Johnny wrote:
> I wonder if the PDP-8 FE might have been for some other PDP-10, but then
> again, did any other PDP-10 have a "real" FE?

Earlier PDP-10 systems were hardwired rather than microcoded, so they
didn't need a console processor to load microcode and initialize the
CPU, but they did often used PDP-8 based communication subsystems.
There were interfaces from the PDP-10 bus to the PDP-8 and the PDP-9
busses for use in constructing I/O subsystems.

The KL10 always has an 11/40 console processor, which is connected to
the 36-bit APR (Arithmetic PRocessor) via a DTE20 (Dec Ten/Eleven
interface). The console processor runs RSX20F. During normal system
operation of a DECsystem-10, it is only used for the console TTY
interface, and to act as a system watchdog. On a DECSYSTEM-20, the
console processor also is used as the interface to unit record equipment
such as card readers, punches, and line printers.

The KL10 can accomodate up to four DTE20s, so there can be up to three
additional directly attached PDP-11 based I/O subsystems. These were
normally DCxx or DNxx communication subsystems.

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