zz: Great explanation by Andrew--

[Ted Nelson <ted@xxxxxxxxxx>]

... of something I didn't know was there.  (Or we
 discussed it so long ago I'd forgotten.

>when input
>is queued up, there's no point in drawing the whole screen when it is
>most likely just about to change again.  More to the point, we want to
>avoid performing large numbers of database lookups for cells and links
>that the user probably didn't need to see right now anyway.  This is
>an extremely significant high-level user interface optimisation without
>which performance of scrolling through many cells can degrade severely
>to the point where the system becomes unpleasant to use, especially on
>slower systems.

Obviously we want to avoid unnecessary optimization,
 do only the ones we have to.  This is a nice example.

Best, Ted


____________________________________________________
Theodor Holm Nelson, Visiting Professor of Environmental Information
 Keio University, Shonan Fujisawa Campus, Fujisawa, Japan
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Professorial home page http://www.sfc.keio.ac.jp/~ted/ 
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Quotation of the day, 98.11.21:
"Life is EXTREMELY strange, except we don't notice."  TN98