Jump to content

IBM 2305

From Alfawiki
IBM
IndustryComputer hardware, data storage
FoundedJune 16, 1911; 115 years ago (1911-06-16)
FounderCharles Ranlett Flint
FateDivested hard disk drive division to Hitachi in 2003
Headquarters
Armonk, New York
,
United States
ProductsHard disk drives, floppy disk drives, magnetic disk storage devices
Websitewww.ibm.com

IBM was engaged in the production of magnetic disk storage devices from 1956 until 2003, at which point it divested its hard disk drive division to Hitachi. The company pioneered both the hard disk drive (HDD) and floppy disk drive (FDD), with numerous technological advancements credited to its engineers. Since the introduction of the IBM 1301, the fundamental mechanical architecture of hard disk drives has stayed largely unchanged, and performance benchmarks have adhered to consistent standards established in the 1950s. Over time, the sector has experienced significant reductions in cost and physical dimensions, coupled with substantial gains in capacity and speed.

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

Throughout its history, IBM employed various designations for its magnetic disk storage devices, including direct-access storage device (DASD), disk file, and diskette file. This article adopts the widely accepted industry terms hard disk drive (HDD) and floppy disk drive (FDD).

IBM 350

The IBM 350 disk storage system, recognized as the inaugural disk drive, was introduced alongside the IBM 305 RAMAC computer on September 14, 1956. A comparable unit, the IBM 355, was launched for the IBM 650 RAMAC system. The first prototype was delivered to Zellerbach Paper Company in June 1956, with production units dispatched starting November 1957 to customers such as United Airlines.

Engineered to support real-time business accounting processes, the IBM 350 housed fifty-two disks measuring 24 inches in diameter, providing storage for five million 6-bit characters (equivalent to 3.75 MB) across one hundred recording surfaces. The disks rotated at a speed of 1200 rpm, facilitating a data transfer rate of 8,800 characters per second. A mechanical access system moved read/write heads to target specific disk pairs and tracks. Several enhanced versions were released during the late 1950s. Leasing costs for the IBM RAMAC 305 system with the IBM 350 disk were approximately $3,200 per month. Production of this model ceased in 1969.

The RAMAC program’s patent US3,503,060 is regarded as a foundational patent for disk drive technology. Initially rejected by IBM's board due to concerns about its potential impact on punch card sales, development proceeded following approval from IBM’s president.

The storage unit’s cabinet measured roughly 60 inches in length, stood 68 inches tall, and was 29 inches deep, weighing close to one ton—necessitating forklifts or cargo aircraft for transportation. Although technically capable of storing more than five million characters, IBM’s marketing team refrained from promoting higher capacities until double-capacity models were unveiled in January 1959.

Acknowledging its historical importance, the RAMAC 350 Disk File was named an International Historic Landmark by The American Society of Mechanical Engineers in 1984. A restoration initiative commenced in 2002 under Al Hoagland’s leadership in partnership with Santa Clara University and was later relocated to the Computer History Museum in Mountain View, California in 2005 where it remains on public display.

IBM 353

The IBM 353, employed with the IBM 7030, bore resemblance to the IBM 1301 but offered a higher data transfer speed. It possessed a storage capacity of 2,097,152 (221) 64-bit words, equivalent to 134,217,728 bits, and achieved transfer rates of 125,000 words per second. A prototype delivered in late 1960 was the first disk drive to implement one head per surface flying on compressed air, similar to the earlier IBM 350. Production units adopted self-flying heads akin to those found in the IBM 1301.

IBM 355

Introduced on September 14, 1956, the IBM 355 served as a complement to the widely used IBM 650. It utilized the IBM 350 mechanism but featured up to three access arms instead of one on the IBM 350, storing six million decimal digits plus 600,000 sign characters. Data transfer involved moving an entire track to and from the magnetic core memory of the 653, an optional component holding sixty signed 10-digit words—sufficient for a single disk track or tape record.

