Mac

AKA how to build a distributed web system on a budget…

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PostgreSQL has a wonderful feature which is called User-Defined types. It allows anyone to create a new datatype, along with the relevant operators, which are then managed almost natively by Postgres.

I decided to use this feature to manage chessboard positions in a more efficient manner than the usual ASCII storage which looks like “rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR”

I named this new type EPD, for “Extended Position Description”. I know that all the relevant data is not present (I shall typically store information like the active color, the casting availability, and a few other fields), but it didn’t sound like a bad choice for a name.

It allows to do some cool things like:

– Create a table with the epd type

chess=# CREATE TEMPORARY TABLE test_epd(my_epd epd);
CREATE TABLE

– Insert a string - it gets automatically converted to a native format and only takes 32 bytes
chess=# INSERT INTO test_epd VALUES (’rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR’);
INSERT 0 1

– And converted back into a string

chess=# SELECT * FROM test_epd;
my_epd
———————————————
rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR
(1 row)

– What’s on A2 ?
chess=# SELECT epd_piece_at(my_epd, ‘a2′) FROM test_epd;
epd_piece_at
————–
n
(1 row)

chess=#

The code is available here. The installation process is:

1. Compile: make
2. Install the .so: make install
3. Configure postgresql: cat epd.sql | psql

Startup the guest Debian.

In VMWare, click on VM / Install VMWare Tools…

/dev/hdc must be unused !

Click on “Install”

VMWare will mount a virtual CD on your system. Copy VMwareTools-.tar.gz to your home directory

cd ~ && tar xzvf VMwareTools*

cd vmware-tools*

apt-get install gcc linux-headers-2.6-686

ln -s /usr/src/linux-headers-2.6.18-6-686 /usr/src/linux
cd /usr/src/linux

apt-get source kernel-image-2.6-686./vmware_install.pl

Answer [ENTER] to all questions - should work

This can obviously be done through the CLI using Apache Workbench.

Another nice interface is Apache JMeter.

This tricks only works if your DVD is in Zone 2.

• Empty the DVD tray
• Power off / Power On
• Wait for the boot
• Press 5 times 0 within 1 second
• Press “Repeat”
• Type: 57538
• You should see a “2″ in the upper left corner of the screen
• Quickly type 9

That’s it.

(Apparently if your DVD is Zone-2 then you should type 76884 instaed of 57538, but I couldn’t confirm it)

… check Googletalk :)

-bash-3.2$ sysctl -a hw.ncpu
hw.ncpu: 8
-bash-3.2$

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Quite easy actually:

• Plug in
• Power on
• On the remote, press “Open”
• And press on 9 as many times as it takes to get a “9″ displayed on the screen

That’s it.

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