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From: jqj@GVAX.CS.CORNELL.EDU.UUCP
Newsgroups: mod.protocols
Subject: Re: Submission for mod-protocols
Message-ID: <8702202111.AA09598@gvax.cs.cornell.edu>
Date: Fri, 20-Feb-87 16:11:29 EST
Article-I.D.: gvax.8702202111.AA09598
Posted: Fri Feb 20 16:11:29 1987
Date-Received: Sat, 21-Feb-87 10:32:35 EST
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Reply-To: jqj@gvax.cs.cornell.edu.cs.cornell.edu (J Q Johnson)
Organization: Cornell Univ. CS Dept. Ithaca NY
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Approved: protocols@red.rutgers.edu

A request for information on Xerox Courier and publicly available
implementations appeared recently on this news group.

It should first be noted that very few compatible implementations of Courier
and the Xerox applications protocols that use it exist.  Most of the Xerox
implementations (for XDE, ViewPoint, Cedar, and Interlisp) interoperate, but
even there there are some incompatibilities.  3Com has an implementation
which interoperates at the Courier level, but not at the applications level;
for example, they use different Clearinghouse properties.  Last I checked,
Fusion's XNS protocol suite was Xerox-compatible at the SPP level but not at
the Courier level.

One non-commercial, but publicly available, implementation of the Courier
protocols is the Cornell xnscourier suite distributed as part of the
"user contributed" software for 4.3BSD.  It is designed to interoperate with
Xerox implementations, especially with the XDE implementation.

The suite includes a stub compiler which takes descriptions in the
Courier language and generates C client and server stubs, a fairly
large runtime library for common dataconversion and applications
problems (e.g. almost all Xerox uses of Courier require dynamic binding
to a network address based on a Clearinghouse name, so the library
includes routines that find a Clearinghouse, use it to translate from a
string to network address, generate the appropriate authentication,
etc.).  Also, the library includes sample applications using some of
the public Xerox protocols layered on Courier:  remote terminal
emulation client and server (GAP protocol), file transfer client
(Filing protocol; a file transfer server is coming soon), printing
client so you can send your Interpress masters to a Xerox printer, and
so on.

The package runs on 4.3BSD on VAXes and UTX 2.0 on Goulds.  I have not
tested it on SUNs, but believe that it would run there with little
problem (requiring currently undistributed SUN XNS kernel support).
For further information on the UNIX Courier package, send me mail.

	jqj@systems.cs.cornell.edu
	jqj@cornell.arpa
	cornell!jqj
	jqj@crnlcs.bitnet