HP2100S musings

Hi, I was poking around inside the HP2100S mini that I acquired recently, and thought some of you might be interested in what's in there. No photos yet, but I expect to have some soon. It appears to me that the computer's backplane is divided into three sections. Two sections are in the front half of the chassis. The left section is coded with a blue color, and I think this is where the CPU itself is. There are nine circuit cards plugged in, with the designations marked A1 through A8 (going left to right), the ninth card isn't marked. The A2 card has a clip-on piece of plastic marked "FP ROM 12901A installed". To the right of the blue section is a section color-coded in red. This appears to the the Input/Output option card section. Slots 10-12 are empty, and starting with slot 13 the card designators are as follows: +8 BIT DUP REG DISC INTF' 2 (13210A) DISC INTF' 1 (13210A) 16 BIT G.P.O. +16 BIT DUP REG RELAY OUT REG JUMPER GRD TRUE IN/OUT GRD TRUE CONTR BUSS DATA BUSS CONTRL JUMPER Some of these are pretty obvious about their functions, but does anybody have any idea what the "DUP REG" functions are? The "BUSS DATA" and "BUSS CONTRL" cards have headers on them that I believe are for attaching a HP peripheral box. This system came out of a HP 8500 Network Analyzer product, and one of the peripheral boxes I got looks to have the other end of the BUSS stuff on it. The docs that I got with the system indicate that the graphics terminal and a printer are attached through the peripheral box. The third main section is in the rear on the left hand side. The power supply occupies the quadrant on the right hand, rear side of the machine. The rear card section is color coded black, and from left to right the card fill is as follows: XYD \ - Connected on top with 02100 60052 jumper header SSA / SSA \ - Connected on top with 02100 60054 jumper header XYD / ID (16K) --| --| These four are interconnected as shown | | along the top using ribbon cables. IDL | --| | | DC --| | | | ID (16K) --| --| XYD \ - Connected on top with 02100 60052 jumper header SSA / SSA \ - Connected on top with 02100 60054 jumper header XYD / The "XYD" boards are HP part number 02100-60053, and appear to me to have mag core driver circuitry. The "SSA" boards look to be the core memory boards. The one I examined had a jumper installed in the "8K" position (the other possible position was "4K"). I'm speculating that the black section is the memory subsystem for the machine, and that the ID & DC boards have something to do with memory addressing, decoding, etc. That's all the info. I have right now. Doesn't look to me like there are any terminal I/O type interfaces in the box. I haven't had the nerve yet to power it up to see if it does anything. If any of ya'll have any info. about this machine, I'd appreciate a shout. Regards, Alex Calculator History & Technology Archive Web Page http://aknight.home.mindspring.com/calc.htm