My suggestion is to just try some ideas in your own image and see
if it's something you want to live with. The intentions are good but
I have a feeling that this is the kind of thing where the inintended
side effects are worse than the problem to be solved.

In my own experience, I have encountered an IO error while saving
the image several times over the years. In every case, the cause has
been a file system full condition. A solution that uses more disc
space would not have been helpful.

Tim mentions using OSProcess, so you can try something based on
"UnixProcess saveImageInBackground" if you want.

Dave

On Thu, Jan 30, 2020 at 12:13:27PM +0000, Thiede, Christoph wrote:
> Hi all!
> 
> 
> > On configurations where overwrite-by-rename is a problem, perhaps an alternate of "copy the existing image to a *.bak file" would work?
> 
> 
> <http://www.hpi.de/>
> Compared to overwrite-by-rename, this proposal would double the storage effort. Provided that I understand you correctly, -1 :-)
> 
> > On configurations where overwrite-by-rename is a problem, perhaps an alternate of "copy the existing image to a *.bak file" would work?
> 
> What would you like to do with this backup file? Keep them permanently? As we speak about hundreds-of-megabytes file sizes, I think this could be quite storage extensive ... Also, it messes up your image folder. We already have two files for each image: .image and .changes. No need for even more files, imho. But there may always be some special application areas, of course :)
> 
> +1 for making a preference for it :-)
> However, my personal flavor would be to rule this behavior via the Squeak.ini file (not sure what's the equivalent on other host platforms), so I would prefer to store this preference image-invariant.
> 
> VM support: What would be the pros and cons of implementing this in the VM?
> First, I don't know whether we already support a way to read the Squeak.ini file from within the image (see above)?
> Second, I *could* imagine (though this is spoken hypothetically) that certain host systems might provide convenient ways for implementing overwrite-by-rename. See my initial mail for my worries about a naive implementation. Again, wouldn't this be an argument for implementing this rather at VM side?
> 
> Ad validation: Sounds interesting! How high would be the effort for that? Could you do this from within the VM (it's also a question of performance, I guess)? Wouldn't this double the store time? Maybe it would be a good idea to have a second (VM) preference for toggling validation.
> 
> Best,
> Christoph
> ________________________________
> Von: Squeak-dev <squeak-dev-bounces at lists.squeakfoundation.org> im Auftrag von tim Rowledge <tim at rowledge.org>
> Gesendet: Mittwoch, 29. Januar 2020 22:05:07
> An: The general-purpose Squeak developers list
> Betreff: Re: [squeak-dev] Image damaged due to IO error while saving
> 
> 
> 
> > On 2020-01-29, at 12:24 PM, Tony Garnock-Jones <tonyg at leastfixedpoint.com> wrote:
> >
> > Oh, I see, so it's probably something that can be arranged entirely
> > image-side, no VM support needed. Right?
> 
> Pretty sure it could be done without VM support, yes. One might even use the OSProcess forking trick to do it, I think.
> 
> > ... it'd be a Preference, I suppose?
> Yet another ...
> 
> 
> tim
> --
> tim Rowledge; tim at rowledge.org; http://www.rowledge.org/tim
> "How many Kdatlyno does it take to change a lightbulb??
> "None. It sounds perfectly OK to them."
> 
> 
> 
> 

>