19 Sep
2015
19 Sep
'15
3:53 a.m.
The biggest risk I remember from the 730 design (I worked in the same hardware
lab, different project: 11/74 CIS) was the extensive use of PALs. This was the
first (I believe) project at DEC to use them, and they were basically buying all
It may well have been. Certainly the 11/730 is full of PALs, this is how (I think) they
got
a complete VAX CPU onto 3 hex boards using standard ICs. The only custom parts (as
opposed to custom programmed parts) in there are the 2 gate arrays for the memory
ECC which are the same as the ones in an 11/750.
DEC were also using the 82S100 PLA at around that time. Whether it was first used
before the 11/730 I don't know (I suspect it was).
Don't get me wrong, I like the 11/730, and apart from the use of DRAM for the
control store I think it is a very interesting and neat design. It is one of only 2
VAX families I would consider trying to run, and due to space constraints it's the
only one I can run (the other being the 11/780, and no way do I have room for one
of those).
-tony