Talk:Diode matrix

PAL v PLA

I think that this page is confusing Programmable Array Logic with Programmable Logic Array FrankFlanagan (talk) 13:51, 30 April 2011 (UTC)[reply]

You may be right.

What can we do to make this less confused?

I see that Dieter Mueller hand-built a few boards out of discrete transistors that are more like a PLA than a PAL[1][2].

I only hesitate to tear out all mention of PAL in this article, and replace it with PLA, because I suspect that replacing "PAL chips" with "either PLA chips or PAL chips" would be more correct.

In particular, the "Programmable Array Logic" and "programmable logic array" articles imply that some minicomputers used one or more "PAL chips" in the CPU, while other minicomputers used one or more "PLA chips" in the CPU.

--DavidCary (talk) 17:13, 4 July 2011 (UTC)[reply]

The microprogrammed machines that I was involved in designing Mentec PDP-11#M11 and Mentec PDP-11#M1used SRAM for control store. I am aware of PLAs being used see for instance: http://www.computerhistory.org/collections/accession/102660026, Microcode and in part for the J11 http://simh.trailing-edge.com/semi/j11.html.
Equally I have used PAL's as part of CPU implementations, but for small pieces of fast combinatorial logic, registers and simple fast state machines.
My not being aware of PALs being used to implement microcode storage is more likely to be evidence of gaps in my knowledge than anything else, but as the architecture of PALs is not really that close to a diode matrix, I think that PAL could usefully be replaced with PLA. My 2 cents only. FrankFlanagan (talk) 21:24, 4 July 2011 (UTC)[reply]