IBM 2314
| Company type | Division (former) |
|---|---|
| Industry | Computer storage |
| Founded | 1956 |
| Defunct | 2003 |
| Fate | Divested hard disk drive division to Hitachi |
| Headquarters | San Jose , United States |
| Products | Hard disk drives, floppy disk drives |
| Parent | IBM |
IBM was a producer of magnetic disk storage equipment 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 breakthroughs attributed to its workforce. The core mechanical architecture of hard disk drives has remained largely unchanged since the introduction of the IBM 1301, and many performance benchmarks set in the 1950s continue to be relevant. This series of products is distinguished by substantial decreases in cost and physical dimensions, coupled with notable advancements in capacity and speed.
Between 1969 and the mid-1980s, IBM manufactured 8-inch floppy disk drives but did not become a leading supplier of the smaller 5.25- or 3.5-inch variants. While IBM consistently marketed its magnetic disk drives, it only started providing them under original equipment manufacturer (OEM) agreements beginning in 1981. By 1996, IBM had discontinued producing HDDs tailored exclusively for its own systems, offering all models solely as OEM products.
IBM has employed various designations for its magnetic disk drives, such as direct-access storage device (DASD), disk file, and diskette file. This article adopts the industry-recognized terms 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 on September 14, 1956, as part of the IBM 305 RAMAC computer system. A comparable model, the IBM 355, was released for the IBM 650 RAMAC system. The initial prototype was delivered to Zellerbach Paper Company in June 1956, with production units distributed beginning November 1957 to customers including United Airlines.
Engineered to support real-time business accounting applications, the IBM 350 had a storage capacity of five million 6-bit characters (equivalent to 3.75 MB). It consisted of fifty-two disks providing one hundred recording surfaces and tracks, rotating at a speed of 1200 rpm with a data transfer rate of 8,800 characters per second. The access mechanism moved read/write heads to select specific disk pairs and tracks. Several enhanced versions were launched throughout the 1950s. The RAMAC 305 system paired with the IBM 350 was leased at $3,200 per month. Production of this drive ceased in 1969.
The patent emerging from the RAMAC initiative is recognized as the foundational intellectual property for disk drives. Although initially rejected by IBM’s Board over concerns about cannibalizing punch card sales, development persisted at IBM’s San Jose facility until receiving approval from IBM's president.
Physically, the IBM 350 cabinet measured approximately long, high, and wide, weighed around one ton, and required forklifts or cargo aircraft for transportation. Currie Munce of Hitachi Global Storage Technologies—successors to IBM’s storage division—has noted that while capacity expansion beyond five million characters was feasible, IBM’s marketing team was reluctant to promote larger capacities. Nevertheless, models with double the original capacity were announced in January 1959 and shipped later 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. A restoration effort commenced in 2002 under Al Hoagland’s leadership in partnership with Santa Clara University and later relocated to the Computer History Museum in Mountain View, California in 2005, where it remains on public display within the Revolution exhibition.
IBM 353
The IBM 353, employed with the IBM 7030, resembled the IBM 1301 but offered a higher data transfer speed. It provided storage for 2,097,152 (221) 64-bit words, equivalent to 134,217,728 bits, and achieved a transfer rate of 125,000 words per second. A prototype delivered in late 1960 was the pioneering disk drive to implement one head per surface flying on a compressed air cushion, similar to the approach used in the IBM 350. Production units featured self-levitating 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. Utilizing the IBM 350 mechanism but enhanced with up to three access arms (in contrast to the single arm on the IBM 350), it stored six million decimal digits plus an additional 600,000 sign indicators. It transferred entire tracks between its magnetic storage and the core memory of the 653, an optional IBM 650 storage unit capable of holding sixty signed ten-digit words—sufficient for one disk track or tape record—alongside two other functionalities.
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 accommodated ten million alphanumeric characters (60 million bits) across 25 disks; Model 2 doubled this capacity to twenty million characters (120 million bits) using fifty disks. The disks rotated vertically at a speed of 1200 revolutions per minute.
Each disk surface contained 200 tracks segmented into five sectors; sectors numbered 0 through 4 were located on top surfaces, while sectors 5 through 9 were on bottom surfaces. Each sector held between 178 and 200 characters. One to three forked access arms each carried two read/write heads positioned on both the top and bottom of a single disk. These arms moved vertically to select among disks (0–49) and horizontally to choose tracks (0–199). Reading or writing a sector required approximately ten milliseconds.
