On 04/05/10 03:25, Grant Edwards wrote:
On 2010-05-04, Charles<c.sand...@deletethis.bom.gov.au> wrote:
I don't see how it's inelegant at all. Perhaps it's
counter-intuitive if you don't understand how a Unix filesystem
works, but the underlying filesystem model is very simple, regular,
and elegant.
but probably makes some bit of the OS's job slightly easier and is
usually good enough in practice. Pragmatism is a bitch sometimes. :-)
I agree that the Unix file system is quite elegant, but can be
counter-intuitive for people who are used to the "one file, one name"
paradigm.
I guess I've been using Unix for too long (almost 30 years). I don't
think I was consciously aware of a "one file, one name" paradigm. Is
that a characteristic of Dos, Windows or Mac filesystems?
[...]
In the OP's case, references to the directory have been removed from
the file system, but his process still has the current working
directory reference to it, so it has not actually been deleted. When
he opens "../abc.txt", the OS searches the current directory for ".."
and finds the inode for /home/baz/tmp, then searches that directory
(/home/baz/tmp) for abc.txt and finds it.
Exactly. I probably should have taken the time to explain that as
well as you did. One forgets that there are a log of new Unix users
who've never been taught how the filesystem works.
actually, what i failed to grok is that whatever '..' refers to is all
that is needed to find the file 'abc.txt' *even if the current directory
has been deleted*. an absolute path just isn't needed. this has really
got nothing to do with how unix filesystems work per se or "one file,
one name", but more to do with simple reference counting. when i
mentioned in my original post how windows handles attempts to delete the
cwd differently, i should have put two and two together and figured this
all out for myself. but i don't think it's immediately obvious what the
consequences of (re)moving the cwd are, even if you've been using unix
filesystems for a while. in know for a fact that i have used several
linux programs in the past that didn't handle this possiblity
gracefully, so it's not just new users that can be caught out by this.
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