February 2006 Archives

Woah! A little while ago the lights went out. The computers but not my monitor is on a relatively powerful UPS so the noise kept going. Vani went "woah". First thought: Breaker switch? Where are my shoes? Then I realize it's dark downstairs too, so it's not just a breaker switch. At the same time I look up and see lots of city lights down in the city, but our whole canyon is dark.

Scramble in the dark to find the maglite I know is somewhere on my desk. Vani lights a candle in the bedroom and I start shutting down the computers on the UPS. At least it's not affecting the datacenter this time.

Now we are sitting here in the dark. I called the LADWP. The automatic system doesn't know about the outage, but they are "currently experiencing high call volumes". Wonder why! :-)

There are lights on the Griffith Observatory and in the houses on one the hill ridges over in that direction. It looks cool in the dark surroundings.

update Now their phone answering machine is telling about the outage. From the description of the area ("Widespread in the Hollywood and Hollywood Hills area, Hollywood Blvd, Beachwood Canyon, Mulholland Dr, Western (?)") then our view is pretty perfect of the dark area. No expected time to repair yet...

Slowly faint lights are appearing in the windows around the canyon.

Andy Lester writes about the NTP Pool

Thanks Andy!

If you have a unix-y system with a static IP, please join the pool.

If you are on a low speed DSL and is concerned about the extra traffic, you can set your "netspeed" low in the management interface on the pool website and you'll be taken out of the global pool. The traffic is very low, but being in the global pool still gives a few "spikes" once in a while (I'm working on that).

Conversely: If you have enough bandwidth to not mind the spikes, then we really need you to join the pool. Since adding the option the total number of servers has gone up nicely, but the global pool has stagnated a bit. Can't have that. Every day thousands¹ of computers start using the pool; we need more to serve it too.

¹ I've no idea if that's right; but thousands of new Linux installations a day doesn't sound unlikely, does it?

I got a pack of Dual Layer DVDs. Woah, that burns slow! I didn't time it, but it's well into feels-like-1x-CD-burners-from-1997 territory.

At least it forces me to work rather than play the Zoo Tycoon 2 game that Vani got me for valentines day. :-)

"Must Love Perl"

In Los Angeles we have a rack (and then some) of old and a few newer servers that not always cooperating. We could use someone to come and help us beat the hardware into shape, reorganize the tangled ethernet and serial cables -- that sort of thing.

If you live in Los Angeles within reasonable (for you) driving distance to downtown and would like to help, please send a mail to ask@perl.org.

update - we got a volunteer who even lives Very Close. Thanks Eric! Now we'll see if we can make him stick with it or if our promises of soda¹ and quiet fame will fall short.

¹ (which you can't even drink by the racks...)

If you use Metamark and are in or near¹ White Plains, NY, please email me.

¹ I'm not really sure how distances work in New York state. In Los Angeles a similar zoom level on the map leaves everything inside "can go there for dinner" distance which I'd call "near".

Took me a little while to sort out that I didn't mess up my firewall rules on the proxy server at home. :-) Google, or at least the datacenter(s) their DNS was sending me to was down for a minute or three.

[root@freja ~]# telnet www.google.com 80
Trying 66.102.7.99...
telnet: connect to address 66.102.7.99: Connection refused
Trying 66.102.7.104...
telnet: connect to address 66.102.7.104: Connection refused
Trying 66.102.7.147...
telnet: connect to address 66.102.7.147: Connection refused
telnet: Unable to connect to remote host: Connection refused

At least there are plenty other reasonable search engines to use.

A few days ago del.icio.us was down for a little while - bye bye bookmarks! That was worse actually. A small app to mirror del.icio.us bookmarks locally would be helpful for backup in a situation like that.

Everyone using unix in their job will once in a while have to run a long running process. Usually right before leaving the office to go to dinner. If you have to check on it later to make sure it finished right then you are stuck with redirecting the output to a file and look there later.

Much better solution: Use screen!

It can do lots of things, but the main one in this context is allowing you to "detach" and "reattach" a terminal.

Start by just running screen:

$ screen

Now you should have a new shell. Start some long running command and then press ctrl-a d. (Hold down control and press a, let go of ctrl and press d).

You are now back at the original shell before you started screen. Logout or go home now.

ctrl-a is the "attention" command in screen. If you want to give the program you are running a ctrl-a you can press ctrl-a a. You can remap the attention command to something else if you want.

When you are back at an internet connection you simply run

$ screen -x

to reattach your old session. There are other ways to reattach, but this one is the easiest. If you have multiple screens running it might say something like

$ screen -x
There are several suitable screens on:
        8762.ttyp9.g5  (Attached)
        19775.ttyp9.g5  (Detached)
Type "screen [-d] -r [pid.]tty.host" to resume one of them.

Then I can either run screen -x 19775 to attach the detached screen or screen -x 8762 to attach the screen that's already attached (another person on another computer maybe - remote pair programming!) (Bonus tip: You just have to type enough of the PID that it's unique, so in this example screen -x 8 or screen -x 1 would be enough).

Easy as pie!

One more trick before you go: In a screen you can press ctrl-a c to create a new "virtual screen". Press ctrl-a n (next) to move to the next virtual screen or ctrl-a p to go to the previous screen.

man screen will give you many more magic keys. screen is such a great tool. Even when I work on small FreeBSD installations on a compact flash card for say Soekris boxes I install screen (but then I also often install perl)...