[geeks] Versioning FIlesystem

[David A de Gruyl]

* on [03-05-24 05:28] Mike Meredith wrote:
>On Friday 23 May 2003 22:34, Jonathan C. Patschke wrote:
>> Because if you used /, -every- userland program would need to know how
>> to tell the difference between a versioned ordinary file and a
>> directory.

>*Every* one ? Most just try and open a file and read/write to it. They rely on 
>the kernel/system library to prevent them doing something dumb with something 
>that isn't a file.

>Of course with a severe head cold, I could be missing something obvious.

Completion.  As many shells and userland programs will select files via 
picklist or completion, the files that people will have to select will 
be directories.  Very confusing.  

But if readdir and open etc. handle this correctly, then the userland 
stuff should be mollified.  But accessing the file would have an odd 
feeling from the shell. And you would either always or never be able to 
look through the versioning information to find the appropriate version 
-- no current version or only current version.

Part of the problem is that directory entries are either directories or 
files (or other things) but cannot be both.  So you can have a 
filesystem that accesses .../file as if it is .../file/0 but if you try 
to open the directory .../file/ you will get .../file/0 because the 
method of accessing them is the same. 

David

-- 
David de Gruyl <david at bhaermandegruyl.org>
Princeton(ish), NJ