Message-ID: <380@mako.UUCP>
Date: Wed, 28-Nov-84 22:15:26 EST
Article-I.D.: mako.380
Posted: Wed Nov 28 22:15:26 1984
Date-Received: Fri, 30-Nov-84 08:15:45 EST
Organization: Tektronix, Wilsonville OR
Lines: 25


A friend of mine has been working on developing a system
that will allow a PC to treat a file on a VAX (running VMS)
as a disk drive.  This is accomplished by writing a server
for the VAX and a device driver for the PC that knows how
to talk to the VAX server through the serial port.  There is
also a utility program that runs on the PC that can be used
to tell the VAX to create, delete, or select files to use
as virtual disks.

The problem is this:  it would be nice if the file on the VAX
did not have to be a hardwired size -- it is desirable to let
it be X number of blocks, where X is completely up to the
user.  MSDOS, however, will not recognize the size specified
in the boot block -- it gets loaded into memory whenever MSDOS
calls the driver with the BUILD_BPB instruction, but the new
size is ignored in subsequent DIR and CHKDSK commands.  MSDOS
is obviously capable of changing dynamically -- one can put a
SSSD disk into a drive and MSDOS will recognize it and won't
keep thinking there is a DSDD disk there -- but how can a
device driver force the new size to be recognized?

			Glen McCluskey
			..tektronix!mako!glenm