Date   : Wed, 17 Jan 1990 10:01:31 EST
From   : SAGE@LL.LL.MIT.EDU
Subject: ZCPR33 vs. ZCPR34?

William Thomas Daugustine asked:

>> Altho I do use NZ-COM (ZCPR34), I have some questions regarding it
>> and the differences from ZCPR33.  About the only difference I know
>> of is that NZCOM is an auto-installing version of ZCPR33. What other
>> differences are there?

   You should take a look at the files containing my columns from The
Computer Journal (names like TCJ##.WZ -- and you should subscribe!).
I do not remember the issue (perhaps #38), but I covered this subject
in detail in one of them, the one in which NZCOM was first announced.
ZCPR34 is not the same as ZCPR33; it is the next revision.  The command
processor in NZCOM is the same command processor that can be installed
manually from the ZCPR34 source code, which is available to those who
insist on doing a manual installation.

   Unfortunately, after more than a year, I can no longer remember what
all the differences were.  One is that Z34 can handle type-4 programs,
those that are fully relocatable.  Type-3 programs, introduced with
Z33, load to a fixed address but one that may differ from 100H (a typical
address is 8000H).  Type-4 programs typically load as high in memory as
possible in the given configuration.  This address is automatically adjusted
for the system size and for the presence of RSXs (resident system extensions)
such as ZEX.

   With Z34 support was added for the new environment data that includes
a complete map of which drives are supported.  MAXDR (max drive) alone
can not cover cases such as drives A, B, F, and G.  Setting MAXDR to G
left the system open to getting hung up if drive C was accessed.  The new
Z3ENV also has the addresses and sizes of the CCP, DOS, and BIOS (starting
address only).  This paves the way for advanced command processors and
DOSs that are larger than those prescribed by CP/M.

   These are the main points, but my recollection is that the TCJ article
mentioned a total of four new features.

-- Jay Sage


End of INFO-CPM Digest V90 Issue #9
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