grinberg@bimacs.BITNET (Dennis Grinberg) (02/20/89)
Here is a collection of the replys about my posting about an AT with
"floppy disk drive memory"
The original posting:
-One of the At's where I work "remember"s the last diskette inserted
-into its drive. If I insert a diskette, do a DIR A:, change diskettes
-and do another DIR A:, I will get a listing of the files on the
-first diskette. If I chkdsk (does this write out buffers?) between
-changing diskettes, I get the correct directory listing the second
-time.
-
-Is anyone familiar with this phenomana?
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Yep...
There are a couple of possible problems with your system. The
first is that the drive change line is no longer being detected by the
BIOS and DOS.
The second is that you have some sort of cacheing software
enabled for drive A. ( cacheing software is only really good for drive
C ) It might be fastopen is you have DOS 3.3 or greater....
Obviously the second is much easier to check for. just check
that the autoexec.bat doesn't start any such cacheing software. The
first requires playing a bit with the hardware..
Hope this helps!
Eric
---
Eric Schnoebelen
egsner!eric@texbell.uucp ...!texbell!egsner!eric
egs@u-word.dallas.tx.us ...!killer!u-word!egs
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I have no idea what other software is installed on your machine --
especially Terminate and Stay Resident (TSR) programs, but... I have see
this EXACT behavior when trying to use the Mace Utilities VKETTE program.
VKETTE speeds up diskette access using a memory caching technique.
Unfortunately (perhaps due to interaction with other TSR's) it does not
seem to know when a different diskette has been put into the drive.
I also saw DIR give the directory of the previous diskette and got VERY
NERVOUS! I then wondered whether all the cached information got written
back to the disk. I was even more concerned that one diskette's
information would get written on top of another's.
The bottom line was that I quit trying to use VKETTE and have not tried any
other diskette caches.
I don't think there is any way in general to tell MS-DOS that a diskette
has been changed. I seem to remember that CPM had some sort of control key
convention for "sync'ing" the diskettes.
I do use the Mace Utilities CACHE and CACHE-EM for the HARD disks. This
appears to speed my Miniscribe 3650 access by at least a factor of two --
with an EMS 256kbyte cache.
I hope this helps.
Laurence Brevard 3500 W.Balcones Center Dr, Austin,TX 78759 [512] 338-3567
ARPA: brevard@mcc.com UUCP: ...!cs.utexas.edu!milano!cadillac!brevard
Microelectronics and Computer Technology Corporation (MCC) VLSI CAD Program
---------------------------------------------------------------------------
Yes, your symptom is familiar. Someone [has|is] [used|using] an altered
[disk|os] on your AT, and your system now thinks that drive A: is a harddisk.
Watch out, this has cause data loss at a local college due to the directory
of the first disk being overwritten on the second.
This symtom was first though to be a virus, but it was later detected
to be a students attempt to speed up floppy access by making the AT think
it was reading a harddisk (the directories of a hardisk are cached to
increase system response (that hard disk ain't going anywhere)).
Matthew Lee Stier (919) 469-8300|
Sun Microsystems --- RTP, NC 27560| "Wisconsin Escapee"
uucp: {sun, rti}!sunpix!matthew |
--------------------------------------------------------------------------
Ugh. This behavior seems all too familiar. Apparently your
drive isn't sending the DISK CHANGE signal to your system. Is this a
new/added drive to your system? Are you using an external disk drive
driver in your CONFIG.SYS file?
Here's one thing you may want to try. Whenever you swap
diskettes, hit ^C at your DOS prompt. This seems to tell DOS to
reread the disk, letting the system know about the new disk directory
and File Allocation Table. WARNING! _NEVER_ write anything to a
diskette if your system is confused about which floppy is in the
drive! If you write data to diskette #2 when your system thinks
diskette #1 is still in the drive, your new disk will be TRASHED.
Always do a "Dir" on your flakey floppy drive to make certain your
system is not confused before writing data. As I said, typing ^C at
the DOS prompt seems to unconfuse DOS. Hope this helps...
Jim
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I've had this happen to me quite a bit. I have an INFO 286 motherboard
with AWARD BIOS (~2.03 or something near that) 10MHz, and a generic(?)
16 bit hard/floppy controller.
I only have room for one floppy drive in my case right now...I have a
3-1/2" drive in there. I can use it directly in a non-standard way
(for backups) as a 1.2MB floppy using DS/DD media. If I load the
device drivers, I can use it as a 720K or 1.44MB floppy.
Anyway, I haven't figured out what causes the "directory memory"
*feature*, but I always run "chkdsk" after changing floppies to
avoid this.
BTW, I have had problems running another floppy as drive b:
cause unknown /\/\/\/\/\/\/\/\/~~~~~~
-Dave
EMAIL: ...!att!holin!doc | "I can't complain but | /^,
VOICE: (201)-949-5308 | sometimes I still do"| / } _, , , __
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Well (it's me again), I didn't do any hardware checks, but I booted from
a fresh copy of DOS (3.2) without any TSR's and the at still had "floppy
memory". The ^C trick worked. I'll have to bring it in for a hardware
checkup one of these days.
Thanks for all the replys, any additional ideas will be appreciated.
--
|----------------------------------------------------------------------------|
|Dennis Grinberg, Math & CS Department, Bar-Ilan University, Ramat-Gan ISRAEL|
|----------------------------------------------------------------------------|
|BITNET: grinberg@bimacs.bitnet |
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|SNAILNET: Dennis Grinberg, 13 Hava Lutzki St., Rehovot, ISRAEL |
|----------------------------------------------------------------------------|
#! rnews 974
Relay-Version: Version 1.7Derick.Hayes@f7.n369.z1.FIDONET.ORG (Derick Hayes) (02/28/89)
This problem can easily be solved provided your 3.5" drive has the same jumper on the rear as nearly all other 3.5" drives have...on the small interface card that your drive cable connects to there SHOULD be a jumper with two settings possible whatever it is set to now it may fix your problem by changing it to the OTHER position...it fixed mine... hope it helps you...