utilized aerodynamic principles to fly over disk surfaces on a thin cushion of air, enabling closer proximity and improved performance.

Connection was established through the IBM 7631 File Control unit, allowing integration with either a single or shared IBM 1410 or IBM 7000 series system.

Pricing reflected its technological sophistication: Model 1 leased at $2,100 per month or purchased for $115,500; Model 2 leased at $3,500 per month or purchased for $185,000. The IBM 7631 controller was available separately for $1,185 monthly lease or $56,000 purchase price. All versions were discontinued by the year 1970.

IBM 1302

Launched in September 1963, the IBM 1302 Disk Storage Unit introduced advancements in recording technology that increased storage capacity to four times that of the IBM 1301, achieving 117 million 6-bit characters per module. It offered an average access time of 165 milliseconds and supported data transfer rates of 180,000 characters per second, more than twice the speed of its predecessor. Each module was equipped with two separate access arms dedicated to the inner and outer cylinders. The Model 2 variant doubled the storage by stacking two modules together. Monthly leasing fees were set at $5,600 for Model 1 and $7,900 for Model 2, with purchase prices at $252,000 and $355,500 respectively. The IBM 7631 controller was an additional cost, available for $1,185 per month or $56,000 to buy. Production of the 1302 ceased in February 1965.

IBM 1311

The IBM 1311 Disk Storage Drive was introduced on October 11, 1962, aimed at medium-sized business and scientific computing environments. Comparable in size to a top-loading washing machine, it utilized removable IBM 1316 disk packs 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 stands roughly four inches tall and weighs approximately ten pounds. It consists of six disks measuring fourteen inches in diameter, providing ten usable recording surfaces. The disks rotate at a speed of 1500 revolutions per minute and employ ten read/write heads mounted on a hydraulically controlled arm. Each surface contains one hundred tracks subdivided into twenty sectors per track; each sector can hold one hundred characters. The disk pack is housed within a protective plastic casing designed for safe handling and insertion into the drive.

The seven IBM 1311 models included master drives with built-in controllers and slave drives without controllers. Master drives had the capability to manage multiple slave units across various IBM systems such as the IBM 1440, IBM 1620, IBM 1401, and IBM 1410 families. Differences among models related to system compatibility and feature sets.

Available optional enhancements comprised:

  • Direct Seek: eliminates the need to return to track zero before moving to a target track.
  • Scan Disk: automates rapid scanning for specific identifiers or conditions.
  • Seek Overlap: allows simultaneous seeking and read/write operations across several drives.
  • Track Record: increases storage capacity by writing a single large record per track rather than multiple sectors, raising total stored bits beyond 17 million depending on configuration.

Master drive models (1,3,4,5) featured additional power supplies and control circuitry, making them approximately one foot wider than the Model 2 slave drives.

IBM 2302

The IBM 2302 represents the System/360 adaptation of the 1302, redesigned to conform with S/360 DASD architecture standards. It employs a fixed module consisting of twenty-five platters with forty-six recording surfaces. The Model 3 configuration contains one such module; Model 4 includes two modules. Each module is equipped with two independent access mechanisms—referred to as access groups—one servicing the innermost 250 cylinders and the other handling the outermost 250 cylinders. Each access group features one read/write head per track. Rotational latency averages seventeen milliseconds with a maximum delay of thirty-four milliseconds; seek times for each access group can reach up to one hundred eighty milliseconds. Tracks hold approximately 4,985 bytes each, resulting in a total module capacity near 112 megabytes. The IBM 2302 interfaces with mainframe systems through the IBM 2841 Storage Control Unit.

IBM 2305

Launched in 1970, the IBM 2305 fixed-head storage device was designed to operate with the IBM 2835 Storage Control and connect to System/360 models 85 and 195 through the IBM 2880 Block Multiplexor Channel. It became increasingly popular with the introduction of System/370's Virtual Storage, frequently utilized as a paging storage on systems such as the 3155, 3165, 3158, 3168, 3033, 4341, and 3081 (the latter requiring specialized microcode). The 2305 was particularly suited for managing small, high-transaction data sets including catalogs and job queues.