Access times varied from around 100 milliseconds up to a maximum of 700 milliseconds for Model 1 and extended to up to 800 milliseconds for Model 2. Model 2 contained one hundred thousand sectors that could hold either two hundred characters in move mode or one hundred seventy-eight characters in load mode, which incorporated a word mark bit per character. Model 1 featured half as many sectors.
IBM 7300
The IBM 7300 Disk Storage Unit was developed for use with the IBM 7070 and introduced alongside Model 2 in 1959. Nevertheless, following the debut of the IBM 1301 on June 5, 1961, customers showed a preference for the IBM 1301 over the IBM 7300. The technology employed in the IBM 7300 bore similarities to that found in the IBM 350, IBM 355, and IBM 1405 models.
IBM 1301
Announced on June 2, 1961, the IBM 1301 Disk Storage Unit was designed for compatibility with IBM 7000 series mainframes as well as the IBM 1410. It stored twenty-eight million characters per module (twenty-five million characters when used with the IBM 1410), utilizing twenty-five large disks featuring forty user-recordable surfaces and two hundred fifty tracks each. The Model 1 configuration included a single module; Model 2 stacked two modules vertically. Disks spun at a rate of eighteen hundred revolutions per minute and transferred data at ninety thousand characters per second.
A significant advancement was its use of individual arms and read/write heads dedicated to each surface that moved simultaneously like a comb assembly. This approach eliminated delays caused by moving heads between disks and reduced maximum access time to one hundred eighty milliseconds. Additionally, the IBM 1301 was pioneering in adopting aerodynamically engineered heads that floated on a thin air cushion above the disk surface, boosting operational efficiency.
Connection to systems was facilitated through the IBM 7631 File Control unit, allowing operation with either an IBM 1410 or a member of the IBM 7000 series computers or enabling sharing between two machines.
From a financial perspective, leasing rates for the IBM 1301 Model 1 were $2,100 monthly or $115,500 for purchase; Model 2 leased at $3,500 monthly or cost $185,000 when bought outright. The IBM 7631 controller carried an additional charge of $1,185 per month or $56,000 if purchased. All versions were discontinued by the year 1970.
IBM 1302
Launched in September 1963, the IBM 1302 Disk Storage Unit expanded storage capacity to 117 million 6-bit characters per module, representing a fourfold increase compared to the IBM 1301. It delivered an average access time of 165 milliseconds and supported data transfer rates of 180,000 characters per second, more than doubling the speed of its predecessor. Each unit was equipped with two separate access mechanisms dedicated to the inner and outer cylinder zones. The Model 2 configuration stacked two such modules to double overall capacity. Leasing fees were set at $5,600 monthly for Model 1 and $7,900 monthly for Model 2, while purchase prices stood at $252,000 and $355,500 respectively. The optional IBM 7631 controller could be leased for an additional $1,185 per month or purchased for $56,000. Production and sales of the 1302 ceased in February 1965.
IBM 1311
Announced on October 11, 1962, the IBM 1311 Disk Storage Drive was designed for medium-scale business and scientific computing applications. Approximately the size of a top-loading washing machine, it utilized removable IBM 1316 disk packs with a storage capacity of two million characters each. Throughout the 1960s, seven different models were released before being phased out by the early 1970s.
Each IBM 1316 disk pack measures about four inches in height and weighs roughly ten pounds. It consists of six disks measuring fourteen inches in diameter, offering ten recording surfaces in total. Operating at 1500 revolutions per minute, each surface contains one hundred tracks subdivided into twenty sectors per track, with each sector storing one hundred characters. The read/write heads are hydraulically actuated and mechanically positioned prior to data operations. The disk pack is enclosed within a transparent plastic casing featuring a locking mechanism that facilitates straightforward insertion and removal—a design approach that gained widespread adoption later on.
The seven IBM 1311 variants include master drives that incorporate controllers capable of managing multiple Model 2 slave drives. Master units were tailored for compatibility with systems such as the IBM 1440, IBM 1460, IBM 1240 (supporting up to four slaves), IBM 1620 or IBM 1710 (up to three slaves), IBM 1401 (up to four slaves), and IBM 1410/7010/7740 (up to four slaves). Differences among models pertained to system compatibility and feature sets; all models were withdrawn by the mid-1970s.
