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1maginary

This is apparently from 2012.

How outdated are some of these numbers?

According to this[1] source (linked in the gist comments), ping is down to 144ms from LA to Amsterdam.

[1]: https://wondernetwork.com/pings/

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I believe that the gist is not really meant to provide accurate numbers in every case. Especially with things like network latency, it is very difficult to say that any time is the 'correct' time because it will be different in any case. The real purpose of the gist, which is posted at regular intervals here, is to illustrate the order of magnitude differences between e.g. the L1 cache and L2 cache latency. It is meant to get a programmer to think about cache locality. If I can keep something in L1/L2 cache, it will be orders of magnitude faster than something that needs to make regular round trips to main memory, which is orders of magnitude faster than something that needs to make regular round trips to disk, and so on.

I guess I took the title too literally. I would expect every competent programmer to know what you explained, and that is probably what the title was alluding to.

Thanks for clarifying.

That sequential reading from an HD varies a lot, and can be anywhere from where it is to somewhat faster than SD (but seek doesn't change much).

The datacenter round-trip and sequential reading from memory sometimes change places now, and sending 1MB on some networks is on the same ballpark of reading 1MB from memory. (There has been some articles about this change here on HN.)

I linked to this interactive chart by year from my blog [1]:

https://people.eecs.berkeley.edu/~rcs/research/interactive_l...

(Use the slider)

It shows disk seek and and sequential SSD read going down a lot. However, it also extrapolates out to 2020.

The code listing does have a lot of sources, and shows the extrapolation done, which I didn't look into in great detail.

[1] http://www.oilshell.org/blog/2016/12/23.html

The data isn't outdated, it just had 1.6 x 10^17 ns latency :)

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