IBM 1405
| Company type | Division |
|---|---|
| Industry | Computer storage devices |
| Founded | 1956 |
| Defunct | 2003 |
| Fate | Divested to Hitachi |
| Products | Hard disk drives, floppy disk drives |
| Parent | IBM |
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 innovations behind both the hard disk drive (HDD) and floppy disk drive (FDD) originated at IBM, with many technological advancements driven by its engineers. The core mechanical architecture of hard disk drives has largely remained unchanged since the introduction of the IBM 1301, with performance metrics and specifications still based on standards set in the 1950s. Over time, these devices have seen substantial reductions in cost and physical dimensions, alongside remarkable enhancements in storage capacity and operational speed.
IBM manufactured 8-inch floppy disk drives from 1969 through the mid-1980s but did not become a leading producer of the smaller 5.25- or 3.5-inch floppy drives. Although IBM marketed its magnetic disk drives, it only started offering them under original equipment manufacturer (OEM) agreements in 1981. By 1996, IBM had discontinued creating hard disk drives exclusive to its own systems, instead supplying all HDDs as OEM products.
Throughout its history, IBM referred to its magnetic disk drives by various names such as direct-access storage device (DASD), disk file, and diskette file. For clarity, this article employs the industry-standard terms hard disk drive (HDD) and floppy disk drive (FDD).
IBM 350
The IBM 350 disk storage unit holds the distinction of being the first-ever disk drive, launched on September 14, 1956, as part of the IBM 305 RAMAC computer system. At the same time, the IBM 355 was introduced for use with the IBM 650 RAMAC system. The initial prototype was delivered to Zellerbach Paper Company in June 1956, while production models began reaching clients such as United Airlines in November 1957.
Engineered specifically for real-time business accounting applications, the IBM 350 could store five million six-bit characters (equivalent to approximately 3.75 MB). Its design incorporated fifty-two disks providing one hundred recording surfaces and tracks, rotating at a speed of 1200 revolutions per minute. The data transfer capability was 8,800 characters per second, managed by a head mechanism that selected pairs of disks and tracks for reading or writing. Throughout the late 1950s, several enhanced versions were released. The IBM RAMAC 305 system equipped with the 350 was leased at $3,200 monthly and remained in service until its retirement in 1969.
A patent originating from the RAMAC development program is foundational to modern disk drive technology. Despite initial cancellation by IBM's Board due to concerns about undermining its punch card business, development persisted with approval from IBM’s president.
The physical dimensions of the IBM 350 cabinet were approximately long, high, and wide. Weighing nearly one ton, it required forklifts and large cargo aircraft for transportation. Currie Munce of Hitachi Global Storage Technologies—successors to IBM’s storage division—noted that while capacity could have surpassed five million characters, IBM's marketing hesitated to promote larger capacities at that time. Nevertheless, double-capacity models were announced in January 1959 and shipped within that year.
In recognition of its historical significance, the RAMAC 350 Disk File was designated an International Historic Landmark by The American Society of Mechanical Engineers in 1984. Beginning in 2002, a restoration effort led by Al Hoagland partnered with Santa Clara University to refurbish an original IBM 350 RAMAC unit. This project transitioned to the Computer History Museum in 2005, where it is now publicly exhibited as part of the Revolution exhibition.
IBM 353
The IBM 353, utilized with the IBM 7030, bore similarity to the IBM 1301 but offered an enhanced transfer speed. It provided storage for 2,097,152 (221) words of 64 bits each (totaling 134,217,728 bits) and achieved a data transfer rate of 125,000 words per second. A prototype delivered in late 1960 was notable as the first disk drive employing one head per disk surface that floated on compressed air, akin to the IBM 350 disk storage (RAMAC). Subsequent production units adopted self-flying heads similar to those found in the 1301.
IBM 355
Introduced on September 14, 1956, the IBM 355 served as a companion device to the widely used IBM 650. It incorporated the IBM 350 mechanism but featured up to three access arms—compared to a single arm on the IBM 350—and held a capacity of 6 million decimal digits plus an additional 600,000 sign characters. The unit transferred entire tracks to and from the magnetic core memory of the 653, an optional storage unit for the IBM 650 containing sixty signed 10-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 offered in two variants. Model 1 stored up to 10 million alphanumeric characters (equivalent to 60 million bits) across 25 vertically arranged disks; Model 2 doubled this capacity to 20 million characters (120 million bits) distributed over 50 disks spinning at a speed of 1200 rpm.
