Jump to content

IBM 3350

From Alfawiki
IBM Magnetic Disk Storage Division
Company typeDivision
IndustryComputer storage
Founded1956
Defunct2003
FateDivested to Hitachi
Key people
Currie Munce (research vice president at Hitachi Global Storage Technologies)
ProductsHard disk drives (HDD), Floppy disk drives (FDD)
ParentIBM

IBM produced magnetic disk storage units from 1956 until 2003, at which point it divested its hard disk drive division to Hitachi. IBM's workforce was responsible for inventing both the hard disk drive (HDD) and the floppy disk drive (FDD), pioneering numerous advancements in these fields. The essential mechanical architecture of hard disk drives has remained largely unchanged since the introduction of the IBM 1301, and performance benchmarks have adhered to consistent standards dating back to the 1950s. Over time, this product category has experienced substantial declines in cost and physical dimensions, coupled with dramatic improvements in storage capacity and efficiency.

Between 1969 and the mid-1980s, IBM manufactured 8-inch floppy disk drives but did not become a significant player in producing smaller formats such as 5.25-inch or 3.5-inch drives. While IBM sold magnetic disk drives, it only began distributing them under original equipment manufacturer (OEM) agreements starting in 1981. By 1996, IBM had discontinued producing hard disk drives exclusively for its own systems, making all HDDs available solely as OEM products.

IBM has employed multiple designations for its magnetic disk drives over time, including direct-access storage device (DASD), disk file, and diskette file; however, this article adopts the contemporary industry terminology hard disk drive (HDD) and floppy disk drive (FDD).

IBM 350

The IBM 350 disk storage unit, recognized as the inaugural disk drive, was introduced by IBM on September 14, 1956, as part of the IBM 305 RAMAC system. A related model, the IBM 355, was launched for the IBM 650 RAMAC system. The acronym RAMAC stood for "Random Access Method of Accounting and Control". The initial prototype was delivered to Zellerbach Paper Company in June 1956, with production units dispatched beginning November 1957 to United Airlines.

Engineered to fulfill real-time accounting requirements, the IBM 350 offered storage for five million 6-bit characters (equivalent to 3.75 MB). It incorporated fifty-two disks measuring in diameter, providing a total of 100 recording surfaces and tracks spinning at a velocity of 1200 rpm. The data transfer speed reached 8,800 characters per second. Its access mechanism allowed vertical and radial movement of read/write heads to select specific tracks. Throughout the 1950s, several enhanced variants were released. The IBM RAMAC 305 system equipped with the 350 was leased at $3,200 monthly. Production of the IBM 350 ceased in 1969.

The patent derived from the RAMAC initiative is regarded as foundational for disk drive technology. Although initially rejected by IBM's Board over concerns about its potential disruption to punch card operations, development persisted until receiving approval from IBM’s president.

The physical dimensions of the IBM 350 cabinet measured approximately long, high, and wide. Weighing nearly one ton, it necessitated forklift handling and transportation via large cargo aircraft. Currie Munce, then research vice president at Hitachi Global Storage Technologies (which acquired IBM’s storage division), noted that while capacity could have surpassed five million characters, marketing hesitated to promote larger drives due to uncertain sales prospects. Nevertheless, models with double capacity were announced in January 1959 and shipped later that same year.

In recognition of its significance, the RAMAC 350 Disk File was designated an International Historic Landmark by The American Society of Mechanical Engineers in 1984. A restoration effort led by Al Hoagland commenced in 2002 at Santa Clara University, focusing on an IBM 350 RAMAC unit. By 2005, this project transitioned to the Computer History Museum, where it is currently exhibited within the Revolution gallery for public viewing.

IBM 353

The IBM 353, utilized with the IBM 7030, resembled the IBM 1301 but offered an enhanced transfer speed. It provided a storage capacity of 2,097,152 (221) 64-bit words, equivalent to 134,217,728 bits, and achieved data transfer rates of 125,000 words per second. A prototype delivered in late 1960 was notable as the first disk drive to employ one head per surface that flew on compressed air, similar to the IBM 350 disk storage (RAMAC). Production versions incorporated self-flying heads comparable to those found in the IBM 1301.

