From: utzoo!decvax!harpo!seismo!rlgvax!guy
Newsgroups: net.unix-wizards
Title: Re: Why overlap I/O and processing?  clutches...
Article-I.D.: rlgvax.300
Posted: Wed Apr 20 12:00:38 1983
Received: Thu Apr 21 07:21:55 1983
References: sun.256 mit-eddi.122

Actually, synchronous I/O with system-provided read-ahead isn't always what
you want; see "Operating System Support for Database Management" by Michael
Stonebraker, CACM, July 1981, Vol. 24 No. 7, pp 412-418.  A DBMS might want
to have O_NOCACHE and O_ASYNC bits in the second argument to "open", so that
it can open or create a file, bypass the UNIX cache entirely, and be able to
start an I/O operation and not wait immediately for it to finish.  (That
article does make a misleading statement about UNIX byte-stream vs. RSX-11M
record-oriented I/O; the RSX-11M kernel does NOT provide record-oriented I/O.
It provides block I/O, and a user-mode subroutine library (FCS or RMS) provides
the record structure.)

					Guy Harris
					RLG Corporation
					{seismo,mcnc,we13}!rlgvax!guy