from
Jargon File (4.4.4, 14 Aug 2003)
hacked off
adj.
[analogous to `pissed off'] Said of system administrators who have
become annoyed, upset, or touchy owing to suspicions that their sites
have been or are going to be victimized by crackers, or used for
inappropriate, technically illegal, or even overtly criminal
activities. For example, having unreadable files in your home
directory called `worm', `lockpick', or `goroot' would probably be an
effective (as well as impressively obvious and stupid) way to get your
sysadmin hacked off at you.
It has been pointed out that there is precedent for this usage in U.S.
Navy slang, in which officers under discipline are sometimes said to
be "in hack" and one may speak of "hacking off the C.O.".
from
The Free On-line Dictionary of Computing (8 July 2008)
hacked off
<jargon> (Analogous to "pissed off") Said of {system
administrators} who have become annoyed, upset, or touchy
owing to suspicions that their sites have been or are going to
be victimised by {crackers}, or used for inappropriate,
technically illegal, or even overtly criminal activities. For
example, having unreadable files in your home directory called
"worm", "lockpick", or "goroot" would probably be an effective
(as well as impressively obvious and stupid) way to get your
sysadmin hacked off at you.
[{Jargon File}]
(1996-08-26)