Xerox 820-II diskette formats

[js at cimmeri.com]

Steven Hirsch wrote:
> On Sun, 3 May 2009, Chuck Guzis wrote:
>> The 820-II 8" samples in my library show 77*1*26*256 and 77*2*26*256 
>> formats.
> That's fairly conservative, but works out to almost a 1MB for the DSDD 
> diskettes.  Most systems I'm familiar with formatted at 32 x 256 in DD 
> mode.
What?!   Using what controller chip?  How that's even possible while 
maintaining the same 360rpm?

 jS