IBM 1405

The IBM 1405 Disk Storage Unit, launched in 1961 for the IBM 1400 series business computers, was available in two variants. Model 1 held 10 million alphanumeric characters (60 million bits) across 25 disks; Model 2 doubled this capacity with 20 million characters (120 million bits) on 50 disks. Disks rotated vertically at a speed of 1200 rpm.

Each disk surface contained 200 tracks divided into five sectors; sectors numbered 0–4 were positioned on top and sectors 5–9 on the bottom. Sector capacity ranged between 178 and 200 characters. One to three forked access arms, each equipped with two read/write heads (one for each disk side), moved vertically to select disks and horizontally for track seeking under electronic control. Reading or writing a sector required approximately 10 milliseconds.

Access times varied from as low as 100 ms up to a maximum of 700 ms for Model 1 and up to 800 ms for Model 2. Model 2 featured a total of 100,000 sectors that could hold either 200 characters in move mode or 178 characters plus a word mark bit in load mode. Model 1 contained half as many sectors.

IBM 7300

Designed specifically for the IBM 7070, the IBM 7300 Disk Storage Unit had a second model announced in 1959. Nevertheless, with the introduction of the 1301 on June 5, 1961, many users of the IBM 7070 and IBM 7074 found it more appealing. The technology within the IBM 7300 shared common elements with that of the IBM 350, IBM 355, and IBM 1405 drives.

IBM 1301

The IBM 1301 Disk Storage Unit was unveiled on June 2, 1961, targeting mainframe computers in the 7000 series as well as the IBM 1410. Each module could store up to 28 million characters (168 million bits), or approximately 25 million when used with the IBM 1410. The design incorporated twenty-five large disks and provided forty recording surfaces accessible to users, with each surface containing about two hundred fifty tracks. Model 1 consisted of a single module; Model 2 stacked two modules vertically. Disks rotated at a rate of eighteen hundred rpm, enabling data transfer speeds of ninety thousand characters per second.

A significant advancement was the inclusion of an independent arm and read/write head for every recording surface that moved simultaneously like a comb. This arrangement eliminated delays caused by moving heads across multiple disks and lowered maximum access time to roughly one hundred eighty milliseconds. The IBM 1301 was also pioneering in employing aerodynamically shaped heads that floated on a thin cushion of air over the disk surfaces, improving overall performance.

Connection was facilitated through the IBM 7631 File Control unit, which allowed operation with either an IBM 1410 or a system from the IBM 7000 series—or enabled sharing between two computers.

Leasing fees for the IBM 1301 Model 1 were $2,100 monthly or $115,500 for purchase; Model 2 leased at $3,500 per month or could be bought for $185,000. The IBM 7631 controller added $1,185 monthly or $56,000 if purchased outright. All versions were phased out by around 1970.

IBM 1302

Launched in September 1963, the IBM 1302 Disk Storage Unit increased the storage capacity of its predecessor, the 1301, by four times, reaching 117 million 6-bit characters per module through enhanced recording techniques. It delivered an average access time of 165 milliseconds and data transfer speeds of 180,000 characters per second, effectively more than doubling the performance of the earlier model. Each module was equipped with two separate access mechanisms—one dedicated to the inner 250 cylinders and another for the outer 250 cylinders. The Model 2 version expanded capacity further by stacking two modules together. Monthly leasing fees were set at $5,600 for Model 1 and $7,900 for Model 2, while purchase costs amounted to $252,000 and $355,500 respectively. The addition of the IBM 7631 controller incurred an extra charge of $1,185 per month or $56,000 if purchased outright. Production of the 1302 ceased in February 1965.

IBM 1311

The IBM 1311 Disk Storage Drive was introduced on October 11, 1962, designed primarily for medium-sized business and scientific computer systems. Comparable in dimensions to a top-loading washing machine, it utilized a removable IBM 1316 disk pack capable of storing two million characters. Throughout the 1960s, seven different models were released before being discontinued in the early 1970s.

An IBM 1316 disk pack stands approximately high and weighs around , containing six disks each measuring in diameter with ten operational recording surfaces. These disks rotate at a speed of 1500 revolutions per minute and feature ten read/write heads mounted on a hydraulically actuated mechanism that physically selects tracks. Each surface is divided into 100 tracks with twenty sectors per track; each sector holds one hundred characters. The disk pack is encased in a transparent plastic shell equipped with a locking system for secure insertion and removal.

