Alan McKinnon wrote:
> I forgot the tongue-in-cheek smiley

  Oh, it's OK.

> I mentioned lilo only because it can be argued it's one of those
> things that could be dropped.

  As an OT thought, I do favor dropping LiLO.  I resisted dropping it on
my own machines only because it was working fine, I was very comfortable
with it and because I detested Grub's drive naming scheme.  After a
while LiLO was gone anyway, but then I got mad at how they made Grub2
terribly convoluted and obese.  I miss LiLO's simplicity and still
detest Grub2, but I do recognize LiLO to be a relic from the past and
suffering from inexcusable limitations to today's standards.

[...]

>>   This is an different matter.  Of course you know this does not
>> accomplish the same thing as the chattr command does: a directory
>> permissions affects *all* files inside the directory.  And using chattr
>> you have two different ways to protect a file: you can set it immutable
>> or just undeletable.  And you cannot implement an append-only or a
>> secure deletion mode on files acting on directory permissions.  All
>> these four modes are supported by ext4.
> I never intended to imply they accomplish the same thing. In
> examination you cannot cover everything, but you can cover enough
> things to give a statistically meaningful result. I've always held
> that given the choice between two possible objectives - one somewhat
> common and one very much less so - the weight should fall to the
> common one. LPI has always worked hard to avoid being seen as an exam
> that has many obscure questions in it. I feel that using lsattr is one
> of those somewhat obscure things - fine if you need it, but I would
> never expect a sysadmin to be familiar with it. I would expect him or
> her to have the entire owner/group/perms model in their head though

  Not that it changes much to the value of your observations, but I'd
like to tell what made me happy about having chattr available.

  I normally run my personal machines without any "Security option"
active, ie without SE Linux or AppArmor.  I felt secure enough with the
/usr mounted read-only.
  Then the / and /usr merge occurred, and I found myself unable to
upgrade the distribution on the Fedora machines keeping the same
filesystem layout.  I then had to put /usr and / on the same partition,
and I could no longer mount /usr ro (I now know this can still be done,
but at the time I did not know it and just got the message from the
distro upgrade command that my partitioning scheme was no longer supported).
  I still resisted switching on SE Linux, so I was content with running
chattr -R +i /usr 2> /dev/null after having put / and /usr on the same
partition and to remember to run chattr -R -i /usr 2> /dev/null before
performing updates.  After all, I still had to remount /usr read-write
before performing updates before the merge, the only difference being
that chattr takes a lot more time than a mount -o remount,ro -U ... /usr.
  The use of chattr has since spread, as it allows me to have read-only
directory subtrees of otherwise rw mountpoints, which is something I
cannot do with mount alone in a non invasive way (that is, without
abusing bind mounts and reworking by hand the distribution's filesystem
layout).
  This probably means that I got biased towards tool that is little used
outside my pen, but I'm really happy about it's simplicity and
effectiveness and think that it is undeservedly underestimated.

>>  Now that one goes right to the heart of how Unix works, and
>> a very worthy exam question.
>>   I thought LPI was about Linux, not UNIX.  Should we drop iptables
>> because other UNIXes don't have it?
> That comes across as facetious.
>
> Linux with GNU userland is at heart a Unix and for the most part sticks
> to proven Unix principles

  I am among those who think that nowadays the reverse is true.  At
EuLinuxCon2012 in Barcelona Jon Corbet, during his keynote address,
first showed a slide representing two red spots on a blank, black
screen.  That, he explained, was the situation of the Linux community a
few years ago: we were chasing taillights.  We would check out how Sun
or SGI or DEC were doing things, and we would copy their way of doing
them.  This would assure some degree of compatibility with those who
were setting the standards and who were leading the innovation.
Then he switched to the following slide, that showed a totally black
screen. And he explained that that is our situation today: there is
no-one in front of us, we are leading the pack (what's left of it) and
thus we, the Linux community, are now in charge of defining the
standards and to lead the innovation.  Linux today is the reference in
the UNIX world.

  No matter how sad it was to see Sun fade away, I thoroughly agree with
Jon: today it does not make sense any more seeing how thing are done in
the other UNIX systems to direct the future development of Linux.  Today
Linux is the UNIX trendsetter.

[...]

>>   Do you really think RCS should be in LPIC-1 or -2?
>>   Do more people use RCS than chattr?
> No, I never said that. I'm quite baffled how you concluded I might have
> meant that. Perhaps you parsed my words completely literally; I did not
> intend that

  Sorry for the misinterpretation, but the topic was about including or
excluding some specific tool and commands into LPIC-*, so I thought your
comment meant that RCS would be a better candidate than chattr for
future inclusion into some exam objective.


-- 
Alessandro Selli
Tel: 340.839.73.05
http://alessandro.route-add.net, VOIP: sip:[email protected]
Chiavi PGP/GPG keys: B7FD89FD, 4A904FD9
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