Readme for !PCRamDisk

!PCRamDisk was inspired by !PCRamDisc produced by 
Rob Wears.  His, in turn, was a modification of 
!ADFSdisc which is supplied with the PC Emulator.

Both !PCRamDisc and !PCRamDisk produce a RAM disc
for DOS without using any of the 640k of RAM used
by DOS.

Rob's program sets up the RAM disc, and from within 
the emulator one then has to initialize this "drive"
and format it.  I found this rather a hassle and I
could never remember what to do.   It seemed a good
idea to create a ready-formatted partition before
entering the emulator.  But such a file would be 
much too large.

I discovered that a formatted, but otherwise empty,
DOS partition of one megabyte capacity could be 
compressed to just over one kilobyte using 
Archimedes ARC, a Public Domain file compression/
decompression program written by David Pilling.

!PCRamDisk takes such a compressed file, called 
1M_RamDisc and decompresses it before invoking the
PC Emulator.  This decompression takes a little
time.

The application also overwrites the !Run2 of the PC 
Emulator, to give the required path to the RAM disc
partition.

I also added a line to the !Boot file of the PC 
Emulator:

COPY <OBEY$DIR>.!RUN2scsi <OBEY$DIR>.!RUN2 F ~C ~V

This overwrites the !Run2 file, restoring it to the
original version, a copy of which I called !RUN2scsi.
The reason for this is that the PC Emulator allows
for up to two DOS partitions.  Ordinarily the first
partition is on my ADFS hard disc and the second is
on my SCSI removable cartridge drive.

So using the RAM disc, I can't use the SCSI disc and
the !Run2 file must be modified.  As the !Boot file
now restores the !Run2 file to its old form, this 
happens whenever the PC Emulator application icon
appears. So by clicking on this icon in the normal 
way the Emulator is entered ordinarily with the 
ADFS hard disc and the SCSI disc as drives C and D
respectively.  But by clicking on the !PCRamDisk 
icon the ADFS hard disc is drive C but now the RAM 
disc is drive D.
    
         *******************************
Make sure you have made a copy of the !Run2 file
before running !PCRamDisk.
         *******************************

There is a compressed 2 megabyte ram disc as well
which can be used by suitably modifying the 
!RunImage file.

This is a very provisional version; just an 
experiment.  It is quite inelegant and clumsy.  If
you come up with a better version then let us know.

Brian Cowan.


      The !RamDisk icon is similar to that of 
          !RamDisc created by Rob Wears. 
  - Imitation is the sincerest form of flattery!