The seven models of IBM 1311 include master drives (Models 1, 3, 4, and 5), which incorporate controllers, and slave drives (Model 2). Master drives have the capability to manage multiple slave drives—up to four or three depending on system compatibility—and were compatible with systems such as IBM 1440, IBM 1460, IBM 1240, IBM 1620, IBM 1710, IBM 1401, IBM 1410, IBM 7010, and IBM 7740.

Several optional features were available to improve functionality and storage capacity:

  • Direct Seek: Removes the need to return to track zero before seeking.
  • Scan Disk: Facilitates rapid automatic searching.
  • Seek Overlap: Permits concurrent seek operations during read/write processes across multiple drives.
  • Track Record: Enhances capacity by writing a single large record per track rather than multiple sectors; this increases storage to approximately 17.9 million bits in "Move Mode" and over 18.7 million bits in "Load Mode."

Due to additional power supplies and control circuitry, master drives are roughly one foot wider than slave drives.

IBM 2302

The IBM 2302 serves as the System/360 counterpart to the IBM 1302, featuring track formatting tailored to S/360 DASD architecture. It employs a fixed module consisting of twenty-five platters with forty-six recording surfaces. Model 3 includes one such module; Model 4 contains 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 provides a single read/write head per track. The average rotational latency is approximately seventeen milliseconds with a maximum of thirty-four milliseconds; maximum seek time within each access group is up to one hundred eighty milliseconds. Tracks hold up to 4,985 bytes; after formatting and allocation for alternate tracks, total capacity reaches about one hundred twelve megabytes. Connection to IBM mainframes is facilitated through the IBM 2841 Storage Control Unit.

IBM 2305

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

During the System/370 period with Virtual Storage (OS/VS2), the 2305 frequently served as a paging device on systems such as the 3155, 3165, and 3081 (utilizing specialized microcode). It was also well-suited for high-transaction small data sets like catalogs and job queues.

The 2305-1 model provides a capacity of 5.4 MB, delivering data at 3.0 MB/s over a 2-byte channel interface, with an average access time of 2.5 milliseconds. The larger 2305-2 variant offers 11.2 MB storage at a data rate of 1.5 MB/s and an average access latency of 5 milliseconds.

Engineered for rapid and continuous access to modest-sized data volumes, the 2305's storage size and speed made it optimal for system-resident functions, work files, job queues, indices, and frequently accessed datasets. Its swift response time was particularly advantageous for heavily loaded environments requiring transaction rates exceeding 1.5 per second.

IBM 2311

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

The Model 1 connects to most IBM mainframes via the 2841 Control Unit; on the System/360 Model 25, it interfaces through a Disk Attachment Control that provides comparable control functions. Disk packs employ IBM’s count key data variable record length format.

Models 11 and 12, designed for use with the integrated control of the System/360 Model 20, operate using a fixed sector format. Due to these format differences, disk packs are not interchangeable between Model 1 and Models 11 or 12.

Mechanically akin to the IBM 1311, the IBM 2311 enhanced recording technology to achieve greater data density, storing up to 7.25 megabytes on a six-platter removable disk pack. It features ten read/write heads mounted on a hydraulically actuated arm, with each surface containing 200 tracks plus three optional spare tracks. Average seek time is approximately 85 milliseconds, while data transfer rates reach up to 156 kB/s.

Uniform electrical interfaces across System/360 models enabled third-party vendors to create plug-compatible disk drives, fostering a competitive market for IBM-compatible storage devices.

IBM 2314 Disk Access Storage Facility Model 1

Debuting in April 1965, the IBM 2314 Disk Access Storage Facility Model 1 was compatible with both System/360 and System/370 platforms. Equipped with a Two Channel Switch feature, it allowed simultaneous connection to two system channels. While its disk mechanism resembled that of the IBM 2311, it achieved higher data density.

