19 Apr
2007
19 Apr
'07
5:40 p.m.
just tell it what particular ICs you're using and
at what port addresses, and
away it goes? Or was it more complex than that, and realistically you'd have
to write your own comms / FDC driver which exposed some defined interface to
CP/M itself?
You had to write something called a CBIOS (Customised Basic Input Output
System IIRC). This was a set of routines to handle terminal I/O (and
printer, paper tape I/O if you wanted that), disk block read/write, and
so on. There's a manual giving the specs for these routines, how to get
CP/M onto the target machine, and so on. The original CP/M distibution
came with the source for a CBIOS for the Intel MDS800 (IIRC)m which you
could use as a starting point
I've never done it, but it ;ooks like quite a 'fun' thing to do for
suitable values of 'fun'. Of course if you bought a packaged machine to
run CP/M it came with a CBIOS written for that machine. And alas you
rarely got the soruce of that :-(
-tony