Trying to get more than 2 floppy drives in windows 9x should not even be attempted IMO, it's a disaster. If you want 3-4 floppies you need to use DOS and/or win 3.1, regardless of the hardware/firmware used to achieve it.

Shouldn't there be no real need for 720k, since a regular 1.44 drive can deal with those?

Unless of course it's a "just because you can" thing

bertrammatrix wrote on 2025-11-01, 15:44:

Shouldn't there be no real need for 720k, since a regular 1.44 drive can deal with those?

Unless of course it's a "just because you can" thing

yep ...you are correct...just cos I had the drive and a spare bay.
I suppose technically the tracks would be wider so less chance of cross talk when writing 720k reusing old disks..
a just because I can thing.

bertrammatrix wrote on 2025-11-01, 15:44:

Shouldn't there be no real need for 720k, since a regular 1.44 drive can deal with those?

Unless of course it's a "just because you can" thing

For reading? Sure.

But writing, you really want a 720K drive if you are creating disks that will be used on other systems. That way a 1.44M drive writes to the disk is a little different. 1.44M drives will read them fine. But 720K drives can have issues.

maxtherabbit wrote on 2025-11-01, 15:31:

Trying to get more than 2 floppy drives in windows 9x should not even be attempted IMO, it's a disaster. If you want 3-4 floppies you need to use DOS and/or win 3.1, regardless of the hardware/firmware used to achieve it.

Totally agree.....took me a while to realise it was foolish to try.
But at least I can have it switched now to use 2 drives in win98 or the full quota in DOS.
😉

SScorpio wrote on 2025-11-01, 16:23:

bertrammatrix wrote on 2025-11-01, 15:44:

Shouldn't there be no real need for 720k, since a regular 1.44 drive can deal with those?

Unless of course it's a "just because you can" thing

For reading? Sure.

But writing, you really want a 720K drive if you are creating disks that will be used on other systems. That way a 1.44M drive writes to the disk is a little different. 1.44M drives will read them fine. But 720K drives can have issues.

nailed it buddy...I wanted a way to write pukka 720k floppies

I have never once had a disk interchange problem with 3.5" DD disks being written on an HD drive.

5.25" sure since the tracks are a different width, but on 3.5" the only difference is the data rate

proper HD drives have a media sense switch to detect the DD diskette and adjust the write current appropriately

FWIW I've decided to build the OS's on CF cards ...with a rear mounted adapter..
That way I can build a DOS/Win 3.1 OS as well ..so can easily be switched out with 98se when needed.
rgds

Well...I.m sorta ready..
All the AT power leads had to be cut and extended.
The AT psu I'm using has a low voltage start-up...so no mains switch at the case front.
Both the power switch and the reset switch on the case were 8mm square momentary switches.
Both were replaced with 8mm square latching versions.
Thus I have a front mounted power switch and a repurposed reset switch which will now turn the quad flop rom on or off.
..and spent a full day drilling cutting and filing a chunk of aluminium window frame support to make an I/O shield of sorts.
My measurements for the AT keyboard din and the MB-8500TTD pcb mounted PS2 mouse socket ...were slightly off.
Nonetheless good enough.....but cutting and filing out 19 and 25 pin D-sub blanks was a pain in the ass...but it had to be done.
Such are the problems of mounting a TX motherboard in an ATX case.
Pity the ally frame wasn't a few mm wider...but still.
It'll do.

maxtherabbit wrote on 2025-11-01, 16:42:

I have never once had a disk interchange problem with 3.5" DD disks being written on an HD drive.

5.25" sure since the tracks are a different width, but on 3.5" the only difference is the data rate

proper HD drives have a media sense switch to detect the DD diskette and adjust the write current appropriately

Right? Neither have I. As a kid I regularly put games on 720k floppies on machines with 1.44mb drives to then use on my ps/2 that only had dual 720k drives. I have also gone both ways and taped 1.44 disk holes and reformatted them to 720k to use on the dinosaur, AND then I have drilled a hole in the 720s to turn them into 1.44s (full reformat needed in both cases, obviously, I actually made a few just yesterday), and - no issues.

That's not to say I've never had a floppy issue of the type "another drive won't read it" - just that if I had that issue it always seemed to be that one writing drive must have been worn out/dirty/junk or something, or, one of those USB floppy drives in which case anything is possible since most are designed to only deal with 1.44s

Ok..the build is complete-ish.

DOS setup ...QF ROM Enabled

A > 1.44mb
B > 1.2mb
C > OS DOS
D > 720K
E > 360K
F > CD

Win98se QF ROM Disabled
A > 1.44mb
B > 1.2mb
C > Win98se
D > CD

Also fitted a SCSI card so I can connect a tape backup drive . Very useful with Veritas desktop backup for disk image storage.

There is one thing that has me confused ?
The MB-8500TTD is supposed to handle 256mb ram
2 x 128 DIM...
But If I fit both ram sticks the system only recognises 128mb
atm I have 1 x 128mb and 1 x 64 mb fitted for a total of 192mb
More than enough really but annoying that I can't max out at 256mb
..
rgds
VS

Track width between 1440k and 720k drives are identical. I have not encountered any compatibility issues that didn't turn out to be mechanical issues or media issues.
5.25 floppy compatibility issues on the other hand are very real and one should definitely have separate dedicated drives to avoid problems.