Available optional capabilities comprised:
- Direct Seek: bypasses returning the heads to track zero before initiating a seek.
- Scan Disk: enables rapid automated searching for specific identifiers or conditions.
- Seek Overlap: permits concurrent seeking and read/write operations across multiple drives.
- Track Record: enhances capacity by recording a single large record per track instead of dividing data into sectors, increasing total storage to roughly eighteen million bits.
Master drives (Models 1, 3, 4, and 5) are equipped with additional power supplies and control circuitry, rendering them approximately one foot wider than Model 2 slave drives.
IBM 2302
The IBM 2302 serves as the System/360 counterpart to the earlier IBM 1302 unit, incorporating track formatting compatible with S/360 DASD architecture. It employs a fixed module containing twenty-five platters with forty-six recording surfaces. The Model 3 configuration includes one such module; Model 4 contains two modules. Each module features two independent access mechanisms—referred to as access groups—that serve the innermost and outermost ranges of 250 cylinders respectively; each access group has one read/write head per track. Average rotational latency is approximately seventeen milliseconds, with a maximum of thirty-four milliseconds; maximum seek time for each access group is up to one hundred eighty milliseconds. Tracks are sized at 4,985 bytes each, resulting in a formatted module capacity of 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 device, paired with the IBM 2835 Storage Control, initially interfaced with the 360/85 and 360/195 systems through the IBM 2880 Block Multiplexor Channel.
During the System/370 period featuring Virtual Storage, the 2305 was frequently utilized as a paging storage unit across various systems such as the 3155, 3165, 3158, 3168, 3033, 4341, and 3081 (the latter requiring specialized microcode). It was also preferred for managing small but highly active data sets like catalogs and job queues.
The 2305-1 model provides a storage capacity of 5.4 MB with a throughput of 3.0 MB/s and an average access latency of 2.5 milliseconds. In contrast, the larger 2305-2 variant offers an 11.2 MB capacity at a transfer speed of 1.5 MB/s and an average access time of 5 milliseconds.
Optimized for rapid and continuous access to modest data volumes, the IBM 2305's combination of capacity and swift data rates made it well-suited for system-resident tasks, temporary work files, job queues, indexing purposes, and frequently accessed datasets. Its quick response times made it particularly effective as a paging device in high-load environments processing more than 1.5 transactions per second.
IBM 2311
The IBM 2311 Disk Storage Drive debuted in 1964 alongside the 2841 Control Unit and supported the IBM System/360 series while also being compatible with the IBM 1130 and IBM 1800 systems. It connected directly to models such as the IBM System/360 Model 20 and Model 25. All units utilized the IBM 1316 Disk Pack, which was originally introduced with the IBM 1311.
While the Model 1 of the 2311 operates through the 2841 Control Unit, on the System/360 Model 25 it employs a Disk Attachment Control that offers similar capabilities. Disk packs are formatted using IBM's variable record length scheme known as count key data. Models 11 and 12, integrated with the Model 20’s built-in control unit, use a fixed-sector format; consequently, disk packs are not interchangeable between these models and Model 1.
Mechanically akin to the IBM 1311, the 2311 enhanced recording technology to boost data density, accommodating up to 7.25 megabytes on a removable six-platter IBM 1316 disk pack. It incorporates ten read/write heads mounted on a hydraulically actuated arm, with each platter surface containing 200 tracks plus three additional spare tracks for fault tolerance. The average seek time is approximately 85 milliseconds while data transfer rates reach up to 156 kB/s.
Uniform electrical interfaces across System/360 models allowed third-party vendors to develop plug-compatible disk drives, which contributed to the emergence of an industry focused on producing compatible storage devices for IBM systems.
IBM 2314 Disk Access Storage Facility Model 1
Released in April of 1965, the IBM 2314 Disk Access Storage Facility Model 1 was designed to support both System/360 and System/370 platforms. Featuring a Two Channel Switch capability, it could connect simultaneously to two separate channels. Building upon the mechanical design of the IBM 2311, it incorporated improved recording technology that enabled higher storage density.
This drive employed an IBM 2316 disk pack consisting of eleven platters—an increase from six in its predecessor—providing twenty recording surfaces and storing roughly twenty-nine million characters. Each surface contained approximately two hundred tracks accessed by twenty read/write heads positioned on a hydraulically actuated arm. Initial access times were comparable to those of the IBM 2311 but were enhanced in later iterations; data transfer speeds doubled to approximately 310 kB/s.
