Re: Platform portable support of heir. file systems

["Tarjei T. Jensen" <tarjei@online.no>]

Larry Kilgallen wrote:
> 
> On VMS:
> 
>         Directories can only be nested 8 deep or so if you want
>         the files they contain to be backed up.
> 
>         Directories cannot be removed until all their contents
>         are removed, regardless of how much privilege you have.
> 
>         Directories are always created with nobody having delete
>         permission, regardless of what the caller specifies (this
>         is independent of the previous rule).
> 
>         Directories have a "version limit" attribute which
>         would logically be set by a creator to get a desired
>         behaviour, even if only to override the default for
>         the default of inheriting from the parent.
> 
>         The directory from which you read might be different from
>         the directory to which you write, given identical
specifications,
>         if the device specified is a rooted directory rather than
a
>         real device.  (Come to think of it, Unix users creating a
>         directory don't even specify the device separately, do
they>?)
> 
> I am certain that other operating systems have quirks as well,
> especially when one gets into permissible name lengths and
> character sets (which are _not_ necessarily the same as for
files).
> 
> A common package for directory manipulation would not seem to be
> very "portable" if the rules differ on each operating system.


Don't be silly!
Exactly this behaviour would be very nice to encapsulate. Much of
what
you think is VMS specific is specific to other operating systems.

Regardless of what is the underlying operating system it is a
general
requirement for some file maintenance primitives. That is why they
appear
in the standard C library. If C programmers think these things
important
then I'm pretty confident that Ada programmers want the same
facilities.

It is trivial to construct a set of primitives that easily can cope
with
file systems of the most common operating systems (I have a paper
somewhere around here on this theme). The point is not to capture all
the
fine points, but enough to keep the programmers comfortable.

Greetings,