version numbers (or backups) on non-Symbolics filesystems

[David Vinayak Wallace <GUMBY@mc.lcs.mit.edu>]

    Date: Thu, 19 Nov 87 00:35:40 EST
    From: royt at pravda.gatech.edu (Roy M Turner)

    I was wondering if anyone knows of a way to get the Lisp machine to 
    make backups when writing files to a non-lispm host.  

I assume you mean unix, because the lisp machine doesn't ordinarily
worry about this -- it lets the host filesystem worry about it.
							  
							  I can get
    GNU to make backups of foo.tex of the form foo.tex.~1~, etc., but
    I don't know how to get the lispm's to do anything similar.

Gnu EMACS (GNU doesn't exist yet, but will have version numbers when
it does) does this by doing the version-number hackery when it writes
a buffer, not when it writes any file.

    Heck, I'd be content with a backup without generation numbers!

I also guess you don't use chaos, since the unix qfile server does
non-numeric backup for you.

    I'm sure that there is a simple way to do it, but I haven't found
    it so far.  Any help would be appreciated.

So, do you want a general solution, or just one for the editor?  In
order of generality and ease:

    o - Write a unix NFILE server.  This would be the best of all.
        Then you could have it hack version numbers transparently, and
        all the power of this protocol.

    o - Modify open for the unix file-access-path to, when a file is
        opened in output mode to do emacs-style rename/open-new-file
        and to link the unnamed version for you when closing.

    o - Modify the appropriate subroutine of com-write-file.  This is
        the quickest and the most likely to screw you (because it will
        only work for files written by hand in the editor).

You could also use a filesystem with version numbers.  I cannot
understand how, in this day and age, people still advocate a
filesystem which has not caught up with the 1960's.