Date   : Mon, 16 Jul 1990 15:54:57 EST
From   : SAGE@LL.LL.MIT.EDU
Subject: ZCPR/ZDOS

This is in response to Will Rose's recent reply to Jay Sage's recent reply
to Will Rose's recent message.

>> Thanks - just as well I didn't continue...  Where do you put the buffers,
>> then - under the fixed memory area and above the BIOS?  I passed on that
>> one, because I couldn't see how to move the BIOS.

One wants to put the buffers above the BIOS.  If you have a complete version
of MOVCPM, this is easy.  Just create a "smaller" system.  If you presently
have, say, a "61K system" and want 4K for ZCPR buffers, then create a "57K
system".  You will still have to add a patch to the BIOS coldboot code to
initialize the buffers.  That is pretty easy to do.

>> Yes, [the DOS is kept on the system tracks of the diskette,] but there
>> are a lot of bytes out there, many of them different...

I'm not sure I quite followed this comment.  Usually there are a couple of
boot loader sectors and then the operating system in one contiguous block.
The CCP occupies 16 records (2k), the DOS 28 records, and the BIOS whatever
it takes.  There are characteristic signatures that allow one to identify
each of the three components.

>> I use ZRDOS 1.7, and consider it a step back from CP/Ms BDOS - I'm very
>> tired of 'ZRDOS error no. ??' messages.

I've never been a fan of ZRDOS, either, but the cryptic error messages were
not the worst thing.  After all, one can look them up, and the program
DOSERR would convert the number into a full-text message.  What I really
objected to was the way public directories were (mis)implemented.  ZDOS
handled that matter nicely (and managed to fit in full error messages
nevertheless -- nothing like good coding!).

ZRDOS does have some good features.  I am told that it does run noticeably
faster than BDOS.  Also, deficient as the public directory implementation
might be, it still makes possible some things that could not otherwise be
done.

In any case, as I mentioned in my earlier message, it is quite trivial to
replace the ZRDOS that comes with NZCOM with either NOVADOS or Z80DOS.  The
latter, I know, comes in the ZRL relocatable format so that it can be
installed without any effort at all.

One other comment about ZDOS.  At $60 (for NZCOM owners), it is not very
much more than DateStamper ($50).  So for only $10 more, you get a superior
form of datestamping (less memory used and more flexibility) and a superior
DOS.

-- Jay Sage



End of INFO-CPM Digest V90 Issue #120
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