Odd floppy drives (was: Orbis

[Chuck Guzis]

On 9/26/2005 at 11:37 PM ard at p850ug1.demon.co.uk wrote:

>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. 

Sorry--I tried to answer two emails at the same time and got my wires crossed.  It's 8x1024.  Data rate is 500K at 360RPM, just like the 8" drives.  The NECs even aped the 8" drives, in using "drive ready" lines instead of the silly "try the operation and see if the 765 hangs" nonsense of the PC.  I can't remember if DOS-J used the polling feature of the 765,however.

Legend has it that the uPD 765 originated at Intel.  When Intel couldn't get it working right, the design was swapped to NEC for the fancy 1024x1024 CRT controller chip used on the later APCs.  NEC later relicensed the updated design back to Intel and Intel called it the 8272.  Anyone know if this is accurate?

Cheers,
Chuck