Tim's Weblog
Tim Strehle’s links and thoughts on Web apps, software development and Digital Asset Management, since 2002.
2004-02-24

Memory resident

Rich Skrenta explains why only RAM is fast:

"A disk head seek is about 9ms, and the human perceptual threshold for what seems "instant" is around 50ms. So if you have just one head seek per user request, you can support at most 5 hits/second on that server before users start to notice latency. If you have a typical filesystem with a little database on top, you may be up to 3 seeks per hit already."