In article <43A86CDD.6010704@neo.rr.com>,
Barry Watzman wrote:

> Not quite correct. I believe that the correct values are:
>
> 360K, 5.25" diskette:
> 40 tracks (40 cylinders)
> Double sided
> Double density (250k bit rate)
> (9 sectors of 512 bytes per track)
> (there was also a 320k format w/8 sectors per track)
> 300 rpm
>
> 720K 3.5" diskette:
> 80 tracks per side (80 cylinders)
> Double sided
> Double density (250k bit rate)
> (9 sectors of 512 bytes per track)
> 300 rpm
>
> 1.2MB 5.25" diskette:
> 80 tracks per side (80 cylinders)
> Double sided
> Quad density (500k bit rate)
> (15 sectors of 512 bytes per track)
> 360 rpm rotational rate
> (sometimes, this same format is accomplished with a 300rpm
> rotational rate and a reduced data bit rate, or even 300rpm
> and 500k bit rate and "wasting" part of the media)
>
> 1.44MB 3.5" diskette:
> 80 tracks per side (80 cylinders)
> Double sided
> Quad density (500k bit rate)
> (18 sectors of 512 bytes per track)
> 300r rpm rotational rate
>
> The original question that started this post stated "360k 3-1/2 inch".
> There was no such animal in the PC world, ever, because even the very
> earliest 3.5" drives used in PCs were 80 track, double sided.
>
> elaich wrote:


Dont forget about the 2.88 3.5" disks that came out with the PS/2

In the early days, we Atari people had single sided, low density 3.5"s
... 360k .. So the drives did exist and would work in a IBM, but i also
have never heard of one actually being shoved in a 'PC'.