Path: utzoo!utgpu!news-server.csri.toronto.edu!rutgers!ucsd!swrinde!zaphod.mps.ohio-state.edu!samsung!munnari.oz.au!metro!natmlab.dap.csiro.au!megadata!andrew
From: andrew@megadata.mega.oz.au (Andrew McRae)
Newsgroups: comp.protocols.tcp-ip
Subject: Re: sockets vs. streams
Summary: User mode file systems?
Message-ID: <339@megadata.mega.oz.au>
Date: 5 Sep 90 14:03:43 GMT
References: <6964@milton.u.washington.edu> <2350@cirrusl.UUCP> <1990Sep5.020521.803@mlb.semi.harris.com>
Organization: Megadata P/L, North Ryde, Sydney, Aust.
Lines: 56

In article <1990Sep5.020521.803@mlb.semi.harris.com>, del@thrush.mlb.semi.harris.com (Don Lewis) writes:
>In article <2350@cirrusl.UUCP> dhesi%cirrusl@oliveb.ATC.olivetti.com (Rahul Dhesi) writes:
>>In <6964@milton.u.washington.edu> mrc@Tomobiki-Cho.CAC.Washington.EDU
>>(Mark Crispin) writes:
>>
>>>If I want to connect to port 0.143 on host 128.95.112.69, why can't I
>>>do something like
>>>  open ("/tcp/128.95.112.69-0.143",O_RDWR|O_CREAT,0);...
>
>Now, if the printer is on a terminal server somewhere, it would
>sure would be nice to be able to do the same sort of thing.
>	cat somefile >/dev/tcp/terminalserver:port

Perhaps a more structured approach to this whole problem is
to back out of the kernel altogether and use the same
paradigm as in some of the Research Unix kernels of a
user mode file system (a la the /proc filesystem); using a
UMFS would remove the complexity of mapping different
file names to network address away from the kernel into
user processes which could then use the BSD socket style
kernel calls to hide the messy details of network programming.

At least then the programs which want to access all those
neato network calls can do so, but for those programs that
want to open the network connection using a file name the
UMFS would then interpret the name accordingly. Then different
servers could be implemented to handle different protocols,
and services e.g.:

        fd = open("/dev/net/stream/cpu.xyz/lat", 2);

This could map to an entirely different protocol family (e.g. DECNet).

 or
        fd = open("/dev/net/tcp/2300/192.34.56.78", 2);

Links could be set up to map "/dev/net/printer" to
"/dev/net/tcp/termserver/printer"...

It should be easy to take skeleton UMFS network servers and
build specialised services (such as a nntp-service file etc.).
A mach-like kernel with good messaging may fit well here..

Whilst the comment that has been made that what most processes
want is a simple full duplex pipe-like stream (and the kind
of open that has been talked about will work OK), I find the more
common network programming I am involved with is using the
datagram facilities (sendto, recvfrom etc) to build distributed
services (especially real time stuff); using broadcasts and
finding out who sent you a data packet is important as well. I
hate to think what I would have to do if all I had was a read or write.

Andrew McRae			inet:	andrew@megadata.mega.oz.au
Megadata Pty Ltd,		uucp:	..!uunet!megadata.mega.oz.au!andrew
North Ryde  2113		Phone:	+61 2 805 0899
NSW    AUSTRALIA		Fax:	+61 2 887 4847