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FASTRAND was a magnetic drum mass storage system built by Sperry Rand Corporation for their UNIVAC 1100 series and 490/494 series computers. A voice coil actuator moved a bar containing multiple single track recording heads, so these drums operated much like moving head disk drives with multiple disks. The heads "flew" on self-acting hydrodynamic air bearings. The drums had a plated magnetic recording film. The Fastrands were very heavy (5,000 pounds) and large, approximately 6' long. They required special rigging and mounts to install. There were reported cases of drum bearing failures that caused the machine to tear itself apart and send the heavy drum crashing through walls. At the time of their introduction the storage capacity exceeded any other random access mass storage disk or drum. There were three models of FASTRAND drives: * FASTRAND I had a single drum. The large mass of the rotating drum caused gyroscopic precession of the unit, making it tend to spin on the computer room floor as the Earth rotated under it. Very few of these devices were delivered. * FASTRAND II (the majority of units produced) had two counter-rotating drums to eliminate the gyroscopic effect. One actuator bar with heads was located between the drums. * FASTRAND III, introduced in 1970, was physically identical to the FASTRAND II, but increased the recording density by 50%. ==Specifications (FASTRAND II)== Storage capacity: 22,020,096 36-bit words = 132,120,576 6-bit FIELDATA characters = 99 megabytes (8-bit bytes) per device Drum rotation rate: 880 RPM (14.7 rotations per second) Heads: 64 Sector size: 28 36-bit words size: 64 sectors (1,792 36-bit words) Track density: 105 tracks per inch Average Access time (seek time plus rotational latency): 92 milliseconds Data transfer rate: 26,283 36-bit words per second = 118 kilobytes per second (8-bit bytes) on 1100 series machines Recording density, one-dimensional: 1,000 bits per inch (along one track) Recording density, two-dimensional: 105,000 bits per square inch of drum surface Max FASTRAND devices (drum units) per controller: 8 Controller price: $41,680 (1968 dollars) FASTRAND device price: $134,400 (1968 dollars) Weight per FASTRAND device: 4,500 pounds Weight per kilobyte: 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「UNIVAC FASTRAND」の詳細全文を読む スポンサード リンク
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