Each disk surface contained 200 tracks subdivided into five sectors (with sectors numbered 0–4 on the top side and sectors 5–9 on the bottom), each capable of holding between 178 and 200 characters. One to three forked access arms carried two read/write heads apiece—positioned on both the top and bottom of a disk. These arms moved vertically to select disks and horizontally to locate tracks under electronic guidance. Seek times averaged around 10 milliseconds per sector.
Access durations varied from as low as 100 milliseconds up to a maximum of approximately 700 milliseconds for Model 1 and up to 800 milliseconds for Model 2. Model 2 included a total of 100,000 sectors with either 200 characters in move mode or reduced to 178 characters when operating in load mode (which added a word mark bit). Model 1 contained half as many sectors at 50,000.
IBM 7300
Designed specifically for use with the IBM 7070, the IBM 7300 Disk Storage Unit was announced with a second model in 1959. However, following the launch of the IBM 1301 on June 5, 1961, customers using the IBM 7070 and IBM 7074 preferred adopting the IBM 1301 over the IBM 7300. The technology underpinning the IBM 7300 bore resemblance to that found in the IBM 350, IBM 355, and IBM 1405 units.
IBM 1301
The IBM 1301 Disk Storage Unit was unveiled on June 2, 1961, aimed at supporting mainframe computers within the IBM 7000 series as well as the IBM 1410. Each module stored approximately 28 million characters (168 million bits), or about 25 million characters for the IBM 1410 variant. The design included twenty-five large disks per module, providing forty user-accessible recording surfaces with two hundred fifty tracks each. The Model 1 consisted of a single module; Model 2 stacked two modules vertically. Disks rotated at a speed of eighteen hundred rpm, facilitating data transfer rates of ninety thousand characters per second.
A significant advancement was incorporating an independent arm and read/write head for every recording surface; these moved simultaneously in a comb-like fashion. This arrangement eliminated delays caused by switching heads and reduced maximum access time to roughly one hundred eighty milliseconds. The read/write heads were aerodynamically engineered to hover on a thin cushion of air just above the disk surfaces, enabling closer proximity and enhanced performance.
Connection was established via the IBM 7631 File Control unit, permitting integration with either IBM 1410 or IBM 7000 series computers or allowing shared use between two systems.
Pricing details included a monthly lease fee of $2,100 or a purchase price of $115,500 for the IBM 1301 Model 1; Model 2 was priced at $3,500 monthly or $185,000 for outright acquisition. The IBM 7631 controller carried an additional cost of $1,185 per month or $56,000 if purchased outright. All versions were phased out by approximately1970.
IBM 1302
Launched in September 1963, the IBM 1302 Disk Storage Unit offered a fourfold increase in capacity compared to the 1301, accommodating 117 million 6-bit characters per module. It delivered an average access duration of 165 milliseconds and data transfer rates reaching 180,000 characters per second—over double the throughput of its predecessor. Each module incorporated two separate access mechanisms dedicated to the inner and outer cylinder groups. The Model 2 variant doubled storage by stacking two such modules. Leasing fees were set at $5,600 monthly for Model 1 and $7,900 for Model 2, while purchase prices were $252,000 and $355,500 respectively. Additionally, the IBM 7631 controller entailed an extra monthly lease cost of $1,185 or a purchase price of $56,000. Production of the 1302 ceased in February 1965.
IBM 1311
Introduced in October 1962, the IBM 1311 Disk Storage Drive was designed for mid-range business and scientific computer applications. It featured removable IBM 1316 disk packs with a storage capacity of two million characters. Throughout the 1960s, seven different models were manufactured before being phased out by the early 1970s.
Each IBM 1316 disk pack measures roughly four inches in height, weighs approximately ten pounds, and contains six 14-inch disks with ten usable recording surfaces (the outer surfaces remain unused). Data access is managed by ten read/write heads mounted on a hydraulically operated actuator that moves across tracks on disks spinning at 1,500 revolutions per minute. Each surface holds 100 tracks subdivided into 20 sectors per track; each sector stores 100 characters. The disk pack is encased in a plastic shell equipped with a locking handle to facilitate installation and removal.
The IBM 1311 lineup included seven models: master drives (Models 1, 3, 4, and 5) contained integrated controllers and power supplies, whereas slave drives (Model 2) relied on masters for operation. Master drives could support multiple slave units—up to four or three depending on the system configuration. Models differed based on compatibility with systems such as the IBM 1401, IBM 1440, IBM 1620, IBM 1410, and IBM 7010.
