What are 'attaches' in vmstat?

[Ozalp Babaoglu]

In article <1962 at brchh104.bnr.ca> ehrlich at cs.psu.edu (Dan Ehrlich) writes:

>I have a question about vmstat.  What does the 'at' field represent?  The
>man page says that 'at' is the number of 'attaches'.  What are 'attaches'?

Being the guilty party that added virtual memory support to bsd unix, I
feel compelled to respond.  The field in question reports on the vm
system's ability to find missing pages without having to do any IO.  'at'
is the rate (pages/sec) at which this is happening. The attached pages
are typically text (code) pages left behind by an exited process that was
executing the same program. It has been a while (over 10 years) since I
did this work along with Bill Joy and I hope I am remembering correctly.

Ozalp Babaoglu				       E-mail:	ozalp at dm.unibo.it
University of Bologna, Dept. of Mathematics
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