Date   : Thu, 26 Jul 1984 19:12:23 pdt
From   : William C. Wells <wcwells%ucbopal.CC@Ucb-Vax.ARPA>
Subject: Re: ZCPR3 and CP/M 3.0

Richard,

In reply to:

       Date: 25 Jul 1984  20:37 MDT (Wed)
       Message-Id: <RCONN.12034273269.BABYL@SIMTEL20>
       From: Richard Conn <RCONN@SIMTEL20>
       To: wcwells@ucbopal (William C. Wells)
       Cc: info-cpm@brl
       Subject: ZCPR3 and CP/M 3.0
       In-Reply-To: Msg of 25 Jul 1984  12:03-MDT
               from wcwells%ucbopal.CC at Berkeley (William C. Wells)

       Yes, ZCPR3, SYSLIB3, Z3LIB, and VLIB all run under CP/M 2.2.
       Due to their direct BIOS calls, they will not run under CP/M
       3.0.  Some degree of modification to the low-level device
       drivers is required in order to get the libraries to be useful
       under CP/M 3.0.

       ZCPR3, however, is another problem, since, as a command
       processor, it directly loads the COM files it selects, a
       knowledge of your bank-switched environment is required.  I
       suspect that the degree of modification to get ZCPR3 to run
       under CP/M 3.0 would be extensive.

       Re the files on SIMTEL20 that you referenced, I am not familiar
       with them.  I am not moving toward the CP/M 3.0 world.

               Rick

The files, I referred to on SIMTEL20 are:

Filename                       Type     Bytes   Sectors     CRC

Directory MICRO:<CPM.CPM3>
BIOS2RSX.ASM.1                 ASCII    11748   92 =  5CH  D10BH
BIOS2RSX.RSX.1                 COM       1536   12 =   CH  7218H

The BIOS2RSX.ASM is the source for BIOS2RSX.RSX and is a copy
of the CP/M Exchange Listing in Dr. Dobb's Journal, July 1984,
starting at page 23.

BIOS2RSX.ASM, to quote the author, Mike Griswold of Fort Worth,
Texas:

       ... will provide CP/M 2.2 compatible BIOS support
       for CP/M 3.x.  Primarily it performs logical sector
       blocking and deblocking needed for some programs.
       All actual I/O is done by the CP/M 3.0 BIOS.

How Resident System Extensions (RSX) may be used is discussed in
an article by Garry M. Silvey in the same issue of Dr. Dobb's Journal
starting at page 36.

Robert Blum, on page 22, stated that he attached the RSX to a CP/M
2.2 version of DU, and that it worked perfectly. Thus it appears
that BIOS2RSX.RSX when attached to a COM file using GENCOM, will
intercept the 2.2 I/O calls and convert them to 3.0 I/O calls.
If this is true for all I/O calls, then it should be possible
to assemble CP/M 2.2 programs that use members of  SYSLIB3, Z3LIB,
and VLIB, attach BIOS2RSX.RSX and have a program that works under
CP/M 3.0.

I suspect you are right about ZCPR3.

Bill Wells
wcwells@Berkeley.ARPA
ucbvax!wcwells
WCWELLS@UCBJADE.BITNET