Several optional features enhanced functionality:
- Direct Seek: bypasses returning to track zero before initiating a seek operation.
- Scan Disk: automates rapid search processes.
- Seek Overlap: permits simultaneous seek operations during read/write activity.
- Track Record: boosts capacity by storing one large record per track rather than multiple sectors—enabling up to approximately 17.9 million bits in Move Mode and about 18.8 million bits in Load Mode.
Master drives are physically wider than slave drives due to additional internal components.
IBM 2302
The IBM 2302 represents the System/360 adaptation of the IBM 1302, tailored to fit S/360 DASD architecture requirements. This model features a non-removable module comprising 25 platters with a total of 46 recording surfaces. The Model 3 includes one such module, while Model 4 houses two modules. Each module contains two independent access mechanisms—one servicing the innermost set of 250 cylinders and another handling the outermost group of 250 cylinders—each known as an access group, equipped with one read/write head per track. The average rotational latency is approximately 17 milliseconds, with a maximum delay of up to 34 milliseconds; each access group has a maximum seek time of around 180 milliseconds. Tracks hold approximately 4,985 bytes each, resulting in a total module capacity near 112 megabytes. Connection to IBM mainframes is managed through the IBM 2841 Storage Control Unit.
IBM 2305
Introduced in 1970 alongside the IBM 2835 Storage Control Unit, the IBM 2305 fixed-head storage device initially interfaced with System/360 Models 85 and 195 via the IBM 2880 Block Multiplexor Channel. Its popularity increased with System/370’s Virtual Storage (OS/VS2), where it served as a preferred paging device on systems such as the Models 3155, 3165, and 3033 through specialized microcode support. The device was also well-suited for handling frequently accessed small data sets like catalogs and job queues.
The smaller-capacity model, the IBM 2305-1, provides storage of approximately 5.4 megabytes with data throughput of about three megabytes per second over a two-byte channel interface and an average access time of roughly 2.5 milliseconds. The larger IBM 2305-2 offers around twice the capacity at about eleven point two megabytes but operates at a lower data rate of approximately one point five megabytes per second with an average access time near five milliseconds.
Engineered for rapid and continuous access to small volumes of data, the IBM 2305’s speed and storage size make it ideal for system-resident files such as work files, job queues, indexes, and other frequently accessed datasets. Its swift response times suit environments with heavy workloads requiring high transaction throughput, establishing it as an effective paging solution within enterprise mainframe systems.
IBM 2311
Launched in 1964 alongside the 2841 Control Unit, the IBM 2311 Disk Storage Drive was engineered for compatibility with the entire IBM System/360 series, as well as the IBM 1130 and IBM 1800 systems. It could be directly connected to the IBM System/360 Model 20 and Model 25. All units utilized the removable IBM 1316 Disk Pack, originally designed for the IBM 1311.
The Model 1 of the 2311 links to most IBM mainframe systems through the 2841 Control Unit, whereas on the System/360 Model 25, it operates with a Disk Attachment Control that provides equivalent functionality. Disk packs employ IBM's count key data format, which supports variable record lengths.
Models 11 and 12, integrated within the System/360 Model 20’s internal control system, use a fixed sector format. Due to this difference, disk packs cannot be interchanged between Model 1 and Models 11 or 12.
While mechanically resembling the IBM 1311, the 2311 incorporates advanced recording technology, enabling storage of 7.25 megabytes on a single removable IBM 1316 disk pack composed of six platters rotating together. It includes ten read/write heads mounted on a hydraulically actuated arm that accurately positions them before operation. Each platter surface offers 200 tracks plus three optional defect management tracks. The average seek time is approximately 85 ms, with a data transfer speed of 156 kB/s.
The uniform electrical interface across System/360 models allowed third-party manufacturers to develop plug compatible disk drives, encouraging a competitive market for IBM-compatible storage devices.
IBM 2314 Disk Access Storage Facility Model 1
Released in April 1965, roughly one year after the System/360 debut, the IBM 2314 Disk Access Storage Facility Model 1 was designed for both System/360 and System/370 platforms. It featured a Two Channel Switch, enabling simultaneous connection to two channels. Building upon the foundation of the IBM 2311, it significantly enhanced data density.
