Date   : Sun, 25 Nov 1990 23:07:16 GMT
From   : zaphod.mps.ohio-state.edu!usc!eve.usc.edu!mlinar@tut.cis.ohio-state.edu (Mitch Mlinar)
Subject: Kaypro ROMs

In article <1990Nov22.110949.12852@hayes.ims.alaska.edu> floyd@hayes.ims.alaska.edu
(Floyd Davidson) writes:
>In article <1990Nov22.030504.6649@simasd.uucp> donm@pnet07.cts.com (Don
Maslin) writes:
>>      In order to use QD drives you need to make changes to both ROM and
>>      BIOS.  There are/were a couple of outfits that had slightly
>>      differing versions: Advent's TurboROM and Micro Cornucopia's MAX
>>      ROM.
>
>I installed a TurboROM on a K-10, and once had a copy of the first
>ROM that Micro C sold.  I don't recall that the BIOS needed to be 
>changed with either of them.  Mind you I could be wrong on that,
>but if I remember right all the code that handles disk blocking and
>so on is in the ROM, all the BIOS does is call the ROM.  On most
>earlier CP/M systems that code was actually in the BIOS itself.

Floyd is part right: all blocking/deblocking of of disk sectors is done
in the ROM itself.  And, although you can use the original BIOS with two
of them (not KayPLUS - the third), why would you want to?  The original
Kaypro BIOS is pretty poor and makes some bad assumptions.  See below.

As far as ROMs, actually MicroCornucopia ROMS are pretty poor, but they
were the *first* Kaypro replacement.  Both TurboROM and KayPLUS are much more
powerful and flexible.  There is also no need to screw around with assembly
language in KayPLUS (and I think TurboROM, too), just run a configuration
program.

Regarding BIOS:  Kaypro assumed that you were in an 8080 world AND interrupts
do not exist.  (They wrote their BIOS in Z80 code, though, and used the
"back-side" Z80 registers.)  Bridger Mitchell (TurboROM) is better here in
that he understands that interrupts might exist, but ALSO assumes that one
lives in an 8080 world only.  In other words, the assumption is that IX and
IY registers are unchanged outside of your program.  KayPLUS does not make
any of those assumptions, especially since 90% of the CP/M computers are
Z80 and replacement operating systems (like QP/M or ZCPR) all exploit the
Z80 instruction set.

The most fun I have had in writing code has been the lack of understanding
about interrupts.  I like to use them because they improve throughput.  Even
early DBASE and Wordstar code fails on interrupt driven CP/M architectures.
Most code I have seen in CP/M in recent years has finally gotten much better
in its understanding of the processor and interrupts.

KayPLUS (MICROCode Consulting) is still sold by Emerald Microware.  

-Mitch


End of INFO-CPM Digest V90 Issue #192
*************************************