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From: ekrell@hector.UUCP (Eduardo Krell)
Newsgroups: comp.sys.att
Subject: Re: TCP/IP or SOCKETS on cheap UNIX box
Message-ID: <3182@ulysses.homer.nj.att.com>
Date: Wed, 18-Nov-87 11:26:35 EST
Article-I.D.: ulysses.3182
Posted: Wed Nov 18 11:26:35 1987
Date-Received: Sat, 21-Nov-87 10:18:22 EST
References: <228@stc-auts.UUCP> <9300030@bradley>
Sender: daemon@ulysses.homer.nj.att.com
Reply-To: ekrell@hector (Eduardo Krell)
Organization: AT&T Bell Labs, Murray Hill
Lines: 15

To trully implement select(2) on System V, you need to change the kernel.
A streams-based TCP/IP can use poll(2) (that's a System V Release 3 system
call) that works much like select(2), but ONLY on stream file descriptors.

The problem with select(2) is that it can be done on an ordinary file,
and you can't do that unless you change the i-node structure and keep
track of the ones that are "selectable".  You also have to change other
I/O drivers as well.

Changing kernel drivers might to be trivial, and changing the file system
is a pain.
    
    Eduardo Krell                   AT&T Bell Laboratories, Murray Hill

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