IBM 355

Introduced on September 14, 1956, the IBM 355 served as an accessory to the widely-used IBM 650 system. It featured the IBM 350 mechanism but increased the number of access arms to three (compared to one on the IBM 350), and could hold 6 million decimal digits plus an additional 600,000 signs. Data was transferred in full tracks between the disk and the magnetic core memory of the 653 option, which contained sixty signed 10-digit words—sufficient for a single disk track or tape record—alongside two other unrelated functions.

IBM 1405

Launched in 1961 for the IBM 1400 series business computers, the IBM 1405 Disk Storage Unit was available in two variants: Model 1 stored up to 10 million alphanumeric characters (60 million bits) across 25 disks; Model 2 doubled this capacity to 20 million characters (120 million bits) using 50 disks. The disks rotated vertically at a speed of 1,200 rpm.

Each disk surface was divided into 200 tracks segmented into five sectors (numbered 0–4 on the top side and 5–9 on the bottom). Each sector accommodated either 178 or 200 characters. Access was managed by one to three forked arms, each fitted with two read/write heads—one per disk side—that moved both vertically and horizontally through electronic control systems to reach specific disks and tracks. Reading or writing a sector required approximately 10 milliseconds.

Access times varied from as low as 100 milliseconds up to a maximum of about 700 milliseconds for Model 1 and up to 800 milliseconds for Model 2. Model 2 contained around 100,000 sectors capable of holding either 200 characters in move mode or 178 characters in load mode, which included an additional word mark bit per character. Model 1 had half as many sectors, totaling approximately 50,000.

IBM 7300

The IBM 7300 Disk Storage Unit was created for use with the IBM 7070 system; its Model 2 version was announced in 1959. Nevertheless, following the release of the IBM 1301 on June 5, 1961, customers using the IBM 7070 and IBM 7074 preferred switching to the IBM 1301 over the IBM 7300. The technology within the IBM 7300 shared elements with 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 was designed for integration with IBM’s 7000 series mainframes and the IBM 1410. Each module could store up to 28 million characters (168 million bits)—or approximately 25 million characters when paired with the IBM 1410. A module contained twenty-five large disks featuring forty user-accessible recording surfaces and two hundred fifty tracks per surface. The Model 1 consisted of a single module; Model 2 stacked two modules vertically. Disks rotated at a speed of eighteen hundred rpm, providing data transfer rates of ninety thousand characters per second.

A significant advancement was having an individual arm and read/write head dedicated to each recording surface; these moved simultaneously like a comb assembly. This innovation eliminated delays caused by moving heads between disks and reduced maximum access time to only one hundred eighty milliseconds. Additionally, the IBM 1301 was pioneering in using aerodynamically designed heads that hovered on a thin cushion of air above disk surfaces to improve performance.

Connectivity was established through the IBM 7631 File Control unit, enabling compatibility with either IBM 1410 or IBM 7000 series systems or allowing sharing between two computers.

Leasing fees for Model 1 were set at $2,100 monthly or $115,500 for outright purchase; Model 2 leased at $3,500 monthly or $185,000 to buy. The IBM 7631 controller cost $1,185 per month or $56,000 purchased outright. All variants were discontinued by 1970.

IBM 1302

Launched 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 incorporated two separate access mechanisms dedicated to the inner and outer cylinders. The Model 2 configuration stacked two such modules to double overall storage capacity. Monthly leasing fees were set at $5,600 for Model 1 and $7,900 for Model 2, while outright purchase prices stood at $252,000 and $355,500 respectively. Adding the IBM 7631 controller increased costs by $1,185 per month or $56,000 for purchase. The IBM 1302 was discontinued in February 1965.

IBM 1311

Introduced on October 11, 1962, the IBM 1311 Disk Storage Drive targeted 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 variations were launched before being phased out by the early 1970s.

Each IBM 1316 disk pack measures approximately four inches in height and weighs about ten pounds. It contains six disks measuring fourteen inches in diameter with ten usable recording surfaces. These disks rotate at 1500 revolutions per minute and employ ten read/write heads mounted on a hydraulically controlled actuator arm. Every surface is organized into 100 tracks with 20 sectors per track; each sector accommodates 100 characters. The disk pack is encased within a plastic shell to safeguard it during handling.

