KDF11-U CPU

KDF11-U card with KTF11-A and KEF11-A

The KDF11-U is the PDP-11 CPU for the PDP-11/24; it used the UNIBUS, unlike the QBUS of the other KDF11 CPUs. It was implemented as a single hex card, the KDF11-UA M7133, using the same 'Fonz' F-11 chip set as the other KDF11 CPUs.

In addition to the basic CPU functionality (including memory mapping and floating point), it also included sockets to hold a 6-chip carrier implementing the PDP-11 Commercial Instruction Set (CIS), and two asynchronous serial lines (led out through the backplane).

There are two different versions of the KDF11-U; in the later M7133-YA (documented in the manual EK-11024-TM-003, Appendix D), in order to reduce the cost, a number of individual DIP chips were replaced with a pair of custom gate array chips, and the board was re-laid-out.