Thursday, April 28, 2005

An ad lib card game

Rules? We don't need no stinkin' rules!

1000 blank white cards appears to be a free-form card game inspired (loosely) by Uno and others. Not only do you invent your own cards, you can do so continually while playing. Indeed, as there are no additional rules, the cards themselves define the game. Many of the existing cards that others have invented appear to increase or decrease your "score" (but none affect the number of cards that you hold; getting rid of all of your cards does not appear to be an objective either).

Perhaps "toy" is a better word than "game", there not even being a defined objective. I must find some people to try this with some time.

(via mefi)

The Electronic Scrolling LED Belt Buckle

Apparently it's for real. Now you can add to the information overload suffered by your friends, family and colleagues: complement the scrolling text messages in pharmacy windows, on bus shelters and in museum foyers with still more messages on your own belt buckle.

Most peculiar. Perhaps there's a market for selling advertising space on people's bodies.

Sunday, April 17, 2005

An Audioblogging Manifesto

Maciej Ceglowski makes the case for audioblogging (transcript), sort of.

Just yesterday I started experimenting with a script to do just this :-)

Link via JWZ.

Thursday, April 14, 2005

Selectively (per-host) ignoring host keys for ssh

Out of the box, the openssh client records (and on subsequent connection attempts, checks for equivalence) the keys of any hosts that it communicates with. If you have (as I do) a development environment in which a test device with a fixed name and IP address is frequently being rebuilt from scratch and is being permitted to regenerate its own ssh host keys (the self-build procedure is part of what is being checked), then you are forever faced with ssh bitching about a changed host key. It is not immediately obvious to me how best to cope with this, but adding the following to my ~/.ssh/config solved my problem:
Host linz
StrictHostKeyChecking no
UserKnownHostsFile /dev/null
Note that this only applies to a specific host, not to all (!). Setting StrictHostKeyChecking to "no" means that, upon encountering a new key, it will just accept and record it without asking. Setting UserKnownHostsFile to "/dev/null" means that it will never find a different existing key about which to complain and that it will never successfully store such a key in the first place.

Wednesday, April 13, 2005

National Day of Reason

For those Americans who feel that a National Day of Prayer is a little unreasonable, a
National Day of Reason is being held, on the same day!

Google Talk aka Monkeys

When I was an engineering undergraduate, I had an assignment to take a body of text and produce from it another body of text with a comparable distribution of three-word passages. It generated some interesting gibberish and was referred to as the Mokees assignment (an infinite number of monkeys at an infinite number of typewriters would, eventually, produce Hamlet; or so the popular thinking runs).

Well, Douwe Osinga has realised that you can do the very same thing with Google. Rather than starting with a randomly selected triplet from Google's index (Google provides no means to do this), simply provide three words as a seed and this page will add next words one at a time, apparently by searching Google for the trailing triplet and then appending the word immediately following the triplet in the first result.

It appears to stop after 9 or 10 iterations. "beginning of the" yielded "beginning of the week and the Olympic Review. OLYMPIC News l. did". "George Bush is" yielded "George Bush is a Liar, He s NOT selling out? it s the End of the World" before turning incoherent.

Monday, April 11, 2005

How to be creative

Hugh MacLeod put together a swath of thoughts on allowing one's creative drives to operate (indeed, to benefit by it); I've finally gotten around to reading it and enjoyed it. Lots of ideas to chew over, and I suspect worth a periodic revisit.

gapingvoid: how to be creative (long version)

The Sound of Silence

Protective and surveillance devices aren't much use when they're not turned on or not connected (or, for any other reason, not recording).

Mystery surrounds empty black box in Afghan air crash. 10/04/2005. ABC News Online: "'Due to technical errors the flight data recorder had nothing recorded,' Afghan defence ministry spokesman Mohammed Zahir Azimi said.

The second black box - the cockpit voice recorder, which records the conversation between the pilot and the air control tower, was never found.


'The device had no records on it 25 hours before the crash time and the reason for that is not known,' Qurban Mohammed Badakhshi said, flight safety director at the Afghan Ministry of Transportation.


The jet airliner was en route from the western city of Herat to Kabul when it hit a 3,300-metre mountain peak during a snowstorm on February 3."

It doesn't hurt enough yet!

