Covert internal 3.5 floppy for use as an external drive

[BobNeff]

I know the first thing you guys are thinking, for $30 I can buy an external floppy drive, but I have a few old 3.5 floppy drives and wanted to try and build my own external drive.
Here is what I want to be able to do:

1. Connect to a Parallel Port

2. Pull power from either the Comp’s power supply or through the parallel port

3. Have it all work with Windows XP

I have tried to find to see if this has been done before and I'm sure it has but all i can find are kits that have on board power supplies and such and are costing around $60. So if you guys have any ideas let me know.

Thanks in advance,
Bob

 

[melone]

Don't try and pull power through the parallel port, it won't be able to handle it!

 

[IRstuff]

You're also probably better off using USB, although it's unclear whether your floppy can run off USB power.

Other drives can:

http://www.aaronix.com/catalog/product_info.php/products_id/2375

and they cost less than $40.

TTFN

 

[JohnFortier]

Quite honestly, this sounds like an exercise in frustration. The expense of hooking up your floppies externally will probably get close to the cost of an external floppy drive, with no guarantee that your lash up is going to work.

Have you considered using those spare floppy drives by doubling up your internal floppy drives on any exiisting PCs? You can copy files directly from floppy to floppy using windows Explorer.

With so many better storage media available, why floppies? I use InCD and I can use my CD drives just like floppies, except they hold over 500 times more data.

Regards

John

 

[automatic2]

sure you can, but you won't want to. Consider that your storage devices utilize DMA transfers. Your parallel port just ain't got it. After tearing out your hair writing a device driver, you'll end up with one of the slowest drives in town. Invest in a couple of LAN cards and router and give the floppy drives to your neighbour's kids.

 

[Reuel]

I just joined this board. I have looked at two threads that were to my interest--connecting a floppy drive to some sort of 8-bit data connection.

The answers most common are, paraphrazed, "Don't do it. Just buy something new instead." I hope this is not the trend.

BobNeff--if you get a useful answer, let me know.

 

[nbucska]

What do you need the external drive for? Why not use the internal drive?

 

[sfi]

If you trying to setup data transfer to an embedded device, an idea might be to tape the serial port then reply it.

 

[richs]

Hi-

I might shed a little light on the subject as in my
checkered past, I helped design floppy disk controllers
in SSI/MSI LS and S parts. We did have a microcontroller
on the card as well. These were the ancient 8 inch floppies
but the principles apply.

You might want to look at the Southbridge chips that are
currently available for an implementation. However, in
this area, I'm speaking in ignorance. I haven't done
a Southbridge design. If you don't do surface mount, then
you will have to move to an alternative as they don't come
any other way (well, I lie, there might be some ball grid
array types). Either of the packages however do NOT lend
themselves to low volume "hobbiest" type of work.

Alternatively, you might want to see if there are some old
40 pin dip floppy disk controllers left on the market. You
might find some. Then it might be possible to construct
a controller. It might not be fast, and will require some
considerable logic around it, but you can certianly try.

The floppy disk interface is a "raw" data signal.
Conditioned, of course, to transfer a digital signal, both
in and out. However, there are some "interesting"
challenges that one has to overcome. Getting the raw data
stream include write precompensation, a digital phase lock
loop, a missing clock generator to detect soft sectors
(the tiny 3.5 inch floppies don't come in hard sectors. In
fact, I don't remember ever seeing 5 inch floppies with
hard sectors). You have to supply stepping functions which
I don't believe are on the 40 floppy controllers. There
are some CRC-16 checks in there too, which in some
controllers, I believe, has to be supplied by the
microprocessor to the controller.

As an alternative, I might suggest that you look at the
newer IDE interface for the hard disks. That is a much
easier interface. Coupled with some of the Compact Flash
cards, you can much more easily implement an interface.

There have been several references to this on these boards.
I too am looking at (but will not implement anytime soon)
an IDE interface to Compact Flash/IDE hard disk.

In any event, when you get something working, please
report back to us you efforts.

Cheers,

Rich S.