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UNIVAC FASTRAND
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<h2 id="specifications-fastrand-ii">Specifications (FASTRAND II)</h2> <p>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 <a href="/facts/Revolutions_per_minute/fdNmLToF">RPM</a> (14.7 rotations per second) <a href="/facts/Disk_read-and-write_head/WdpxUpjK">Heads</a>: 64 <a href="/facts/Disk_read-and-write_head/WdpxUpjK">Sector</a> size: 28 36-bit words Track size: 64 sectors (1,792 36-bit words) Track density: 105 tracks per inch Average Access time (<a href="/facts/Seek_time/leXXc5qd">seek time</a> plus <a href="/facts/Rotational_latency/leXXc5qd">rotational latency</a>): 92 milliseconds Data transfer rate: 26,283 36-bit words per second = 118 kilobytes per second (8-bit bytes) on 1100 series machines <a href="/facts/Computer_storage_density/FCqKjVdU">Recording density</a>, 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 <a href="/facts/Peripheral_device/3lEBPE14">devices</a> (drum units) per controller: 8 <a href="/facts/Disk_controller/dfRSYlMq">Controller</a> price: $41,680 (1968 US dollars) FASTRAND device price: $134,400 (1968 dollars, equivalent to $1.22 million in 2024 dollars) Weight per FASTRAND device: 4,500 pounds Weight per kilobyte: 6 ounces (170 g) </p> <h2 id="storage-allocation">Storage allocation</h2> <p>Despite the name, FASTRAND was slow. The head positioning time was significant, so software allocated storage by tracks (1,792 words, 10,752 characters or 8,064 eight-bit bytes) or "positions", a group of 64 tracks (114,688 words, 688,128 characters or 510,096 eight-bit bytes) which were under the heads at a single time. This storage allocation method remained on the 1100 series machines long after drums had been replaced by disks. </p><p>The track storage units were checkboarded so that, with precise computation of the program's processing time, one could create software with processing time per unit of Fastrand blocks that resulted in a program running in synchronism with the data transfer rate of the drum. Further, the track-to-track head movement time afforded an additional processing speed coordination possibility that permitted the computational rate to match the data transfer rate for large (for the time) data sets without being delayed by losing synchronism with the mass storage transfers. </p> <h2 id="see-also">See also</h2> <ul><li><a href="/facts/List_of_UNIVAC_products/lzfpYIFY">List of UNIVAC products</a></li> <li><a href="/facts/History_of_computing_hardware/83xXSmuW">History of computing hardware</a></li> <li><a href="/facts/The_Story_of_Mel/9fNoVEAR">The Story of Mel</a></li></ul> <h2 id="external-links">External links</h2> <ul><li><a href="http://www.fourmilab.ch/documents/univac/fastrand.html">The FASTRAND II</a></li> <li><a href="https://www.youtube.com/watch?v=luPM6XaKZuU">YouTube video</a></li></ul>