So, having determined that Telstra's service levels in RARA are inadequate, we are still demanding the entrenchment of the problem. For crying out loud people, put the provision of these loss-making services out to tender as a taxpayer-funded essential service. If Telstra offers the most attractive package, then by all means award the contract to Telstra. Mandating that Telstra supply this service means has the side effect of granting Telstra an unshakeable monopoly and there can therefore be no competitive service provision. As a result, RARA politicians are essentially demanding a course of action that will prevent the problem from ever being fixed.

Madness, utter madness.

Farmers fear Telstra sale safeguards lack focus. 11/04/2005. ABC News Online: "A Senate committee is investigating a bill requiring Telstra to maintain a presence in regional, rural and remote areas if it goes into full private ownership.


Federal Communications Minister Senator Helen Coonan says the Telstra inquiry is being held irrespective of any Government plans to sell off the rest of the company.


'It goes to things like the competitive environment, the access environment - it's something that competitors of Telstra have sought and something that Telstra itself has welcomed,' she said."

UPDATE: It appears that I spoke a little too soon. The National Farmers' Federation (NFF) appears to have grasped the problem, I am no longer following the ins and outs closely enough to be able to work out who's pushing the "it's Telstra's job" line, but at least the NFF has realised that maybe making a single provider solely responsible is an undesirable solution.

Farmers hold Govt responsible for Telstra services. 11/04/2005. ABC News Online: "NFF's strong position is that it is the Government's responsibility, and not that of any particular provider, to ensure that service standards are up to scratch," [Mark Needham] said.

Sunday, April 10, 2005

Memories coming up during a car accident

_grau is Robert Siedel's attempt to convey the flood of memories experienced by someone (himself I assume) during a car accident. The film version in particular is mesmerising; it evokes for me the end sequence to Kubrick's 2001 A Space Odyssey, with almost no colour and a gentler sound track.

US excercising tighter control over its airspace

That the US is exercising such control is hardly a surprise (whether or not it is reasonable is another question), but what surprises me is that they did not refuse access to US airspace until after the plane was in the air.

KLM plane denied access to US over passengers. 10/04/2005. ABC News Online: "US authorities have ordered a KLM plane to return to the Netherlands, saying two of its passengers were barred from entering US territory or airspace, the airline says.

The incident happened on Friday as the plane, with 278 people on board, was bound for Mexico and due to cross US airspace.

A KLM spokesman said the two passengers were not on any Dutch or European watchlist."

Thursday, April 07, 2005

Making Sense of tcp_tw_reuse

So, you've killed a server process (e.g. tomcat) on your Linux host and it won't restart immediately because it can't bind port 8180 (or whatever). Here's what's happening, I think:
  • TCP requires that the side of a "connection" that requested a teardown (first to send a FIN) hang around for 2*MSL (4 minutes, as MSL is 2 minutes) in TIME-WAIT.
  • Out of the box, most UNIXen will not allow a process to bind a TCP port that has another connection still active on it, regardless of where the process intends to connect; presumably this is about enforcing the TCP TIME-WAIT state and/or about constraining (to 1) the number of processes that can listen on a port.
  • So, if you kill a process which tends to behave as a client (e.g. Mozilla) while it has a connection open, the connection will hang around in TIME-WAIT for 4 minutes. This will not upset a restarted Mozilla because when it binds ports for making connections as a client it allows the OS to select a(nother) port for it.
  • On the other hand, if you kill a server process while it has open connections to the port(s) that it listens on, those ports themselves (e.g. 8180 for tomcat) are party to connections that the server host is responsible for shutting down (the server process was killed, rather than, say, the client sent a FIN) and will consequently have TIME-WAIT connections hanging around for 4 minutes. As the server process will want to bind the same port(s) again upon restart, there will be a problem.
So, to get around this,
echo 1 > /proc/sys/net/ipv4/tcp_tw_reuse
The kernel documentation says:

Allow to reuse TIME-WAIT sockets for new connections when it is
safe from protocol viewpoint. Default value is 0.
It should not be changed without advice/request of technical
There is also tcp_tw_recycle:
Enable fast recycling TIME-WAIT sockets. Default value is 0.
It should not be changed without advice/request of technical
which looks to me like an "ignore 2MSL altogether" and goes further than is neccessary for the solving of this problem.