The IBM 1311 system included master drives equipped with controllers that managed multiple Model 2 slave drives:

  1. Master drive compatible with IBM 1440, 1460, or 1240 systems; capable of controlling up to four Model 2 drives (1962–1971).
  2. Slave drive designed to support specialized features of its master drive (1962–1975).
  3. Master drive for IBM 1620 or 1710 systems; controls up to three Model 2 drives without additional features (1962–1971).
  4. Master drive intended for IBM 1401 systems; manages up to four Model 2 drives (1962–1971).
  5. Master drive for IBM 1410, 7010, or 7740 systems; handles up to four Model 2 drives and includes standard Direct Seek functionality (1963–1971).
  6. & #7 Likely represent master and slave models introduced in 1968 and withdrawn by the early seventies.

Available optional enhancements comprised:

  • Direct Seek: Removes the need to return to track zero before seeking a new track.
  • Scan Disk: Enables rapid automatic scanning for specific identifiers or conditions.
  • Seek Overlap: Permits overlapping seek operations with simultaneous read/write activities across multiple drives.
  • Track Record: Increases storage capacity by writing one large record per track instead of dividing into sectors, boosting total storage up to roughly 18.7 million bits.

Master drives are approximately one foot wider than slave units due to additional power supply components and control circuitry.

IBM 2302

The IBM 2302 represents the System/360 adaptation of the 1302 disk storage unit, reformatted for the S/360 DASD architecture rather than the earlier 7000 series. It employs a fixed module containing twenty-five platters with forty-six recording surfaces. The Model 3 includes a single module; Model 4 incorporates two modules. Each module contains two independent access mechanisms—referred to as access groups—serving the innermost and outermost sets of 250 cylinders respectively. Every access mechanism provides one read/write head per track. The average rotational latency is approximately seventeen milliseconds, with a maximum delay of thirty-four milliseconds, while maximum seek time per access group reaches up to one hundred eighty milliseconds. Tracks hold about 4,985 bytes each; after formatting and including alternate tracks for reliability, each module offers around 112 megabytes of storage capacity. Connectivity to IBM mainframes is achieved through the IBM 2841 Storage Control Unit.

IBM 2305

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

With the advent of Virtual Storage on System/370, the 2305 became increasingly popular, frequently utilized as a paging device on systems such as the 3155, 3165, 3158, 3168, 3033, 4341, and 3081 (the latter requiring specialized microcode). It also served well for managing small, high-transaction data sets like catalogs and job queues.

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

Engineered for rapid and uninterrupted access to modest-sized data volumes, the 2305 was ideal for resident system files, work datasets, job queues, indices, and frequently accessed information. Its swift response times made it particularly suitable for paging tasks in systems with heavy workloads exceeding 1.5 transactions per second.

IBM 2311

Introduced in 1964 together with the 2841 Control Unit, the IBM 2311 Disk Storage Drive was designed for compatibility across 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 removable IBM 1316 Disk Packs, initially launched with the IBM 1311.

The Model 1 version of the 2311 links to most IBM mainframes via the 2841 Control Unit; however, for the System/360 Model 25, a Disk Attachment Control unit provides control functions. Disk packs are formatted using IBM's count key data variable-length record structure.

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

While mechanically akin to the IBM 1311, the 2311 features enhanced recording technology and stores 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 that locks mechanically at each track position. Each disk surface contains 200 tracks plus three spare tracks for defect management. The average seek time is approximately 85 ms with a data transfer rate reaching up to 156 kB/s.

The standardized electrical interface across System/360 systems enabled third-party manufacturers to develop plug compatible disk drives, fostering a competitive market for IBM-compatible storage products.

IBM 2314 Disk Access Storage Facility Model 1

Released in April 1965, the IBM 2314 Disk Access Storage Facility Model 1 supported both System/360 and System/370 platforms, featuring an optional Two Channel Switch that allowed simultaneous connection to two channels. Its disk mechanism shared similarities with the IBM 2311 but achieved higher data density.

This drive holds about 29 million characters on a removable IBM 2316 disk pack composed of eleven diameter disks providing twenty recording surfaces. The actuator carries twenty individual read/write heads hydraulically positioned and mechanically latched at each track; each surface includes approximately 200 tracks. Subsequent versions improved upon the original model’s access times while doubling data transfer speeds to roughly 310 kB/s.