The 2305-1 variant delivers a capacity of 5.4 MB with a data transfer rate of 3.0 MB per second via a 2-byte channel interface and an average access latency of 2.5 milliseconds. In contrast, the larger 2305-2 model offers an 11.2 MB capacity at a transfer speed of 1.5 MB per second, averaging a 5-millisecond access time. Its rapid response and elevated data throughput made it optimal for system-resident tasks, work files, job queues, indices, and frequently accessed datasets. It proved especially efficient as a paging device in heavily utilized systems processing more than 1.5 transactions per second.

IBM 2311

The IBM 2311 Disk Storage Drive debuted in 1964 alongside the 2841 Control Unit, supporting the IBM System/360 architecture and also compatible with the IBM 1130 and IBM 1800 systems. It was directly attachable to System/360 Models 20 and 25. All units employed the removable IBM 1316 Disk Pack, which originated from the IBM 1311 design.

The Model 1 connects to most IBM mainframes via the 2841 Control Unit; however, the System/360 Model 25 utilizes a Disk Attachment Control performing equivalent functions. Disk packs are formatted using IBM's count key data variable-length record format.

Models designated as 11 or 12 interface with the integrated control of Model 20 and utilize fixed-sector disk packs that are not interchangeable with those used by Model 1.

While mechanically akin to the IBM 1311 but featuring enhanced recording technology, the IBM 2311 stores approximately 7.25 megabytes on a six-platter IBM 1316 disk pack. It incorporates ten read/write heads mounted on a hydraulically actuated arm, with each surface containing 200 tracks plus three spare tracks reserved for defect management. The average seek time is approximately 85 milliseconds, while data transfer rates reach up to 156 kilobytes per second.

Uniform electrical interfaces across System/360 models allowed third-party manufacturers to develop plug compatible disk drives, encouraging competition within the market for IBM-compatible storage solutions.

IBM 2314 Disk Access Storage Facility Model 1

Released in April of 1965, the IBM 2314 Disk Access Storage Facility Model 1 was designed to support both System/360 and System/370 platforms. Its Two Channel Switch capability permitted simultaneous connection to two channels. Building upon the foundation of the IBM 2311 design, it provided increased data density.

This drive employed an enlarged IBM 2316 disk pack consisting of eleven disks (totaling twenty recording surfaces), capable of storing over twenty-nine million characters (calculated as 200 tracks × 20 surfaces × approximately 7,294 bytes per track). Twenty read/write heads were hydraulically actuated with mechanical detents for precise track positioning. While initial access times were comparable to those of the IBM 2311, subsequent enhancements improved performance further. The data transfer rate doubled to approximately 310 kilobytes per second.

The Model 1 system was delivered as a package containing nine disk drives bundled together; additional components shipped separately included a storage control unit, one single-drive module, and two modules each housing four drives. Drives were installed in drawer-like assemblies facilitating easy disk pack handling—earning these units the nickname "Pizza Ovens." At any given time, only eight drives were accessible; the ninth served as either a spare or for offline maintenance purposes. Drive addressing was achieved through user-replaceable plugs, allowing for rapid reassignment when needed.

An optional 2844 Control Unit could be incorporated to enable two System/360 channels simultaneous access to distinct drives within this storage facility.

Later versions of the IBM 2314 expanded upon these initial features:

IBM 2314 Direct Access Storage Series

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

  • The 2312 Disk Storage consisted of a single-drive unit.
  • The 2313 Disk Storage offered a four-drive configuration.
  • The 2318 Disk Storage provided a two-drive setup.

IBM 2319

To rival plug-compatible manufacturers producing storage subsystems comparable to the 2314, IBM launched in 1970 the cost-effective three-drive module named 2319. This model originated by removing one drive from the four-drive 2313 and rebranding it as the 2319 A1. This strategy reduced leasing expenses for new clients while preserving higher charges for existing users. The 2319-A1 connects to integrated controllers designed for System/370 Models 135 and 145. Additionally, traditional 2314 DASD units like the 2312 or 2318 are compatible with the 2319-A1. The 2319 B series supports configurations of three, six, or nine drives linked to a novel 2314 Model B Storage Control Unit.

