[comp.sys.hp] Interleave Factor required - help

kjc@and.cs.liv.ac.uk (05/27/91)

I am trying to find out the recommended interleave factor for the disk drives 
listed below. They don't appear to be in our version of disktab which came 
with HPUX 7.0. 

    HP7959S (SCSI)
    HP2203A (HPIB)
    HP2213A (SCSI)
    RodimeRO3000T (SCSI)

In fact looking through disktab, non of the SCSI drives have this information -
is there any reason for this?

Any help would be appreciated.

Thanks in advance.

Kenny Chan

postal: Kenneth Chan
        Computer Science Dept.
        University Of Liverpool
        PO Box 147 
        Liverpool 
        L69 3BX.

email:  kjc@uk.ac.liv.cs.and

kinsell@hpfcdj.HP.COM (Dave Kinsell) (05/31/91)

>I am trying to find out the recommended interleave factor for the disk drives 
>listed below. They don't appear to be in our version of disktab which came 
>with HPUX 7.0. 
>
>    HP7959S (SCSI)
>    HP2203A (HPIB)
>    HP2213A (SCSI)
>    RodimeRO3000T (SCSI)

>In fact looking through disktab, non of the SCSI drives have this information -
>is there any reason for this?

The disktab entries don't include interleave information unless something
other than the default value is optimal.  Newer disk drives all have the
capability of reading and writing contiguous sectors, so the default value
(which is contiguous sectors) works fine.  All of the SCSI Winchesters work
best with the default.  In fact, most SCSI mechanisms will ignore other
values that you attempt to use when formatting them.

Things get more interesting at 8.0, where drives are supported that can 
handle more aggressive file system tuning to deliver higher throughput
than was possible in the past.  Comments have been added to the various
disktab entries indicating how to change the file system tuning to
optimize performance.  The install process has been modified to allow
tuning to be changed before installing an OS to a disk.  This applies to the
68K 8.0 release, I'm not familiar with what's happening for S800.


>Any help would be appreciated.

>Kenny Chan

Regards
Dave Kinsell
kinsell@hpfcmb.hp.com