Date : Wed, 25 Apr 1984 07:04:00 MST (Wed)
From : Keith Petersen <W8SDZ@Simtel20.ARPA>
Subject: Neophyte CP/M 2.2 Question - flushing disk buffers
Tell your supplier he goofed. He should have done the patch to BDOS,
shown below. The "flush buffers" (which may be in BOTH conin and
conout) are completely unneeded and cause unnecessary disk activity.
In addition, some "install" programs (like the one from MicroPro for
DATASTAR) read in one sector of a .COM file, patch it, and then write
it back to disk. Without this patch nothing happens.
--Keith
---inserted file 22DBLOCK.DOC from SIMTEL MICRO:<CPM.GENDOC>---
DIGITAL RESEARCH CP/M [R] 2.2 FIELD SOFTWARE CHANGE
Copyright (c) 1980 Digital Research
ID# CPM22-0001 PROGRAM: BDOS ISSUE DATE: 02/19/80
ERROR DESCRIPTION: The following change affects only those CP/M
systems which are using the optional blocking and deblocking al-
gorithms listed in Appendix G of the CP/M Alteration Guide. If
you are in doubt as to the applicability of this field change,
please contact Digital Research or your CP/M distributor.
PATCH PROCEDURE: Ensure you have an archive copy of the distri-
buted MOVCPM.COM file. Make changes to a version of MOVCPM>COM
by carefully following the steps shown below: MOVCPM.COM is
loaded into memory using DDT and the changes are made using the
Assemble (A) and Set (S) commands. After making the changes,
return to the console command processor using the Go (G) command,
and SAVE the altered memory image on disk. The memory image on
tracks 0 and 1 must also be updated. This can be accomplished
by executing the new MOVCPM program, as described in the CP/M
Alteration Guide, and integrating your customized I/O system.
ddt movcpm.com
DDT VERS 2.0
NEXT PC
2700 0100
-a1cd2
1CD2 nop
1CD3 nop
1CD4 lxi h,0
1CD7
G0
save 38 movcpm.com
NOTE: This Field Software change is not installed in the CP/M
version 2.2. It must be installed in all systems which use the
deblocking algorithms listed in Appendix G of the CP/M Alteration
Guide.