[ale] Linux kernel

[Steve Litt]

Jon "maddog" Hall said on Sat, 18 Nov 2023 12:35:54 -0500

> "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

10 hours for 1306 records? Even a bubble sort is better. Let me guess:
He went through the whole list, found the lowest, wrote it, put it in a
variable, and then repeated in order to find the next lowest.

I spent a lot of time on a PDP-11/23, so I'm aware of the power and
lack thereof of those computers. But come on, I could have done it by
hand with pencil and paper quicker. I know Quicksort is a difficult
algorithm to write and understand, but geez, even a multiple merge sort
would have been much faster.

By the way, I never had to write a sort program professionally because
my client used a third party software called RTsort, which functioned
beautifully, just like today's Linux sort command does.

SteveT

Steve Litt 

Autumn 2023 featured book: Rapid Learning for the 21st Century
http://www.troubleshooters.com/rl21