Hello!

If you are receiving this email, it is because I found your name during a websearch about 'classic computing'. At any rate, I have obtained two computers and I'd like to find out what they are. if you could help me identfy them i would greatly appreciate it. I was told by the source of these computers (who seemed very convinvced) that they were PDP-4 computers. Every site I've seen that covers the pdp-4 says that there were only about 50 of them ever sold. However, Digital's own site does mention that some were sold for nuclear applications, and the computers I got were indeed from a nuclear lab. The thing is, there doesnt seem to be any mention of "Digital" or the PDP name anywhere. I'll describe the computers: One looks newer, it says "Tracor Northern TN-1610" on the faceplate. It has 18 ligts across the face and 18 switches directly below, in a bank labeled "Switch Register". There is another bank of 6 ligts labeled "RUN, CPU BUS, VIRT, PWR, BUS, USER" There is a small bank of 3 switches labeled ADDR/DATA, PHYS/VIRT, and INTR. There is a last bank of 6 switches labelled LOAD ADDR, EXAM, CONT, ENAB/HALT, START, LOAD DATA. There is also a power switch. On the bottom of the faceplate is a logo raised in plastic which I didn't understand until I looked inside the case and found a circuit board which said "California Data Procesors" (the logo said "CDP" in a funky '60s style), I've never heard of CDP- perhaps I heard "PDP4" when he actually said "CDP-4"? The second computer looks older. (1960's vs. 1970s). It's faceplate says "ND812" and "Nuclear Data Inc". There is a rotating switch labelled "Select Register" with the following positions: Status, S, R, K, J, Address, PC, External. There is a keyswitch with three postions: Power off, Power on, Control off. There is a bank of 12 lights, labelled "Selected Register", the lights are labelled 0-11 and an extra (13th) light labeled "Overflow". There is another bank of 12 lights, labeled "memory Register", again labeled 0-11. Next to it is a pair of lights labeled "Memory Field" 0 or 1. next to that is another pair of lights labeled "Run" and "Interrupt. Under the lights is a bank of 12 switches labeled "Switch Register". There are two switches simply labeled 0 and 1. There are two switches labeled Start and Stop Another two switches labeled Load AR and Load MR Another two labeled Next Word and Cont And another two labeled Step and Instr The older computer seems put together in a complicated sort of way (stacked PCB's wired together) whereas the newer one is more modular (I.E. large cards that are simply slide in and out of sockets.) Both seem to have core memory but it's arranged in such a way that I can't actually see it with out breaking some paper seals which I dont want to do unless necessary. The parts of the boards that I can see have intricate patterns that seem to indicate core memory (plus the guy told me that they both used core mem). I have a (kind of lousy) digital camera and i can take pictures of the faceplates if you think this might help in your identification. As I said, both were in use in a lab. The older one has a set of two tape drives (they look to be regular audio cassette size) and the newer one has one tape drive. However I was supplied with piles of punched tape programs (i guess there was a tape reader with these computers at some point?) i was given a lot of documentation but most of it has "NDI" written on it and it is about taking nuclear data measurements. Both are in large rackmount cases (which I don't have) and were mounted with other equipment. I'm interested to know what these computers are, how much they cost when new, and what their capabilities are. Supposedly they were replaced by a single $4000 MCI interface card in a PC. If you have no idea but you think you know someone who might, please do not hesitate to suggest that person to me. Thank you for taking the time to read this email. -Kev _____________________________________________ Free email with personality! Over 200 domains! http://www.MyOwnEmail.com