Dave, Super useful info again. In the meantime the machine has arrived, in very good shape. I'll post pictures when I have time tomorrow, and a video hopefully. I took a quick look inside to confirm - there is a DCPC and a MEM protect card - Memory controller is an older 2102A - Three are three 8k 2102A memory boards - No MEM card in slot 112 - Under the processor board there is a screwed on card, which seems to have ROM on it. Microcode I presume, but I don't know if that's the one you were talking about. I'll post photos to confirm The IO cards and the paper tape reader / punch that came with it suggest that it was configured with a paper tape reader, a paper tape punch, a mag tape and a TTY interface. A plausible story is that this was an early machine setup for paper tape and TTY and didn't have extended memory. The early 2102A controller fits that picture well. So I might be in the hunt for the cards or alternate solutions you mentioned. Marc From: "J. David Bryan" <jdbryan at acm.org> On Tuesday, May 19, 2015 at 23:12, Marc Verdiell wrote: You're welcome. First, are you sure that the machine does not have DMS installed? It was a very common option that became standard later on, as all versions of the RTE operating system after RTE-II (circa 1976) required it. Second, if the machine originally came with DMS but was stripped for resale, then possibly only the MEM card (in slot 112) was removed. The firmware card is screwed onto the CPU board on the underside of the machine and is only accessible if the bottom cover is removed. So maybe it was overlooked, and the availability of MEM cards is likely to be reasonable, as the same card (but with different firmware) was used in the E/F-Series machines. Third, if the machine has neither DMS part, then indeed finding an M-Series DMS firmware card might be difficult. However, DMS firmware was also included with the later M-Series Fast FORTRAN Processor firmware (product number 12977B). Again, the FFP was a common option, and availability of that card might be better than the older standalone DMS firmware card. Fourth, if you can find a standalone MEM card, the M-Series DMS/FFP firmware source is part of the HP 1000 Software Collection on Bitsavers, so you could burn the required firmware PROMs and install them on a 12791A Firmware Expansion Module card, which plugs into the I/O backplane and cables to the CPU board. Both the FEM and the MEM were used on E/F-Series machines, so availability should be reasonable. Finally, the simplest HP operating system that used DMS (RTE-III) had additional hardware requirements: a Memory Protect card, a Dual-Channel Port Controller (i.e., DMA) card, one of several console I/O cards, a Time- Base Generator (i.e., clock) card, and either an HP 7900A or 7905/06/20/25A hard drive and its associated I/O interface(s). The latter may be the most difficult and expensive part. You can avoid the hard drive and use Ansgar Kueckes' HPDrive emulator with an HP-IB I/O card, but that requires RTE-IVB as the minimum OS, which requires at least 96KW of memory (128KW if you want to do anything other than boot the system :-). MP and DCPC also were exceedingly common options, so I'd be surprised if your system didn't contain them, unless they've been stripped out for resale. Without DMS, you're limited to 32KW. In that, you could run (with some additional hardware, most notably an HP hard drive) DOS-III or RTE-II. Without a hard drive, you'd be limited to running one of several paper tape or mag tape-based HP OSes. There are third-party OSes that run on the 1000, but I know nothing about them. At least software is no problem; virtually everything that HP developed for the 2116/2100/1000 machines is available via the Bitsavers collection. -- Dave