Do inter-process pipes use secondary (disc) memory for buffering?

[Johan Finnved]

In article <5566 at umcp-cs.UUCP> chris at umcp-cs.UUCP (Chris Torek) writes:
>> .. whether interprocess pipes use primary (main) or secondary (disc) memory
>
>The answer is "yes" and "yes".
>... However, in most cases the data in pipes never gets out of the block
>file system buffer cache (main memory).
>
Version 7 does a poor job at avoiding disc writes when using pipes:
Whenever a write operation fills up a buffer a write is started even though
the odds are high that the data will soon be read and no longer needed.
Moreover when pipe reads have consumed a buffer it does not clear the
B_DELWRI bit so delayed writes of no longer referenceable data happen.
So using a pipe usually creates writes but seldom reads.

Are later versions different ?

		Johan Finnved, Objecta, Sweden <jf at sal.UUCP>