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From: Stephen Fuld <sfuld@alumni.cmu.edu.invalid>
Newsgroups: comp.arch
Subject: Re: Architectural implications of locate mode I/O
Date: Wed, 31 Jul 2024 22:20:44 -0700
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On 7/31/2024 6:41 PM, Lawrence D'Oliveiro wrote:
> On Sat, 6 Jul 2024 06:15:56 -0000 (UTC), Stephen Fuld wrote:
> 
>> As you posted below, the whole PDS search stuff could easily be a
>> disaster.  Even with moremodest sized PDSs, it was inefficient has
>> hell.
> 
> Would locate mode have helped with this?

No.  The problem was that the PDS search was a linear search of records 
on the disk drive i.e. typically multiple disk revolutions), and 
furthermore, it required (until the fast PDS search came along) that the 
host channel take action on each disk record checked, even the ones that 
didn't match, including resending the search argument to the disk 
controller.

This has nothing to do with locate mode.



-- 
  - Stephen Fuld
(e-mail address disguised to prevent spam)