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Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!ames!pacbell!rtech!gonzo!daveb
From: daveb@gonzo.UUCP (Dave Brower)
Newsgroups: comp.unix.wizards,comp.unix.questions
Subject: Re: sockets vs. STREAMS, also intermachine networking on SV
Message-ID: <510@gonzo.UUCP>
Date: 11 Feb 89 19:25:11 GMT
References: <438@laic.UUCP> <11191@ulysses.homer.nj.att.com> <11196@ulysses.homer.nj.att.com> <506@gonzo.UUCP> <11199@ulysses.homer.nj.att.com>
Reply-To: daveb@gonzo.UUCP (Dave Brower)
Distribution: usa
Organization: Gonzo Media Group
Lines: 49

In <11199@ulysses.homer.nj.att.com> ekrell@hector.UUCP 
(Eduardo Krell) wonders:
>In article <506@gonzo.UUCP> daveb@gonzo.UUCP (Dave Brower) writes:
>
>>The main reason you want a
>>stream pipe is so you can use poll() in your server, which is supposed
>>to pay attention to a number of connected clients. Now SVR3 has no
>>generically supported method for doing this as far as I can tell. 
>
>I don't understand your question. The poll() system call in SVR3 works
>like BSD's select() except that you can only apply it to STREAMS
>file descriptors. A file descriptor obtained by opening a (full
>duplex) connection through /dev/spx IS a STREAMS file descriptor.

I understand that fine, but it is not the issue.

The point is that generic SVR3 does not, by default, contain a usable
local IPC mechanism for use by a server supporting multiple simultaneous
connections.  

You only have a workable system for _local_ IPC if the system happens to
have TLI and a _networking_ device.  Both are optional, and the latter
often comes from a third party vendor.  And you probably pay a real
performance penalty going through all the networking code that you
really don't need.  There are no documented local stream devices,
despite the /dev/tivc so prominantly displayed in the "Network
Programmer's Guide."

/dev/spx isn't a documented, supported device you can count on having
around, and it has some severe limitations if it is available.  You need
to run your server as root and can only get 255 channels open at the
same time.  

On a stripped system the only choice is /dev/spx, which is a kludge. And
if it's really stripped (no/dev/spx), then you seem to be SOL.  And it's
reasonable to drop spx becuase it is only supposed to be used by RFS,
and without networking, why carry it around?

All of which is a rude awakening when you start looking at the reality
of the available SVR3 environments.  Despite the license flap, you can't
count on being able to get there from here.

Heck, even AIX has had usable sockets for a year or so.

Frustratedly,
-dB
-- 
"Godot will have SVR4 when he comes."	- Estragon
{sun,mtxinu,amdahl,hoptoad}!rtech!gonzo!daveb	daveb@gonzo.uucp