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From: pls@soessx.UUCP (P.L.Sullivan)
Newsgroups: net.unix-wizards
Subject: Re: tar fs copy
Message-ID: <716@soessx.UUCP>
Date: Fri, 27-Sep-85 23:53:09 EDT
Article-I.D.: soessx.716
Posted: Fri Sep 27 23:53:09 1985
Date-Received: Wed, 2-Oct-85 00:37:47 EDT
References: <832@burl.UUCP> <221@drivax.UUCP> <842@burl.UUCP> <240@investor.UUCP> <233@drivax.UUCP> <249@investor.UUCP> <239@drivax.UUCP>
Reply-To: pls@soessx.UUCP (P.L.Sullivan)
Organization: AT&T Tech-NS, Atlanta
Lines: 17
Keywords: 10
Summary: pipe size

In article <239@drivax.UUCP> alan@drivax.UUCP (Alan Fargusson) writes:
>> How big is the pipe?  I read somewhere pipes use the root file system,
>
>Pipes use an inode on the root file system. They are limited to 5120 bytes
>on System V, and 4096 on some other systems, by code in the kernel.

On System V, pipes are 10 physical blocks long, with the 11th thru 13th
block pointers reserved for pipe activity descriptions.  This makes pipes
10240 bytes max on systems with 1k byte physical blocks (e.g. 3b2 and 3b20), 
20480 bytes max on those with 2k byte physical blocks (e.g. 3b5 and 3b15).

Guy Harris posted a reply to the above article, but didn't mention this - 
is this peculiar to AT&T hardware??

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Pat Sullivan - {akgua|akguc|ihnp4}!soessx!pls - voice 404-257-7382