page_title: History of hard disk drives
section_title: 1950s–1970s
hierarchical_section_title: History of hard disk drives / 1950s–1970s
caption_attribution_description: English: IBM 350 RAMAC, capacity 5Mb, that is being restored by volunteers in the en:Computer History Museum in Mountain View, CA. source: Silicon Valley Sleuth blog Deutsch: IBM 350 RAMAC, Kapazität 5 MB, von Freiwilligen im Computermuseum in Mountainview, Kalifornien, USA wiederhergestellt
context_page_description: In 1953, IBM recognized the immediate application for what it termed a "Random Access File" having high capacity and rapid random access at a relatively low cost. After considering technologies such as wire matrices, rod arrays, drums, drum arrays, etc., the engineers at IBM's San Jose California laboratory invented the hard disk drive. The disk drive created a new level in the computer data hierarchy, then termed Random Access Storage but today known as secondary storage, less expensive and slower than main memory but faster and more expensive than tape drives.
  The commercial usage of hard disk drives began in 1957, with the shipment of a production IBM 305 RAMAC system including IBM Model 350 disk storage. US Patent 3,503,060 issued March 24, 1970, and arising from the IBM RAMAC program is generally considered to be the fundamental patent for disk drives.
  Each generation of disk drives replaced larger, more sensitive and more cumbersome devices. The earliest drives were usable only in the protected environment of a data center. Later generations progressively reached factories, offices and homes, eventually becoming ubiquitous.
context_section_description: The IBM 350 Disk File was developed under the code-name RAMAC by an IBM San Jose team led by Reynold Johnson. It was announced in 1956 with the then new IBM 305 RAMAC computer. A variant, the IBM 355 Disk File, was simultaneously announced with the IBM RAM 650 computer, an enhancement to the IBM 650.
  The IBM 350 drive had fifty 24-inch (0.6 m) platters, with a total capacity of five million 6-bit characters (3.75 megabytes). A single head assembly having two heads was used for access to all the platters, yielding an average access time of just under 1 second.
  The RAMAC disk drive created a new level in the computer data hierarchy, today known as secondary storage, less expensive and slower than main memory (then typically core or drum) but faster and more expensive than tape drives.  Subsequently there was a period of about 20 years in which other technologies competed with disks in the secondary storage marketplace, for example tape strips, e.g., NCR CRAM, tape cartridges, e.g., IBM 3850, and drums, e.g., Burroughs B430, UNIVAC FASTRAND, but all ultimately were displaced by HDDs.  Today SSDs compete with HDDs in the marketplace.
  The IBM 1301 Disk Storage Unit, announced in 1961, introduced the usage of heads having self-acting air bearings (self-flying heads) with one head per each surface of the disks. It was followed in 1963 by the IBM 1302, with 4 times the capacity.
  Also in 1961, Bryant Computer Products introduced its 4000 series disk drives. These massive units stood 52 inches (1.3 m) tall, 70 inches (1.8 m) long, and 70 inches (1.8 m) wide, and had up to 26 platters, each 39 inches (0.99 m) in diameter, rotating at up to 1,200 rpm. Access times were from 50 to 205 milliseconds (ms). The drive's total capacity, depending on the number of platters installed, was up to 205,377,600 bytes (205 MB).
  
  The first disk drive to use removable media was the IBM 1311 drive.  It was introduced in 1962 using the IBM 1316 disk pack to store two million characters.  It was followed by the IBM 2311 (1964) using the IBM 1316 disk pack to store 5 megabyte, IBM 2314 (1965) using the IBM 2316 disk pack to store 29 megabytes, the IBM 3330 using 3336 disk packs to store 100 megabytes and the 3330-11 using the 3336-11 to store 200 megabytes.
  Memorex in 1968 shipped the first HDD, the Memorex 630, plug compatible to an IBM model 2311 marking the beginning of independent competition (Plug Compatible Manufacturers or PCMs) for HDDs attached to IBM systems.  It was followed in 1969 by the Memorex 660, an IBM 2314 compatible, which was OEM'ed to DEC and resold as the RP02.
