Several MPE-Image colleagues have called me and emailed me, asking for 
"my personal opinion" regarding LargeFile Datasets (LFDS).

As with everything, there are pluses and minuses with LFDS.  I highly
recommend that, before even considering installing LFDS, you should
have a serious consultation with your HP software support person(s).

WARNING: The version of DBSCHEMA released with MPE/iX 7.5 (released
         by HP in August 2002) produces incorrect LFDS.  Without
         realizing it, you may have already created bad LFDS.  

IMAGE version C.11.0 (not yet released by HP) corrects this LFDS problem. 

With IMAGE version C.11.0, the relationship between IMAGE blocks and
the file RECORDS that encapsulate them has been subtly altered for
LFDS.  

Regular (non-privileged) access to IMAGE data entries (via DBGET, 
DBPUT, DBUPDATE, and so on) continues to function without any change
for LFDS.

MultiRecord NoBuf access to IMAGE blocks (which contain IMAGE media
entries -- which, in turn, contain IMAGE data entries -- plus block
bitmaps) is subtly different with LFDS.  

If we were to extrapolate the schedule and budget that Adager Corporation
has invested (and will have to continue to invest, to tie up a couple of 
loose ends that we need to update to be able to support the latest HP 
version), and if we were to multiply Adager's LFDS schedule and budget
"times the number of commercial products and home-grown solutions that
use MultiRecord NoBuf access to IMAGE blocks", we would come up with
several person-years and several million U.S. Dollars.  

Bottom line: The fact that Adager supports LFDS turns out to be
irrelevant, because people do not use MPE-Image just for the fun of
running Adager.  People use MPE-Image to be able to run APPLICATIONS,
such as Suprtool, that process data to produce information.  If these
applications (many of which use MultiRecord NoBuf access to IMAGE blocks
for performance reasons) break down with LFDS (because of the subtle
differences in the relationship between IMAGE blocks and the file 
RECORDS that encapsulate them), then you can NOT use LFDS.

So, besides having a serious consultation with your HP software
support person(s), you must have a serious consultation with your
non-Adager suppliers (and with your in-house programmers, should you
have home-grown solutions that use MultiRecord NoBuf access to IMAGE 
blocks for performance reasons).  What are the total combined schedules 
and budgets required to make these non-Adager systems LFDS-savvy?

It's all a matter of time and money.  

My personal opinion: I wish I had more time and more money.

  _______________
 |               |
 |               |
 |            r  |  Alfredo                  http://www.adager.com                     
 |          e    |                            
 |        g      |  F. Alfredo Rego                   
 |      a        |  Manager, R & D Labs           
 |    d          |  Adager Corporation
 |  A            |  Sun Valley, Idaho 83353-3000            U.S.A.
 |               |
 |_______________|

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