Linked by Thom Holwerda on Wed 28th Jun 2017 19:28 UTC
Hardware, Embedded Systems

Last week I wrote a Mandelbrot set program for the Xerox Alto, which took an hour to generate the fractal. The point of this project was to learn how to use the Alto's bitmapped display, not make the fastest Mandelbrot set, so I wasn't concerned that this 1970s computer took so long to run. Even so, readers had detailed suggestions form performance improvements, so I figured I should test out these ideas. The results were much better than I expected, dropping the execution time from 1 hour to 9 minutes.

Articles like this are very satisfying to post, because we can all agree this is just plain awesome, no ifs or buts.

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great stuff!
by project_2501 on Wed 28th Jun 2017 22:56 UTC
project_2501
Member since:
2006-03-20

especially the bit about turning off the screen ..

Reply Score: 2

RE: great stuff!
by DeepThought on Thu 29th Jun 2017 05:43 in reply to "great stuff!"
DeepThought Member since:
2010-07-17

Turning off the screen also improved speed on ZX81 :-) The "FAST" mode.

Reply Parent Score: 3

RE[2]: great stuff!
by avgalen on Thu 29th Jun 2017 07:54 in reply to "RE: great stuff!"
avgalen Member since:
2010-09-23

Turning off the "screen" is still a valid approach for many tasks.

dir /a /s on c:\ takes forever because it is displaying all the output, but dir /a /s > %temp%\c.txt finishes a whole lot quicker

Basically all automation tasks should be run with either their window minimized or with https://excel.tips.net/T002498_Turning_Off_Screen_Updating.html

We are living in a computerworld where literally tens of billions of computations are done per second and processing times are often measured in miliseconds while screen refresh is mostly once per 17 miliseconds.

I once improved the performance of a program by a factor 100 by not updating the progressbar every time something changed but only once per second.

Reply Parent Score: 3