The Model 1 was delivered as nine interconnected disk drives managed by a separate storage control unit—comprising one single-drive module plus two four-drive modules. The drives were installed in drawers facilitating easy disk pack replacement, earning them the nickname "Pizza Ovens." Eight drives could be accessed simultaneously while the ninth remained offline as a spare to allow maintenance without interrupting operation. Each drive’s system address was configurable via user-swappable plugs, permitting physical reassignment or designation as a spare drive.

An optional IBM 2844 Control Unit provided dual-channel capability enabling concurrent access to two distinct drives within the storage facility.

Additional variants of the IBM 2314 were introduced subsequently:

IBM 2314 Direct Access Storage Facility - Model Variants

In 1969, IBM segmented the original facility into distinct models, each accommodating up to nine drives (with eight accessible online) connected to a 2314 Storage Control:

  • 2312 Disk Storage, featuring a single-drive configuration.
  • 2313 Disk Storage, comprising four drives per module.
  • 2318 Disk Storage, designed with two drives in a unit.

IBM 2319

To challenge plug compatible manufacturers producing storage comparable to the 2314, IBM launched the cost-effective three-drive 2319 series in 1970 by removing one drive from the four-drive 2313 and marketing it as the 2319 A1 at significantly lower rental fees. This approach reduced expenses for new clients while preserving higher charges for existing users. The 2319-A1 connects to integrated controllers used with System/370 Models 135 and 145; it also supports attachment of standard 2314 DASD units like the 2312 or 2318. The 2319 B series offers 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 specifically for IBM 4331 midrange computer systems. Each drive provided a capacity of 64.5 MB and utilized fixed-block architecture, compatible with DOS/VSE and VM operating systems on S/370 platforms.

IBM 3330

The IBM 3330 Direct Access Storage Facility, internally referred to as Merlin, debuted in June 1970 targeting IBM System/370 and System/360/195 environments. Initially offered as Model 1 (two drives) and Model 2 (one drive), it employed removable disk packs with a storage capacity of 100 MB each, a 30 ms access latency, and a data transfer rate of 806 kB/s. A notable advancement was built-in error correction via fire codes, which improved dependability and lowered costs by allowing tolerance for disk surface defects.

The foundational setup consisted of a storage control unit (3830 Model 1) that could connect to between one and four drives in a series (up to eight drives maximum). In August 1972, IBM introduced the separate 3830 Model 2 Storage Control alongside the 3333 Disk Storage and Control, where a director-type controller managed multiple drive strings. The initial unit in each string—the 3333—combined controller functions with two drives and was capable of managing up to three additional attached 3330 units, enabling up to eight drives per string. The 3830 Model 2 allowed connection of two such strings for a maximum of sixteen drives under one control unit; additionally, the 3333 optionally supported linkage to two storage controls via a string switch.

In 1973, IBM rolled out double-density (-11) variants—3333–11, 3330-11, and 3336–11—that doubled disk pack capacity to 200 MB. Mixing single-density and double-density drives within the same string was not permitted. Upgrading from original models to Model 11 in the field was possible but involved complex procedures requiring drive conversion along with complete data migration.

The IBM 3330 series was discontinued in 1983.

IBM 3340 and IBM 3344

While the IBM 3340 and IBM 3344 share many characteristics, only the IBM 3340 can function as the head of a drive string; there are no A model versions of the IBM 3344, which must be connected to an IBM 3340 A model serving as the head unit.

IBM 3340

Introduced in March 1973 for the IBM System/370, the IBM 3340 Direct Access Storage Facility, known internally as Winchester, came in three configurations: the 3340-A2 with two drives plus a controller, the B2 with two drives, and the B1 featuring a single drive. Up to eight B-units could be linked to an A2 controller.

This system utilized removable data modules that housed both the head and arm assemblies; the module’s access door mechanically opened and closed during load and unload operations, eliminating the need to remove any covers. It offered an average access time of 25 milliseconds and a data transfer rate of 885 kB/s. Three variants of IBM 3348 Data Modules were available, providing storage capacities of 35 MB, 70 MB, and a 70 MB model with an additional fixed-head segment of 500 KB designed for faster retrieval. The 3340 incorporated error correction technology and remained in production until its withdrawal in 1984.

