VDX - Virtual Disk Package

This is semi-weird, so bear with me. This package enables you to create
a disk on a part of another disk. The virtual disk is a contiguious file
of any size on the real disk. The virtual disk driver adds the starting
logical block of the file to any IO.WLB and IO.RLB requests issued to
it and passes the I/O packet on to the real disk driver. The virtual disk
(file) is INIed, MOUnted, and used like any other disk.

The program AVD assigns a file to a virtual disk unit and optionally can
create a file. The format of its commands are:

	>AVD VDn:=file[/sw]

		/CR:n	Create file of "n" blocks
		/RK	Create file of 4800 blocks
		/RO	Access file in readonly mode

The program DVD deassigns the file. Its command form is simply >DVD VDn:

The package is very useful for separating projects from each other and
avioding UIC and filename conflicts.


			MAINTENENCE NOTES

The command file 'VDXGEN.CMD' assembles and builds VDX.  Before using
VDXGEN, check the location of the system's RSXMC.MAC against where
'VDXASM.CMD' expects to find it.  VDXASM may need to be changed.
Also, decide how many VD: units you want, and set the symbol 'V$$D11'
in 'VDPRE.MAC' accordingly.
This stuff works correctly on both 11M and 11M+ systems.  The code is
conditionally assembled based on the symbol 'R$$MPL' in RSXMC.MAC, so
make sure the RSXMC for the target system is used.