Problem w/ V/AT fdisk and hard disk >1023 cyls?

Bob Thrush rd at tarpit.uucp
Sat Aug 12 09:34:01 AEST 1989


  I am having a problem using fdisk with a Miniscribe 3085 (7 heads,
1170 cylinders).  fdisk barks about an invalid partition table every 
time I try to make the (1) 1170 cylinder partition active.  It 
then proceeds to clear the partition table.  If I only create a
partition of 1023 cylinders all is well except I can't use the last
~8.8 Mb of the disk.  If I then create a 2nd partition for this last
part of the drive, fdisk barks again and clears the table.  
Apparently, one cannot use fdisk to partition a drive with more
than 1023 cylinders.  Has anybody else seen this problem or know a 
solution?  Comments?  (I know the original AT disk controller had 
this 10 bit cylinder limitation but the controller I'm using does not.)

  The test configuration uses a drive type of 12 (7 heads, 855 cyls)
which I alter to the correct geometry within fdisk.  

  Since /dev/rdsk/0s10 spans the range of drive 0, I have tried 
"dd if=/dev/rdsk/0s10 of=/dev/null bs=17b" and it returns 8183 
blocks which is expected, ie. 7*1169.  It appears that the device 
driver can access the entire drive.

  Is there a known fix or work around to fully utilize this geometry?

Thanks
-- 
Bob Thrush                 DOMAIN: rd at aii.com       UUCP: uunet!tarpit!rd
Automation Intelligence,   1200 W. Colonial Drive, Orlando, Florida 32804



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