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SubjectRe: Strange IDE performance change in 2.6.1-rc1 (again)
On Sat, 03 Jan 2004 04:33:28 +0100, Tobias Diedrich <>  said:

> Very interesting tidbit:
> with 2.6.1-rc1 and "dd if=/dev/hda of=/dev/null" I get stable 28 MB/s,
> but with "cat < /dev/hda > /dev/null" I get 48 MB/s according to "vmstat
> 5".

'cat' is probably doing a stat() on stdout and seeing it's connected to /dev/null
and not even bothering to do the write() call. I've seen similar behavior in other
GNU utilities.
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