RE: Single level store & record blocking on update files (was RE:Where is IBM?)

Also, consider the physical aspects of disk storage.  The S36 and its
predecessors required contiguous storage space for all files.  A file HAD to
exist as a single stream of bytes on the disk, making blocking MUCH simpler
to accomplish.

Eric DeLong
Sally Beauty Company
MIS-Project Manager (BSG)
940-898-7863 or ext. 1863



-----Original Message-----
From: Douglas Handy [mailto:dhandy1@xxxxxxxxxxxxx]
Sent: Wednesday, April 23, 2003 8:34 PM
To: Midrange Systems Technical Discussion
Subject: Re: Single level store & record blocking on update files (was
RE: Where is IBM?)


Dan,

>On the AS/400, there is no record blocking for update files, period.  I
fail to see why this is,
>especially in light of the AS/400's single level store.

I think this is only true when there is a unique access path, and the
suppression of record blocking is simply to force an immediate test for
duplicate keys.

Under SSP on the S/36, it could block them anyway and you didn't find out
about
the duplicates until the keysort when the file was closed.  (Remember those
nasty messages?)

I believe the 400 can block record updates, provided the physical and
associated
logicals do not have a unique access path.  In practice this means most
files
cannot be blocked for update.

Doug
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