IBM 3310

Released on January 30, 1979, the IBM 3310 Direct Access Storage Device was tailored for IBM 4331 midrange computer systems. Each drive provided a storage capacity of 64.5 MB and employed fixed-block architecture (FBA). It was compatible with DOS/VSE and VM operating systems running on S/370 platforms.

IBM 3330

The IBM 3330 Direct Access Storage Facility, internally codenamed Merlin, debuted in June 1970 for use with IBM System/370 and System/360/195 machines. Initially, it was available as a two-drive Model 1 and a single-drive Model 2. It utilized removable disk packs holding 100 MB each, featured an average access time of 30 ms, and supported data transfer speeds up to 806 kB/s. A noteworthy advancement was its integrated error correction, employing fire codes capable of correcting error bursts up to eleven bits, which improved dependability while lowering overall costs.

The original configuration combined a storage control unit (3830 Model 1) physically attached to one 3330 drive, with the option to bolt up to three more drives together, forming an eight-drive string.

In August 1972, IBM introduced the 3830 Model 2 Storage Control and 3333 Disk Storage and Control, which separated control units from the drive strings. The upgraded 3830 functioned as a director-type controller overseeing multiple strings. The first unit in each string—the 3333—included both a controller and two drives and could manage up to three additional attached 3330 drives, allowing eight drives per string. The enhanced 3830 Model 2 could connect two such strings simultaneously, supporting up to sixteen drives per control unit; furthermore, the 3333 offered an optional string switch enabling dual control connections for redundancy or load balancing.

In 1973, IBM released double-density (-11) variants: the models designated as 3333–11 and 3330-11 along with larger-capacity (200 MB) disk packs labeled as the 3336–11. Mixing standard-density and double-density drives within a single string was not supported. Field upgrades from original models to Model-11 versions were feasible but required converting drives and migrating data accordingly.

The IBM 3330 series was phased out in 1983.

IBM 3340 and IBM 3344

While sharing many characteristics, the IBM 3340 and IBM 3344 differ in their string leadership capabilities: only the IBM 3340 can function as the head of a string. The IBM 3344 must be connected behind a head-of-string IBM 3340 A model since there are no head-of-string capable A model variants of the IBM 3344 available.

IBM 3340

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

This system utilized removable data modules that incorporated both the head and arm assembly. Unlike earlier disk packs, the module’s access door opened automatically during loading and unloading, removing the need to detach covers manually. The drive offered a 25 ms average access time and a data transfer rate of 885 kB/s. Three IBM 3348 Data Module versions were available, providing capacities of 35 MB, 70 MB, and a 70 MB model equipped with 500 KB of fixed heads for accelerated access. The 3340 included error correction features and remained in production until 1984.

Developed under Ken Haughton’s guidance at IBM’s San Jose facility, the design initially targeted two removable 30 MB modules—this inspired the Winchester codename, referencing the .30-30 rifle. Although storage capacity was later expanded, the nickname endured.

A significant technological breakthrough was its cost-effective head design that allowed heads to land on and lift off from spinning disks without unloading. This "Winchester technology" greatly simplified the head and arm mechanism, leading to reduced manufacturing expenses. The approach set a precedent widely embraced across disk drive production.

The terms Winchester or Winnie remained popular descriptors for hard drives into the early 1990s but gradually fell out of common usage thereafter.

IBM 3344

The IBM 3344 shares similarities with the 3340 but differs by employing fixed media instead of removable IBM 3348 data modules. Each spindle contained four logical drives, each matching the capacity of a 3348–70 module. Available solely as dual-drive configurations, it lacked an A-series (head-of-string) model. The 3344-B2F variant differed from the standard 3344-B2 by incorporating fixed heads over certain cylinders on both drives. Both models required a 3340-A2 or 3340-A2F unit to serve as the head-of-string controller. Internally, the IBM 3344 was identical to the IBM 3350 except for differences in control unit microcode.