The Model 1 was shipped as a set of nine disk drives bundled together along with separate control units and modules. Drives were installed in drawer-like assemblies facilitating easy removal and insertion of disk packs, earning them the nickname "Pizza Ovens." At any given time, eight drives were active while one served as a hot spare or was available for offline maintenance. System addresses for each drive could be reassigned flexibly by swapping user-installable plugs, allowing designation of spare units as needed.
An optional IBM 2844 Control Unit permitted two System/360 channels to access different drives within the storage facility concurrently.
Additional variants of the IBM 2314 were introduced in subsequent releases:
IBM 2314 Direct Access Storage Facility - Model Variants
In 1969, IBM segmented the 2314 storage system into distinct models, each supporting up to nine drives (with eight accessible online) connected to a 2314 Storage Control unit:
- 2312 Disk Storage, featuring a single-drive configuration.
- 2313 Disk Storage, comprising four drives.
- 2318 Disk Storage, equipped with two drives.
IBM 2319
To address competition from plug-compatible manufacturers offering alternatives similar to the 2314, IBM launched the cost-effective three-drive 2319 series in 1970. This series was derived by removing one drive from the four-drive 2313 and marketing it as the 2319 A1, which was offered at a notably lower rental rate aimed at attracting new clientele while maintaining higher charges 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 could 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 designed specifically for IBM 4331 midrange computer systems. Each unit provided a storage capacity of 64.5 MB. The device utilized fixed-block architecture and was compatible exclusively with S/370 operating systems DOS/VSE and VM.
IBM 3330
The IBM 3330 Direct Access Storage Facility, internally codenamed Merlin, debuted in June 1970 for IBM System/370 and System/360/195 platforms. Initial offerings included a two-drive Model 1 and a single-drive Model 2. The removable disk packs had a capacity of 100 MB each. Notable technological improvements featured error correction via fire codes, which enhanced reliability and lowered expenses by accommodating imperfections on disk surfaces. The device delivered an access time of 30 ms and data transfer speeds reaching 806 kB/s.
Originally, one storage control unit (3830 Model 1) managed up to four drives in a chain (with a maximum of eight drives per chain). In August 1972, IBM introduced the 3830 Model 2 Storage Control alongside the 3333 Disk Storage and Control, separating control units from drive chains. This architecture enabled up to sixteen drives per storage control by linking two 3333 units—each managing eight drives—with optional string switching for dual-controller access.
In 1973, IBM announced double-density (-11) models: the 3333–11, the 3330-11, and the larger-capacity 3336–11 Disk Packs holding up to 200 MB. Mixing single- and double-density drives within the same chain was not supported, and upgrading existing drives required significant conversion efforts and data migration.
The IBM 3330 series was discontinued 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 drive string. Since no A model exists for the IBM 3344, it must connect to an IBM 3340 A model acting as head of string.
IBM 3340
The IBM 3340 Direct Access Storage Facility, known by its codename Winchester, was introduced in March 1973 targeting IBM System/370 systems. Three variants were released: the 3340-A2 with two drives plus controller, and the B2 (two drives) and B1 (single drive) units. The B-series models connect to the A2 controller model, supporting up to eight drives in total.
This system employed removable data modules that included both the read/write head and arm assembly; during mechanical load/unload operations, an access door opened on the module itself to engage with the drive—unlike previous disk packs that required cover removal. It achieved an average access time of 25 ms and data transfer rates of approximately 885 kB/s. Three versions of the IBM 3348 Data Module were offered: one with a capacity of 35 MB, plus two versions with capacities of 70 MB—one of which featured an additional fixed-head area providing faster access to about 500 KB of data. The IBM 3340 incorporated error correction capabilities and was retired in 1984.
Developed at IBM’s San Jose facility under Ken Haughton’s leadership, initial designs emphasized two removable modules each holding approximately 30 MB—a configuration dubbed "30/30" that inspired its Winchester nickname after the Winchester .30-30 rifle cartridge. Although capacities increased over time, this codename persisted.
A significant breakthrough was its economical head design that eliminated the need for unloading heads from media surfaces during power cycles. Winchester technology permitted heads to land on and lift off from spinning disks during power transitions, dramatically simplifying head and arm mechanisms while reducing costs. This design became widely adopted across the industry.
