A Control Unit for a DEC PDP-8 Computer and a Burroughs Disk

The control unit maps a semicontinuous address space of the computer into a segmented BCD-addressed address space of the disk. An interesting buffering system provides for the maximum memory access time of the PDP-8 and high disk transfer rate. In principle, the buffering could be generalized to handle arbitrarily long waiting delays. The position of the disk may be read under program control. The execution of erroneous command sequences are not permitted (and hardware detected). Out-of-range disk addresses are detected.