[R] save.image() issue resolved - I hope

ripley@stats.ox.ac.uk ripley at stats.ox.ac.uk
Sun Apr 14 15:00:42 CEST 2002

On Sun, 14 Apr 2002, Prof Brian D Ripley wrote:

> On Sat, 13 Apr 2002, Marc R. Feldesman wrote:
> > I've been combing through logs I keep of all my activities.  I've found a
> > possible correlation between the save.image() problem I'm having and one
> > particular event.
> >
> > My system has a rewriteable DVD drive.  I keep a 4.7 GB DVD/RW disk in the
> > E: drive and have a system scheduler synchronize the contents of the g:
> > drive with the e: drive every Friday night.  Interestingly, both times I've
> > discovered the save.image() problem have been on Saturday mornings.  I
> > discovered that if I copy the entire data directory on the g: drive to a
> > new directory on the same drive, I don't have the save.image()
> > problem.  However, if I manually synchronize the two drives (G -> E),
> > save.image() fails.  The only difference I can see between the data
> > directory *before* synchronization and *after* synchronization is that
> > synchronization "unsets" the archive bit.  If I make a new directory, the
> > "archive bit" is set and save.image() works.
> >
> > I'm not sure why this is a problem for the routines in R -- it certainly
> > doesn't seem to be a problem with other programs -- but either avoiding
> > synchronization (a straight copy also works, but copies far more than is
> > actually necessary), or manually resetting the archive bit before using R
> > seems to "solve" the problem.

I can't reproduce any problem with the archive bit manually unset.

> Renaming via the ISO C call is an unusual thing for Windows programs to
> use.  The Windows implementation is not POSIX-compliant.  I'll see if there
> are better ways to do this under Windows (but not for 1.5.0).  Sometimes
> Explorer can works with files that tools ported from Unix think are in use.

It seems that most Windows applications would use DeleteFile/MoveFile (not
unlink/rename) and Windows NT (but not 9X) supports renaming existing
files using MoveFileEx.  Looks like it would be worth exploring the latter
for 1.6.x.

Brian D. Ripley,                  ripley at stats.ox.ac.uk
Professor of Applied Statistics,  http://www.stats.ox.ac.uk/~ripley/
University of Oxford,             Tel:  +44 1865 272861 (self)
1 South Parks Road,                     +44 1865 272860 (secr)
Oxford OX1 3TG, UK                Fax:  +44 1865 272595

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