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Path: utzoo!linus!decvax!microsoft!uw-beaver!cornell!vax135!ariel!hou5f!hou5g!hou5h!eagle!harpo!seismo!hao!pag
From: pag@hao.UUCP
Newsgroups: net.unix-wizards
Subject: Local system calls in 4.2bsd
Message-ID: <754@hao.UUCP>
Date: Tue, 6-Dec-83 20:05:28 EST
Article-I.D.: hao.754
Posted: Tue Dec  6 20:05:28 1983
Date-Received: Fri, 9-Dec-83 06:28:41 EST
Organization: High Altitude Obs./NCAR, Boulder CO
Lines: 17

In 4.1bsd, sysent[62] was "reserved for local sites".  I made mods to
4.1 to use it as local system call indirect which directs you to a
"secondary" sysent[] table (loc_sysent[]).  This method enables a site
to add local system calls without conflicting with the standard ones.
We had to do this for NCAR's custom NSC Hyperchannel network.  The
changes are pretty simple -- a minor mod to trap.c, creation of the
loc_sysent[] table, etc.  In porting this change to 4.2, I discovered
much to my dismay that sysent[62] is used for fstat, and there is no
replacement.  Since the change does need one sysent[] slot, my choice
has been to add one on at the end (151).  Is there any official policy
about this?  Why did they take away the reserved-to-local-site slot?

--peter gross
hao!pag

PS.  If anyone wants the changes, let me know.  I will either mail them,
     or if there are sufficient requests, post them to the net.