The drive accommodated around 29 million characters on a removable IBM 2316 disk pack containing eleven platters measuring 14 inches in diameter, providing twenty recording surfaces. The actuator carried twenty read/write heads hydraulically positioned over each surface with mechanical detents ensuring precise track alignment. Each surface contained 200 tracks. Initial access times were similar to those of the IBM 2311 but improved in subsequent models due to actuator refinements. The data transfer rate doubled to approximately 310 kB/s.
The initial Model 1 configuration grouped nine disk drives under a single price category and was supported by a separate storage control unit comprising one drive module and two modules housing four drives each. Each drive was installed in its own drawer for convenient disk pack access and earned the nickname "Pizza Ovens" because of their appearance. Although nine drives were present, only eight could be accessed simultaneously; the ninth functioned as an offline spare to allow maintenance without disrupting operations. Users could set drive system addresses via removable plugs, facilitating flexible reassignment including designating spares.
An optional IBM 2844 Control Unit allowed two System/360 channels to access different drives within the facility concurrently.
Later versions of the IBM 2314 were introduced following these initial models.
IBM 2314 Direct Access Storage Facility - Model Variants
In 1969, IBM categorized the storage facility into distinct models capable of supporting up to nine drives (with eight accessible online) connected through a 2314 Storage Control. These included:
- 2312 Disk Storage, featuring a single drive module.
- 2313 Disk Storage, comprising a four-drive module.
- 2318 Disk Storage, consisting of a two-drive module.
IBM 2319
To challenge plug-compatible vendors producing subsystems comparable to the 2314, IBM launched the affordable three-drive 2319 modules in 1970. This was achieved by removing one drive from the four-drive 2313 and rebranding it as the 2319 A1, which was offered at a lower rental cost. This approach reduced expenses for new clients while retaining higher fees for existing users. The 2319-A1 connects to integrated controllers designed for System/370 Models 135 and 145; traditional 2314 DASD devices such as the 2312 or 2318 can also be linked. The 2319 B series supports configurations of three, six, or nine drives connected to a newly introduced 2314 Model B Storage Control Unit.
IBM 3310
Unveiled on January 30, 1979, the IBM 3310 Direct Access Storage Device was aimed at IBM 4331 midrange computer systems. Each unit provided a storage capacity of 64.5 MB and operated using fixed-block architecture, compatible with VSE and VM operating systems that support FBA devices.
IBM 3330
The IBM 3330 (code-named Merlin), introduced in June 1970 for IBM System/370 and System/360/195 platforms, featured removable disk packs with a capacity of 100 MB each. It offered a response time of 30 ms and a data transfer speed of 806 kB/s. Notably, it incorporated error correction through fire codes to enhance reliability and lower costs by accommodating disk defects.
Initial configurations included one storage control unit (3830 Model 1) attached to a single 3330 drive, with the option to add up to three more units in a string, allowing a maximum of eight drives.
In August 1972, IBM introduced the 3830 Model 2 Storage Control alongside the 3333 Disk Storage and Control, which separated control functions from storage. The 3830 became a director-type controller overseeing multiple strings. The first unit in each string, the 3333, combined controller functions with two drives and could manage up to three connected 3330 units, totaling eight drives per string. Two such 3333 units could interface with one 3830 Model 2 controller for up to sixteen drives, with optional string switches enabling dual storage control connections.
In 1973, IBM released double-density (-11) versions—3333–11, 3330-11, and 3336–11—featuring disk packs capable of storing up to 200 MB. Mixing single-density and double-density drives within the same string was not supported. Field upgrades to Model 11 were feasible but required conversion of drives and complete data migration.
The IBM 3330 line was phased out in 1983.
IBM 3340 and IBM 3344
The IBM models 3340 and 3344 share many characteristics; however, only the IBM 3340 can function as the head of a string. The IBM 3344 must be connected to an IBM 3340 A model acting as the string head.
IBM 3340
The IBM 3340 Direct Access Storage Facility, known by its code name Winchester, was launched in March 1973 for use with IBM System/370. It was available in three configurations: the 3340-A2 (two drives with integrated controller), and B2 (two drives) and B1 (one drive), both designed to connect to the A2 for up to eight drives.
This system utilized removable data modules that incorporated both head and arm assemblies. It employed a mechanical load/unload mechanism that did not require removing any covers during operation. The access time was approximately 25 ms, with data transfer rates reaching up to 885 kB/s. Three types of removable IBM 3348 Data Modules were offered: one with a capacity of 35 MB and two versions with capacities of 70 MB—one of which included an additional fixed-head area providing faster access to approximately 500 KB. The system featured error correction capabilities and was discontinued in 1984.
