I'd wager probably more people today don't know what the TERM
environment variable really does than do (yes, everyone who used to
use ed over a 300-baud acoustic-coupler is laughing, but times have
changed!).
I recently got hit by what was, at the time, a strange bug.
Consider the following trivial Python program, that uses curses and
issues the "hide the cursor" command.
$ cat curses.py
import curses
curses.initscr()
curses.curs_set(0)
curses.nocbreak()
curses.echo()
curses.endwin()
If you run it in your xterm or linux console, nothing should
happen. But change your TERM to
vt102 and it won't work:
$ TERM=vt102 python ./test.py
Traceback (most recent call last):test-curses.py
File "./test-curses.py", line 5, in <module>
curses.curs_set(0)
_curses.error: curs_set() returned ERR
(obvious when you explicitly reset the term, no so obvious when
some script is doing it behind your back -- as I can attest!) So,
what really happened there? The
curs_set man page gives us
the first clue:
curs_set returns the previous cursor state, or ERR if the requested visibility is not supported.
How do we know if visibility is supported? For that, curses
consults the
terminfo library. This is a giant database
streching back to the dawn of time that says what certain terminals
are capable of, and how to get them to do whatever it is you want them
to do. So the
TERM environment variable tells the terminfo
libraries what database to use (see
/usr/share/terminfo/*)
when reporting features to people who ask, such as
ncurses.
man 5 terminfo tells us:
cursor_invisible civis vi make cursor invisible
So curses is asking terminfo how to make the cursor invisible, and
getting back "that's not possible here", and hence throwing our
error.
But how can a person tell if their current terminal supports this
feature?
infocmp will echo out the features and what escape
codes are used to access them. So we can check easily:
$ echo $TERM
xterm
$ infocmp grep civis
bel=^G, blink=\E[5m, bold=\E[1m, cbt=\E[Z, civis=\E[?25l,
$ TERM=vt102 infocmp grep civis
$
So we can now clearly see that the
vt102 terminal doesn't
support
civis, and hence has no way to make the cursor
invisible; hence the error code.
If you're ever looking for a good read, check out the
termcap/terminfo
master file. The comments are like a little slice of the history
of computing!
Contratulations to Bob Finch and Nathan Dalrymple for becoming our
first customers to fly a rocket using a
TeleMetrum
board last Saturday! The rocket was Nathan's stretched BSD Horizon flying on a
CTI Pro29 6xl 305-H226-14A Skidmark motor as shown in
this launch photo.
I met both Bob and Nathan at the monthly club launch run by the
Albuquerque Rocket Society at the same site in
Rio Rancho, NM, earlier this year. That was the day I flew my
first test flight
with on-board GPS. They got excited about what they saw, and became two of
our first customers for production boards.
Other than some rough edges with our first-generation ground software, Bob
reported that everything worked as expected, and the GPS location received
in the downlink got them to within about 10 feet of where the rocket set down.
In communicating their success to us on IRC, Bob said "MANY thanks to you guys,
not only for the product but also for all the help getting me to the point of
being able to use it !!". The pleasure is all ours, though, because after
Bob asked us lots of new-user questions online, he wrote up his notes for us
as "documentation for mere mortals" that will soon form the basis of a
"getting started" section in our user manual.
Pretty cool stuff!
So. I was wondering, which nice distro specific tools do exist in debian/gnome or in $other/kde that debian/kde is missing?
We have 
If anybody is interested or can attend: Tomorrow and the day after (Wednesday and Thursday 12-13/05/2010) 
Just uploaded tomoyo-tools and is waiting in the NEW queue.Thanks to Moritz Muehlenhoff, tomoyo kernel support should be available in Debian with kernel 2.6.32-13 and above.
Weeks ago, I was at a TravelWatchSW meeting in Taunton for 
Zoe's a week old today. As such things tend to do, this feels like both an
eternity and no time at all.
We've been back to the paediatrician twice since I last blogged. Zoe's
weight is now on the increase again. Today she weighed in at 6 lbs 3 oz
(2806 grams) (I think. My brain has gone a bit fuzzy)
We're largely sticking with bottle feeding pumped breast milk for now.
Apparently 7 lbs is the magic size where they've got enough strength to feed
exclusively at the breast.
Sleep-wise, I think we're all doing reasonably well. Zoe just eats, sleeps
and poops. Sometimes we need to wake her up to have a feed. I think the
longest we've let her got is 4.5 hours. She's taking a lot of milk at each
feeding session - up to 90 mL, so I expect that she'll have blasted past her
birth weight by the time she's two weeks old.
It'll be good when she's exclusively breastfeeding. The current regime is a
little bit tiring. Zoe wakes up (or gets woken up). I change her diaper and
give her a bottle. Sarah tries a little bit of breastfeeding. I put Zoe back
in her crib. Sarah pumps some milk for the next feeding session, and I go
and wash and sterilise bottles and pumping paraphernalia.
If Zoe's feeding every three hours, this only really gives us two hours to
get anything else done.
Not that I'm complaining, mind you. At the paediatrician's this morning,
there was another father with the same LPCH diaper bag that we'd received
while we were in the hospital. Turned out he had a two-week old boy. I asked
how the sleep levels were going, and he exclaimed about how they were only
getting 2.5 hours at a time, and his son would raise the roof. I mentioned
the 4.5 hour stint that we'd managed to have, and he was totally gobsmacked.
In other news, it seems like Sarah has a bit of UTI, which has totally wiped
her out this afternoon. She got a 3 day course of antibiotics this
afternoon, so hopefully that'll fix her up.
I'm happy to conclude quoting the acknowledgments section of the
paper:
Acknowledgments
I just updated the software at 
Italian
the usual short overview about my RC bug activities:
