[Discuss] odd file permissions problem with cygwin, windows XP, and matlab

[pw]

Adam Parkin wrote:
> pw wrote:
>> Incidentally, my XP user account has administrative permissions
>> so I can't understand where matlab has a problem with any file.
>> Not that I'd want to but I should be able to load my pagefile.sys
>> into matlab and it shouldn't care, nor should XP.
> 
> This won't be particularly helpful, but pagefile.sys can't be opened by 
> any program while Windows is running as the file is repeatedly being 
> written to by the OS.

It was an exaggeration.
I was being facetious.


>> Anyway, I'm wondering if anyone has run into any related types
>> of file/directory permissions problems with cygwin or matlab
>> on XP.
> 
> I have, although not quite like you describe.  I've found that sometimes 
> Cygwin gets confused about who the owner of a file is on a NTFS-based 
> filesystem.  For example, I once moved some files around on a 
> Windows-based machine using Windows Explorer, and then in Cygwin a "ls 
> -Fl" showed the owner as "????????" IIRC.  I ended up having to do chown 
> and chmod on the files manually to fix.
> 
> I think a big part of the problem is that there is no native concept of 
> Unix like permissions (UGO and RWX) in NTFS, so there is always some 
> trickery/hackery involved in getting programs that expect Unix-like 
> permissions to work correctly in Cygwin.  Then again, I'm not hugely 
> familiar with the NTFS filesystem, so take all this with a good sized 
> grain of salt.
> 
> At any rate, I have no idea why any of this would affect Matlab the way 
> you describe.


It's rather odd. I did try chown and chmod on the files
but to no avail.

Taking ownership and resetting permissions in XP does nothing either.
I wonder if cygwin is setting/not-setting system bits that XP
uses to mark files as 'system only'.

Peter