Developed at IBM’s San Jose facility under Ken Haughton’s leadership, the initial design targeted two removable modules each holding about 30 MB—hence its Winchester nickname, inspired by the Winchester .30-30 rifle cartridge. Despite increases in capacity over time, this codename remained associated with the product.
A significant innovation was its cost-effective head design that allowed heads to land on and lift off from spinning disk media during spin-up or spin-down phases without unloading heads completely. This Winchester technology greatly simplified head and arm mechanisms while reducing costs, setting an industry standard.
The term Winchester or Winnie became widely used within hard drive terminology throughout the early 1990s but has gradually fallen out of common usage worldwide since then.
IBM 3344
The IBM 3344 shares similarities with the 3340 but distinguishes itself by utilizing fixed media rather than the removable 3348 data modules. Each spindle accommodates four logical drives, each offering storage equivalent to a 3348–70. This model is exclusively available as a dual drive configuration and does not include an A (head of string) variant. The 3344-B2F model differs from the 3344-B2 by incorporating fixed heads over certain cylinders on both drives. Both models require a 3340-A2 or 3340-A2F to serve as the head of string. Internally, the IBM 3344 matches the IBM 3350 in design; differences are confined to variations in the control unit's microcode.
IBM 3350
The IBM 3350 Direct Access Storage Facility, codenamed Madrid, debuted in 1975 for use with the IBM System/370. Its sealed head-disk assemblies (HDAs), which integrated heads and arms, established a design precedent for future IBM DASD products. Each HDA contained 555 cylinders, 30 heads, and stored 19,069 bytes per track, resulting in a total capacity of approximately 317.5 MB.
Models designated A2, A2F, B2, B2F, C2, and C2F each included two HDAs. The A2 and A2F models featured an extra electronic board facilitating connection to storage control units (SCUs), often referred to as controllers or head-of-string units. These controllers arranged devices into strings with configurations such as -A, -AB, -ABB, -ABBB, -AC-, -ABC-, or -ABBC-. Typically, the A2 controller incorporated a string switch that permitted concurrent I/O operations to two separate HDAs through two SCUs like the 3830 Model 2 or integrated storage control within CPUs such as the 3148. Subsequent controllers such as the 3880 maintained backward compatibility.
The C2 controller included a secondary controller designed to provide an alternate path if the primary A unit controller failed; however, its connectivity options were more limited compared to the A unit.
Models marked with "x2F" (for example, A2F) featured fixed head areas spanning the first five cylinders on both HDAs. This arrangement eliminated seek times within those cylinders and was optimized for frequently accessed checkpoint regions in HASP or JES2 spool devices, thereby enhancing performance by reducing head travel. Additionally, the fixed head zones supported system swap data for TSO and MVS environments, improving efficiency during context switches.
The IBM 3350 series was phased out in September 1994.
IBM 3370
Released in January 1979, the IBM 3370 Direct Access Storage Device was designed for midrange systems including the IBM 4331, 4341, and System/38. It consisted of seven fixed 14-inch disks per unit and provided a total capacity of 571 MB. Notably, it was the first hard disk drive to employ thin-film head technology developed at IBM’s Thomas J. Watson Research Center during the late 1960s. The device 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 counterpart to the 3370 but employed count key data architecture necessary for operating systems such as OS/360 and its successors.
IBM 3380
Introduced on June 11, 1980, the IBM 3380 incorporated thin-film head technology and delivered a unit capacity of 2.52 GB through two hard disk assemblies each equipped with two actuators accessing approximately 630 MB per assembly. It achieved data transfer rates of up to 3 MB/s with an average access time of about 16 milliseconds. Initial pricing ranged from $81,000 to $142,200. Due to tribological challenges between heads and media surfaces, shipments commenced in October 1981.
Standard configurations consisted of one A unit plus up to three B units; each IBM 3380 contained four devices allowing strings up to sixteen devices connected via IBM’s 3880 storage control units which supported two simultaneous I/O operations across different HDAs.
In February 1985, IBM released the double-density Extended Capability Model (3380 E) doubling capacity to approximately 5.04 GB per unit. Later in August 1987, the triple-capacity Model K offered up to about 7.562 GB per unit along with an optional four-path mode enabled by the IBM 3990 storage control unit that allowed up to four concurrent I/O processes across as many as thirty-two devices.
