From: Olivier Broschart

Hello all BB users,

I finally figured out how to use DoubleSpace on a J-Link'ed drive.  I
have doublespaced the virtual boot drive (c:) easily before, but could
never quite have my J-Link'ed drives (D:,E:,F:) to be compressed
automatically. I have successfully given a 25 meg virtual JLink drive
file, the capacity of 52 megs.

I figured it was a good little trick to share with all BB users.

The first thing you need to do is to create your J-Link drive file.
Read the BB manual for clear instructions.  If you have the space on
your Amiga drive, you may as well max the file to 32 megs.

Once the file has been created on the Amiga side,
On the PC side, fill the drive up completely. (i.e. copy all of C: to D:
and then some).  I try to fill it to the last remaining free byte by
copying small files and renaming them a few times when I'm near the
drive capacity.  When it's full, delete everything in this new virtual
drive.  You will now have an empty drive D: but because J-Link drives
"grow" to their full capacity, the virtual drive file on the Amiga side
will be maxed out to size you set it to.

Run DBLSPACE, and compress drive D:.  Because it is empty, it shouldn't
take too long to complete.  All the necessary modifications will be made
to your config.sys.

The problem now, is that DBLSPACE is launched in the config.sys, but
JLink'ed drives are mounted after in the autoexec.bat.  So, we must edit
the autoexec.bat file to MOUNT the compressed drives. You should have
your JLINK drive mounting command near the top of the autoexec.bat.  I
have mine right after the PATH statement.  The DBLSPACE mounting command
should follow after.

The autoexec.bat will look somewhat like this:
PATH  (whatever you've set in the path follows here)
JLINK D: DH0:PCDRIVES/DDRIVE  (or whatever location of your virtual file)
DBLSPACE /MOUNT D:
...
etc...plus whatever else you've got in there.

The DBLSPACE /MOUNT D: command will properly recognize the compressed
volume and you will have a much greater drive capacity, without hogging
all that space on the valuable Amiga partition.

I have been running this for a couple of weeks now, under heavy use and
all works fine, including AREAD'ing and AWRITE'ing to and from that
compressed drive.  It's been tested under DOS 6.2 and Windows 3.1


Have fun!
Olivier