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From: narayan@lll-ati.arpa (Narayan Moharram)
Newsgroups: comp.protocols.tcp-ip.ibmpc
Subject: Re: In this corner -- sockets!   In that corner -- TLI & streams!
Message-ID: <21851@lll-tis.arpa>
Date: Mon, 23-Nov-87 12:40:08 EST
Article-I.D.: lll-tis.21851
Posted: Mon Nov 23 12:40:08 1987
Date-Received: Thu, 26-Nov-87 01:39:11 EST
References: <283548.871111.PAP4@AI.AI.MIT.EDU> <302@halley.UUCP> <3373@hoptoad.uucp>
Sender: nobody@lll-tis.arpa
Reply-To: narayan@lll-ati.arpa (Narayan Moharram)
Organization: Lawrence Livermore National Laboratory, Livermore CA
Lines: 17

Each operating system (SV.3 and 4.x BSD) has its own idea of async
I/O capabilities. So the question is not select/poll, but what benefits
does sockets have over TLI or vice versa.

One of the biggest defects in sockets is the fact that connections
are accepted by the underlying protocol without giving the user
a chance to reject an incoming connection request. This is not quite
as bad as the fact that using TLI you cannot do scattered I/O
which is essential for networking protocols. Sockets has a sendmsg
/recvmsg capabilty whereby various layers can build thier own headers,
in non contiguous buffers, and pass it down to the transport layer.
This proves to be a big expense in the TLI mechanism as a lot of
copying has to be done (or preknowledge of the next layers headers
is necessary).

If anyone is interested I can post a paper that was done comparing
the two interfaces in various categories.