brent timothy saner on 10 Feb 2009 22:42:03 -0800

[Date Prev] [Date Next] [Thread Prev] [Thread Next] [Date Index] [Thread Index]

Re: [PLUG] OT (but not really): Tough Interview questions

Hash: SHA1

Mag Gam wrote:

> For instance, I had a client as me over the telephone:
> What is ELF and how does it differ from other formats?  -- Unix related position

forgot what it was an acronym for but i knew it's the standard binary
format these days. i know it replaces a.out but i have no clue how they
differ. shout look into that...

> What is kept in a journal of a journalized file system? -- Unix related position

knew this one by heart. :) journal keeps track of changes to prevent
data corruption/loss. also deprecates needing to run 3 or 5 "sync"
commands before shutting down since it tracks writes made and writes to
be made.

> What is a poll and select? -- UNIX related position

this i didn't know. but i think it's more dev-related than sysadmin
related (i'm a sysadmin).

> I consider these fairly tough questions -- what do you think?

seem pretty good questions to me.

> Just curious what are some other ridiculous questions you faced -- I
> am not talking about brain teasers or behavioral type questions...

back when i was really green, octal modes threw me; especially uncommon
ones (like 0314 - i now know that it's --wx--xr-- right away but that's
because i bothered to sit down and learn the octals. not so scary once
you learn them. and granted, that's a pretty useless and ridiculous set
of permissions, but it's definitely going to be the make-or-break-it to
see if someone really knows modes or if they just know the more common
ones like 0755/0644, etc.)

another good ones to ask prospective sysadmins is how to search kernels
for a particular component and to see if it's enabled or not. as always
in *NIX, there are lots of different ways:

1. if you're lucky enough to have the config.gz option enabled in the
kernel, zgrep -iHn <COMPONENT> /proc/config.gz suffices QUITE nicely.
(the config.gz may also be in /boot depending on the distro)

2. if it's already been compiled, good chance you can do grep -iHn
<COMPONENT> /usr/src/<KERNEL-VERSION>/.config

3. if it's a new kernel you're setting up, you can hit / in menuconfig
and search for the component that way- nice thing about this method is
it tells you which menu section it's in and if it's enabled, disabled, a
module, etc.

oh, here's a trick question:
what will   echo "/dev/null" > /proc/sys/kernel/modprobe   do?

(correct answer: unleash horsemen of the apocalypse. don't do this, it's

aside from that, there's not a lot of sysadmin-y questions you can ask-
most of that is through practice, task, and method (which is why most
linux certs such as RHEL certification rely on tasks rather than quizzing).
Version: GnuPG v2.0.9 (GNU/Linux)
Comment: Using GnuPG with Mozilla -

Philadelphia Linux Users Group         --
Announcements -
General Discussion  --