IBM 3350

Released in 1975 for IBM System/370 systems, the IBM 3350 Direct Access Storage Facility bore the codename Madrid. It introduced sealed, non-removable head-disk assemblies (HDAs) that combined heads and arms into integrated units, establishing sealed HDAs as a standard for IBM DASD moving forward. Each HDA contained 555 cylinders, supported by 30 heads, with approximately 19,069 bytes per track—resulting in around 317 MB total capacity per assembly.

Models such as A2, A2F, B2, B2F, C2, and C2F housed two HDAs each. The A2 and A2F units included an additional electronics board which enabled connection to storage control units and functioned as controllers or head-of-string devices. These units were arranged in strings beginning with an A2 or A2F followed by up to three B2 units or combinations including C2 units. Typically, an A2 model featured a string switch allowing simultaneous attachment to two storage control units for concurrent I/O operations across HDAs. Supported control units comprised the Model 2 of the IBM 3830 Storage Controller, Integrated Storage Controllers within CPUs like the IBM 3148, and later backward-compatible models such as the IBM 3880. The C2 unit contained a backup controller usable if the primary controller on an A unit failed but offered limited connection capabilities.

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

The suffix "x2F" (for example, A2F) denoted that both HDAs featured fixed-head areas spanning the first five cylinders. This design eliminated seek times within this zone and was intended to boost performance for frequently accessed data such as HASP or JES checkpoint files and system swap areas used by TSO environments (MVT, SVS) and MVS systems by reducing head movement and improving context-switching efficiency.

The IBM 3350 product line was retired in September 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 model incorporated seven fixed 14-inch platters, delivering a storage capacity of 571 MB per unit. It was notable as the first hard disk drive to implement thin-film head technology, developed at IBM's Thomas J. Watson Research Center. The 3370 utilized a fixed-block architecture and was compatible with DOS/VSE and VM operating systems on S/370 platforms.

IBM 3375

The complementary IBM 3375 employed count key data architecture, which was necessary for operating systems such as OS/360 and its successors.

IBM 3380

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

Standard setups typically consisted of one A unit alongside up to three B units; each 3380 housed four devices, enabling as many as sixteen devices per string. These units generally connected to a 3880 storage control unit via dual paths, facilitating concurrent I/O operations targeting different hard disk assemblies.

In February 1985, IBM introduced the Extended Capability Models (3380 E) featuring double density with a capacity of 5.04 GB per unit—two actuators each managing 1.26 GB. Later, in August 1987, the triple-capacity variant known as the 3380 K was announced, providing 7.562 GB per unit with two actuators at 1.89 GB each. Models J and K included an optional four-path mode supporting up to thirty-two devices per string when linked to a 3990 storage control unit, allowing four simultaneous I/O processes.

The IBM 3380 family encompassed twelve models: six A-units (which served as string heads incorporating controller logic), five B-units (attachable to A- or C-units), and one C-unit (offering direct channel connectivity). The final models were retired in May 1996 after an extensive fifteen-year production period.

IBM 3390

Introduced in November 1989, the IBM 3390 series of Direct Access Storage Devices provided capacities reaching up to 22 gigabytes distributed across multiple drives. Depending on configuration and size, system prices ranged from $90,000 to $795,000.

A typical 3390 configuration includes a central A unit containing four or eight devices, optionally accompanied by one or two B units each housing up to twelve devices. Operating in four-path mode when connected to a 3990 storage control unit, the system can support a second string of 3390 devices for a total of sixty-four devices.

The Hard Disk Assemblies (HDAs) consist of two actuator-head units and platters: Model 1 delivers an unformatted capacity of 1.89 GB per HDA; Model 2 doubles this to 3.78 GB per HDA. Announced in September 1991, Model 3 increased capacity by fifty percent to reach 5.67 GB per HDA, while Model 9 (introduced in May 1993) tripled it further to achieve 11.3 GB per HDA.

Unlike previous DASD models that employed AC motors for HDAs, the IBM 3390 series incorporated DC motors integrated within the enclosure itself. Notably, Model 9 marked IBM’s final iteration of the Single Large Expensive Disk (SLED) drive design.

