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The personal site of Jamie Knight, an autistic web developer, speaker and mountain biker who is never seen far from his plush sidekick Lion. View the Archive

Topics: Autism Development

Computers are Fast: Computers are Slow

Computer are weird and performance is hard to understand.

Computers are fast.

Earlier this evening i was playing around with the first billion digits of pi, i was looking for patterns in it (eg upwards counting strings like 123456789 and how often the occur). It took my mid spec 3 year old laptop about 10 seconds to run the command each time using standard unix tools.

The speed as which my laptop can juggle a billion digit problem is amazing. At a human scale, in a few seconds my laptop is doing what would take me lifetimes.

Computers are slow.

I sometimes take on video projects, i did one a few weeks ago which involved encoding a bunch of high bitrate files down to lower bitrate files in order to move into iTunes for streaming to an Apple TV / loading onto iPads etc.

This shows how slow computers are compared to our needs. My top spec iMac — one of the fastest Macs ever sold — can barely convert the video much faster than real time. I was running the encoding job overnight in order to get it done in a reasonable amount of time.

I was not doing a task that was very high end, the video files being juggled where only 1080p and not 4K. They are only marginally larger than the video files an iPhone could record.

Performance is complex.

Here’s what i think is going on.

For the first task i have an idea of the complexity, i could if i wanted conduct the billion digits of pi task myself. I’d never complete it, but i can grok the complexity of the work being done at a human scale.

For the video encoding i can’t understand the complexity as i dont know what it’s doing. Because i don’t know what it’s doing being “lots of stuff” and the task seems trivial (make a video play on the Apple TV etc) it feels slow. I’m not left in awe at what it is doing, i am just annoyed its not faster.


I don’t really have a conclusion to this, just documenting some of my throughts about performance. I think this covers more than computing too, i get the same effect between F1 and WRC. World rally looks faster, perhaps because i can relate to it better.

Published: 3 September 2016 | Categories: , Permalink


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