Date   : Mon, 05 Jan 1987 13:02:12-EST
From   : prindle@nadc.ARPA
Subject: re: Commodore 128 BIOS Versions

There were essentially 4 versions - one dated August (something or other), and
three dated 4 Dec 85, 6 Dec 85, and 8 Dec 85.  The 4 Dec 85 version was the
first to support RS-232 serial I/O; this bore a RED warning message when booted
to the effect that it was a Beta-Test release.  The 6 Dec 85 and 8 Dec 85 
versions are essentially identical, the former being released via various
BBS systems, the latter being distributed on diskette by Commodore - these both
support RS-232 serial I/O and the 1700/1750 RAM Expansion units as ramdisk M:.
There have been no further releases (actual release date of the 8 Dec 85
version was in the spring of 86.)  Along with the newer versions of the BIOS
are supplied two new BIOS specific utilities: CONF.COM which allows on-the-fly
patching of various BIOS configuration options (such as screen colors, RS-232
baud rate, keyboard sampling rate, keyclick volume, printer translation mode,
etc.); and C1571.COM which speeds up writes to the 1571 drive by bypassing
read-after-write validation.  Also of interest are releases of IMP, MEX,
MODEM7,
and BYE which utilize the added "pseudo" UART port.  As a result of the method
necessary to implement the RS-232 I/O, namely running an interrupt routine at
3 times the baud rate, all of the newer versions cause the 128 CP/M to run
anywhere from 6% to 300% slower than the old August version - a rule of thumb
to avoid slow-down: set BAUD to 110 when not using the RS-232 port (it defaults
to 300); this minimizes the interrupt rate without making the keyboard slug-
gish.  The new keyboard scan routine, integrated with the RS-232 interrupt
routine, effectively eliminates all those ugly key-bounce problems common to
earlier versions - keyclick added too!

All the necessary files to update to the newest version are available on 
SIMTEL20 CP/M archives in directory PD:<CPM.C128>.  These are:

NEWSYS.COM     - Installs new bios into CPM+.SYS
C128-NEW.DOC   - Doc on above
C128-NEW.IRV   - More doc
C128CNF3.LBR   - CONF.COM and CONF.HLP files
C1571-2.COM    - Latest (less buggy) C1571.COM file
C128-MEX.COM   - MEX for 128
IMP-C128.COM   - IMP for 128
BYE128.LBR     - BYE for 128
BYE128.DOC     - How to use BYE128.LBR
M7*            - Various MODEM7 overlays for 128
CP4-C128.LBR   - Kermit for 128

Sincerely,
Frank Prindle
Prindle@NADC.arpa