Date   : Wed, 15 Jun 2005 14:14:37 +0100
From   : jgh@... (Jonathan Graham Harston)
Subject: Re: BBC IDE Drive compatibility list

John Kortink <kortink@...> wrote:
> >IDEDump now checks for this. If &38lo is zero, it swaps &38lo and
> >&37lo to get the correct figure.
> 
> Be careful drawing conclusions. There have been
> major changes in what the Identify command returns
> since revision 6 (early 2002) of the ATA standard.
 
When I noticed this I remembered reading somewhere that some
drives did this. They put some of their data "upside down". I know
the t13 documents document some drives that return string data the
wrong way round, so instead of "Conner Peripherals" you get
"oCnnreP repieharsl".
 
HDInit allows the user to manually specify a drive size, so if it
gets really confused and gives the wrong drive size it can be
overrulled.
 
> Also, older revisions did not understand LBA, and
> have no LBA fields. In later revisions they were
 
Yes, this was really annoying when I started developing. I
immediately wrote test code that used LBA, as it was so logical -
I want logical sector X, I don't care where it is on the drive, so
give me LBA sector X.  Then all the drives I tries it one didn't
support LBA.  Grrrr!!!!!
 
Thankfully, evey drive I have tested supports jommetry remapping,
so I set it to 64*4*cylinders, which is nice and easy to do as
64*4 is a whole byte.
 
-- 
J.G.Harston - jgh@...                - mdfs.net/User/JGH
BBC BASIC for Windows and Internationalisation
  See http://mdfs.net/Software/BBCBasic/Windows/ProgTips