CP/M 2.2 Sector Translation Question - test-drb@ccmp.vtda.org

23 Jan 2009

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Subject: CP/M 2.2 Sector Translation Question
   From: "ROBO5.8" <robo58 at optonline.net>
   Date: Thu, 22 Jan 2009 18:30:54 -0500
     To: "'General Discussion: On-Topic Posts Only'" <cctech at
classiccmp.org>

Hi,

I'd like to know if CP/M 2.2 is "Zero" biased when it comes to Sector
Translation.  Since v2.2 supports Blocking/Deblocking I would assume it has
to be.  I've looked at lots of code examples via Google and searched the
documentation but I cannot find a statement to that effect. 
The short answer is yes.

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Asking it another way:  The Sector Translation routine is passed the
requested sector number in Registers B&C.  Does CP/M request Sector 0 or 1
when it wants the first sector on any track. 
Zero, Zed, 0.

It's up to the bios to: 
 A)translate that to a physical address, 
 B) do what is needed for sector skew
 C) deblock if required.

Allison

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 Thanks Robo 