glen@aecom.UUCP (Glen Marianko) (02/09/84)
> > In reply to: > uokvax!emjhm Jan 30 17:32:00 1984 > > Jim asks for general info about the ConIX shell for CP/M-80, > and specifically, about a problem that might arise on systems > implementing a BIOS in ROM. > Tis true. ConIX will not work properly on systems that implement a BIOS in ROM. That is because ConIX must modify the CONST, CONIN, CONOUT, LSTOUT and SELDSK jmps in order to intercept a program's request for I/O during redirection and ExpanDisk (16 drive) references. There is, however, a theoretical way around this. "Theoretical" because I have never tried it, but it should work. In short, you should SYSGEN CP/M for a slightly smaller memory size to make room for a RAM BIOS table, which is simply an exact duplicate of the ROM-resident jmp table. You wouldn't even need the BIOS src for this. Just disasm the top of the ROM and copy the table into the new BIOS. This should be easy enough to try before taking a jmp into ConIX. The only gotcha is if CP/M is resident in ROM with the BIOS. In such a case, this fix wouldn't work as well. Since the CP/M ROM occupies space in memory, you'd have to MOVeCPM much farther back into RAM because you can't write the new CP/M and BIOS on ROM. This may cost something like 5K of TPA space. That's not too terrible, but considering you're probably losing about 7K with the ROMs, ... it may not be desirable. Maybe the CP/M ROM could be plucked out of the address space (hardware fun-time)? I have heard of systems that use ROM for the BIOS and/or CP/M, but I don't know of the names of the manufacturers of such systems. Maybe someone could enlighten me. There might be a fix that I haven't yet thought of. There are probably some users out in netland that have already purchased ConIX. They may be willing to comment on it. I can only say that it's fast and it works, since I am: Glen Marianko Computer Helper Industries Inc. ConIX Software Designer Feel free to pick my brains but, please, leave something over for me. {philabs,pegasus}!aecom!glen