Developed under Ken Haughton’s leadership at IBM San Jose, the initial concept centered on two removable 30 MB modules. The codename "Winchester" was inspired by the .30-30 rifle cartridge due to this dual-module design; although storage capacities expanded over time, the nickname persisted.

A significant advancement was the introduction of a cost-effective head design allowing the heads to land on and take off from spinning disks without unloading, thereby simplifying mechanics and reducing expenses considerably. This feature, termed "Winchester technology," set a new industry benchmark for disk drives.

Throughout the early 1990s, "Winchester" or "Winnie" became generic terms for hard disk drives but have since fallen out of common usage worldwide.

IBM 3344

The IBM 3344 bears similarity to the 3340 but differs by employing fixed media instead of detachable 3348 data modules. Each spindle supports four logical drives, each matching the capacity of a single 3348–70 module. This model was offered exclusively as dual-drive units and did not include an A (head-of-string) variant. The 3344-B2F version features fixed heads positioned over certain cylinders on both drives. Both the 3344-B2 and 3344-B2F require connection to a 3340-A2 or 3340-A2F unit acting as head-of-string. Internally, the architecture aligns with that of the IBM 3350; distinctions lie solely in control unit microcode.

IBM 3350

Launched in 1975 for IBM System/370, the IBM 3350 Direct Access Storage Facility—code-named Madrid—featured sealed head-disk assemblies (HDAs) integrating both heads and arms in a non-removable design. Its disk geometry consisted of 555 cylinders, 30 heads per cylinder, and approximately 19,069 bytes per track, resulting in around 317 MB capacity per HDA. The adoption of sealed HDAs set a precedent for later IBM DASD products.

The product line included models A2, A2F, B2, B2F, C2, and C2F, each housing two HDAs. Models A2 and A2F incorporated an additional electronic board facilitating connection to storage control units—often referred to as controllers or heads-of-string. These units were arranged in strings beginning with an A2 or A2F unit followed by up to three B2 units or combinations including C2 units. Typically, the A2 model contained a string switch enabling concurrent I/O operations across two distinct HDAs via dual control units such as the IBM 3830 Model 2 or Integrated Storage Control (ISC) embedded within IBM CPUs like models 3148, 3158, and 3168. Subsequent controllers like the IBM 3880 maintained backward compatibility. The C2 unit also housed a controller serving as a secondary path but was primarily reserved as a backup if the A unit’s controller failed; however, its connectivity options were limited.

Valid string configurations for the IBM 3350 included -A, -AB, -ABB, -ABBB, -AC-, -ABC-, and -ABBC- arrangements.

Models designated with "x2F" (such as A2F) featured fixed-head zones spanning the first five cylinders on both HDAs. This design eliminated seek time within that area and was typically allocated for frequently accessed files like HASP or JES2 checkpoint data to reduce head movement on spool devices. Additionally, it supported TSO swap data along with system swap data utilized by OS/360 successors (MVT and SVS) and MVS by optimizing context switching between users or batch jobs.

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

IBM 3370

Released in January 1979 for IBM 4331, 4341, and System/38 midrange systems, the IBM 3370 was equipped with seven fixed 14-inch platters, delivering a storage capacity of 571 MB. It was pioneering as the initial hard disk drive to implement thin-film head technology, which originated at the Thomas J. Watson Research Center during the late 1960s. The 3370 utilized a fixed-block architecture and was compatible with DOS/VSE and VM operating systems on S/370 platforms.

IBM 3375

The IBM 3375 served as a complementary model featuring count key data architecture and supported OS/360 along with its subsequent versions.

IBM 3380

Debuting on June 11, 1980, the IBM 3380 employed film head technology and offered a storage capacity of 2.52 GB per unit, consisting of two hard disk assemblies each with dual actuators accessing 630 MB. It achieved a data transfer speed of 3 MB/s and an average seek time of 16 milliseconds. Initial pricing varied between $81,000 and $142,200. Due to challenges related to tribology between the heads and media, deliveries commenced in October 1981.

