[Oberon] filesystem with directories ?
chris at gcjd.de-web.ws
Mon May 1 13:36:11 CEST 2006
p.provoost at rn.rabobank.nl wrote:
>And of course the directories are a must when the number of files
>increases. In the days that Oberon fitted on a floppy disk, one
>root-direcotry was fine. But now that it is about 100 MB with hundreds
>of files, I think the time has come to use a more sophisticated file
Probably yes, but I don't think that reimplementing the current Unix
trends results in a good solution.
I think common hierarchical file systems (hfs) are not a good idea at
all. (I don't know what reasons Wirth and the other implementors of
I try to explain:
The identity of a file has to be defined. In the Oberon file system
(ofs) a file is either a object (pointer) or, if named, it has unique
persistent identity by its name. That's well defined. In a hfs the name
is not unique and thinking of Unix style fs a thing named path comes
up. Is the path part of the name or not? Is a move to another place in
the tree of the hfs a rename operation or a create-new/copy/delete-old
operation resulting in a new file?
The idea of a path is problematic beacuse a path is very fragile.
Renaming/moving an upper level directory breaks the access path to all
childs. Unpleasant UI is also a result.
The large picture in my opinion is that current hfs are
fundamentally flawed. All common filesystems are simple hfs,
where everything is organized as a simple acyclic (or not so acyclic)
directed tree. The only relation that can be expressed is
is-subordinate-to. If there are Users, Data, Applications it's not
obvious what is subordinate to what in different environments like
personal-single-user or multi-user-managed or else. The real relations
cannot be expressed but must be artificially made hierarchic and that
creates lots of problems. I believe that adding more
fixes/conventions/meta-tools above the hfs only make things
more complicated and worse.
The cure to this problem which occurs in many parts of current OS's is a
really new filesystem with a richer set of relations. I believe (only)
this will get us to the next step in usability. Then it would be
possible for example that moving an Application includes all Data
related to the Application and at the same time all Data from one User
is contained in one place. Backups would be much more pleasant to
Essentially I think one needs a kind of well designed database to handle
and organize lots of files.
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