Re: 1541IDE and 1541IDE-S

From: Marko Mäkelä (
Date: 2007-12-05 21:13:45

On Wed, Dec 05, 2007 at 05:16:30PM +0100, wrote:
> > Maybe this will clear things: an harddisk
> > sector contains 512 bytes. Using an 8 bits interface means that one can
> > only access 256 of these 512 bytes. Writing $00, $01 .... $FF to a
> > sector with my interface and reading the same sector using a PC will
> > give $FF, $00, $FF, $01, $FF, $02 ..... $FF, $FE, $FF, $FF.
> Ah yes, this makes it much more clear for me. You cannot store more than 256 
> bytes because you don't have a 9th line providing that extra bit of
> information for storage? Hmmm. Bit sad, that. Can't we grab some 1541 line
> somewhere? :-)

That would be 8 more lines.  It is not a matter of a missing address line,
but a matter of missing half the data lines.  The AT/IDE bus is 16 bits
wide, you know.  And there is only one unused 8-bit I/O port on one of
the 6522s inside the 1541.

> But, I'm also concerned with using the PC for getting out a "neat" d64 image 
> out of all the GCR mess.....

The PC has so much processing power that this should not be an issue.


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