The IBM 3380 product line encompassed twelve models: six A-units functioning as string heads with controller logic; five B-units connected downstream from A- or C-units; and one C-unit which interfaced directly with IBM channels. Production of these models concluded in May 1996 after a significant fifteen-year market presence.
IBM 3390
Introduced in November 1989, the IBM 3390 series of Direct Access Storage Devices provided storage capacities up to 22 gigabytes distributed over multiple drives. Depending on the configuration and storage size, prices varied between $90,000 and $795,000.
A typical 3390 configuration includes a central A unit housing either four or eight devices, with the option to add one or two B units, each supporting up to 12 devices. It functions in a four-path mode and connects to a 3990 storage control unit, which can link a second 3390 string, allowing up to 64 devices within a single subsystem.
Hard Disk Assemblies (HDAs) consist of two actuator-head assemblies and platters. The initial model offered 1.89 GB per HDA, while the second model doubled this to 3.78 GB. Announced in 1991, Model 3 increased capacity further to 5.67 GB per HDA, and by 1993, Model 9 reached 11.3 GB per HDA.
Unlike previous DASD units that used large alternating current motors driving the HDAs via belts, the 3390 incorporated a direct current motor housed inside the enclosure. The Model 9 also represented IBM’s final iteration of Single Large Expensive Disk (SLED) drives.
IBM 9345
Launched in November 1990 as a Request for Price Quotation (RPQ) for IBM’s SuperComputing Systems Extensions (SCSE), the IBM 9345 hard disk drive was developed at IBM’s San Jose facility under the codename Sawmill. It delivered up to 1.5 GB capacity within a full-height 5¼-inch form factor using as many as eight 130 mm disks. Notably, it was the first HDD to utilize Magnetoresistive (MR) heads, which improved read performance.
IBM 9340
In October 1991, IBM released the 9345 as part of the 9340 channel-attached count key data (CKD) DASD subsystem family for IBM mainframes, including those in the ES/9000 line. The Model 1 featured two HDDs of 1.0 GB each, while Model 2 contained two HDDs of 1.5 GB each.
While functionally comparable to the 3990/3390 systems, the 9340/9345 lacked non-volatile RAM cache found on the 3990 and supported a shorter maximum block length compared to the 3390. The operating system’s Input/Output Supervisor (IOS) identified these devices through the IECCINIT initializer, which detected both the absence of non-volatile cache in the 9340 and reduced track capacity in the 9345, assigning device types accordingly.
9330 family of disk drives
- Models 1 and 11 of the 9331 Diskette Unit contained one 8-inch floppy disk drive; models 2 and 12 included one 5-inch floppy disk drive.
- The 9332 Direct Access Storage Device utilized the IBM 0667 hard disk drive.
- The 9333 High Performance Disk Drive Subsystem employed either IBM 0664 or IBM 0681 HDDs depending on specific models.
- The 9334 Disk Expansion Unit connected between one and four SCSI hard drives to RS/6000 systems.
- The 9335 Direct Access Storage Subsystem featured the "Kestrel" HDD developed at IBM Hursley in the UK—an 850 MB device with three fourteen-inch platters and dual rotary actuators accessing multiple surfaces. This rack-mountable unit was introduced alongside the October 1986 IBM 9370 Information System. There is no known original equipment manufacturer (OEM) version of this HDD.
- The 9336 Disk Unit incorporated the IBM 0681 HDD (also known as Redwing).
- The 9337 Disk Array Subsystem made use of IBM’s IBM 0662 (Spitfire) or IBM 0663 (Corsair) hard drives.
IBM 2310
The IBM 2310 Removable Cartridge Drive was first announced in conjunction with the IBM 1800 in 1964 and later with the IBM 1130 in 1965, likely shipping initially with the latter late that year. It stored up to 512,000 sixteen-bit words (equivalent to one million twenty-four thousand bytes) on an IBM 2315 cartridge. This cartridge housed a single oxide-coated aluminum platter enclosed within a plastic shell featuring openings for both the read/write arm and two heads.
