Re: Extensions to HFS filesystem

Albert Cahalan (
Wed, 1 May 1996 14:09:43 -0400 (EDT)

>> The umsdos filesystem is severely broken. There are very few times
>> that a symbolic link is not equivalent to a hard link. You don't
>> even need hard links on the root partition. You could have the system
>> call return an error or make a symbolic link (a mount option?), but
>> please don't try to pretend that hard links exist when they don't.
> No choice at all! Many utilities use hard link. passwd for one and few
> other. patch for another. Even if those hard links are not permanent,
> they still are needed. A umsdos based linux system would have been
> impossible without it.

Not at all. Perhaps passwd and patch use hard links, but they don't
really _need_ to. It's not going to be a POSIX filesystem anyway,
maybe it can be stable.

> The real problem of the hard link of umsdos is that some hidden files
> remains in directory, often preventing the removal of the says directory.
> No the emulation of umsdos is not perfect, yet it allows fair operation
> of linux and very easy installation.

How can you think it allows fair operation if you get hidden files
that prevent removal of directories? That's severely broken!

Better to just live without hard links. We need to get used to the
idea that hard links may be impossible, because they often are.
The hfs design sounds fast - it would be slower if it couldn't store
some blocks in the directory entries.

It's not POSIX if you don't have hard links. Oh well.
It's not usable or safe if a user can make a directory get "stuck".
This "hard link" emulation reminds me of flock().