Shark and Cylinder Allocations

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Shark and Cylinder Allocations
With the new Shark devices and 'virtual' disks, is the idea of allocating on
cylinder boundaries still valid? Any thoughts would be appreciated.

Thanks
Dave.



Chris Blaicher

Re: Shark and Cylinder Allocations
(in response to DPetro@AOL.COM)
Allocation on cylinder boundaries is combined hardware/software question.
It has nothing to do with SHARK devices per se.

In the old days, any non-cylinder aligned allocations would cause track
level interrupts, no matter what device it is on. If a program is still
using seek commands, then this is still true, even for a SHARK device.
However, most all, if not all, programs have been modified to use the define
extent and locate record commands. By using them many of the old time
considerations have dropped away.

I would still recommend using cylinder allocations for any data set over 10
tracks. Housekeeping is easier.

This is just my opinion and does not reflect an official position of BMC.

Chris Blaicher
BMC Software, Inc.
Austin Research Labs
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-----Original Message-----
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Sent: Tuesday, December 12, 2000 7:51 PM
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Subject: Shark and Cylinder Allocations


With the new Shark devices and 'virtual' disks, is the idea of allocating on
cylinder boundaries still valid? Any thoughts would be appreciated.

Thanks
Dave.