IBM 9345

Released in November 1990 as a special order 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. It offered capacities up to 1.5 GB within a full-height 5¼-inch enclosure, utilizing as many as eight 130 mm platters. Notably, it was the pioneering HDD to employ Magnetoresistive (MR) read/write heads.

IBM 9340

In October 1991, IBM launched the 9345 DASD as a member of the 9340 channel-attached count key data (CKD) DASD subsystem series designed for IBM mainframe systems, including the ES/9000 line. The Model 1 of the 9345 incorporated two HDDs each with 1.0 GB capacity, whereas Model 2 contained two drives with 1.5 GB each.

From a functional perspective, the 9340/9345 models paralleled the features of the 3990/3390 series; however, they did not include the non-volatile RAM cache found in the 3990 and supported a shorter maximum block size compared to the 3390.

During system initialization, the OS Input/Output Supervisor (IOS) utilized a specialized initializer named IECCINIT to identify this device’s properties. It acknowledged the absence of non-volatile cache in the 9340 and noted the limited track count in the 9345, leading to these devices being assigned distinct device types different from those of the 3990/3390.

9330 family of disk drives

  1. The 9331 Diskette Unit models 1 and 11 included a single 8-inch floppy disk drive; models 2 and 12 featured one 5¼-inch floppy disk drive.
  2. The IBM 0667 HDD was employed in the 9332 Direct Access Storage Device.
  3. The high-performance disk drives within the 9333 subsystem utilized either IBM 0664 or IBM 0681 HDDs depending on specific configurations.
  4. The 9334 Disk Expansion Unit connected between one and four SCSI hard drives to RS/6000 platforms.
  5. Featuring an IBM-designed "Kestrel" HDD, the 9335 Direct Access Storage Subsystem contained an 850 MB drive made up of three large 14-inch disks with dual rotary actuators that accessed several surfaces. Announced in October 1986 alongside the IBM 9370 Information System, this rack-mountable unit had no known OEM equivalents.
  6. The IBM 0681 (Redwing) HDD powered the 9336 Disk Unit.
  7. The IBM 0662 (Spitfire) or IBM 0663 (Corsair) HDDs were integrated into the 9337 Disk Array Subsystem.

IBM 2310

The IBM 2310 Removable Cartridge Drive debuted in 1964 with the IBM 1800 and was subsequently introduced with the IBM 1130 in 1965, likely first shipping late that year with the latter system. It stored a total of 512,000 sixteen-bit words (equivalent to just over one million bytes) on an IBM 2315 cartridge. This cartridge consisted of a single fourteen-inch oxide-coated aluminum platter housed within a plastic casing featuring openings for both read/write heads and their actuator arm.

IBM 5444

Introduced in September of 1969 as part of System/3 and developed at IBM's Hursley facility in England, the IBM 5444 utilized a disk cartridge known as the IBM 5440 containing one fourteen-inch platter. Its lineup included three variants:

  • Model 1: equipped with one fixed disk plus one removable disk, each having one hundred tracks per surface, providing a capacity of approximately 1.23 MB
  • Model 2: featuring one fixed and one removable disk, each with two hundred tracks per surface, delivering around 2.46 MB
  • Model 3: consisting solely of one removable disk with two hundred tracks per surface, also offering about 2.46 MB

IBM 62GV

The IBM 62GV, which began shipping in May of 1974 from IBM’s Hursley laboratory under its codename Gulliver, initially delivered five megabytes of storage capacity. Subsequent versions increased capacity to ten megabytes (62TM) and fourteen megabytes. This model incorporated a Swinging Arm actuator mechanism paired with a single fourteen-inch platter. The Swinging Arm design became one of IBM’s most widely licensed electromechanical innovations, adopted industry-wide throughout HDD manufacturing during the eighties and remaining prevalent nearly four decades later. Approximately 177,000 units of the IBM 62GV were sold, marking it as the first hard drive to surpass sales of one hundred thousand units.

