From bcw142@21:1/101 to All on Tue May 19 12:36:12 2026
Back in the old days we had S100 Bus 8080 based systems (at least I did) and the original BBS system was the same. Ward Christiansen started the first BBS on such a system. It wasn't long before the Z80 came out and CP/M was invented and began to take over for the older 8080 (same code would be run on both). There were CP/M systems with either CPU. The Z80 had a bigger instruction set but CD was a call on either as was C8 and other variations (type of call).
CD was a normal call and C8 was if the accumulator was zero it called. You could branch if higher or lower on the compare as well. That was down at the machine code level, but some things were written that way.
I wrote a custom BIOS PROM for my system and OS (Not CP/M but much the same with word based commands as CP/M and later MS-DOS were. Various DOS (Disk operating Systems) based systems became common after CP/M. Generally jump
table based (as was mine & CP/M and later MS-DOS). Being word based commands you could execute from basic text based code. Later BASIC was a like based
code and even compiler BASIC after that. All of which made a good base the
BBS. The modems quickly went from 110 baud and up and up till 56k with fall-back to 38,4k for line noise. Just fast enough for character moving text and graphic blocks with color. That started the modern BBS with games and\ such. Then in the 1990's hypertext and the basic internet HTML was invented. Then after some time the BBS used telnet to go anywhere on the net by the
late 1990's and early 2000's. And here's an example of that we all get to use.