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Re: inode open

Jason Thorpe wrote:

On Jul 17, 2008, at 9:39 AM, David Laight wrote:

In certain OS (eg RSX/11M) the lookup and open were different system
calls.  File open was always done by inode number and sequence.
(Modulo rusty brain cells!)

That's essentially how the Mac OS Carbon/CoreServices File Manager works. You call FSPathMakeRef() to get an FSRef, and then everything you do after that is done with the FSRef.

I gotta say, tho, I'm not a big fan of that API :-)

One difference to RSX is probably that in RSX, you don't need to get a reference to the file first through a lookup if you don't want to. If you know the file id, you can use it right away. It's just a plain integer. This also means that you more or less can search and open any file in the file system, even if you can't read the directory in which the file is located. So file protections in RSX is for that file only. Directories don't have any bearing on the files located in that directory any further than in order to enter/remove an entry from a directory you need read/write access to the directory file.

If people want to know more, I can run through a lot of the details on how FILES11A works. In some ways it's similar to FFS, but in others it is rather different.


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