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by Textarcana 3383 days ago
#84 I am basing on Dijkstra's statement here that "from a microsecond to a half an hour of computing time confronts us… with the ratio of 10^9"

See here: http://infiniteundo.com/post/117192619718

"Time grain" seems like the wrong word here I will replace it with something more specific. Thank you for pointing this out and if you still dispute my math I would consider it helpful to hear why :)

1 comments

I think he's talking about the ratio of a microsecond to a half hour to express scale, a microsecond to a half hour is approximate (to an order of magnitude) to 10^9.

1000000 (microseconds/second) * 60 (sec/min) * 30 (min for a half hour) = 1800000000

10^9= 1000000000

Ok. I was just extrapolating out that if from a microsecond to a half hour 10^9 which is within a couple of orders of magnitude of the age of the universe in seconds, then from a microsecond to a year would result in a ratio that when expressed as an integer is much larger than the age of the universe.

I'm realizing as I type this that I am not totally clear here and I will do some reflection now as to how to rewrite this point so it does not raise such objections. Thank you again for your help with this.

But I am talking about scale. The number of different size "bricks" or "units" of time that you can choose in which to execute concurrent or dependent logic is staggering. And all too often this is overlooked. Thus "February 29 bugs" and "New Years Day" bugs, not to mention the entire error classes of race conditions and cascading failures.

You'll have to check the math but how about something like:

"Modern processors can process more instructions in a month than there are seconds in the age of the universe."

Both Intel and AMD have processors which can process over 300,000 MIPS [1], that's 300 billion IPS.

Universe age in seconds = (13,820,000,000 * 365 * 24 * 60 * 60) = 4.35828E+17

instructions per day = (300,000,000,000 * 24 * 60 * 60) = 2.592E+16

Universe age in seconds / instructions per day = ~16.8 days to process as many instructions as there have been seconds

[1] https://en.wikipedia.org/wiki/Instructions_per_second