Difference between "Junction points" and "Hard Links" ?

C

Carla Lacrosse

What is the difference between Junction points and Hard Links?

I have read a couple of articles about them but it does not become clear.

Are the following statements correct?

1.) Junction Points and Hard Links can both point to files AND folders

2.) Deleting the target file or folder of a Junction Point makes the "second" reference unusable
Deleting the target file or folder of a Hard Link let the "second" reference still full alive/exist

3.) Permissions, attributes for Junction Points and originals can be different
Permissions, attributes for Hard Links and originals are always the same

Can someone confirm these statements?

Carla
 
P

Pegasus \(MVP\)

Carla Lacrosse said:
What is the difference between Junction points and Hard Links?

I have read a couple of articles about them but it does not become clear.

Are the following statements correct?

1.) Junction Points and Hard Links can both point to files AND folders

2.) Deleting the target file or folder of a Junction Point makes the
"second" reference unusable
Deleting the target file or folder of a Hard Link let the "second"
reference still full alive/exist

3.) Permissions, attributes for Junction Points and originals can be
different
Permissions, attributes for Hard Links and originals are always the
same

Can someone confirm these statements?

Carla

You can easily find the answers to your questions by trial and error. An
overall comment might be in order:
- The command
linkd e:\w c:\Windows
creates a junction point e:\W which reflects the folder structure of
c:\Windows. This is useful when some application expects to find its files
in a location other than the physical location.

- When you create a hard link then you create a second (and perhaps a third
and a fourth) entry in the directory list(s) of a partition. Since hard
links are indistinguishable from the real thing, they can cause an
administrative nightmare: You might delete a large file, yet the disk space
it consumed it not released - because it is held by a second or third hard
link in a different folder under a different name.
 
P

Pegasus \(MVP\)

Carla Lacrosse said:
What is the difference between Junction points and Hard Links?

I have read a couple of articles about them but it does not become clear.

Are the following statements correct?

1.) Junction Points and Hard Links can both point to files AND folders

2.) Deleting the target file or folder of a Junction Point makes the
"second" reference unusable
Deleting the target file or folder of a Hard Link let the "second"
reference still full alive/exist

3.) Permissions, attributes for Junction Points and originals can be
different
Permissions, attributes for Hard Links and originals are always the
same

Can someone confirm these statements?

Carla

You can easily find the answers to your questions by trial and error. An
overall comment might be in order:
- The command
linkd e:\w c:\Windows
creates a junction point e:\W which reflects the folder structure of
c:\Windows. This is useful when some application expects to find its files
in a location other than the physical location.

- When you create a hard link then you create a second (and perhaps a third
and a fourth) entry in the directory list(s) of a partition. Since hard
links are indistinguishable from the real thing, they can cause an
administrative nightmare: You might delete a large file, yet the disk space
it consumed it not released - because it is held by a second or third hard
link in a different folder under a different name.
 
V

VanguardLH

Carla said:
What is the difference between Junction points and Hard Links?

I have read a couple of articles about them but it does not become clear.

Are the following statements correct?

1.) Junction Points and Hard Links can both point to files AND folders

2.) Deleting the target file or folder of a Junction Point makes the "second" reference unusable
Deleting the target file or folder of a Hard Link let the "second" reference still full alive/exist

3.) Permissions, attributes for Junction Points and originals can be different
Permissions, attributes for Hard Links and originals are always the same

Can someone confirm these statements?

Note: Inappropriate use of FollowUp-To header was ignored. If you
cross-post to multiple groups then you decided your post was on-topic to
all of them and they were related to your post. Don't be rude by
stealing away the discussion from there. Original newsgroups list
restored in my reply.