The drive stored roughly 29 million characters on a removable IBM 2316 disk pack consisting of eleven platters (14-inch diameter), providing twenty recording surfaces. It incorporated twenty read/write heads mounted on a hydraulically actuated arm featuring mechanical detents for precise track positioning. Each surface contained 200 tracks. Initial access times were similar to those of the IBM 2311 but improved in later iterations due to actuator enhancements. Data transfer speeds doubled to approximately 310 kB/s.

The Model 1 system included nine disk drives sold as an integrated unit along with a storage control unit: one single-drive module and two four-drive modules. Drives were housed in drawer-like enclosures for convenient disk pack handling—earning them the nickname "Pizza Ovens." At any given time, eight drives were active while the ninth functioned as an offline spare, facilitating maintenance without interrupting operations. Drive system addresses were set by user-swappable plugs, enabling address reassignment simply by exchanging plugs.

Incorporating a 2844 Control Unit allowed two System/360 channels to concurrently access distinct drives within the facility.

Later versions of the IBM 2314 further expanded these functionalities:

IBM 2314 Direct Access Storage Facility - Series Overview

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

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

IBM 2319

To address competition from plug compatible manufacturers producing storage subsystems comparable to the 2314, IBM launched the cost-effective three-drive 2319 series in 1970. This was accomplished by removing one drive from the four-drive 2313 model, renaming it the 2319 A1, and offering it at a significantly lower rental rate—providing savings for new clients while retaining higher fees for existing customers. The 2319-A1 interfaces with integrated controllers designed for System/370 Models 135 and 145. Additionally, traditional 2314 DASD units such as the 2312 or 2318 can be connected to the 2319-A1. The 2319 B series supports configurations of three, six, or nine drives linked to a newly introduced 2314 Model B Storage Control Unit.

IBM 3310

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

IBM 3330

The IBM 3330 Direct Access Storage Facility, internally called Merlin, debuted in June 1970 targeting IBM System/370 and System/360/195 environments. Initial offerings included a two-drive Model 1 and a single-drive Model 2. The removable disk packs stored 100 MB each, featured a 30 ms access time, and supported data transfer rates up to 806 kB/s. A notable advancement was the incorporation of error correction through fire codes, which improved dependability and lowered costs by accommodating imperfections on disk surfaces.

Originally, one storage control unit (3830 Model 1) directly managed a chain of up to four drives (with a maximum of eight drives per chain). In August 1972, IBM introduced the 3830 Model 2 Storage Control along with the 3333 Disk Storage and Control, which separated control functions from disk arrays. The 3830 Model 2 served as a director-type controller overseeing multiple chains. The first unit in each chain—the 3333—combined controller capabilities with two drives and could manage up to three additional attached 3330 drives (allowing up to eight drives per chain). Two such chains could be connected to a single storage control unit, enabling support for as many as sixteen drives; optional string switches allowed connection to two controllers.

In 1973, IBM released double-density (-11) variants—3333–11, 3330-11, and 3336–11—that doubled disk pack capacity to 200 MB. Mixing original single-density and double-density drives within one chain was not feasible; upgrading to Model-11 required substantial drive modification and data transfer efforts.

The IBM 3330 product line was discontinued in 1983.

IBM 3340 and IBM 3344

While sharing many characteristics, the IBM 3340 and IBM 3344 differ in that only the IBM 3340 can function as the head of string; no A model exists for the IBM 3344. Consequently, an IBM 3344 must be connected behind an IBM 3340 A model serving as head of string.

IBM 3340

Introduced in March 1973 for the IBM System/370, the IBM 3340 Direct Access Storage Facility, nicknamed Winchester, came in three variants: the 3340-A2 (which included two drives and a controller), and the B2 (two drives) and B1 (one drive) models. Up to eight B-units could be linked to a single A2 controller.

This system utilized removable data modules that housed both the head and arm assemblies; during mechanical load and unload operations, the module’s access door opened to engage with the drive—eliminating the need to remove any covers as was required with earlier disk packs. It provided an average access time of 25 milliseconds and supported data transfer rates of 885 kB/s. The IBM 3348 Data Module was available in three configurations offering either 35 MB or 70 MB capacities, with one 70 MB variant featuring fixed heads of 500 KB for enhanced access speeds. Incorporating error correction capabilities, the 3340 was retired from the market in 1984.