I also do not reccomend using Win9x for archival reasons. Windows will alter sectors with out asking.

https://www.os2museum.com/wp/the-ihc-damage/

Here is a link describing how Windows 9x modifies the boot sector on any non write protected floppy.
While the result is almost always harmless, it has been known to hinder software preservation attempts.

akimmet wrote on 2025-11-06, 00:23:

https://www.os2museum.com/wp/the-ihc-damage/

Here is a link describing how Windows 9x modifies the boot sector on any non write protected floppy.
While the result is almost always harmless, it has been known to hinder software preservation attempts.

Interesting...I shall give it a read/watch.
I am going to be using the quad-flop pc mostly in DOS with IMD.
I have other stand alone drives I use with XP and Win7 ...such as Kryoflux, SCP and greaseweazle for archiving.
Thanks for the link.
all information is good information 😉

So far this quad-flop build is more than paying for itself in that I am going through my collection of 720k MFD 2DD floppies atm and formatting them in the 720K floppy drive.
...discarding any that dont produce the magic numbers 730,112 bytes total...1,024 bytes in each allocated unit.....713 allocated units available on disk..first time..
No second pass or chances.
4 floppies failed ...45 have passed ..so far.
Many more to go I think.
What I have noticed is that these MFD 2DD floppies are far more reliable/durable than their 1.44mb HD counterparts.
Just adding to my belief that floppy disks were made better back then...and to last better over time.

I suspect there will be a lot more 1.44mb HD disks that dont make the cut...but that's a few days away yet.

Still on the 720k disks atm.
Not sure just how many more I'll be able to rescue...but over 100 that formatted just fine in the dedicated 720k drive.
The tally of rejects so far only 15.
looking good 😀
I tried an experiment just to see if my theory regarding track width held water.
Formatted a 720k disk in the72ok drive.
Wrote some files to the disk with the same drive.
Then formatted that disk in a 1.44mb ...
Then read the directory of that disk back in the 1.44mb and sure enough the data had been erased by the formating.
The read that same disk back in the 720k drive.
Effectively reading a narrow track that previously held data with a wider head.
There was my proof..
The disk claimed empty reformatted and ready for re-use....but listing fragments of previous entries/data.
Nothing a re format in the 720k drive wouldn't fix...but proof that residual data can be left behind when using reclaimed disks.

Needless to say I will be using the 720k drive going forward to ensure that like the 100+ disks already salvaged are fully 'clean'.

Even more time consuming is removing old disk labels...some peel off easily if done slowly...but some are seriously feel more like they have become part of the plastic case.
any tips on removing them would be most appreciated.
cheers

Well this has been a labour of love..
Having built a win98se OS on a 64gb CF card...
I turned my attention to building a WFW 3.11 OS on a 2gb CF card.
It transpires that the only graphical Windows version that will operate with 4x Floppy drives connected ..is 3.1X.
Now there are only 2x ISA slots on this socket 7 mobo...one of which plays host to the Quad-Flop card.
The other has a creative awe 32 sound card in it.
All the rest of the slots are pci.
3com PCI network card..
Banshee video card

...and an ADAPTEC AHA2940 card.
So win98se runs just fine but requires the quadflop rom switched off ..
It cannot handle 4 floppies and thus wont boot.
The reset button was replaced with a latching switch for disabling the QF rom
In WFW 3.11 the rom is enabled and all 4 floppy drives are seen.
It only took nearly a week of getting the WFW OS playing nice with the various cards.
It now has sound ...CD...SCSI...4 floppies...720k 1.2mb 360k and 1.44mb
What was and still is a PITA is that no working drivers to enable the Banshee to function in 3.11
I thought I was stuck with low res 16 colours..which doesn't give much screen real estate.
Ok I couldn't find Banshee Drivers....but I did find one that gives me SVGA rather than VGA.
Certainly a step in the right direction.
Learning how to install drivers and stuff was a steep learning curve....and the last addition was getting the Network card functional ...and now I can access Network drives.
Not that it can handle long file names..doh!
All in all I'm really pleased with this build...but DOS will be the main function ...Dave Dunfields IMD etc.
😉
...and has the added advantage of soundblaster and banshee in 98se...for occasional retro gaming....by switching out the CF card.

I was curious if after installing the Adaptec scsi card...if there was a tape backup version that would work with 3.11 ? and my Sony DAT DDS4 drive.
Apparently there may well have been...and was directed to Seagate backup exec v6.11
...but after some searching I have failed to find it.
I found older Conner versions ...which are tape drive specific
and a seagate version v5.4 which is CD-R specific.
Any idea of an archive that might host v6.11 ?

Veritas apparently bought out the backup company which I have on CD...but only installs on win95 and up to and including 98se ...also possibly early NT.
a later version is needed for XP and later.
rgds

Much searching later ...still not found backup exec 6.11
...but during my searches did find what I suspect are DAT DDS3 drivers.
had to extract the 3 self extracting zip/exe files in DOS ...then managed to make .ima files of these 3 disks.
They _might_ be useful If I can get these Dell OEM drivers installed.
Not sure of course if they will work with a DDS4 drive....but still.
For future reference I'm tagging them to this post.