Um, was there a... [Otrona Attache]

On Thu, 2003-10-30 at 20:02, Ron Hudson wrote: I worked on the 8088/MSDOS card back when. The machine was a Z80 CP/M machine (with every chip known to Zilog in it; the designer was a real ahrdware guy...) The Z80 had an expansion slot that had a little 8-bit-wide IO prot, only. No access to peripherals, the screen, memory or disk. The 8088 side was the CPU, memory and an EPROM, and a fast buffer chip to talk to the Z80 via this (essentially a) parallel port. There was Z80-side software that consumed 100% of the cpu, and simply waited for the 8088 to issue commands to the Z80, which would go off and service them. I wrote the Z80 code, and I thik some of the 8088, but maybe not. It was a horror. The 8088 had hardware that detected references to PC-side things like "memory mapped video": when the 8088 referenced a reserved hardware address, the 8088 was put into an infinite wait state, the Z80 got an interrupt, read a code from the 8088::Z80 interface, figured out what needed to be done (say, write to CRT line 2, col 3), calculate the appropriate Z80/Otrona IO address from the 8088 "PC memory mapped video" address, issue all the commands. Slower than dog doo. Same for every character read/written to the serial port, disk, keyboard, etc. FOr things handled within the MSDOS BIOS (I wrote that) there were explicit commands issued to the Z80 for disk-block-read, etc. (Recall this was before the IBM PC caught on, so all the things you might assume for that machine, eg. ROM BIOS, standard serial ports at 0x3f8 and all that, didn't exist. When you got say a word processor program, you had to tell the program what kind of screen hardware you had. For the Otrona MSDOS, you used ANSI.) Historical footnote: The first Fido/FidoNet BBS software ran on one of these things, until the CRT module caught on fire (eg. smoke & flames). I sold it to some guy via eBay (maybe on this list!). I had two Attache's, the Fido/burned up one which was the 8088 hardwaqre prototype and not saleable, and this other one I wangled out of them. I once had the nylon carrying case. It's all gone now... I have copies of all the Otrona software (binaries) and CP/M stuff, as well as other junk, if anyone cares. I oughta put it up on the net I suppose. tomj The MSDOS "memory mapped video"