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From: S_ASCHMIDT@iravcl.ira.uka.de (|S| Angela Schmidt)
Newsgroups: comp.sys.amiga.programmer
Subject: Re: HD CMD_READ solved - solution and question
Message-ID: <1991Jun27.111625.9945@ira.uka.de>
Date: 27 Jun 91 11:33:43 GMT
Article-I.D.: ira.1991Jun27.111625.9945
References: <1991Jun24.125808.48207@cc.usu.edu> <1410@cbmger.UUCP> <1991Jun26.133654.48232@cc.usu.edu>
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In-Reply-To: sl87m@cc.usu.edu's message of 26 Jun 91 19: 36:54 GMT
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In <1991Jun26.133654.48232@cc.usu.edu> sl87m@cc.usu.edu writes:
> 
> Curiosity yes/no question:
> 
> CMD_READ seems to be taking an absolute block number, ignoring any partitioning
> of the drive. Is this true? (I have to convert partition block numbers into
> absolute block numbers to access the correct block.  e.g. DH0: goes from track
> 2 to track 445 with 26 sectors/track, 7 heads/cylinder -- I have to add 2*26*7
> = 364 to DH0's block number to get at it.)
> 

Yes, that's true! Only the filesystem knows about your partitions. The device
doesn't know anything about it. But some programs - like sectorama - don't
know this.

To get infos about the mounted partitions you have to read the devicelist.
I posted an article how to do this 2 days ago. If you don't read the
devicelist your program will only run on Amigas with the same harddisks
and harddisk-partitions like yours. (If you coded your program to run
on _your_ Amiga). That's no good solution...

In some harddisk the partition-information is also contained in the
Rigid-Disk-Blocks (on the first cylinders of the harddisk).

If you're interessted I see your Rigid-Disk-Blocks (I think you use some,
since your partition begins at cylinder 2), you can read them using the
device. It also makes fun to find non-coded passwords in there (like
in ALF2.0 :-).

You even can get information about the Rigid-Disk-Blocks using a simple
diskmonitor (for harddisks): Mount the Rigid-Disk-Block as an own partition
(without using a standard filesystem, instead take somethink like a
dummy-handler) and you can use the diskmonitor to look into these blocks.
Or just take sectorama. :-)

> 
> James
> 

Hope it helps

Angela




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