[st-users] Some thoughts on ST-Developer v7

[Steve Waterbury]

David Loffredo wrote:

> .... core object indices that
> should dramatically increase traverse-by-type speed and should also
> eventually reduce memory usage.
> 
> The only externally visible side effect from all of this will be that
> objects in a part 21 file will be written out sorted by type rather
> than in order of creation as they are now.  ....
> 
> I'm curious what folks think about this side-effect.  In my mind, the
> locality of reference in the original scheme was handy sometimes, but
> this new way can be really nice too, since you have a great picture of
> the types of entities in the file, and they are conveniently grouped.
> 
> It also opens up a bunch of other options, like writing the object
> types in alphabetic order, using a graph ordering alogorithm to
> minimize forward references and so forth ....

IMO, the advantages of the core object indices greatly outweigh 
anything lost by the side-effects mentioned.  

This is kind of interesting, in that the structuring of the file 
in this way brings out the (otherwise subtle) "relational" 
aspect of the data:  the file containing successive groups of 
instances of entity types could be interpreted as the 
concatenation of a bunch of interlinked relational "tables".  :^)

Presentation aspects of the Part 21 format will probably be less 
and less significant as more work is done on the XML format 
(pure speculation, of course! ... ;^).

Cheers,
-- Steve.

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"Sometimes you're the windshield; sometimes you're the bug."
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Stephen C. Waterbury                       Component Technologies
Code 562, NASA/GSFC                  and Radiation Effects Branch
Greenbelt, MD 20771           Engineering Web/Database Specialist
Phone/FAX: 301-286-7557/1695        
email:                              steve.waterbury at gsfc.nasa.gov
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