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From: joels@tekred.UUCP
Newsgroups: comp.sys.amiga
Subject: Pipes
Message-ID: <946@tekred.UUCP>
Date: Fri, 23-Jan-87 19:56:24 EST
Article-I.D.: tekred.946
Posted: Fri Jan 23 19:56:24 1987
Date-Received: Sun, 25-Jan-87 05:47:37 EST
Organization: Tektronix Inc., Beaverton, Or.
Lines: 22



>The key thing about a pipe is that it's a FIFO queue, with a limited
>buffer size. You can pass unlimited amounts of data through one, yet
>it will always use a small amount of space. Most OS's have some kind
>of facility to do this, so you can do pipes on most OS's.

	<mike

The real advantage of pipes over files that imitate them is that all
processes in the chain can run simultaneously. The second process can start
as soon as the pipe buffer has data in it. After the first buffer of
data has passed through the chain, and you are reading the data on the screen
the other processes can keep the display buffer full and ready for
display. This also means that if you only need to look at the beginning
of the data only the beginning needs to be processed. With imitation pipes
the first process must process all of the data and close the file and the
second does the same, etc. All of the preliminary processes must
process all the data even if you only need to see the first line.

Joel Swank
Tektronix, Redmond, Oregon