Developed under Ken Haughton in San Jose, its original design targeted two removable 30 MB modules, inspiring the Winchester codename after the Winchester .30-30 rifle. Despite subsequent increases in storage capacity, this designation remained.

A notable advancement was its economical head design that allowed heads to land on and lift off from spinning disk media without unloading, thereby simplifying and lowering costs for the head and arm mechanism. This approach, known as "Winchester technology," set a precedent later adopted industry-wide.

Throughout the early 1990s, terms like "Winchester" or "Winnie" were widely used to describe hard disk drives but have since largely disappeared from common usage globally.

IBM 3344

The IBM 3344 shares similarities with the 3340 but replaces removable 3348 data modules with fixed media. Each spindle supports four logical drives, each matching the capacity of a 70 MB 3348 module. Offered exclusively as dual drive models, it does not include an A (head of string) variant. The 3344-B2F differs from the standard 3344-B2 by incorporating fixed heads over certain cylinders on both drives. Both models require a 3340-A2 or 3340-A2F unit to serve as the head of string. Internally, the IBM 3344 is identical to the IBM 3350; distinctions arise solely from variations in control unit microcode.

IBM 3350

Released in 1975 for IBM System/370 systems, the IBM 3350 Direct Access Storage Facility bore the code name Madrid. It featured sealed head-disk assemblies (HDAs) that integrated both head and arm mechanisms within a non-removable unit. The disk geometry consisted of 555 cylinders with 30 heads per cylinder and stored approximately 19,069 bytes per track, resulting in around 317 MB capacity per HDA. This sealed HDA design became standard for IBM DASD products thereafter.

Available models included A2, A2F, B2, B2F, C2, and C2F configurations, each housing two HDAs. The A2 and A2F models contained an additional electronics board enabling connection to a control unit—often referred to as controllers or heads of string. Storage units were arranged in strings beginning with an A2/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 control unit connections for concurrent I/O operations on separate HDAs. Compatible storage control units encompassed the 3830 Model 2, Integrated Storage Control (ISC) embedded in IBM CPUs like the 3148, 3158, and 3168 models, along with later backward-compatible units such as the IBM 3880.

The C2 model also included a controller acting as a backup path if the primary A unit’s controller failed; however, it supported fewer connections and could interface with only one storage control unit.

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

Models designated with "x2F" (for example, A2F) incorporated fixed-head regions covering the first five cylinders on both HDAs to eliminate seek time within that area. This section was commonly reserved for frequently accessed files such as HASP or JES checkpoint data to reduce head movement on spool devices. Additionally, it could accommodate TSO swap data and system swap data under operating systems like MVT, SVS, and MVS—thereby enhancing efficiency during context switches between TSO users or batch jobs.

The IBM 3350 series was discontinued in September 1994.

IBM 3370

In January 1979, IBM introduced the IBM 3370 Direct Access Storage Device, tailored for IBM 4331, 4341, and System/38 midrange systems. This model incorporated seven fixed 14-inch platters, delivering a total storage capacity of 571 MB. It was pioneering as the first hard disk drive to integrate thin-film head technology, a development originating from the Thomas J. Watson Research Center during the late 1960s. The 3370 featured a fixed-block architecture and was compatible with DOS/VSE and VM operating systems, the sole S/370 platforms supporting FBA devices.

IBM 3375

The accompanying IBM 3375 employed count key data (CKD) architecture, engineered to operate with OS/360 and its subsequent versions.

IBM 3380

Launched on June 11, 1980, the IBM 3380 Direct Access Storage Device utilized thin-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 achieved a data transfer speed of 3 MB/s and an average seek time of 16 milliseconds. Initial pricing ranged between $81,000 and $142,200. Due to tribological challenges involving the interaction between heads and media surfaces, deliveries commenced in October 1981.

A typical setup included one A unit along with up to three B units; each 3380 housed four devices allowing configurations of up to sixteen devices connected in series. These were generally managed by a 3880 storage control unit featuring dual paths that enabled simultaneous input/output operations across different hard disk assemblies.

