I seem to be getting interested in HP9000/200 stuff.... So far I've got (IIRC) : HP9816 with the compact keyboard. This has 768K RAM (256K on the CPU board, 2 off 256K RAM boards, one in each DIO slot). HP9817 + HP-HIL keyboard and monitor. 2M RAM (2 off 1M RAM cards), text and graphics video boards. And therefore 2 empty DIO slots, both with external access [1] [1] These machines have expansion slots called 'DIO'. Some cards have brackets with connectors on them, for example an RS232 board. The spacing of the slots in the backplane is half the height of the connector bracket, so such cards go in every alternate slot. The intermediate slots can be used for RAM cards, the DMA controller, and so on. The video card in the 9817 takes a pair of slots, the text card has a bracked with aBNC connector fro video output, the graphics card fits in the slot immediately above it, and carries a ribbon cable that links to the text card. HP9836A. This one is hard to get to at the moment, so I am working from memory. I think it has 1M RAM (4 off 256K cards), and therefore 4 avaialbe DIO slots, all with external access. I have the monitor, and of course it has 2 built-in 5.25" floppy drives. Assorted DIO cards. The useful ones are a couple of GPIOs, a low-speed HPIB DMA controller,, and an RS232 card. The last will almost certainly end up in the 9836, which doesn't have RS232 as standard (my other 2 machines do). As regards drives, I have a 9122 with the normal grease problem (hut the heads are OK). I can probably find a few 9121a, a 9133H, and a 9154, if they're going to be useful. I also have HP BASIC 5.0 and 5.1 on original 3.5" disks. I'll prboably use these machines (as far as I use them at all) in much the way HP intended -- as control/logging systems. Questions : 1) What softwware do people recomend? HP BASIC looks reasonable, actually, it does at least support named procedures with formal parameters. Anything else reocmended? 2) How much RAM do I reasonably need. If I pulled one of the 256K cards useful? 3) I've been reading the 9836 service manual [2]. I makes reference to the 'Developer's Documentation' or some such, which apparently contains information for people who want to design DIO cards and/or port OS's to the machines. Does anyone have this (it's not on bitsavers or the Australian museum that I can see). It certainly sounds like something I should read if I can. 4) Anything elase I need, or should keep an active lookout for? [2] Yes, it's a boardswapper guide. No, I don't approve of boardswapping. But that doesn't mean I don't read the manuals. There are some useful points in it. -tony