IBM 5444
Introduced in September 1969 as a component of System/3, the IBM 5444 was engineered at IBM's Hursley laboratory in England, where it was known internally as Dolphin. This model utilized the 5440 disk cartridge, which housed a single 14-inch disk. It was available in three variants:
- Model 1: included one fixed disk and one removable disk, each featuring 100 tracks per surface; the cartridge offered a capacity of 1.23 MB
- Model 2: comprised one fixed disk and one removable disk with 200 tracks per surface; cartridge capacity reached 2.46 MB
- Model 3: contained only one removable disk with 200 tracks per surface; cartridge capacity was 2.46 MB
IBM 62GV
The IBM 62GV, first delivered in May 1974 from IBM’s Hursley facility in the UK under the codename Gulliver, initially provided a storage capacity of 5 MB. Subsequent versions expanded this to 10 MB (designated 62TM) and later to 14 MB. It employed a Swinging Arm actuator mechanism paired with a single 14-inch disk. This actuator design became IBM’s most widely licensed electromechanical innovation, extensively adopted across hard disk drives throughout the 1980s and beyond. Approximately 177,000 units of the IBM 62GV were sold, marking it as the first HDD to surpass sales of 100,000 units.
OEM and Small Systems HDDs
This section outlines IBM-produced hard drives marketed as OEM products or designed for IBM’s smaller systems such as System/3, System/32, /34, /36, and AS/400. Drives are referenced by their OEM model numbers and organized by their initial shipment dates.
IBM 0680
The IBM 0680 debuted in 1979 on many IBM small systems and lower-tier System/370 configurations, known there as the 3310 direct access storage device. Officially announced as the OEM model 0680 in September 1981, it was developed at IBM’s Hursley laboratory in the UK under the codename Piccolo. This drive featured six 8-inch (210 mm) disks with an enhanced rotary actuator and initially offered up to 65 MB of storage.
A higher-capacity variant, the 62SW, was introduced in June 1984 but experienced limited sales due to its cost per megabyte being comparable to that of the earlier 62GV.
IBM 0676
Released in November 1982 as the 5247 Disk Storage Unit for the IBM System/23 Datamaster, the 0676 was developed at IBM Rochester, Minnesota under the internal designation 21ED. It was an eight-inch HDD initially available with either two or four disks (210 mm), delivering capacities of 15 or 30 MB respectively. In 1983, it was integrated into the S/36’s 5360 System Unit. By increasing tracks per surface in 1984, its capacity doubled and it was incorporated into the System/36’s subsequent 5362 System Unit.
IBM 0665
Launched in October 1985 within the PC AT (5170) system unit, the IBM 0665 was developed at IBM Rochester under the codename "Pixie." This hard drive featured a 5¼-inch form factor and came with storage options of 20, 30, or 44 MB.
IBM 0667
The 0667 began shipping in August 1986. Created at IBM Rochester under the codename "Grant," this full-height ESDI hard drive measured 5¼ inches and supported up to four disks sized at 130 mm each, offering a maximum capacity of 70 MB. It was deployed in select PC RT models (6150, 6151, and 6152) as well as System/36 Model System Units (5363 and 5364).
IBM 0669
Introduced in 1987 and developed at IBM Rochester, Minnesota under the codename "Grant-Prime," the 0669 was a full-height five-inch HDD featuring up to four disks of size 130 mm with a total capacity reaching up to115 MB. This drive served as the internal hard disk for both the System/36 model 5363 and the Series/1 model 4956 system units.
IBM 0671
Launched in 1987, the 0671—originally developed under the codename "Lee" at IBM Rochester—was a full-height 5-inch HDD utilizing ESDI technology with a capacity of up to 316 MB. It contained as many as eight 130 mm platters and represented IBM's inaugural implementation of a thin metal film recording surface. This drive was incorporated into the IBM AS/400 9404 System Unit in 1988, supporting configurations of two or three drives per chassis.
IBM 0661
Introduced in 1989 as model 371 and initially codenamed "Lightning" at IBM facilities in Rochester and Hursley, UK, the 0661 was a SCSI hard disk drive offering 320 MB capacity. It utilized up to eight 95 mm platters with fourteen heads, followed by an enhanced 400 MB "Turbo" variant released in 1990. This model became a standard storage component for prominent IBM systems such as the AS/400 System Unit Model CXX.
IBM 0681
The 0681, developed under the codename Redwing at IBM Hursley and released in April 1990, was the final HDD product from that laboratory. It featured a full-height 5-inch form factor with twelve 130 mm disks, delivering up to 857 MB of storage. Notably, it was IBM’s first drive to incorporate PRML data decoding technology. This HDD powered the 9333 Disk Drive Subsystem introduced in early 1992, which later included an upgraded version offering 1.07 GB capacity.
