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Super-Slasher
June 27th, 2003, 12:26 AM
My old IBM will only support 720KB 3.5" floppy disks. Is there a way to either make it 1.44MB compatiable, either through software updates or external 1.44MB drive, or is it doomed to a life of 5.25" disk useage?

CP/M User
June 27th, 2003, 02:18 AM
"Super-Slasher" wrote in message:

> My old IBM will only support 720KB 3.5" floppy
> disks. Is there a way to either make it 1.44MB
> compatiable, either through software updates
> or external 1.44MB drive, or is it doomed to a
> life of 5.25" disk useage?

Well I believe that the 1.44Mb floppy compacity
can be done on IBM XT (with the relevant
hardware - such as I/O card which support the
higher compacitys). So in theory, the same
should apply for ATs. If it has 16bit ISA slots
on the mainboard, then it should be fairly
easy to find the right hardware.

Cheers.

Thomas Hillebrandt
June 27th, 2003, 02:41 AM
My old IBM will only support 720KB 3.5" floppy disks. Is there a way to either make it 1.44MB compatiable, either through software updates or external 1.44MB drive, or is it doomed to a life of 5.25" disk useage?

1.44 MB was never a standard format for 5.25" disks - certainly not in IBM compatible machines. The HD format allowed for 1.2 MB, though, so it's not far off...

...and it should be possible, provided you get a floppy-controller that can handle it. Check eBay, or maybe Google your way to some hardware surplus online stores (I found some once, but I've lost the URL's, alas).

I actually think it's a 1.2MB 5.25" drive in my AT :wink: ...

Super-Slasher
June 27th, 2003, 02:58 AM
The problem I think lies in the IBM AT BIOS/SETUP, in the floppy drive designation. For those who are unfamilliar with the setup, just like with HD's, you have to choose the type of drive that's connected (or not) to the A: and B: ribbions. The only drives in the list are 360KB 5.25", 1.2MB 5.25", and 720KB 3.5" drives - no 1.44MB 3.5".

So even if I put a controller for a 1.44MB 3.5" drive in the AT, wouldn't it still not recognize 1.44MB disks?

On a related note, can 1.44MB disks be formatted in 720KB form and be useable as 720KB disks?

Thomas Hillebrandt
June 27th, 2003, 04:14 AM
So even if I put a controller for a 1.44MB 3.5" drive in the AT, wouldn't it still not recognize 1.44MB disks?

Oh, sorry, I thought you wanted 1.44 MB on 5.25" disks... Well, the BIOS might just be smart enough to reckognize the possibility for 1.44 disks if the controller is installed. I honestly cannot say for sure. At any rate, the BIOS should be upgradable...Anyone?


On a related note, can 1.44MB disks be formatted in 720KB form and be useable as 720KB disks?

No problem...At least, usually no problem. I certainly used HD (1.44) disks on my Amiga 500 and Amiga 1200 back in those days with no problem (High Density compatibility was only standard on the Amiga 4000). I had a friend, though, also with an Amiga 1200, who couldn't read DD formatted HD disks, unless the extra hole was covered with something. So he put scotch tape on the HD-hole (opposite side of the write-protect hole) and was all set. :)

CP/M User
June 27th, 2003, 11:17 PM
"Thomas Hillebrandt" wrote in message:

>> So even if I put a controller for a 1.44MB 3.5" drive
>> in the AT, wouldn't it still not recognize 1.44MB disks?

Yes, you'll need:
1) A BIOS which supports 1.44Mb compacity (I don't
think it's a issue - well maybe the earlier ones are?)
2) A I/O card which supports floppy disks & has
support for 1.44Mb compacity.

My old I/O card which I have in my XT only supports
720k disks, however the card itself has it's own way
of setting which disks to use. In this case I think it
only supports 360k & 720k. This is selected through
a set of DIP switches on the card itself (you'd need
the manual to set it to the approate settings). I'm
not sure if there are other cards out there like this
which support 1.44mb, but if there are then it
should also work on ATs.

> Oh, sorry, I thought you wanted 1.44 MB on 5.25"
> disks... Well, the BIOS might just be smart enough to
> reckognize the possibility for 1.44 disks if the
> controller is installed. I honestly cannot say for sure.
> At any rate, the BIOS should be upgradable...Anyone?

This is out of my league. I've just stuck with the BIOS
the computer has on the card. I've tried to get the
chip out of the mainboard on one of my machines,
but it seems to be sealed in.

Cheers.

barryp
June 27th, 2003, 11:56 PM
>1) A BIOS which supports 1.44Mb compacity (I don't
>think it's a issue - well maybe the earlier ones are?)
>2) A I/O card which supports floppy disks & has
>support for 1.44Mb compacity.

You're talking about High Density, which AT's support. That's part of the "Advanced Technology". :lol:

>My old I/O card which I have in my XT only supports
>720k disks, however the card itself has it's own way
>of setting which disks to use. In this case I think it
>only supports 360k & 720k.

Yes, 360KB and 720KB are double density. It depends directly on the controller chip used. Many XTs have problems with 80-track drives though, most fixable by DOS.

There are, however, 8-bit HD controller cards.

Classicsat
July 18th, 2003, 01:56 PM
You may be able to use a dos driver (driver.sys?) to make it work 1.44
I know I got my XT to recognize a 720K drive that way.