Ethan, The z80 believe it or not is still in production and has to be one of the most common 8 bitters along with the 6502. It also has one of the bigger resources for tools, code, and knowledge around. < I gave away a couple of 68K S100 boxes to a friend a couple of years ago. < Since then, I've gotten that Z80 Starter Kit with the S100 connectors. Wh < sorts of boards might I be able to find for which there is Z80 code? Coul Unlike PCs the z80 world doesn't really revolve so closely around boards or one vendors word of how the OS is implemented. So... it sorta makes the question open ended. < I find/build a floppy controller and get some sort of CP/M BIOS ROM and < turn it into a CP/M machine? I guess I'd need a serial port for a console Getting a bios rom would be near impossible, as most cpm systems did not do rom bios like PCs do! The bios was loaded at boot time. the loader was a minimal chunk of code (as small or smller than 128 bytes) that loaded the bios which then loaded the rest of the OS. That made the bios very changable as the users discression. Writing your own bios and putting it an eprom(or EEprom) is very doable. The book you need (or the chapter in) is the CP/M alteration guide. that can be found at the site listed. Finding more boards (assuming S100) is also not that hard. there are people here that can help right here on classiccmp. One development platform is to get MYZ80(it's on the web at the SIMTEL site) a z80 and CP/M emulator that runs on 386 or higher dos(or win 3.x, maybe w95) platforms. With that on your PC you can surf the web for tools and apps needed to run languages, assemblers, debuggers and what have you to develop code. < at least a 5.25" controller, and BIOS source (with a cross assembler). Any disk size/format you may want is doable from old single density 8" to IDE or SCSI. You might find hardware for any or all, but 5.25/8" was common. FYI: if your writing the code, most 8" double density controllers with 765 or the more commonly used in that time frame WD179x can also do 3.5" formats. < Anything else? Is 32K reasonable for CP/M, or should I go for 48K? The For CP/M 32 is the minimum to do useful work even though you can run the assembler and debuggers in 20k. A good system is 48 or better 56k with some setup to switch out the eprom to get access to all 64k. < only copy I happen to have, BTW, is an original CP/M distribution disk < for the Commodore 128. Will that be adequate, or should I dig for somethi < more generic? The C128 is furthest from generic IMHO, but if you have a c128 it's a good place to start as a development platform. FYI with notable exceptions CPM (primary componenets are CCP, BDOS and BIOS) is generic for all 8080/8085 and z80 system and only the bios code is different as that's where all the IO work is done for terminals and disks. There is a CP/M website on the net where you can get binaries or even sources as well as manuals. I'd look here if I were you: Visit the "Unofficial" CP/M Web site. MAIN SITE AT : http://cdl.uta.edu/cpm MIRROR AT : http://www.mathcs.emory.edu/~cfs/cpm Applications, look at the FTP site at OAKLAND.EDU and SIMTEL, I'd guess there are 20-30,000 programs out there and most with sources. Good luck, Allison