Configurations for the IBM 3380 included one A unit plus up to three B units; since each unit contained four devices, strings could comprise as many as sixteen devices. Typically connected through a 3880 storage control unit with dual-path capability, it allowed two concurrent I/O operations targeting different hard disk assemblies.

In February 1985, IBM launched the Extended Capability Model (3380 E) with double density, doubling capacity to 5.04 GB per unit. Later in August 1987, the Model K tripled this capacity to 7.562 GB per unit and introduced optional four-path mode connectivity via a 3990 storage control unit, supporting up to four simultaneous I/O processes across as many as thirty-two devices.

The IBM 3380 series consisted of twelve models: six A-units (which housed string heads and controller logic), five B-units (attached to either A- or C-units), and one C-unit (providing direct channel connectivity). Production concluded in May 1996 after a distinguished fifteen-year lifecycle.

IBM 3390

The IBM 3390 Direct Access Storage Device line was launched in November 1989, delivering storage capacities up to 22 gigabytes across multiple drives. The price range for systems varied from $90,000 to $795,000 depending on configuration and capacity.

A typical 3390 string includes a central A unit containing four or eight devices, along with up to two B units that can hold as many as twelve devices each. Operating in four-path mode, it connects to a 3990 storage control unit that can optionally support an additional 3390 string, allowing for a maximum of sixty-four devices.

Hard Disk Assemblies (HDAs) feature dual actuator-head units paired with platters: Model 1 offers 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 capacity again to achieve 11.3 GB per HDA.

Distinct from earlier DASD models that used large AC motors driving HDAs via belts, the IBM 3390 incorporated DC motors housed within the enclosure itself. The Model 9 represented IBM’s final iteration of Single Large Expensive Disk (SLED) technology.

IBM 9345

The IBM 9345 hard disk drive was released in November 1990 as a Request Price Quotation (RPQ) specifically for IBM's SuperComputing Systems Extensions (SCSE). Developed at IBM’s San Jose facility under the codename Sawmill, it was a full-height drive measuring five and one-quarter inches with up to eight platters sized at 130 mm each, offering a maximum capacity of 1.5 GB. This model was notable for being the first HDD to integrate Magnetoresistive (MR) heads.

IBM 9340

In October 1991, IBM launched the 9345 DASD as a component of the 9340 family of channel-attached count key data (CKD) DASD subsystems designed for IBM mainframes, including the ES/9000 line. The 9345 Model 1 was equipped with two 1.0 GB hard disk drives, whereas Model 2 contained two 1.5 GB drives.

From a functional standpoint, the 9340/9345 series paralleled the 3990/3390 devices but did not include the non-volatile RAM cache found in the 3990 and supported a shorter maximum block length compared to the 3390. The OS Input/Output Supervisor (IOS) detected these distinctions through the IECCINIT initialization routine, which recognized the absence of non-volatile cache in the 9340 and the reduced track size in the 9345, thereby assigning unique device types accordingly.

9330 series disk drives

  1. Models 1 and 11 of the 9331 Diskette Units incorporated a single 8-inch floppy disk drive (FDD), while models 2 and 12 featured one 5¼-inch FDD.
  2. The 9332 Direct Access Storage Device utilized the IBM 0667 hard disk drive.
  3. The 9333 High Performance Disk Drive Subsystem deployed either IBM 0664 or IBM 0681 HDDs, depending on the specific model.
  4. The 9334 Disk Expansion Unit connected between one and four SCSI hard drives to RS/6000 systems.
  5. The 9335 Direct Access Storage Subsystem included an IBM Hursley-designed "Kestrel" HDD—an 850 MB device comprising three 14-inch disks and dual rotary actuators enabling access to multiple surfaces. This rack-mounted unit was introduced in October 1986 alongside the IBM 9370 Information System. There are no known OEM versions.
  6. The 9336 Disk Unit employed the IBM 0681 HDD (Redwing).
  7. The 9337 Disk Array Subsystem integrated IBM 0662 (Spitfire) or IBM 0663 (Corsair) hard disk drives.

IBM 2310

The IBM 2310 Removable Cartridge Drive debuted in 1964 with the IBM 1800 and subsequently in 1965 with the IBM 1130, likely shipping first with the latter in late that year. It stored a total of 512,000 sixteen-bit words (equivalent to 1,024,000 bytes) on an IBM 2315 cartridge, which consisted of a single oxide-coated aluminum disk housed within a plastic shell featuring openings for both the read/write arm and two heads.

