[ale] Linux kernel

[Jon "maddog" Hall]

 "Well wait. If the original took 15:03 and the the new one took 15 minutes
less, then the new one took 3 seconds, which is an astonishing advantage.
How long did the original take?"

When I was teaching at Hartford State Technical College (1977-1980) we had
a "programmer" write a program for our PDP-11/70 running the RSTS/E
operating system.

When he ran his program (always at high priority) it took 10.5 HOURS to
sort 1306 32-byte records, and while his program was doing that all the
student programs (on the same system) would come to a grinding halt.  Of
course the students complained.

Because of a mandatory teacher's union I was prevented from re-writing the
program, but I described to a student how to re-write it to be more
efficient.

The program then performed exactly the same task in less than three minutes
at normal priority, so the other students did not even know it was running.

md



On Fri, Nov 17, 2023 at 8:04 PM Steve Litt via Ale <ale at ale.org> wrote:

> Charles Shapiro via Ale said on Fri, 17 Nov 2023 14:20:13 -0500
>
> >Heh. Reminds me of the guy at one of my old gigs who spent several
> >weeks of coding and testing to replace all of the simple sequential
> >loop searches in a pretty big application with sorts + binary
> >searches.   The original application took several hours to finish.
> >After his optimizations, the new version took about fifteen minutes
> >less time.  **Always** profile before you optimize!
>
> Well wait. If the original took 15:03 and the the new one took 15
> minutes less, then the new one took 3 seconds, which is an astonishing
> advantage. How long did the original take?
>
> SteveT
>
> Steve Litt
>
> Autumn 2023 featured book: Rapid Learning for the 21st Century
> http://www.troubleshooters.com/rl21
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