  
  In 1964, Burroughs introduced the B-475 disk drive, with a head per track, as part of the B5500.
  In 1970, IBM introduced the 2305 disk drive, with a head per track.
  In 1973, IBM introduced the IBM 3340 "Winchester" disk drive and the 3348 data module, the first significant commercial use of low mass and low load heads with lubricated platters and the last IBM disk drive with removable media. This technology and its derivatives remained the standard through 2011. Project head Kenneth Haughton named it after the Winchester 30-30 rifle because it was planned to have two 30 MB spindles; however, the actual product shipped with two spindles for data modules of either 35 MB or 70 MB. The name 'Winchester' and some derivatives are still common in some non-English speaking countries to generally refer to any hard disks (e.g. Hungary, Russia).
  Also in 1973, Control Data Corporation introduced the first of its series of SMD disk drives using conventional disk pack technology. The SMD family became the predominant disk drive in the minicomputer market into the 1980s.
  Smaller diameter media came into usage during the 1970s and by the end of the decade standard form factors had been established for drives using nominally 8-inch media (e.g., Shugart SA1000) and nominally 5.25-inch media (e.g., Seagate ST-506).
  During the 1970s, captive production, dominated by IBM's production for its own use, remained the largest revenue channel for HDDs, though the relative importance of the OEM chann
caption: A partially disassembled IBM 350 (RAMAC)
exif: {"Image Make": "Canon", "Image Model": "Canon PowerShot A95", "Image Orientation": "0", "Image XResolution": "180", "Image YResolution": "180", "Image ResolutionUnit": "Pixels/Inch", "Image DateTime": "2006:09:12 08:14:24", "Image YCbCrPositioning": "Centered", "Image ExifOffset": "184", "Thumbnail Compression": "JPEG (old-style)", "Thumbnail XResolution": "72", "Thumbnail YResolution": "72", "Thumbnail ResolutionUnit": "Pixels/Inch", "Thumbnail JPEGInterchangeFormat": "2008", "Thumbnail JPEGInterchangeFormatLength": "7157", "EXIF ExposureTime": "1/30", "EXIF FNumber": "14/5", "EXIF ExifVersion": "0220", "EXIF DateTimeOriginal": "2006:09:12 08:14:24", "EXIF DateTimeDigitized": "2006:09:12 08:14:24", "EXIF ComponentsConfiguration": "YCbCr", "EXIF CompressedBitsPerPixel": "3", "EXIF ShutterSpeedValue": "-99/32", "EXIF ApertureValue": "95/32", "EXIF ExposureBiasValue": "0", "EXIF MaxApertureValue": "95/32", "EXIF MeteringMode": "Pattern", "EXIF Flash": "Flash did not fire, compulsory flash mode", "EXIF FocalLength": "125/16", "EXIF FlashPixVersion": "0100", "EXIF ColorSpace": "Uncalibrated", "EXIF ExifImageWidth": "360", "EXIF ExifImageLength": "343", "Interoperability InteroperabilityIndex": "R98", "Interoperability InteroperabilityVersion": "[48, 49, 48, 48]", "Interoperability RelatedImageWidth": "360", "Interoperability RelatedImageLength": "343", "EXIF InteroperabilityOffset": "1860", "EXIF FocalPlaneXResolution": "2592000/283", "EXIF FocalPlaneYResolution": "486000/53", "EXIF FocalPlaneResolutionUnit": "2", "EXIF SensingMethod": "One-chip color area", "EXIF FileSource": "Digital Camera", "EXIF CustomRendered": "Normal", "EXIF ExposureMode": "Auto Exposure", "EXIF WhiteBalance": "Auto", "EXIF DigitalZoomRatio": "1", "EXIF SceneCaptureType": "Standard"}