Multiple floppies in one system?

From: Jerome Fine <jhfine_at_idirect.com>
Date: Thu Feb 28 11:41:46 2002

>David C. Jenner wrote:

> I'm putting together an old 486 system, one of whose main purposes will be to
> read/write floppies of several formats. Like 5.25" 360K, 720K, 1.2M, RX50, etc.,
> and 3.5" 720K and 1.44M. I also want to be able to copy RX50s disk to disk on
> the appropriate drive type.

Jerome Fine replies:

I am definitely a PC dummy, so I will not comment on any of the other solutions.
However, your mention of the RX50 floppy media leads me to make the following
comments.

When I did use the RX50 media on my PC in the past (I have not needed to
do so for a while), I always felt that it was vital to verify the data AFTER I
had done a write. If the file structure is RT-11, you can BINCOM individual
files. If not, then in RT-11, you can verify the whole floppy or just individual
blocks (from the 800 block total). My suggestion if you are going to copy
RX50 floppy media (especially if you are making more than ONE copy)
is to do the following.:

The E11 hobby version of the emulator is assumed to be in use -
"MOUNT DU0: B:/RX50"

(a) Copy the floppy to an image on the "hard drive image"
COPY/DEVICE/FILES/NOQU DU0: DU0.DSK
(b) Verify that the "hard disk image" copy is correct
DIFF/BIN DU0: DU0.DSK
(c) Copy the "hard disk image" copy to the RX50 copy
COPY/DEVICE/FILES/NOQU DU0.DSK DU0:
(d) Verify that the new RX50 floppy is correct
DIFF/BIN DU0: DU0.DSK

In general, you will also find that this takes no additional
time (especially if you put the commands in a COM file
or type quickly) since the time taken to access the
"hard disk image" copy is negligible compared to the
floppy access. For example, two COM files could be
used, the first with the first two commands and the other
with the last two - so you have time to remove and
insert a second floppy if you are using only one drive.

Over the years, I have not experienced many problems
with floppy media, but on the few occasions when the
WRITE operation was unsuccessful, a separate READ
pass was essential to verify that all of the data had been
correctly written. The above COPY/VERIFY approach
ensures that. In addition, it takes no more time even with
one copy and saves half the time on multiple copies after
the first.

========================================

I said I would not comment on the PC, but I do have a question.
What drive letters are assigned when there are more than
two floppy drives? In addition, if you use just two floppy
drives at one time (by safely unplugging both power and
the flat cable), then don't you also need to tell the BIOS
which floppy drive is being used? Recently, I upgraded
to a newer PC. Originally there was JUST a 3 1/2" floppy
as the A: drive. BUT when I added the 5 1/4" floppy as
the B: drive and even told the BIOS as well, Windows98
would NOT recognize the second B: drive UNTIL I
first removed the A: drive. ONLY at that point when the
STUPID STUPID Wizard (????) had to look for all
the floppy drives did both A: and B: drive become included
in the list of drives for the system.
Received on Thu Feb 28 2002 - 11:41:46 GMT