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DIR2
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DRESET.ZIP
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READ.ME
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Text File
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1993-11-08
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4KB
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91 lines
Dear PSL:
This disk is sent in response to my noticing
FANTOM 1.0 on your December additions disk.
The program DReset.exe was my way of dealing
with this problem until I upgraded my hardware.
Although I haven't looked at FANTOM 1.0, my
understanding of this situation is as follows:
a. If you have a high-density diskette drive,
(1.2Mb or 1.44 Mb) the drive will signal
to MS-DOS when the diskette door/latch is
released, and DOS will know that the
diskette may be changed. DOS will know
that the diskette hasn't been changed if
it hasn't received any such signal.
b. If you have a dual-density drive (360kb
or 720kb), DOS will know that the drive
doesn't signal, and will always re-read
the file allocation table/directory from
the diskette whenver it accesses it, which
is whenever you ask for a directory or open
a file.
c. If you have both kinds of drive on the same
controller, it will be a high-density
controller, and DOS will thus expect to
get signals whenever the drives are unlatched,
but the dual-density drive(s) are not able
to signal. This will cause DOS to do the
wrong thing -- assume the disk hasn't been
changed when it has. (It is possible that
some kind of jumper setting may remove this
problem in some cases, but I don't know for
sure -- I'm not a hardware wizard) If the
worst consequence of this error is just
getting the wrong directory on your screen,
you're very lucky. DOS will also direct any
writes to the new diskettes to the physical
location on the disk where they would have
gone on the diskette for which it last read
the file allocation table. The result will
be very badly scrambled / unreadable data.
You will probably lose both all the data
previously on the diskette and the new data
you tried to add.
The best fix for this is to replace your dual-
density drives with high-density drives. For most
people, diskette drives are very affordable, and
the cost of a data disaster is too high to risk.
The enclosed DReset program is an alternative fix.
It is very small and just does one thing, which
doesn't take very long. It invokes the MS-DOS
service to reset the disk system. This tells DOS
to flush any of the file allocation/directory data
that it has saved in memory, so it has to read any
that it needs from the disk when it needs it. I put
commands to run this program in all my batch files,
before and after every command to run a program that
might access a diskette. This pretty much eliminated
the problem, except for occasional absent-mindedness
when entering commands from the keyboard. Of course
you can run this program from the command line too;
no parms are needed or used.
As I have remedied the problem on my own system by
upgrading the hardware, I have not used this
program for a few years. It has not been tested
for compatability with smartdrive, windows, OS/2,
or doublespace. I would be surprised if there is
any problem with these, but you never can tell.
I wouldn't run it while multi-tasking unless I had
real good back-ups. Of course, not many machines
with such advanced software will have dual-density
drives.
You (PSL) may distribute this program for your usual
shareware fees. There is no license fee for users of
this version, and no registration or fee. This is
offered in appreciation of your fine service.