[comp.unix.cray] remote editing

klietz@uxe.cso.uiuc.edu (06/21/89)

In 1985, I did a study of character-at-time I/O on a Cray-2.
Although the quantitative results of those studies are private,
I can you some generalizations.

In general, it should be noted that the overhead for character-at-a-time
processing tends to be proportional to the # of users who are doing
it.  People don't type faster as computers get faster, thus the
overhead in terms of the number of machine cycles consumed per unit
of time is a constant.

In the meantime, the number of cycles per unit of time that a
supercomputer can deliver has increased exponentially with each
new model.  Thus, the fraction of supercomputer processing power
dedicated to keystroke processing is reduced exponentially.

For example (these numbers are fake) if we assume that the overhead
of 32 people typing in the vi editor was, say, 12% of a Cray-1S in 1985,
it would be less than 1% today with a Cray YMP.

I concluded that overhead of character-at-a-time I/O is outweighed by
the benefit of better user interaction.  Cray Research blessed this
concept with the introduction of X Windows under UNICOS in 1987.

--
Alan E. Klietz
University of Illinois at Urbana-Champaign
National Center for Supercomputing Applications
152 Computing Applications Building
605 E. Springfield Avenue
Champaign, IL  61820
Ph: +1 217 244 8024            ARPA:  aklietz@ncsa.uiuc.edu