This patch to RAMMER was made to allow the creation of a 720K ramdisk on a
1024K system where a physical 720K disk drive is being used. Duplicating a
720K disk can be frustrating with a single 720k physical drive, especially
when you want to DIRCOPY (to unfragment the disk contents) rather than BACKUP. The patched RAMMER should be included in the OS9Boot file with the original
versions of R0 and MD. Make sure 1024K of ram has been accessed via the
MEGA utility (provided with the 1024K upgrade from CRC/Disto) before you
try to create a ramdisk larger than 400K. The ramdisk can be set up
as follows:
(1) if you want to change the ramdisk size the DMODE utility (found
elsewhere) can be used to change the number of tracks. R0 is set up
to use 8K blocks with each cyl equal to one block. The number of
cylinders ( cyl= ) for the 3 r0 provided are:
r0 (KBytes) cyl (HEX) cyl (Decimal)
-----------------------------------------------
360 $2D 45
512 $40 64
720 $5A 96
To change the size of r0 use DMODE /r0 cyl=$xx where xx is the new number
of cylinders in hex. Maximum cylinders is $60 (96 Decimal) for a 768K
ramdisk.
(2) INIZ r0 (to initialize r0)
(3) FORMAT /r0 ( or FORMAT /r0 r "R0" ) To format the ramdisk. The contents
of a ramdisk already in use can also be wiped out by reformatting /r0.
To DEINIZ the ramdisk and recover reserved memory for other purposes use:
DEINIZ r0 You may have to repeat this step a few times. You may also
have to UNLINK r0 to release memory depending on what has been done
with r0.
This patch has been tested on an Coco 3 OS9 Level II system using the
CRC (Disto) 1 meg (1024K) memory upgrade. The patch appears to be free
of bugs, however the author cannot be responsible for any problems which
may occur during it's operation. Use it at your own risk!! Reports of
problems or helpful suggestions can be forwarded to me on Delphi (User:
DocBear) or to the Sysop on the ISIS BBS at 203-872-3737.
Special thanks to Kevin Darling whose RAMMER utility was the target of this
effort.
Future plans include a patch to allow the use of 2 devices (R0, R1) of
360K each and a patch to autosense memory size, setting a 376K ramdisk
limit on a 512K machine and a 768K limit on a 1024K machine.