OEM and Small Systems Hard Drives

This segment details IBM-produced hard disk drives marketed as OEM components and utilized in IBM's smaller systems, including the System/3, System/32, /34, /36, and AS/400 series. The drives are categorized by their OEM model designations and arranged according to their initial shipment dates.

IBM 0680

Introduced in 1979, the 0680 was deployed across many IBM small systems and the entry-level System/370 as the 3310 direct access storage device. Officially announced in September 1981 as the 0680 OEM variant, it was engineered at IBM's Hursley facility in the United Kingdom under the project name Piccolo. This model incorporated six 8-inch (210 mm) platters with an enhanced rotary actuator and initially offered storage capacities up to 65MB.

A version with doubled capacity, known as the 62SW, was launched in June 1984; however, its market penetration was limited due to pricing comparable to the 62GV model.

IBM 0676

The 0676 made its debut in November 1982 as part of the 5247 Disk Storage Unit designed for the IBM System/23 Datamaster. Developed at IBM Rochester, Minnesota under the internal code 21ED, this 8-inch hard drive initially provided options for either 15MB or 30MB capacity distributed over two or four platters. By 1983, it was integrated into the S/36's 5360 System Unit. In 1984, its capacity was enhanced by increasing track density per platter surface and subsequently incorporated into the S/36's 5362 System Unit.

IBM 0665

The 0665 entered production in October 1985 as part of the PC AT (5170) system configuration. Created under the codename "Pixie" at IBM Rochester, this 5-inch hard drive offered multiple capacity options of 20MB, 30MB, and 44MB.

IBM 0667

Released in August 1986, the 0667 was developed at IBM Rochester with the project name "Grant." This full-height ESDI format 5-inch hard drive contained up to four platters measuring 130 mm each and provided a maximum capacity of 70MB. It was installed in select PC RT models (6150, 6151, and 6152) as well as System/36 Model System Units (5363 and 5364).

IBM 0669

The 0669, introduced in 1987 and designed at IBM Rochester under the codename "Grant-Prime," was a full-height, five-inch hard drive supporting up to four 130 mm platters with a total capacity reaching 115 MB. This model served as the internal drive for both the System/36 5363 and Series 1 4956 System Units.

IBM 0671

Also launched in 1987 from IBM Rochester under the internal name "Lee," the 0671 was a full-height five-inch ESDI hard disk offering a maximum of 316 MB storage across eight platters sized at 130 mm each. This drive represented IBM’s inaugural use of thin metal film recording technology and was incorporated into the IBM AS/400 9404 System Unit in 1988, supporting configurations with two or three drives.

IBM 0661

First shipped in 1989 as model number 371, the 0661 was developed collaboratively at IBM Rochester and Hursley under the codename "Lightning." It was a SCSI hard disk providing up to 320 MB across eight platters measuring 95 mm each. A subsequent "Turbo" variant delivering a capacity of 400 MB appeared in 1990. This model became a standard component within several IBM systems, including the AS/400 System Unit Model CXX.

IBM 0681

Introduced in April of 1990 and produced at IBM Hursley under the codename Redwing, the 0681 marked Hursley’s final hard disk product. It featured a full-height five-inch form factor housing twelve platters of 130 mm diameter, delivering capacities up to 857 MB. This model also pioneered PRML data decoding technology. It powered the early-1992 release of the 9333 Disk Drive Subsystem, which later that year received an upgraded version offering increased density with a capacity of approximately 1.07 GB.

IBM 0663

Introduced in late 1991 and internally designated "Corsair," the 0663 was a compact 3-inch hard disk drive featuring a half-height (1.6-inch) form factor. It offered a storage capacity of up to 1 GB across eight 95 mm platters. This model was incorporated into select PS/2 and RS/6000 systems and marked IBM’s first use of Magnetoresistance (MR) heads in an OEM drive.

IBM 0664

Released in November 1992, the 0664 was developed at IBM Rochester, Minnesota, under the codename "Allicat." This full-height 5-inch HDD, measuring 3.25 inches in height, effectively combined two 3-inch drives and provided a maximum capacity of 2.013 GB utilizing up to eight 95 mm disks.

