Size limit to changes

Sam Adams ssadams at
Wed Aug 12 14:09:44 UTC 1998

4b will be fine.  In my ST80 porting efforts, I have often generated very large
changes files.  Filing in 2-3 megs of source several times will get you there
quite fast.  Also, some of my code generators for large model scaffold
construction and window building can generate several 100K's a pop.  But I
think 32MB is a reasonable barrier.

In my experience, once your changes get really large, its a good time to stop,
reorganize and file out change sets, edit the build script, and build a new
working image from a clean state.  This approach also keeps you from ending up
with the "Tektronix Troubleshooter" syndrome.  Any of you old Tek's can tell
the story better than I, but here goes.

"Troubleshooter" was an amazing prototype built at Tektronix in the early 80's
on the Tek Magnolia Workstation, which hosted Tek's implementation of
Smalltalk-80.  It was a prototype for a technician's assistant that would
visually guide the tech through diagnosis and repair of a board via an embedded
expert system.  The problem was that much of it had been hand crafted into
existence, with lots of  "workspace code" used to build the objects and data.
It was very difficult for the developers to move it to another image, and
impossible for those who hadn't written the code.

The moral of the story:  regularly moving your Smalltalk applications to new
images guarantees that you can move them at all.


Sam S. Adams, Distinguished Engineer, IBM Network Computing Software Division
tie line 444-0736, outside 919-254-0736, email: ssadams at
<<Hebrews 11:6, Proverbs 3:5-6, Romans 1:16-17, I Corinthians 1:10>>

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