Working 8" Floppy drives??? (from originator)

From: Þórhallur Ragnarsson <thorh_at_ismennt.is>
Date: Fri May 9 21:17:01 2003

At 23:17 9.5.2003, you wrote:
> > ? Re: Working 8" Floppy drives??? (Fred Cisin)
> > from yesterday's digest?
> >
> > Fred asks if we have considered substituting 1.2M 5.25"
> > drives. Hmmmm. I didn't know there were such drives.
> > I know of DSDD 360K 5.25 drives and 1.44M 3.5 drives,
> > even 720K 5.25 drives, but not 1.2M 5.25 drives.
>
>Oh yes, the 1.2M drive (that's 1.2 'IBM Megabytes' -- 1000*1024 bytes)
>was a common drive on PC/AT (286) and later PCs. The PC I am typing this
>on has one fitted.
>
>It's a double-sided 80 cylinder unit turning at 360 rpm (like an 8"
>drive, all other 5.25" and most 3.5" [1] drives turn at 300 rpm). It uses
>the higher data rate (500kbps) like an 8" drive.
>
>I have successfully used such a drive in place of an 8" drive. It's not a
>drop-in replacement -- the cable/connectors are different, and there are
>minor differences in some of the signals. Btu it can noramlly be got to
>work. The problems really start if the drive you're replaceing wasn't a
>standard 8" drive (the cannoical example of this is the DEC RX01 or
>RX02), or if it uses some of the features on the 8" drive (data
>separator, hard sector sector/index hole separation) that were never
>provided on 5.25" drives
>
>[1] Early 3.5" drives, often used by HP, rotated at 600rpm. And for
>completness, there was a 5.25" drive that rotated at 180 rpm, allowing
>the use of 1.2M disks on a normal (not high density) controller.
>
> >
> > On the general subject of using a substitute drive. I
> > have actually been considering if this could be done. I
> > have not suggested doing that because I need to find out
> > the feasibility. I would hope we could at least get into
> > the 1990s with a 1.44M 3.5 in floppy drive.
>
>It's possible, but if you want to go that route, get the machine working with
>a 1.2M 5.25" drive first. Once that works correctly, then get it working
>with the 3.5" unit. By doiing the conversion in 2 stages, you will have a
>clearer idea as to where any problems are coming from.
>
>[...]
>
> > These replies will probably be helpful to someone with a
> > hardware background (which I'm not). They point out the
>
>I sometimes forget that not everybody was born holding a soldering iron
>and screwdriver :-).. Although I do find it hard to understand how anyone
>can attempt to maintain and/or modify a computer without understanding
>some hardware (and for that matter some programming).
>
> > 11. Re: Working 8" Floppy drives??? (Tony Duell)
> >
> > Your answer is not silly at all. I didn't know whether
> > such drives would be very rare or plentiful in the
> > "vintage" market. I see now that there are "plenty" of
>
>They are not rare. I don't know how easy they are to find for sale --
>certainly I am not selling any of mine. But there are plenty of working
>drives still around (Even if most of them are attached to working vintage
>computers).
>
> > The client has been repairing the drives for years. They
> > are in heavy constant use. I get the impression that
> > they are simply getting too fragile to repair.
>
>I find that very hard to believe. These drives were _very_ solidly made.
>I supplse it's possible the heads have worn out with all that use, but
>just about anything else can be fixed quite easily. Heads can be replaced
>if you can find them, BTW....
>
>-tony
Received on Fri May 09 2003 - 21:17:01 BST