Platter from a CDC 813 auxiliary storage unit
UvA Computer Museum catalogue nr 96.72
Colleague Pieter Hartel stands beneath a 25-inch platter from a Control Data 813 disk storage system (about 1968). According to [1] the characteristics of this system were:
- moveable heads (see the close-up)
- 100 million 6-bits characters storage capacity
- average access time 34 msec, rotation time 50.8 msec
- transfer rate 196000 characters per sec
- montly rental $3450 (1968)
The 813 system contained 36 platters like the one shown here, in two stacks of 18 on vertical spindles [2]. There are 64 usable surfaces, each containing 12582912 bits, equivalent to 1.5 Mbytes in modern terminology (the top and bottom platters of each stack were used for the R/W heads positioning servo subsystem).
[1] Adams Associates: Computer Characteristics Quarterly 8(1968)#1.
[2] Control Data 3234 Mass Storage Controllers
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This disk was donated by L. van Zwets.
rev July, 2017
