RAM disk.

Richard Tobin richard at aiai.ed.ac.uk
Thu Oct 11 00:35:20 AEST 1990


In article <1850 at necisa.ho.necisa.oz> boyd at necisa.ho.necisa.oz (Boyd Roberts) writes:
>When I hear `ram disk' I reach for my revolver.  Now, repeat after me...

>    What is the buffer cache? -- A ram disk.

As has been pointed out elsewhere, there *is* a difference - most unix
filesystems will try to increase reliability by forcing certain writes
to take place synchronously.  This makes creating files faster on a ram
disk regardless of the buffer cache size.  Whether this affects you
depends on whether you write a few large files or lots of small ones.

However, it is reasonable for /tmp to be a filesystem which does not
do any synchronous writes, if you don't find it important to maintain
/tmp across crashes.  Once you do this, its performance should be
similar to (or better than) a ram disk.

-- Richard

-- 
Richard Tobin,                       JANET: R.Tobin at uk.ac.ed             
AI Applications Institute,           ARPA:  R.Tobin%uk.ac.ed at nsfnet-relay.ac.uk
Edinburgh University.                UUCP:  ...!ukc!ed.ac.uk!R.Tobin



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