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From: tcs@usna.UUCP (Terry Slattery )
Newsgroups: net.lan
Subject: Re: socket library under System V?
Message-ID: <115@usna.UUCP>
Date: Sun, 18-Aug-85 12:00:40 EDT
Article-I.D.: usna.115
Posted: Sun Aug 18 12:00:40 1985
Date-Received: Sat, 24-Aug-85 01:26:51 EDT
References: <284@SCIRTP.UUCP> <3070002@csd2.UUCP> <413@cheviot.uucp>
Organization: U.S. Naval Academy
Lines: 31

> I always thought that a library implementation of sockets simply mapped 
> calls like socket, bind and send more or less directly into open,
> ioctl and write. I don't see why you can't keep all the protocol dependent
> code inside the kernel. Is it really that difficult to bend the socket
> interface to fit the conventional device driver interface?

I'm using the Excelan front-end protocol suite on their Unibus card
and it does exactly that.  The drivers do have to do some additional
work since they have to handle unexpected process deaths, timeouts
for the select() implementation, and byte swapping between host and interface.

The new protocol software is now in beta test and looks a lot better
than the previous in terms of macro support for common functions that
vary between unix implementations.  The rlogin and telnet daemons are
now handled on the board (look like a DH driver to the host) for
performance.  I have measured 60Kby per second between my PDP11
running the front end software and a vax 11/780 running link level
mode (Excelan 204 cards in each host).  This is strictly memory-to-memory
transfers though.  Your milage may vary with disks and cpu speed.

On the topic of a VMS implementation, 
they do offer VMS and RSX support now, but only for
telnet and ftp.  The wollongong package supposedly offers mail, but
from Bary's note on using the Software Tools package, you might
be better off going with the Excelan and the Software Tools mailer.
	-tcs
	Terry Slattery	  U.S. Naval Academy	301-267-4413
	ARPA: tcs@brl-bmd     UUCP: decvax!brl-bmd!usna!tcs

ps. I don't have any connections with Excelan other than using
their products.