Five and quarter drives

From: Scott Stevens <>
Date: Sat Feb 12 14:29:02 2005

On Fri, 11 Feb 2005 19:34:02 -0500
Steve Thatcher <> wrote:

> just bought a 720K drive a few weeks ago on eBay... it is the drive
> that Intel used in their iPDS... I seem to recall that Heath used them
> also in some of their systems.
> At 07:19 PM 02/11/2005, Dwight K. Elvey wrote:
> >Oops!
> > I see you are talking 720K versus 1.2M. I would guess
> >the there is a difference in rotation that would distinguish
> >the two. The 720K should be the same rate as the 360K.
> >I would guess both number of steps and rotation would
> >determine the difference. Luckily, there were not that
> >many 720K drives out there.
> >Dwight

Just a hint, for something I tried and that worked, years ago.

I had an Intel iPDS system, with the 720K 'Quad Density' 5-1/4" drive.

I didn't have any media for it besides the Intel original diskettes.

I pulled the drive out of the system and jumpered a 3-1/2" 720K drive to
be a second drive, and attached both drives on an altered cable.

I then used the isis commands to duplicate all the Intel original
diskettes onto 720K 3-1/2" media.

The iPDS hardware didn't know, and didn't care, that the target diskette
wasn't a 5-1/4" diskette in a 5-1/4" drive. The copy worked
transparently, and I archived the 5" drive and media, and switched to
working with the iPDS with (then) commonly available 3-1/2" 720K

These days, though, the 720K 3" disks are also rare. I no longer have
the iPDS (actually it was two units, with dual-processors). Yes, I
regret that I no longer have them.

Received on Sat Feb 12 2005 - 14:29:02 GMT

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