Bob wrote:
( I gotta Google on a PDP-6, I dunno that one, but I
know what a -10 is!)
The PDP-6 was DEC's first 36-bit computer system. The processor was the
Type 166. The architecture is nearly identical to the KA10, which was the
first PDP-10 CPU.
The PDP-6 was not considered to be a commercial success. Only 23 were
produced, and they were considered to be somewhat unreliable. The 36-bit
product line was cancelled for the first of several times. Reportedly
Harlan Anderson, one of the cofounders of DEC, was blamed for the
failure and pushed out of DEC as a result.
Presumably the PDP-10 was called that rather than a PDP-6/B or the like
due due to the PDP-6 stigma. Apparently the people lobbying for a new
36-bit computer represented it to upper management as a process control
system rather than a timesharing system, though it is likely that few
were ever used that way.
Eric