HP LaserJet 1020 on Ubunut 9.04

After an update, the printer does not work any more.

Linux hpws 2.6.28-17-generic #58-Ubuntu SMP Tue Dec 1 18:57:07 UTC 2009 i686 GNU/Linux

Delete the printer and reinstall HPLIP

sudo apt-get install hplip

The printer is found, but still does not print.
Only after clicking Download Firmfare in HP Device Manager, it starts to respond to the printing request.

What is the web service language/framework Barbara Liskov mentioned

In her talk titled "The Power Of Abstraction" given in OOPSLA2009, Barbara Liskov mentioned that she started to learn web services programming, and the language or framework she used has many global variables. I really wonder what she was using.

The talk is good and especially reveals the history of development of abstract data type by the list of influential papers.

Zero copy for Java HTTP file server

This makes it impossible for normal Java-based HTTP service to take the advantage of zero copy.

in reference to:

"It is not possible to create a channel for an arbitrary, pre-existing socket, nor is it possible to specify the SocketImpl object to be used by a socket associated with a socket channel."
- SocketChannel (Java 2 Platform SE 5.0) (view on Google Sidewiki)

Free DNS servers

Maybe some ISP's like this. The last time I tried to find a free DNS is two years ago when the ISP DNS was down. I like the ip they choose, easy to remember.

Maybe DNS is the first place that browsing statistic can be collected.

in reference to:

"To try it out: Configure your network settings to use the IP addresses 8.8.8.8 and 8.8.4.4 as your DNS servers or Read our configuration instructions."
- Google Public DNS (view on Google Sidewiki)

Rich Hickey on function, time, and process

All the concurrency and timing puzzles suddenly become reasonable after listening to his talk titled "Are we there yet". I borrowed the book of "Process and Reality" from the library, and started to learn Whitehead's system.

If you do multithreading programming, or play with JavaScript and XHR, or like Erlnag, Clojure, or Scala, then you would perhaps enjoy his talk.

/bin/perl^M: bad interpreter

After digging for a while, it turns out the cause is the perl interpreter on Linux cannot recognize the end of line character CRLF in windows files. What it expects is LF.

Using EOL as end of statement is not system independent.

Slides for TRLab Erlang workshop

These are the slides I prepared for the last session of the workshop.