Peter Pearson <pkpearson@nowhere.invalid> wrote:
> On Fri, 28 Sep 2018 15:01:41 +0100, Chris Green <c...@isbd.net> wrote:
> > Chris Green <c...@isbd.net> wrote:
> >> Brian Oney <brian.j.o...@googlemail.com> wrote:
> >> > Could you please try another tool like `convert'? E.g.
> >> > 
> >> > $ convert 102_PANA/P1020466.JPG test.png
> >> > 
> >> > 
> >> > What does that say?
> >> 
> >> Well, after having returned home with the laptop where this was
> >> failing and doing exactly the same thing again, it now works.  However
> >> it did take several seconds before the >>> prompt appeared.
> >> 
> >> The problem seems to be intermittent as I'm calling the function while
> >> importing images from a camera SD card and, sometimes, the import
> >> hangs but most times it works OK.
> >> 
> >> I'll see if I can see anything common to when it hangs.
> >> 
> > ... and the result is that it now hangs several images later in the
> > sequence!  It's almost as if some resource is running out.
> >
> > If I try convert on the 'problem' image it too hangs absolutely
> > solidly needing a 'kill -9'.
> >
> > After some experimentation....  OK, it's some sort of file
> > accessibility problem between the SD card and the computer:-
> >
> >   Running 'convert 102_PANA/P1020493.JPG /tmp/xyz.png' hangs
> >
> >   So 'kill -9' the convert
> >
> >   Run 'cp 102_PANA/P1020493.JPG /tmp/fred' takes several seconds but returns
> [snip]
> 
> If copying that particular file takes longer than copying other files,
> I'd start to suspect that it's stored in a failing spot in memory.  Is
> 102_PANA/P1020493.JPG being read from a camera's flash memory?  Does
> "convert" hang on /tmp/fred? Does 102_PANA/P1020493.JPG have an unusual
> size?  Can you use smartctl to ask the storage device if it's
> encountering many errors?
> 
Thanks, that sounds like a good explanation.  The SD card has been in
use for quite a while so it might have some problems.  I think I'll
retire it and see how things go.

-- 
Chris Green
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