[comp.sys.amiga.tech] what track is disk directory on 3.5" disk?

IO00844@MAINE.BITNET (Zero Batzell) (12/06/90)

Forgive my ignorance, but I just upgraded to an Amiga. I know the disk director
y is on track 18 on a 5.25" disk, but WHERE is the directory on a 3.5" disk?
I'm also interested in any other interesting information having to do with the
internals of 3.5" disks (just when you get familiar with something...it's time
to upgrade).                                         Thanks (((ZERO)))

peterk@cbmger.UUCP (Peter Kittel GERMANY) (12/29/90)

In article <90339.140456IO00844@MAINE.BITNET> IO00844@MAINE.BITNET (Zero Batzell) writes:
>Forgive my ignorance, but I just upgraded to an Amiga. I know the disk director
>y is on track 18 on a 5.25" disk, but WHERE is the directory on a 3.5" disk?
>I'm also interested in any other interesting information having to do with the
>internals of 3.5" disks (just when you get familiar with something...it's time
>to upgrade).                                         Thanks (((ZERO)))

Simply spoken: directory on an Amiga disk is always exactly in the
middle of the disk (or partition).

More detailed: In that middle you find the "Root block", which is
the main directory. But you must note that the organisation of
the directory and its entries differs heavily (better: totally)
from that on old C64 which you obviously refer to. Such detail
informations are found in any good book about AmigaDOS internals.
The official book for this is the "AmigaDOS manual" (sp?) from
Bantam Books.

-- 
Best regards, Dr. Peter Kittel  // E-Mail to  \\  Only my personal opinions... 
Commodore Frankfurt, Germany  \X/ {uunet|pyramid|rutgers}!cbmvax!cbmger!peterk

lcline@sequent.UUCP (Larry Cline) (12/29/90)

In article <90339.140456IO00844@MAINE.BITNET> IO00844@MAINE.BITNET (Zero Batzell) writes:
>Forgive my ignorance, but I just upgraded to an Amiga. I know the disk director
>y is on track 18 on a 5.25" disk, but WHERE is the directory on a 3.5" disk?
>I'm also interested in any other interesting information having to do with the
>internals of 3.5" disks (just when you get familiar with something...it's time
>to upgrade).                                         Thanks (((ZERO)))

The Amiga does not use tracks for the disk directory.  It uses blocks.  The
root block tends to be in the middle of whatever device you are using.  On
a 5 1/4 inch disk which has 880 blocks the root block is at 440.  On a
3.5 inch disk which has 1760 blocks it is on block 880 (which is normally
on track 40).  On my 380 MB Maxtor it is around block 330000.  If you are
looking to examine the blocks and such you might look into a utility such
as DiskX or Sectorama to do this for you.

Larry