KB11-A,D Central Processor Unit

This maintenance manual provides technical information regarding the KB11-A and KB11-D central processor units (CPUs) used in PDP-11/45, 11/50, and 11/55 computer systems. It covers the functional description, system concepts (including microprogramming and virtual machines), block diagrams, address modes, instruction sets, operation, and maintenance procedures. The document is designed for maintenance personnel to facilitate on-site troubleshooting and repair. It includes detailed logic descriptions, flowcharts for instruction sequences, and diagnostic program listings.