There is a com file for Ver 3.20 in this library - I did not attempt to
document the changes and don't know who did them.  
	Bruce Morgen 12/17/84

Documentation for Memdisk Ver 3.10-

Credits:

07/03/84 Memdisk Ver 3.10 Perfected removal code and made minor changes
	 Richard Solomon

07/01/84 Memdisk Ver 3.00 Added code to remove MEMDISK upon query if already
         installed.
	 Richard Solomon

06/28/84 Memdisk Ver 2.00-Changed installed drive from M: to D:, other minor
	 changes made.
	 Richard Solomon

11/15/83 Memdisk Ver 1.00-Added startup message and install query.
	 Richard Solomon

??/??/?? Memdisk Ver 0.05-original program
	 author unknown


    There is little need for documentation of memdisk as there are few
queries and all are self-explanatory.  Here I will mention a few choices
and list useful addresses to change.  To remove the MEMDISK once installed
(via the MEMDISK program) simply answer Y to the ...WISH TO INSTALL...
question and the program will, if it detects the presence of the MEMDISK
will ask you if you wish to  remove it.
    As no source code was released for Ver 0.05, I cannot offer that
although I hope to eventually disassemble the program and comment the
resulting source code.
    Although the original MEMDISK would run on an 8080, some of the mods I
implemented use Z80 commands, it shouldn't be too difficult to find and
replace these but since most modern CP/M systems use the Z80 I decided to
take advantage of the minor speed increase afforded by Z80 commands.
    For those of you wishing to setup MEMDISK as a drive other than D:, the
procedure is simple, the drive is coded (in HEX) as 00=A, 01=B, etc... The 
only address which must be changed is 0356H, change this to the code of the
drive you want used as "MEMDISK" - NOTE: The memdisk may be installed as ANY
drive although your system may only allow a limited range and it IS POSSIBLE
to install the memdisk as a drive which already exists, this locks out access
to that drive.  Install the hex value of the ASCII character for the correct 
: disk drive letter at locations 0208H, 0235H, 03EDH AND 044BH, if desired 
(for looks).  [addresses taken from MEMDSK32.COM, I didn't investigate the
other COM file - Bruce Morgen 12/17/84.]
    If you make any mods to this program, PLEASE leave a copy of the updated
program on Charlie Hoffman's RCP/M (813) 831-7276.
						Richard Solomon.

    There is some really dumb coding in this program but in the interests of
providing a current version of the source code (warts and all), I have not
bothered to correct the errors. If you can see where the bugs are you will
know what to do about them, if not... then watch out. As supplied this code
will install on my 62k system but causes the system to crash on any function
that is performed AFTER Memdisk is removed. From examining the code it seems
that the program originally adjusted itself to any reasonable TPA size but
now the code is so hacked about that it will only run on a 64k system.
    So what... it's a demonstration program anyway. If you like the speed
increase that RAM based disks give you then go and buy some more memory and
do the job properly.
						Edmund Cramp.

     To avoid the crash problem (it seems to be a re-entrant BDOS error),
just don't be logged in to the virtual drive when you do the removal.  The
latest version (MEMDSK32.COM) runs fine on my 58K system, as long as I
don't try to create a drive with a letter higher than "C" (my ZCPR3 CCP
won't let me log in to "C" drive, but I can get around that with a named
directory entry.)  The program shrinks my TPA to about 15 Kbytes, too small
for very much useful work, but it sure makes a neat demo!  People with
63-64 Kbyte vanilla CP/M might be able to do more (WordStar, for example,
needs only 17-18 Kbytes, I believe).  Lacking a Z80 assembler, I won't
bother to try and modify the program for a more sensible MEMDISK-capacity/
TPA balance, but I'd sure appreciate it if someone would.  Incidentally, the
addresses I inserted into Richard Solomon's patching instructions apply to
MEMDSK32.COM and may or may not work on the older version, MEMDSK31.COM.
						Bruce Morgen