Note that ODT will not function correctly in the LSI-11s unless there is main memory on the QBUS. The reason for this restriction is unknown: the KDF11 CPUs and KDJ11 CPUs, which also use ODT, do not have this limitation; e.g. a system consisting only of a KDF11-A CPU and a serial console will run ODT.
Both LSI-11s are Q16 devices; they only drive 16 address lines. Although they can be plugged into a Q18 or Q22 backplane, they will only function with Q16 main memory. (With Q22 memory, the pins used for BDAL18-21 are used for other, internal signals by the LSI-11. The reason for the incompatability with Q18 memory is currently unknown.)
There were CPU options were available for the LSI-11s: the KEV11-A, for the EIS/FIS instructions; the KEV11-B provides EIS without FIS; the KEV11-C provides a subset of the PDP-11 CIS (it also apparently includes the EIS, but not the FIS).
They also supported the optional KUV11 Writeable Control Store.
|v • d • e PDP-11 Computers and Peripherals|
| Unibus PDP-11s - PDP-11/20 • PDP-11/15 • PDP-11/35 • PDP-11/40 • PDP-11/45 • PDP-11/50 • PDP-11/55 • PDP-11/70 • PDP-11/05 • PDP-11/10 • PDP-11/34 • PDP-11/04 • PDP-11/44 • PDP-11/60 • PDP-11/24 • PDP-11/84 • PDP-11/94
Clones: CM 1420