From: Christian Groessler (cpg_at_aladdin.de)
Date: 2002-11-07 00:20:06
Hi, On 11/05/2002 10:56:48 AM PST "Shawn Jefferson" wrote: > >>>> Christian Groessler <cpg_at_aladdin.de> 11/04/02 04:39PM >>> >> >>Also there lurk some more problems for a general solution of the >>sector size issue: If I read sectors 1 to 3 on a 256 byte formatted >>disk, I still have to specify sectorsize 128. So sectors 1-3 are >>always 128 bytes on the xf551. > >This is indeed my problem. If I set the sector size to 256 and try >to read sectors 1-3 I get an error. Sectors 4 to n, are no problem. >Is this the dio code giving the error or the OS? Might I have to set >the sector size to 128 for the first three sectors, then 256 for the >remaining? Same effect here with the xf551. > >>Are sectors 1-3 on any medium always 128 bytes? How is this handled >>e.g. in the SmartIDE code? > >Would large partitions, such as 16 MB Sparta format be 128 bytes in >the first 3 sectors? I don't know. > >Let me see... I couldn't see anything in the code that does anything >special when reading sectors 1-3. Bob is hooking the D: handler so >that if the drive number corresponds to a hard drive partition it >goes to his code, if not it goes to the regular D: handler code. His >read code just grabs as many bytes as required from the hard drive >after converting sector number to physical head/track/sector. If >anything special is going on regarding the first 3 sectors it would >be in the OS code. In the xf551 it's apparently handled by the disk drive rom. I now changed the DIO read and write functions to always use a sector size of 128 for sectors 1-3, regardless of sector size setting. This works for xf551, the question is, whether it restricts needed functionality (someone needing to access the 2nd 128 bytes of sectors 1 to 3). regards, chris ---------------------------------------------------------------------- To unsubscribe from the list send mail to majordomo_at_musoftware.de with the string "unsubscribe cc65" in the body(!) of the mail.
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