IBM 5444

Released in September 1969 as part of System/3, the IBM 5444 was developed at IBM's Hursley facility in England under the codename Dolphin. It utilized the IBM 5440 disk cartridge containing one fourteen-inch disk. Three models were offered:

  • Model 1: included one fixed and one removable disk, each with one hundred tracks per surface, providing a cartridge capacity of approximately 1.23 MB
  • Model 2: featured one fixed and one removable disk, each with two hundred tracks per surface, doubling capacity to roughly 2.46 MB
  • Model 3: contained a single removable disk with two hundred tracks per surface, also offering about 2.46 MB capacity

IBM 62GV

The IBM 62GV, initially shipped in May of 1974 from IBM's Hursley laboratory under the codename Gulliver, started with a storage capacity of five megabytes. Subsequent versions (designated as 62TM) expanded this capacity first to ten megabytes and later to fourteen megabytes. It employed a Swinging Arm actuator paired with a single fourteen-inch disk. This actuator design became IBM’s most widely licensed electro-mechanical innovation, adopted broadly across the industry throughout the 1980s and remaining standard nearly four decades later. With production surpassing 177,000 units, the IBM 62GV was notable as the first hard disk drive to exceed shipments of one hundred thousand units.

OEM and Small Systems Hard Drives

This segment focuses on IBM-produced hard disk drives marketed as OEM components and designed for IBM's smaller systems, including the System/3, System/32, /34, /36, and AS/400 series. Drives are categorized by their OEM model numbers and arranged according to their initial shipment dates.

IBM 0680

Introduced in 1979, the 0680 was deployed in the majority of IBM small systems and entry-level System/370 models 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 contained six 8-inch (210 mm) platters, delivering up to 65MB capacity, and incorporated an enhanced rotary actuator mechanism.

A double-capacity version known as the 62SW became available in June 1984; however, its market penetration was limited due to pricing that closely matched the 62GV model.

IBM 0676

The 0676 appeared in November 1982 as part of the 5247 Disk Storage Unit for the IBM System/23 Datamaster. Originating from IBM Rochester, Minnesota under the designation 21ED, this 8-inch hard drive initially provided capacities of either 15 or 30 MB via two or four 210 mm platters. By 1983, it was incorporated into the System/36’s 5360 System Unit. In 1984, its storage doubled through increased track density per surface, leading to its inclusion in the System/36’s upgraded 5362 System Unit.

IBM 0665

Released in October 1985 within the PC AT (5170) chassis, the 0665 was developed at IBM Rochester under the codename "Pixie." This 5-inch hard drive offered storage options of 20, 30, and 44 MB.

IBM 0667

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

IBM 0669

The 0669 was introduced in 1987 by IBM Rochester, Minnesota under the internal codename "Grant-Prime." It featured a full-height form factor with a 5-inch width and supported up to four 130 mm platters for a total capacity of 115 MB. This drive served as the internal storage solution for both the System/36’s 5363 and Series 1’s 4956 System Units.

IBM 0671

Also launched in 1987, the 0671 was developed at IBM Rochester under the name "Lee." This ESDI full-height hard drive measured five inches across and housed eight platters of 130 mm diameter, achieving a maximum capacity of up to 316 MB. Notably, this model represented IBM's initial implementation of thin metal film recording technology. By 1988, it had been integrated into the IBM AS/400’s 9404 System Unit configuration, accommodating two or three drives.

IBM 0661

The 0661 made its debut in 1989 as model number 371. Initially designed under the codename "Lightning" at both IBM Rochester and Hursley in the UK, this SCSI hard disk featured eight platters measuring 95 mm each with a total of fourteen heads, delivering a capacity of approximately 320 MB. A subsequent "Turbo" variant offering a larger capacity of around 400 MB was introduced in 1990. This drive became a standard option within prominent IBM systems such as the AS/400 System Unit Model CXX.

