Five and quarter drives

From: Randy McLaughlin <>
Date: Fri Feb 11 17:44:55 2005

From: "William Layer" <>
Sent: Friday, February 11, 2005 5:00 PM
> On Fri, 11 Feb 2005 09:05:56 +1030
> "Parker, Kevin" <> wrote:
>> Can someone refresh my memory please whether it was possible to visually
>> tell 360K and 1.2MB 5 1/4 inch floppy drives apart (the drive that is,
>> not the media).
> Unless I'm quite mistaken, the 1.2M drives have two r/w heads - one for
> each side of the media, whereas the 360K have only one.
> --
> ---------------------------------------------
> -. William W. Layer .- -. St. Paul, MN USA .-
> ---------------------------------------------------
> -. Cheif bottlewasher, Atma-Sphere Music Systems .-
> -. .-
> --------------------------------

No the PC's 1.2M & 360K have two heads, the 160K(180K) only has one head.

Most 360K drives were black face and most 1.2M were beige but there were
some 1.2M black and many 360K beige.

Most PC BIOS's step the drive out more than 40 tracks then step back and
count the steps to the track 0 sensor. It then knows if it is a 48TPI (40
track drive) or 96TPI (80 track drive).

If you hook an unknown drive to a PC the BIOS will know if it is 360K drive,
if it's not it will not know if it is 1.2M 5.25", 720K 5.25", 720K 3.5", or
1.44M 3.5".

Please note there are three "standard" types of 5.25" drives 48TPI, 96TPI DD
(720K), 96TPI HD (1.2M). There are more types than that but they were rare.
Visually you can not tell them apart unless you are fairly familiar with
that particular model.

In general the best way is to go by the model number.

There are even many 48TPI drives that could only handle the first 35 tracks
(SA400), these only came full height.

If the drive will not step at least 50 tracks it is a 48TPI drive. If it is
48TPI and has two heads it is a 360K drive.

Received on Fri Feb 11 2005 - 17:44:55 GMT

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