Actually I was only concerned with the D/A and A/D boards and termination points. Really didn't care about the controller itself. One that I really wish I had was a UDAC. The UDAC was marketed by Reliance Electric and was an 8 bit system that ran CP/M or a program like it.. The control program was written in an interactive basic. If you want a valve open that was on I/O point 197, you punched it "Let V197 = 1" and the valve opened. IT was really cool. I installed it in a Nabisco margarine (then a division of Standard Brands) in 1977. I remember the 8" floppies. It was finally given to a mechanic at the plant. His wife put it out in the pasture when they were divorced. I found it almost 9 years later. Way too late for a rescue. Sellam Ismail wrote:

On Thu, 20 Jun 2002, James L. Rice wrote: Even given that this was done before you knew any better, thus the offense is somewhat forgivable, I still think you're a brave man to admit such a thing on this list. -brian.

On Thu, 20 Jun 2002, James Rice wrote: If it was 5 years ago then that's about the beginning of the list. I think back then, most of the people on the list were mainly interested in micros. I know I was. It took time for me to mature and realize the importance of ALL historic computer artifacts :) I remember a time when William Donzelli had a hard time rousing enough support to rescue some PDP-8a's. Sellam Ismail Vintage Computer Festival ------------------------------------------------------------------------------ International Man of Intrigue and Danger http://www.vintage.org * Old computing resources for business and academia at www.VintageTech.com *

--- John Allain <allain(a)panix.com> wrote: For me, it was seeing a $10,000 PDP-8 (new) marked $250 and haggling it down to $35. That was at Dayton, 20 years ago. It was my first classic machine (well... the first machine that was already a classic when I got it; I had an Elf and a PET, but they weren't classic yet). -ethan __________________________________________________ Do You Yahoo!? Yahoo! - Official partner of 2002 FIFA World Cup http://fifaworldcup.yahoo.com

These were all decomissioned and scrapped in the 1986-1990 time frame. The last one I removed was in 1997. James Brian Chase wrote:

Is there an Intersil 6100 chip on there somewhere? That would indicate it's a PDP-8 clone. They should rather interesting! Zane

Here is what I found on the net a little bit ago at this webpage: http://www3.sk.sympatico.ca/jbayko/cpu2.html Zane Part VI: Intersil 6100, old design in a new package . . . The IMS 6100 was a single chip design of the PDP-8 minicomputer (1965) from DEC (low cost successor to the PDP-5 (1963)). The old PDP-8 design was very strange, and if it hadn't been so popular, an awkward CPU like the 6100 would have never had a reason to exist. The 6100 was a 12 bit processor, which had exactly three registers - the PC, AC (an accumulator), and MQ. All 2 operand instructions read AC and MQ, and wrote back to AC. It had a 12 bit address bus, limiting RAM to only 4K. Memory references were 7 bit (128 word) offset either from address 0, or the PC. It had no stack. Subroutines stored the PC in the first word of the subroutine code itself, so recursion wasn't possible without fancy programming. 4K RAM was pretty much hopeless for general purpose use. The 6102 support chip (included on chip in the 6120) added 3 address lines, expanding memory to 32K the same way that the PDP-8/E expanded the PDP-8. Two registers, IFR and DFR, held the page for instructions and data respectively (IFR always used until a data address was detected). At the top of the 4K page, the PC wrapped back to 0, so the last instruction on a page had to load a new value into the IFR if execution was to continue. The PDP-8 itself was succeeded by the PDP-11 (though a version called the PDP-12 was produced, it was part of the PDP-8 series, not a replacement). The IMS 6120 was used in the DECmate (1980), DEC's original competition for the IBM PC, but lacked the processor and RAM capacity (a Z-80 or 8086 card could be added (reducing the 6120 to an I/O coprocessor) but lacked IBM PC compatability). DEC also tried competing with the 8086 based Rainbow, and the PDP-11 based PRO-325 personal computers, but none caught on. Intersil was eventually bought by Harris Semiconductors, which produces versions of the 8088 and 8086, 1802, and 68HC05.