October 2008 Archives

As you might remember, back in 2007 I wrote about Exhibit which in meantime released version 2.0 and moved to google code.

This time, I made few more converters which enable you to:

• Convert tab separated data into Exhibit with GD::Graph::sparklines inline graphs in table
• Create Exhibit from simple SQL query [timeline of this blog as Exhibit from this SQL query]
• Subversion as timeline [timeline of svn.rot13.org]

This is probably best test of JavaScript speed in your browser. Exhibit seems to work best with around 500 items in older browsers, but Firefox 3.1b2 works with 3000 objects, even on EeePC :-)

I have been very impressed by the way xrandr handles external LCD screens, connected to DVI or VGA. But, today, I unplugged my laptop from dock, and than plugged it back in after a while without any preparation before unplugging it!

For a surprise, my usb mounted storage was again there (no idea how :-) and everything worked more-or-less great, except external LCD connected to DVI which was in power saving mode. None of the buttons (including off!) on monitor worked. For a moment my mind glimpsed upon idea of rebooting monitor, but I quickly rejected that silly idea.

So, I rebooted Linux instead. I still wonder how did that usb storage got mounted... since it reported write errors on shutdown it probably wasn't there alltough I saw usb-storage claming device again after I plugged laptop back into dock.

Rebooting laptop was a mistake. My laptop boots nowhere near 5 seconds so I had to wait a longish time while monitor was still in power save mode. Buttons on it still didn't work.

When I started X again, and when xrandr again apparently positioned it correctly above internal LCD, I run off options and unplugged power from external LCD monitor. Right after I plugged it back in, picture was there. In optimal resolution. As it should. I just rebooted my monitor!

Last week I was playing around with understanding serial protocol between RFID reader and computer. For a start, I had a windows application which could communicate with RFID reader over USB serial adapter (which is included in device, so device looks like USB device).

First, I needed to sniff USB serial traffic under Windows to understand protocol between device and program.

Then I wrote a simple script to reformat output from portmon to more readable format, and found out that packets have two byte checksum in them.

After I tried all simple combinations to produce valid checksum, I decided to ask a question about checksum guessing at stackoverflow.com. This was great idea, because selwyn stepped in and confirmed that my checksum is CCITT.

Having all that parts in place, next step was to write perl script using Device::SerialPort to communicate with serial port, and thus RFID reader. Right now, I'm pondering how to integrate it with Koha, but that's topic for another post...