Re: Extra chips in PDP11/23 plus cpu board
> On Dec 20, 2017, at 1:16 AM, Nigel Williams via cctalk > wrote: > > On Wed, Dec 20, 2017 at 4:45 PM, Douglas Taylor via cctalk > wrote: >> There is a CPU board for sale on ebay, M8189, and it has the usual 3 chips >> CPU, MMU, FPU. However, there are 2 extra chips and I've never seen that >> before. > > https://en.wikipedia.org/wiki/PDP-11_architecture#Optional_instruction_sets > > Microcode ROMs for the CIS (Commercial Instruction Set) I believe PDP11 COBOL makes use of those if available, and the RSTS kernel will use the string move instruction for block memory copies if it sees CIS. paul
Re: Extra chips in PDP11/23 plus cpu board
On Wed, Dec 20, 2017 at 4:45 PM, Douglas Taylor via cctalk wrote: > There is a CPU board for sale on ebay, M8189, and it has the usual 3 chips > CPU, MMU, FPU. However, there are 2 extra chips and I've never seen that > before. https://en.wikipedia.org/wiki/PDP-11_architecture#Optional_instruction_sets Microcode ROMs for the CIS (Commercial Instruction Set)
Extra chips in PDP11/23 plus cpu board
There is a CPU board for sale on ebay, M8189, and it has the usual 3 chips CPU, MMU, FPU. However, there are 2 extra chips and I've never seen that before. Anyone know what this is? Ebay item 122867114663 - Vintage Mint Digital DEC M8189 CPU Module Board KDF11-B Doug