The term Winchester or colloquially Winnie remained common parlance for hard disk drives into the early part of the 1990s but has since largely fallen out of everyday use worldwide.
IBM 3344
The IBM 3344 shares similarities with the 3340 but distinguishes itself by employing fixed media instead of the removable 3348 data modules. Each spindle accommodates four logical drives, each offering storage capacity equivalent to a 3348–70. This model is exclusively available in dual-drive configurations and does not include an A (head of string) variant. The 3344-B2F version incorporates fixed heads spanning certain cylinders on both drives. Both the 3344-B2 and 3344-B2F require a 3340-A2 or 3340-A2F unit to serve as the head of string. Internally, the IBM 3344 matches the IBM 3350 in design; its differences are limited to variations in control unit microcode.
IBM 3350
The IBM 3350 Direct Access Storage Facility, codenamed Madrid, was introduced in 1975 for use with IBM System/370 systems. Its sealed, non-removable head-disk assemblies (HDAs) integrated both heads and arms, establishing a design benchmark for subsequent IBM DASD products. Each HDA contained 555 cylinders, 30 heads, and stored 19,069 bytes per track, resulting in roughly 317 MB of storage capacity.
Models A2, A2F, B2, B2F, C2, and C2F featured two HDAs each. The A2 and A2F included an extra electronic board functioning as controllers or head-of-string units, facilitating connections to storage control units like the 3830 Model 2 or Integrated Storage Control (ISC) embedded in CPUs such as the 3148 and 3158. Later control units such as the 3880 maintained backward compatibility. Deployment typically involved strings led by an A2/A2F controller with up to three B2 units or combinations including C2 units, which acted as secondary controllers with restricted connectivity.
"x2F" variants incorporated fixed head regions over the initial five cylinders on both HDAs, eliminating seek time within this area. This design enhanced performance for frequently accessed data zones such as HASP or JES2 checkpoint information and improved system swap efficiency for TSO and MVS by minimizing head movement during context switches.
The IBM 3350 series was discontinued in September 1994.
IBM 3370
Released in January 1979 for IBM's midrange systems including the 4331, 4341, and System/38, the IBM 3370 comprised seven fixed 14-inch disks with a total capacity of 571 MB. It was the first hard disk drive to utilize thin-film head technology developed at the Thomas J. Watson Research Center during the late 1960s. The drive employed a fixed-block architecture and was compatible with DOS/VSE and VM operating systems.
IBM 3375
The IBM 3375 functioned as a companion device featuring count key data architecture and supported OS/360 along with its successor operating systems.
IBM 3380
Introduced on June 11, 1980, the IBM 3380 incorporated film head technology delivering a capacity of 2.52 GB per unit—each unit consisting of two hard disk assemblies with two actuators accessing approximately 630 MB each. It offered a data transfer rate of up to 3 MB/s and an average access latency of around 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.
The typical configuration included one A unit accompanied by up to three B units; each IBM 3380 contained four devices allowing for as many as sixteen devices per string. These were generally connected through a 3880 storage control unit featuring dual paths that supported two simultaneous I/O operations directed at separate hard disk assemblies.
In February 1985, IBM launched the double-density Extended Capability Model (3380 E), doubling capacity to 5.04 GB per unit—comprising two actuators at 1.26 GB each on two assemblies.
The triple-capacity Model K followed in August 1987, providing storage of up to 7.562 GB per unit via two actuators holding approximately 1.89 GB each. Models J and K were capable of operating in four-path mode, connecting up to thirty-two devices across two A units and multiple B units through a single 3990 storage control unit—enabling four concurrent I/O processes.
The IBM 3380 family consisted of twelve models: six A-units serving as string heads with additional logic interfacing with storage control units; five B-units connecting to either A or C units; and one C-unit designed for direct connection to an IBM channel.
Production continued until May of 1996, marking a significant fifteen-year lifespan for this disk drive family.
IBM 3390
Introduced in November 1989, the IBM 3390 series of Direct Access Storage Devices provided storage capacities up to 22 gigabytes distributed over several drives. Depending on the chosen configuration and storage size, system prices varied between $90,000 and $795,000.
A typical 3390 configuration consists of a central A unit containing either four or eight devices, which can be optionally accompanied by one or two B units hosting up to twelve devices each. This setup functions in a four-path mode linked to a 3990 storage control unit, capable of supporting an additional 3390 string, thereby enabling a maximum of 64 devices within a single subsystem.
