Xerox 820 system disks in Teledisk format?

Christian Corti cc at
Sat May 9 02:46:09 CDT 2009

On Fri, 8 May 2009, Steven Hirsch wrote:
> Now, I'm trying to figure out how to format a SSDD diskette for the Xerox. 
> They use a screwy format where track 0 is FM 128 bytes/sector (26 x 128) and 
> all the others are MFM 256 bytes/sector (26 x 256).

That's not screwy, that is standard IBM format for higher density disks 
(except that IBM didn't have a SSDD variant, only SSSD, DSSS and DSDD).


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