Open-source floppy reader: the data separator/sync-er works!

Fred Cisin cisin at xenosoft.com
Tue Apr 10 19:35:57 CDT 2007


On Tue, 10 Apr 2007, Christian Corti wrote:
> Ok, I was referring to the IBM 5114 maintenance manual which describes FM
> and MFM encoding that IBM used for their drives/controllers. But you are
> right, e.g. the "Floppy Disk Data Separator Design Guide for the DP8463" says
> that the address mark $A1 has a clock pattern of $0A. I don't really know
> what IBM meant with "missing clock bits 2, 3 and 4"... I think it applies
> to the $FE or $F8 address mark in FM.

While you are at it, notice that the 1771 can create some FM data address
marks that the 179x can not.  Worse yet, they are used in TRS80 (model 1)
disk formats.






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