Odd floppy drives (was: Orbis

[Tony Duell]

> 
> 
> On 9/25/2005 at 10:34 PM ard at p850ug1.demon.co.uk wrote:
> 
> >Since both 720K and 1.44M 3.5" disks (on a PC) rotate at 300 rpm, I am 
> >trying to figure out why you'd want a 360rpm 3.5" drive. I've never seen 
> >one...
> >
> >(600 rpm is another matter...)
> 
> You've obviously never run into a NEC 9800 PC (or just about any other 

Indeed I haven't.

> version of Japanese MS-DOS) diskette.  77 cylinders of 5x1024 sectors, 
> spinning at 360 RPM, just like an 8" drive. 

I am puzzled as to why that would spin at 360rpm. The format would be 
possible on a '720K' drive turning at 300 rpm using the normal 250kbps 
double-density data rate. If you double the data rate to 500kbps, you 
should be able to get more that 5 sectors, even at the faster spindle 
speed. 

What was the data rate at the interface connector of these Japanese machines?

> 
> Most USB drives understand this format automatically.

Not having got anything that supports the useless serial botch interface, 
I've not looked at such drives.

-tony