IBM 0681

Introduced in April of 1990 from IBM’s Hursley facility under the codename Redwing—the final hard disk developed there—the 0681 provided storage capacities up to approximately 857 MB using twelve platters sized at 130 mm each within a full-height five-inch form factor. It was also notable for being IBM’s first hard drive to utilize PRML (Partial Response Maximum Likelihood) data decoding technology. The drive powered the early-1992 launch of the 9333 Disk Drive Subsystem; by May that year, an enhanced version with a higher density of about 1.07 GB had been added.

IBM 0663

Released in late 1991, the 0663—known internally as "Corsair"—was a compact 3-inch hard disk drive with a half-height (1.6-inch) profile. It provided a maximum capacity of 1 GB distributed over eight 95 mm platters. This model was incorporated into select PS/2 and RS/6000 systems and marked the first OEM HDD to utilize Magnetoresistance (MR) read heads.

IBM 0664

The 0664 became available in November 1992. Developed at IBM Rochester, Minnesota under the codename "Allicat," this full-height 5-inch drive (measuring 3.25 inches in height) combined two 3-inch units, delivering up to 2.013 GB across eight 95 mm disks.

IBM 0662

Introduced in June 1993, the 0662—codenamed "Spitfire" and also developed at IBM Rochester—was a full-height (1-inch tall) 3-inch HDD offering 1.05 GB capacity using three disks or five surfaces. It functioned as the internal hard drive for both the 9336 Disk Unit and the 9337 Disk Array.

Floppy disk drive

IBM was a pioneer in floppy disk technology, launching the first 8-inch FDD in 1971 as a read-only device for program loading, followed by its initial read/write model in 1973 within the 3740 Data Entry System. While IBM played a significant role in setting early standards for 8-inch floppy drives, it never marketed these drives individually, allowing industry-wide independent development.

At one stage, IBM was the largest consumer of OEM 5-inch floppy drives; its preference for two-sided models with a density of 48 tracks per inch helped establish this configuration as standard across the market. Although IBM planned to produce these and smaller formats internally, all such manufacturing initiatives were discontinued by 1985. Additionally, its 1983 effort to OEM a smaller 4-inch DemiDiskette was unsuccessful.

"Star" series of HDDs

On October 17, 1994, IBM Storage Systems introduced three distinct lines of hard drives: the Travelstar series featuring 2-inch drives for notebook computers, the Deskstar line with 3-inch drives designed for desktop use, and the Ultrastar series of high-performance 3-inch drives aimed at demanding systems.

IBM's first HDD compared to its final HDDs

The following table contrasts IBM’s original HDD, the RAMAC 350, with the latest models from its "Star" OEM hard drive series. It illustrates substantial advancements in storage capacity and efficiency alongside dramatic reductions in physical size and cost over nearly five decades.

Parameter (units) RAMAC 350 Ultrastar 146Z10 Deskstar 180GXP Travelstar 80GN Improvement over 46 years (maximum)
Announced 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 (8100 BTUs/hour), up to 5500 VA depending on model 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 ($234,000 adjusted to 2002 dollars) 1,200 360 420
Cost per megabyte (Template:US$) \$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 35,000,000
Areal density (kilobits per square millimeter) 0.003 40,708 71,765 108,500
Volume density (gigabytes per cubic inch) 0.00000003 6 8 20 622,100,131
Volume density (megabytes per cubic centimeter) 0.000002 388 478 1,203
Average latency (milliseconds) 25 3 4 7
Average seek time (milliseconds) 600 5.9 10.2 12
Data transfer rate (megabytes per second) 0.001 103 29.4 43.75


DASD Devices Distinct from HDDs and FDDs

Within certain IBM operating systems, both HDDs and FDDs are categorized as DASDs (direct access storage devices). This classification also encompasses other storage technologies such as:

IBM 7320 Drum

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

IBM 2301 Drum

The IBM 2301 is a magnetic drum storage unit developed in the late 1960s.

IBM 2303 Drum

Introduced in 1964, the IBM 2303 is another example of a magnetic drum storage device.

IBM 2321 Data Cell

Debuted in 1964, the IBM 2321 Data Cell employs 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, which came out in 1974, functions as a tape cartridge library. It stages data onto IBM 3330 or 3350 disk drives and provides the system with virtual disk drive interfaces.

See also

External links

Retrieved from "https://www.alfawiki.org/index.php?title=IBM_3350&oldid=28547"