backups

[josch <josch Rcs1 urz tu-dresden de>]

Hi!

I would like to add some thoughts about backup files saved by various
programs. Often I see and hear of new users deleting their working
files in one way or another. One case was just last week: using ``save
as ...''  you get a dialog ``File exists. Really overwrite ...?''.
After ``yes'' the old file is almost always physically erased from
disk. No backup file is beeing created. This was with Word 6, but I
guess most programs work this way.  And why not?  There was a prompt,
the user had the choice. This user thought the new file would be
appended to the old one---bad idea?  Big error: four days of work gone
... with one klick.

The usual backup with ``save'' is a copy of the last version edited.

Programmers know something like a source or revision control system,
saving not only the last version of their work but the complete
history of changes done. All the versions back to ``hello world''---if
you like to.  Storage may be done in a space efficient manner (see
e.g. [1]) and disk space is no longer rare.

Wouldn't it be nice to have this feature present in user programs,
too? Maybe it could even be built into the OS: a filesystem that keeps
track of any changes for selected file-types. Of course this would
need some clever interface to access the older versions ... :-)

As Donald Norman writes: humans make errors, so design things in a way
that errors are not critical. The waste basket of the Mac was a step
in this direction but some people just use Word to delete their files
(actually they don't use any other program).

Hope this is interesting to anyone, comments welcome,

   Johannes




[1] Walter F.  Tichy, RCS--A System for Version Control,
    Software--Practice & Experience  15,  7  (July  1985), 637-654.



-- 
Johannes Sch"afer, Schweriner Str. 42, 01067 Dresden, (+351) 49 019 49
    mailto:josch@rcs.urz.tu-dresden.de