In February 1985, IBM unveiled the Extended Capability Models (3380 E) with double density, effectively doubling storage capacity to 5.04 GB per unit (two actuators at 1.26 GB each). Later in August 1987, the Model K increased capacity to 7.562 GB per unit (two actuators at 1.89 GB). Both Models J and K supported four-path mode connectivity, permitting up to thirty-two devices per string via a 3990 storage control unit capable of handling four concurrent I/O processes.

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

Manufacturing continued until May 1996, marking an impressive production span of fifteen years—surpassing the typical lifespan of disk drives from that period.

IBM 3390

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

A standard 3390 configuration consisted of a central A unit containing four or eight devices and up to two B units each holding as many as twelve devices. Operating in four-path mode, these units connected through a 3990 storage control unit that could support an additional 3390 string, enabling up to sixty-four devices in total.

Each Hard Disk Assembly (HDA) housed two actuator-head assemblies and platters. The Model 1 HDAs delivered an unformatted capacity of 1.89 GB; Model 2 doubled this to 3.78 GB per HDA. Announced in September 1991, the Model 3 increased capacity by fifty percent to reach 5.67 GB per HDA, while the Model 9 introduced in May 1993 further expanded this threefold to achieve 11.3 GB per HDA.

Distinct from earlier DASD designs that used large AC motors driving HDAs via belts, the IBM 3390’s HDA employed an internal DC motor for direct drive. The Model 9 represented IBM’s final iteration of the Single Large Expensive Disk (SLED) technology.

IBM 9345

Released 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 supported up to eight 130 mm platters, offering a top capacity of 1.5 GB. Notably, it was the pioneering HDD to incorporate magnetoresistive (MR) read/write heads.

IBM 9340

In October 1991, IBM launched the 9345 DASD within the 9340 series of channel-attached count key data (CKD) DASD subsystems tailored for IBM mainframes, including the ES/9000 line of processors. The 9345 Model 1 contained two drives with 1.0 GB each, whereas Model 2 housed two drives with a capacity of 1.5 GB each.

While functionally analogous to the IBM 3990/3390 series, the 9340/9345 lacked a non-volatile RAM cache present in the 3990 and supported a shorter maximum block length compared to the 3390.

The device was recognized by the OS Input/Output Supervisor (IOS) through a dedicated initializer named IECCINIT, which also handled other DASD devices. During initialization, the OS detected the absence of non-volatile cache on the 9340 and identified the reduced track capacity on the 9345, assigning it a unique device type distinct from that of the 3990/3390.

9330 family of disk drives

  1. The 9331 Diskette Unit models 1 and 11 incorporated a single 8-inch floppy disk drive (FDD), whereas models 2 and 12 were equipped with 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 employed 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 systems.
  5. The 9335 Direct Access Storage Subsystem featured an IBM "Kestrel" HDD developed at IBM Hursley in the UK—this drive offered an 850 MB capacity across three 14-inch platters with dual rotary actuators accessing six surfaces. Introduced in October 1986 alongside the IBM 9370 Information System, this rack-mountable unit has no known OEM variants.
  6. The 9336 Disk Unit made use of the IBM 0681 HDD, also known as Redwing.
  7. The 9337 Disk Array Subsystem incorporated either IBM 0662 (Spitfire) or IBM 0663 (Corsair) hard disk drives.

IBM 2310

The IBM 2310 Removable Cartridge Drive was announced in conjunction with the IBM 1800 in 1964 and subsequently with the IBM 1130 in 1965, with initial shipments likely beginning late that year alongside the IBM 1130. It provided storage for approximately 512,000 sixteen-bit words (equivalent to about 1,024,000 bytes) on an IBM 2315 cartridge. This cartridge contained a single oxide-coated aluminum platter encased within a plastic shell featuring openings for both the read/write arm and two heads.