Regarding your question(s), see:
http://www.rekenwonder.com/linkmagic.htm#Junction Link
http://www.microsoft.com/technet/prodtechnol/windows2000serv/reskit/core/fncc_fil_wmkc.mspx?mfr=true
http://support.microsoft.com/kb/205524
http://en.wikipedia.org/wiki/NTFS_reparse_point
http://en.wikipedia.org/wiki/NTFS_junction_point
http://en.wikipedia.org/wiki/Symbolic_link
http://en.wikipedia.org/wiki/Hard_link


Regarding the use of FollowUp-To header:
<rant>
Don't use the FollowUp-To header. Posting to, say, 3 newsgroups but
moving replies to just 1 of them or to a completely different one means
you disconnect the visitors of those other 2 (or 3) newsgroups from the
rest of the discussion. If a newsgroup is appropriate for your post
then it is also appropriate for the replies. Or, converserly, if the
continued discussion of your post is not appropriate in all the
newsgroups to which you cross-posted then you should not have posted to
those other newsgroups in the first place. You are using the
FollowUp-To header to move replies to YOUR "home" newsgroup but which
the users of the other newsgroups may not visit. After all, if you
cross-post and include your "home" newsgroup then you'll see all those
replies in your home newsgroup and meanwhile all the other users can
still see the replies in their newsgroup where you decided to also
publish your post.

In http://www.faqs.org/faqs/usenet/primer/part1/, it says, "For a
cross-post, you may want to set the Followup-To: header line to the most
suitable group for the rest of the discussion". Read another way, that
means you disconnect the discussion from all the visitors of the other
newsgroups to which you decided to publish your post. Why did you
publish to those other newsgroups if you are going to yank the
discussion away from those users and perhaps even from the respondents
you were attempting to elicit? It is exasperating to post a reply and
never see it in the newsgroup where you read the original post. If your
post was appropriate for all the groups to which you cross-posted then
why wouldn't those same groups be appropriate for the replies? To yank
away the discussion to your "home" group is rude since that is probably
not the "home" group for your respondents. You wanted replies which may
require further replies but now your respondents no longer see the
thread in the newsgroup that they visit to where you published your
post. Also, the respondents may not know if their reply is appropriate
in the "home" group that you happen to choose. In general, malcontents
and spammers use the FollowUp-To header to hide negative replies to
their flame or spam posts, often sending the replies off to a *.test
newsgroup. Is that the company of users to which you want to be
associated?

There are some cases where FollowUp-To should be used. For example, say
a newsgroup is supposed to only get used for citing the content of a
spam e-mail. Discussions about that spam are not supposed to be
published in that citing newsgroup. Just the exhibits are published
there. If someone wants to discuss that particular spam, their replies
should go into a different newsgroup meant for those discussions. I
believe that is how some of the NANAE newsgroups operate but the
principle may apply elsewhere; however, it is rare few newsgroups where
FollowUp-To is appropriate. For the vast majority of newsgroups,
FollowUp-To is *not* appropriate. If you do not want continue the
discussion in the other newsgroups then don't cross-post over there to
only then use FollowUp-To to yank away the continued discussion. If the
discussion is not appropriate in those other newsgroups then it seems
you have self-nominated your post to be off-topic and hence spam.

If you do use the FollowUp-To header, you are expected per netiquette to
alert the readers of your post that you used that header. Be polite and
add a note (at the start of your post) saying that you used the header
(ex., "WARNING: FollowUp-To was used and points to <newsgroup>". You
might also want to explain why you consider any further discussion in
the other newsgroups is inappropriate despite your rudeness in posting
to those other newsgroups. Many times respondents wonder where their
reply post went because they expect to see it in the group they visited
and where they read your post. Not all NNTP clients alert the user that
the poster used the FollowUp-To header. Think about it: you post to
multiple newsgroups but yank the replies to a different newsgroup than
where your respondents visited, then you need more help and reply to
those replies but which are now only in your "home" newsgroup, but the
respondents won't see their posts nor will they see your replies to them
asking for more help. FollowUp-To is not required when you cross-post
since your "home" newsgroup should be one those that were specified in
the list of newsgroups. You'll watch the discussion in your home
newsgroup and the respondents or lurkers can watch that same discussion
in their own newsgroup. If you don't want replies to show up in all the
newsgroups to which you cross-posted then don't cross-post over there in
the first place!

When crossposting, there are not multiple copies of your post that
wastes bandwidth for each to get them propagated to other NNTP servers
and there aren't multiple copies of your post consuming disk space. A
single copy gets sent to the other NNTP servers and a single copy
resides on each NNTP server with pointers to it to make it show up in
multiple newsgroups. You aren't saving bandwidth or disk space by
redirecting replies for a cross-posted message to a single newsgroup.
You are just being rude to the visitors of the other newsgroups to which
you cross-posted but tried to yank away the discussion.
</rant>
 

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