IBM 0663
Shipping from late 1991 and developed as "Corsair," the 0663 was a compact half-height (1.6-inch) HDD with a 3-inch form factor. It provided up to 1 GB of storage across eight 95 mm platters and appeared in select PS/2 and RS/6000 models. This drive was IBM’s initial OEM product equipped with Magnetoresistance (MR) head technology.
IBM 0664
Released in November 1992 and created under the codename "Allicat" at IBM Rochester, Minnesota, the 0664 was a full-height (3.25-inch) 5-inch HDD combining two separate 3-inch drives within one unit. It offered maximum capacity of up to 2.013 GB using as many as eight 95 mm disks.
IBM 0662
The 0662, branded internally as "Spitfire," shipped in June 1993 from IBM Rochester. This full-height (1-inch) 3-inch HDD delivered storage of up to 1.05 GB spread over three platters or five surfaces. It found application within IBM’s own hardware such as the 9336 Disk Unit and the 9337 Disk Array.
Floppy disk drive
IBM was a pioneer in floppy disk technology, introducing the first 8-inch floppy disk drive in 1971 primarily as a read-only program load device. By 1973, IBM launched its initial read/write floppy disk drive with the release of the 3740 Data Entry System, which helped establish early standards for the 8-inch floppy format. Despite this innovation, IBM never marketed these drives separately, allowing floppy disk technology to evolve largely outside its direct influence.
At one point, IBM was the largest purchaser of OEM-manufactured 5-inch floppy disk drives. Its preference for two-sided units with a density of 48 tracks per inch contributed to this becoming an industry norm. Although IBM had plans to produce these drives internally along with smaller form factors, all such manufacturing initiatives were abandoned by 1985. Additionally, an attempt in 1983 to OEM a smaller, 4-inch DemiDiskette did not succeed.
"Star" series of HDDs
On October 17, 1994, IBM's Storage Systems division unveiled three new families of hard disk drives: the Travelstar series featuring compact 2-inch drives designed for notebook computers; the Deskstar line consisting of 3-inch drives aimed at desktop systems; and the Ultrastar series comprising high-performance 3-inch drives intended for advanced computing environments.
IBM's first HDD versus its last HDDs
The following table compares IBM's first hard disk drive, the RAMAC 350, with the last three models from its "Star" series of OEM HDDs. It demonstrates substantial decreases in both cost and physical dimensions, alongside remarkable improvements in storage capacity and operational efficiency.
| Parameter (units) | RAMAC 350 | Ultrastar 146Z10 | Deskstar 180GXP | Travelstar 80GN | 46-year improvement (maximum) |
|---|---|---|---|---|---|
| Introduction Date | September 1956 | July 2002 | October 2002 | November 2002 | |
| Storage Capacity (gigabytes) | 0.004 | 146 | 180 | 80 | 48,000 |
| Size (inches) | 60×68×29 | 4×1×5.75 | 4×1×5.75 | 2.75×0.38×3.95 | |
| Size (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 | |
| Mass (pounds) | 2,140 | 1.7 | 1.4 | 0.2 | 1,244 |
| Mass (kilograms) | 971 | 0.8 | 0.64 | 0.095 | |
| Power Consumption (watts) | Approximately 2374 watts (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 |
| 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 in 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 | |
| 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 Technologies Beyond HDDs and FDDs
Within certain IBM operating systems, hard disk drives and floppy disk drives are categorized under DASDs (direct access storage devices). Additional DASD formats include:
IBM Model 7320 Drum
The IBM 7320, launched in 1962, represents a magnetic drum storage system.
IBM Model 2301 Drum
Introduced in the late 1960s, the IBM 2301 is another magnetic drum-based storage device.
IBM Model 2303 Drum
The IBM 2303, which debuted in 1964, is also a magnetic drum storage apparatus.
IBM Model 2321 Data Cell
Announced in 1964, the IBM 2321 Data Cell utilizes short magnetic tape strips for data storage and contains ten removable cells of approximately forty megabytes each, totaling a capacity of four hundred megabytes.
IBM Model 3850 Mass Storage System
The IBM 3850, introduced in1974 as the IBM3850 Mass Storage System, operates as a tape cartridge library that stages information onto IBM3330 or3350 disk drives while emulating virtual disk drives for the host system.