Each Hard Disk Assembly (HDA) contains two actuator-head mechanisms along with platters: Model 1 delivered 1.89 GB per HDA, Model 2 doubled this to 3.78 GB. The 1991 Model 3 upgrade raised capacity to 5.67 GB per HDA, and the 1993 Model 9 further increased it to 11.3 GB per HDA.
Differing from previous DASD models that utilized large alternating current motors driving belts, the 3390 HDAs incorporated direct-drive DC motors housed inside the enclosure. The Model 9 represented IBM's last release of a Single Large Expensive Disk (SLED) drive.
IBM 9345
Released in November 1990 as a Request Price Quotation (RPQ) option for IBM's SuperComputing Systems Extensions (SCSE), the IBM 9345 hard disk drive was developed at IBM's San Jose laboratory under the codename Sawmill. It offered up to 1.5 GB capacity within a full-height 5¼-inch form factor by utilizing up to eight 130 mm platters. This model was IBM’s first HDD to incorporate Magnetoresistive (MR) head technology.
IBM 9340
In October 1991, IBM launched the 9345 DASD as part of the channel-attached count key data (CKD) subsystem family known as the IBM 9340, designed for IBM mainframes including ES/9000 processors. The Model 1 configuration featured two drives with 1.0 GB each, while Model 2 contained two drives of 1.5 GB capacity.
While functionally similar to the combination of the 3990 controller and the 3390 storage device, the 9340/9345 lacked the non-volatile RAM cache found in the 3990 and supported a shorter maximum block length than the 3390. The operating system’s Input/Output Supervisor (IOS) detected these devices through the IECCINIT initializer, which identified the absence of non-volatile cache and adjusted device type settings accordingly.
9330 family of disk drives
- Models 1 and 11 of the 9331 Diskette Units included one 8-inch floppy disk drive; models 2 and 12 contained one 5-inch floppy disk drive.
- The 9332 Direct Access Storage Device utilized an IBM 0667 hard disk drive.
- The 9333 High Performance Disk Drive Subsystem employed either IBM 0664 or IBM 0681 hard disk drives depending on specific models.
- The 9334 Disk Expansion Unit enabled connection of one to four SCSI hard drives to RS/6000 systems.
- The 9335 Direct Access Storage Subsystem featured the "Kestrel" hard disk drive developed at IBM Hursley, UK—an 850 MB device with three fourteen-inch platters and dual rotary actuators accessing multiple surfaces. This rack-mountable system was introduced alongside the October 1986 IBM 9370 Information System. No known OEM variants exist.
- The 9336 Disk Unit incorporated the IBM 0681 hard disk drive, also known as Redwing.
- The 9337 Disk Array Subsystem integrated either IBM’s IBM0662 (Spitfire) or IBM0663 (Corsair) hard disk drives.
IBM 2310
Announced in conjunction with the IBM 1800 in 1964 and later with the IBM1130 in 1965—most likely first shipping with the latter in late that year—the IBM2310 Removable Cartridge Drive stored up to 512,000 sixteen-bit words (equivalent to one million twenty-four thousand bytes) on an IBM2315 cartridge. This cartridge consisted of a single oxide-coated aluminum platter enclosed within a plastic casing featuring openings for both read/write arms and two heads.
IBM 5444
Introduced in September 1969 as a component of the System/3, the IBM 5444 was engineered at IBM's Hursley facility in England, where it was known internally as Dolphin. This unit utilized the 5440 disk cartridge, which housed a single 14-inch disk. The series included three variants:
- Model 1: equipped with one fixed and one removable disk, each featuring 100 tracks per surface; cartridge storage capacity reached 1.23 MB
- Model 2: contained one fixed and one removable disk, each with 200 tracks per surface; cartridge capacity doubled to 2.46 MB
- Model 3: comprised solely of one removable disk with 200 tracks per surface; offering a capacity of 2.46 MB
IBM 62GV
The IBM 62GV, launched in May 1974 and developed under the codename Gulliver at IBM’s Hursley lab, initially provided a storage size of 5 MB. Subsequent versions expanded capacity to 10 MB (designated as 62TM) and eventually to 14 MB. It featured a Swinging Arm actuator mechanism paired with a single 14-inch disk. This actuator design became IBM’s most widely licensed electro-mechanical innovation, broadly adopted across the HDD industry throughout the 1980s and remaining a standard nearly forty years later. More than 177,000 units of the IBM 62GV were distributed, marking it as the first hard disk drive to surpass shipments of 100,000 units.
OEM and Small Systems HDDs
This section focuses on hard disk drives manufactured by IBM that were marketed as OEM products or intended for attachment to IBM small systems such as System/3, System/32, /34, /36, and AS/400. The drives are identified by their OEM model numbers and arranged in order based on their initial shipment dates to customers.
IBM 0680
The IBM 0680 made its debut in 1979 across most IBM small systems and entry-level System/370 configurations, where it was known as the 3310 direct access storage device. Officially announced under the OEM designation 0680 in September 1981, this model was developed at IBM’s Hursley laboratory in the UK under the codename Piccolo. It initially offered up to 65 MB of storage utilizing six 8-inch (210 mm) disks and incorporated an enhanced rotary actuator.
A higher-capacity variant dubbed the 62SW was released in June 1984 but experienced limited market penetration due to its cost per megabyte being comparable to that of the IBM 62GV.
IBM 0676
First delivered 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 code name 21ED. This drive featured an 8-inch form factor with initial capacities of either 15 or 30 MB distributed over two or four disks measuring 210 mm each. In 1983, it was integrated into the S/36’s 5360 System Unit. The following year saw its capacity doubled through an increase in tracks per surface, leading to its inclusion within the System/36’s upgraded 5362 System Unit.
IBM 0665
The IBM 0665 entered service in October 1985 within the system unit for the PC AT (model 5170). Developed at IBM Rochester under the codename "Pixie," this hard drive employed a compact 5-inch form factor and was available with capacities of 20, 30, and 44 MB.
IBM 0667
Released in August 1986, the 0667 HDD was created at IBM Rochester under the code name "Grant." It was a full-height, ESDI interface device measuring five inches and supporting up to four disks sized at 130 mm each for a maximum capacity of approximately 70 MB. This drive was offered as an option on selected PC RT models (6150, 6151, and 6152) as well as within System/36 Model Units (5363 and 5364).
IBM 0669
The 0669, developed at IBM Rochester under the internal name "Grant-Prime," shipped in 1987. This full-height five-inch hard drive supported up to four disks sized at 130 mm each, delivering storage capacities reaching up to approximately115 MB. It served as the built-in hard disk for both the System/36 model unit (5363) and Series/1 (4956) system units.
IBM 0671
Released in 1987, the 0671 was developed at IBM Rochester under the codename "Lee." This full-height 5-inch ESDI hard drive offered capacities up to 316 MB utilizing as many as eight 130 mm platters. It represented IBM's inaugural implementation of a thin metal film recording layer. By 1988, the drive was integrated into the IBM AS/400 9404 System Unit, supporting configurations with two or three drives.
IBM 0661
Introduced in 1989 as model 371, the 0661 was created at IBM Rochester and Hursley (UK) with the project name "Lightning." This SCSI hard disk provided up to 320 MB storage across eight 95 mm platters. A subsequent "Turbo" variant with a capacity of 400 MB was launched in 1990. The drive became a standard component in multiple IBM systems, including the AS/400 System Unit Model CXX.
IBM 0681
The 0681 arrived in April 1990 from IBM Hursley, where it was developed under the "Redwing" project—the final hard disk developed at that location. It featured a full-height 5-inch form factor with twelve 130 mm platters and offered storage up to 857 MB. Notably, it introduced PRML data decoding technology. This model powered the 9333 Disk Drive Subsystem released in early 1992, followed by a higher capacity 1.07 GB version in May of that year.
IBM 0663
Launched late in 1991 and codenamed "Corsair," the 0663 was a compact half-height (1.6-inch) 3-inch hard drive delivering up to 1 GB capacity via eight 95 mm platters. It was incorporated into select PS/2 and RS/6000 systems and marked IBM's first OEM drive to utilize Magnetoresistance (MR) head technology.
IBM 0664
The 0664, introduced in November 1992 and developed under the "Allicat" codename at IBM Rochester, Minnesota, was a full-height (3.25-inch) 5-inch hard disk that combined two smaller 3-inch drives into one unit. It provided storage capacities reaching up to 2.013 GB on up to eight 95 mm platters.