IBM 5444

Introduced in September 1969 as part of System/3 and developed at IBM's Hursley laboratory in England under the codename Dolphin, the IBM 5444 utilized a disk cartridge known as the IBM 5440 containing one fourteen-inch platter. It was available in three configurations:

  • Model 1: comprised one fixed and one removable disk, each supporting one hundred tracks per surface; cartridge capacity reached approximately 1.23 MB
  • Model 2: featured one fixed and one removable disk with two hundred tracks per surface; capacity doubled to roughly 2.46 MB
  • Model 3: included only one removable disk with two hundred tracks per surface; capacity also about 2.46 MB

IBM 62GV

The IBM 62GV was initially released in May 1974, created at IBM's Hursley facility in the UK, and was known internally as Gulliver. It started with a storage capacity of 5 MB. Subsequent versions expanded this to 10 MB (62TM) and later to 14 MB. This model employed a Swinging Arm actuator paired with a single 14-inch platter. The actuator mechanism, developed at Hursley, became IBM's most widely licensed electromechanical innovation, gaining broad adoption across the industry during the 1980s and remaining a standard design nearly four decades later. Approximately 177,000 units of the IBM 62GV were sold, making it the first hard drive to surpass the 100,000-unit sales milestone.

OEM and Small Systems HDDs

This section details hard drives manufactured by IBM that were supplied as OEM components or designed for IBM's smaller systems such as the System/3, System/32, /34, /36, and AS/400. Drives are identified by their OEM model numbers and organized by their initial shipment dates.

IBM 0680

The 0680 model was first delivered in 1979 for use with various IBM small systems and entry-level System/370 configurations as the 3310 direct access storage device. Officially announced as the OEM version 0680 in September 1981, it was engineered at IBM's Hursley laboratory under the project name Piccolo. This unit featured six 8-inch (210 mm) platters and offered an initial maximum capacity of 65 MB along with an enhanced rotary actuator.

A higher-capacity variant named the 62SW was introduced in June 1984 but experienced limited market success due to pricing comparable to that of the 62GV.

IBM 0676

Released in November 1982, the 0676 served as a 5247 Disk Storage Unit for the IBM System/23 Datamaster. Developed at IBM Rochester, Minnesota under the designation 21ED, this hard drive featured eight-inch platters with capacities initially available at either 15 or 30 MB through configurations of two or four disks measuring 210 mm each. In 1983, it became part of the System/36’s 5360 System Unit lineup. The storage capacity was doubled in 1984 by increasing the number of tracks per surface, which led to its inclusion in the System/36’s upgraded 5362 System Unit.

IBM 0665

The model 0665 was introduced in October 1985 within the PC AT (5170) system unit. Developed under the codename "Pixie" at IBM Rochester, it utilized a 5¼-inch form factor and offered storage options of 20, 30, and 44 MB.

IBM 0667

The 0667 arrived on the market in August 1986. Also developed at IBM Rochester with the codename "Grant," this full-height ESDI hard drive had a 5¼-inch size and could accommodate up to four disks measuring 130 mm each, delivering a maximum capacity of 70 MB. It was available as an optional component for select PC RT models (6150, 6151, and 6152) as well as System/36 Model System Units (5363 and 5364).

IBM 0669

Introduced in 1987, the 0669 was developed at IBM Rochester under the project name "Grant-Prime." This full-height drive measured five inches and supported up to four disks of 130 mm each with a maximum storage capacity of approximately 115 MB. It functioned as the internal hard disk for both the System/36 model 5363 and Series 1 model 4956 System Units.

IBM 0671

Also launched in 1987 and created at IBM Rochester under the codename "Lee," the 0671 was an ESDI full-height five-inch hard drive capable of holding up to eight disks measuring 130 mm each with a total capacity reaching up to 316 MB. This model represented IBM’s inaugural use of thin metal film recording technology. By 1988, it had been integrated into the AS/400’s 9404 System Unit architecture, supporting configurations with two or three drives.

IBM 0661

The 0661 made its debut in 1989 as model number 371. Developed under the codename "Lightning" at both IBM Rochester and Hursley locations, it was a SCSI hard disk featuring up to eight disks sized at 95 mm with fourteen read/write heads, delivering a capacity of around 320 MB. A subsequent "Turbo" version offering a higher capacity of approximately 400 MB followed in 1990. This drive became a standard component across multiple IBM platforms including various AS/400 System Unit Model CXX configurations.

