"TMS INC - PL11013 CPU/RAM board rev B"

[RedskullDC]

Hi All,

Pics of a bare "TMS INC - PL11013 CPU/RAM board rev B" board for the 48 pin bus were recently posted on VCFED:

https://forum.vcfed.org/index.php?threa ... y.1239482/

Anyone seen this before?

Regards,
Leslie

[bxdanny]

I never heard of this TMS before, but a Google search for "TMS Ohio Scientific" brought up the following:

https://www.usaopps.com/government_cont ... -S-INC.htm

which seems to have been a company that made data acquisition products. The name is even spelled with the same spacing (T M S INC) as is on your board, so it may have been the same company. The link that is supposed to go to the company's own website doesn't go there, so they are probably out of business now, but if they are the same T M S, it is interesting that they survived into at least the start of the web era.

I read the thread that you linked on the Vintage Computer Federation site (what is the ed in vcfed.org, education?), and putting the various answers you got there together with what I know about OSI systems, I don't think there's too much mystery left about what the board was. It was what it said, a CPU and RAM board, namely a 6502 CPU with 8k of 2114 RAM. The two 24-pin chips would have been a 6850 ACIA and some kind of monitor ROM, and the two 40-pin chips were the 6502 CPU and (almost certainly) a 6821 PIA. (I say that simply because that is what OSI systems, and clones like those from D & N, routinely used for I/O. The ACIA would have been addressed at $FC00, as on most OSI systems, while the PIA might have been at one of several addresses that were used for parallel I/O, such as $F700, $C700, or $F400.)

[bxdanny]

Looking over this again, I realize now that vcfed.org simply stands for Vintage Computer FEDeration. I don't know why I was separating the f and the ed in my mind. I also see that RedSkullDC has other OSI hardware and hardly needed a summary of their typical peripheral chip usage and addressing.