IBM 0662
Unveiled in June 1993 and known internally as "Spitfire," the 0662 was a full-height (1-inch) 3-inch HDD delivering 1.05 GB across three disks or five surfaces. This drive served as the internal storage device for both the 9336 Disk Unit and the 9337 Disk Array.
Floppy disk drive
IBM pioneered floppy disk technology by introducing the first 8-inch floppy disk drive in 1971 as a read-only program loader, followed by its initial read/write model in 1973 with the release of the 3740 Data Entry System. While IBM established early standards for these large-format drives, it did not market them separately, allowing external manufacturers to independently advance floppy disk technology.
At one time, IBM was the largest buyer of OEM-produced 5-inch floppy drives; its adoption of two-sided drives with a track density of 48 tracks per inch helped establish this specification as an industry norm. Although IBM prepared to manufacture these and smaller formats internally, all such plans were scrapped by 1985. Additionally, IBM’s attempt in 1983 to OEM a smaller, proprietary "4-inch DemiDiskette" format was unsuccessful.
"Star" series of HDDs
On October 17, 1994, IBM Storage Systems unveiled three distinct hard disk families: the Travelstar series featuring compact 2-inch drives designed for notebook computers; the Deskstar line comprising larger 3-inch desktop drives; and the Ultrastar series of high-performance 3-inch drives intended for demanding computing environments.
Comparison between IBM's first and final HDDs
The following table contrasts IBM’s inaugural hard disk, the RAMAC 350, with its last three OEM models from the "Star" series. The comparison highlights substantial advancements including drastic reductions in physical size and cost alongside significant gains in storage capacity and operational efficiency.
| Parameter (units) | RAMAC 350 | Ultrastar 146Z10 | Deskstar 180GXP | Travelstar 80GN | Maximum improvement over 46 years |
|---|---|---|---|---|---|
| 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 (mm) | 1500×1700×700 | 102×25×146 | 102×25×146 | 70×9.5×100 | |
| Volume (in³) | 118,320 | 23 | 23 | 4 | 29,161 |
| Volume (litres) | 1,939 | 0.4 | 0.4 | 0.1 | |
| Weight (lbs) | 2,140 | 1.7 | 1.4 | 0.2 | 1,244 |
| Weight (kg) | 971 | 0.8 | 0.64 | 0.095 | |
| Power consumption (watts) | 8100 BTUs/hour (2374 watts), up to5500 VA depending on model | 16 | 10.3 | 1.85 | 1,283 |
| Power efficiency (megabytes/watt) | 0.0016 | 9,125 | 17,476 | 43,243 | 27,375,856 |
| List price (Template:US$) | $34,500 ($234,000 adjusted to2002 dollars) | $1,200 | $360 | $420 | |
| Price per megabyte (Template:US$) | $9,200 ($68,000 adjusted to2002 dollars) | $0.0082 | $0.0020 | $0.0053 | 4,600,000 ($34 million adjusted to2002 dollars) |
| Areal density (megabits/in²) | 0.002 | 26,263 | 46,300 | 70,000 | |
| Areal density (kilobits/mm²) | 0.003 | 40,708 | 71,765 | 108,500 | |
| Volumetric density (gigabytes/in³) | 0.00000003 | 6 | 8 | 20 | 622,100,131 |
| Volumetric 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 (megabytes/s) | 0.001 | 103 | 29.4 | 43.75 |
DASD Devices Beyond HDDs and FDDs
Within certain IBM operating systems, hard disk drives (HDDs) and floppy disk drives (FDDs) are categorized as DASDs (direct access storage devices). Additional technologies classified under DASD include:
IBM 7320 Drum
The IBM 7320 represents a magnetic drum storage unit that was launched in 1962.
IBM 2301 Drum
Introduced in the late 1960s, the IBM 2301 is a magnetic drum-based storage device.
IBM 2303 Drum
The IBM 2303, unveiled in 1964, is another example of a magnetic drum storage system.
IBM 2321 Data Cell
Announced in 1964, the IBM 2321 Data Cell employs short strips of magnetic tape for data storage. It accommodates ten removable cells each with a capacity of 40 MB, resulting in a total storage of 400 MB.
IBM 3850 Mass Storage System
The IBM 3850 Mass Storage System, introduced in 1974, functions as a tape cartridge library that stages data onto IBM 3330 or 3350 disk drives. These drives are then presented to the system as virtual disks.