IBM 0681

Introduced in April 1990 and engineered at IBM Hursley under the project name "Redwing," the 0681 marked the final hard disk drive developed at the Hursley facility. This full-height 5-inch HDD supported capacities up to 857 MB by utilizing as many as twelve 130 mm platters. Notably, it was the first HDD to incorporate PRML (Partial Response Maximum Likelihood) data decoding technology. The 0681 served as the core drive for the 9333 Disk Drive Subsystem released in early 1992, with an enhanced 1.07 GB high-density variant introduced in May of the same year.

IBM 0663

The 0663, launched in late 1991 under the codename "Corsair," was a compact hard disk drive featuring a half-height (1.6-inch) form factor and a 3-inch platter size. It provided up to 1 GB capacity distributed over eight 95 mm disks. Integrated into select PS/2 and RS/6000 systems, this model represented IBM’s initial OEM HDD to utilize Magnetoresistive (MR) head technology.

IBM 0664

Released in November 1992, the 0664—developed under the "Allicat" project at IBM Rochester, Minnesota—was a full-height 5-inch HDD standing 3.25 inches tall. It effectively combined two 3-inch drives into one unit, offering storage capacity up to 2.013 GB across eight 95 mm platters.

IBM 0662

The 0662, introduced in June 1993 with the codename "Spitfire" at IBM Rochester, was a full-height (1 inch tall) HDD utilizing three disks or five recording surfaces on 3-inch platters. It delivered a capacity of 1.05 GB and was employed internally within the 9336 Disk Unit and the 9337 Disk Array products.

Floppy disk drive

IBM was a pioneer in floppy disk technology, debuting the 8-inch floppy disk drive in 1971 primarily as a read-only medium for program loading. The company followed with its first read/write version in 1973, integrated into the 3740 Data Entry System. Although IBM established early standards for the 8-inch floppy drives, it did not market these drives separately, allowing other manufacturers to develop independently.

At one time, IBM was the largest original equipment manufacturer buyer of 5-inch floppy disk drives. Its early adoption of two-sided drives with a track density of 48 tracks per inch helped establish this configuration as an industry norm. IBM had plans to produce these and smaller drives but ceased all manufacturing efforts by 1985. Additionally, its attempt in 1983 to OEM a smaller 4-inch DemiDiskette did not succeed.

"Star" series of HDDs

On October 17, 1994, IBM Storage Systems unveiled three families of hard disk drives: the Travelstar series featuring compact 2-inch drives for notebook computers; the Deskstar line with 3-inch drives aimed at desktop PCs; and the Ultrastar series consisting of high-performance 3-inch drives designed for demanding computing environments.

IBM's first HDD versus its last HDDs

The following table contrasts IBM’s original RAMAC 350 hard disk drive with its final trio of "Star" series OEM HDD models. The comparison underscores significant advancements including drastic reductions in physical size and cost, alongside remarkable 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
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) ~2374 watts (~8100 BTUs/hour), up to ~5500 VA depending on configuration 16 10.3 1.85 ×1,283
Power Efficiency (MB/watt) 0.0016 9,125 17,476 43,243 ×27,375,856
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

Within certain IBM operating systems, both hard disk drives (HDDs) and floppy disk drives (FDDs) fall under the category of DASDs (direct access storage devices). Additionally, IBM has developed other DASD technologies, including:

IBM 7320 Drum

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

IBM 2301 Drum

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

IBM 2303 Drum

The IBM 2303, launched in 1964, is a magnetic drum-based storage unit.

IBM 2321 Data Cell

Announced in 1964, the IBM 2321 Data Cell employs short magnetic tape strips 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

Introduced in 1974, the IBM 3850 Mass Storage System functions as a tape cartridge library that stages data onto IBM 3330 or 3350 disk drives. These drives are presented to the system as virtual devices.

See also

External links

Retrieved from "https://www.alfawiki.org/index.php?title=IBM_2305&oldid=28534"