Xref: utzoo misc.wanted:11612 comp.sys.misc:3019 comp.os.cpm:4184 alt.folklore.computers:6131 Path: utzoo!attcan!uunet!cs.utexas.edu!sun-barr!olivea!orc!inews!iwarp.intel.com!omepd!pzbaum!reed!tektronix!percy!nosun!techbook!fzsitvay From: fzsitvay@techbook.com (Frank Zsitvay) Newsgroups: misc.wanted,comp.sys.misc,comp.os.cpm,alt.folklore.computers Subject: Re: Need info for an S-100 bus system Message-ID: <1990Oct14.205630.7222@techbook.com> Date: 14 Oct 90 20:56:30 GMT References: <1990Oct12.235220.18522@techbook.com> <1990Oct13.163615.6218@news.clarkson.edu> Organization: TECHbooks of Beaverton Oregon - Public Access Unix Lines: 65 In article <1990Oct13.163615.6218@news.clarkson.edu> demarem@clutx.clarkson.edu writes: >From article <1990Oct12.235220.18522@techbook.com>, by fzsitvay@techbook.com (Frank Zsitvay): >> In article <1990Oct12.000849.12599@news.clarkson.edu> demarem@clutx.clarkson.edu writes: >>>I suspect that your choices for an OS are CP/M or CP/M :-). You >>>can probably order documentation and/or CP/M drivers for your >>>devices, but you may have a bootstrap problem..you need the system >>>running CP/M in order to modify CP/M for the system. One nice thing >>>about CP/M is that the BIOS sources (in assembler) come with it >>>so you ought to do okay. I would recommend aquiring the following >>>items (to run on another system while getting your S-100 up): >>> >>>8080 cross-assembler >> >> An 8080 cross assembler on a cp/m machine?? go figure... >> > >I was thinking in terms of assembling some code on his "real" machine >and keying it in through the monitor or frontpanel (ugh). I have seen >some nice 8080 assemblers running on PDP-11's (under Unix lev. 6). > opps. sorry... actually, if you can find a cross assembler for a dos machine to write z80 code, you'd be farther ahead of the game provided it worked much like cp/m's ASM.COM or RMAC. but the easiest route (if you had to config cp/m from scratch) is to find someone with a cp/m machine that has the same disk format, and hack the bios. the beauty of this is that you can write a boot disk for the target machine on the source machine. It is a bit of trial and error, but if you're careful, you'll be succesfull. >>>Small-C (8080 version, source code is available, I have seen it in >>> *very* old Doctor Dobbs Journals, and believe that some >>> user groups have it available in machine readable form). >> NO! >> >> Don't do this! Bad idea. >> >> you don't want to write a bios in c. you're only restricted to >> a maximum address space of 64k, so your bios has to be as small and >> as fast as possible. this is very important if you plan to add >> double density drives to the system, since that requires some form >> of sector blocking/deblocking. you do that in c and the bios will >> be much larger than it needs to be. the best tools to use when writing >> or hacking a bios is either ASM (which comes wth cpm) or RMAC, DR's >> relocating macro assembler. the job is easier with RMAC because it >> will generate your DPHs and DPBs for you. My cpm mentor tells me MASM >> will not work for this. > >Quite clearly you are correct, it is inappropriate to code a BIOS >in C. But I had something a little different in mind..realating >to AFTER he got the system up. > ah, i see. in addition to small c, there is microsoft's basic compiler, and bds c. which i think is still undergoing development. nevertheless, you'll want to get 64k in the machine as soon as possible, as cp/m takes 8k to begin with, and most of these compilers tack on their own run time code -- fzsitvay@techbook.COM - one of these days i'll get it right... Version 2 of anything is usually the version that works.