IBM 0662

The 0662, launched in June 1993 and known as "Spitfire" during development at IBM Rochester, was a full-height (1-inch tall) 3-inch hard drive. It delivered 1.05 GB of storage using three platters or five recording surfaces. This drive was deployed internally within the 9336 Disk Unit and the 9337 Disk Array.

Floppy disk drive

IBM was a pioneer in floppy disk technology, introducing the initial 8-inch floppy disk drive in 1971 as a read-only device for program loading. The company then released its first read/write floppy disk drive in 1973 alongside the 3740 Data Entry System. Although IBM established early standards for the 8-inch floppy format, it refrained from selling these drives independently, allowing the broader market to develop on its own.

At one time, IBM was the largest original equipment manufacturer (OEM) buyer of 5-inch floppy disk drives. Its preference for two-sided models with a density of 48 tracks per inch contributed significantly to making this format an industry benchmark. Despite plans to produce these and smaller sizes, IBM discontinued all such projects by 1985. Additionally, its 1983 initiative to OEM the smaller 4-inch DemiDisk was unsuccessful.

"Star" series of HDDs

On October 17, 1994, IBM Storage Systems unveiled three new families of hard drives: the Travelstar series featuring compact 2-inch drives designed for laptops; the Deskstar line consisting of 3-inch drives aimed at desktop computers; and the Ultrastar series comprising high-performance 3-inch drives intended for demanding applications.

IBM's first HDD versus its last HDDs

The following table contrasts IBM’s original hard disk drive, the RAMAC 350, with the final three models from its "Star" series of OEM HDDs. The comparison highlights remarkable advancements including substantial reductions in physical size and cost alongside dramatic improvements in storage capacity and operational performance.

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
Capacity (gigabytes) 0.004 146 180 80 48,000×
Dimensions (inches) 60×68×29 4×1×5.75 4×1×5.75 2.75×0.38×3.95
Dimensions (millimeters) 1500×1700×700 102×25×146 102×25×146 70×9.5×100
Volume (cubic inches) 118,320 23 23 4 29,161×
Volume (liters) 1,939 0.4 0.4 0.1
Weight (pounds) 2,140 1.7 1.4 0.2 1,244×
Weight (kilograms) 971 0.8 0.64 0.095
Power consumption (watts) ~2374 watts (~8100 BTUs/hour), up to 5500 VA depending on variant 16 10.3 1.85 1,283×
Power efficiency (megabytes per watt) 0.0016 9,125 17,476 43,243 27,375,856×
Retail price (Template:US$) \$34,500 (\$234,000 adjusted to 2002 dollars) \$1,200 \$360 \$420
Cost per megabyte (Template:US$) \$9,200 (\$68,000 adjusted to 2002 dollars) \$0.0082 \$0.0020 \$0.0053
Areal density (megabits per square inch) 0.002 26,263 46,300 70,000
Areal density (kilobits per square millimeter) 0.003 40,708 71,765 108,500
Volumetric density (gigabytes per cubic inch) 0.00000003 6 8 20
Volumetric density (megabytes per cubic centimeter) 0.000002 388 478 1,203
Average rotational latency (milliseconds) 25 3 4 7
Average seek time (milliseconds) 600 5.9 10.2 12
Data transfer rate (megabytes per second) 0.001 103 29.4 43.75


DASD Devices Beyond HDDs and FDDs

Within certain IBM operating systems, 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 technology encompass the following:

IBM 7320 Drum

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

IBM 2301 Drum

The IBM 2301, a magnetic drum storage device, was launched during the late 1960s.

IBM 2303 Drum

Released in 1964, the IBM 2303 is another example of a magnetic drum storage apparatus.

IBM 2321 Data Cell

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

IBM 3850 Mass Storage System

The IBM 3850 Mass Storage System, introduced in 1974, is a tape cartridge library designed to stage data onto IBM 3330 or 3350 disk drives. This system presents these drives as virtual devices to the host system.

See also

External links

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