Bats!

This is a bit of a saga, so I’ll do a quick intro before I get to the guts of it. I purchased a house in December 2006, and after a month or so living there I noticed a scratching noise in the walls. I pulled out the air-con, and looked into the wall cavity, and there was a roosting bat. So I did a bit of research into them, and decided they were getting in around the air-con, so I left the air-con out one night, and late in the evening sealed up the hole, and put it back in. Of course the next night there was still scratching, but not only there, in the ceiling as well.

The main issues I have with them is the smell of their droppings, and the rashes which we all get when we are at the end of the house they are in, so I assume there is something in the droppings which we are allergic to.

Pulling the roof off I discovered a large colony of bats living there, probably about 20 I guess. They were living everywhere, including under the ridge cap, and especially under the insulation bats. It turns out that the walls aren’t sealed in the ceiling, so the real path bats took to get into the wall was via the ceiling, and the exit appears to be via an unsealed ridge cap end.

So, I’ve tried a sonic deterant, but this doesn’t seem to effect them at all. The best information I’ve found so far seems to imply that the frequency it is using is outside the range which will effect bats. It does have a test mode which 1/2s the frequency, but this is quite loudly heard by the rest of us in the house, which is not really desirable.

What has seemed to be a way of controlling them is to remove the insulation bats, and placing fluorescent lights in the roof space. The bats just seem to crawl, not fly, so perhaps they are actually babies. This was suggested by the national parks people.

So the plan as it stands is to clear out a perimeter around where they are mainly congregating, done by removing insulation, cleaning, lighting, and placing naphthalene in the cleared space. Then I’m going to try to do a sweep of the rest of the roof to make sure there are no other signs of them around, followed by blocking up all the wall tops where there are no bats present, and then trying to contain those in the wall. I think I will give the infested wall cavity direct access to the outside world, probably by removing the air-con, and hopefully with time they will move on.

Then the cleanup operation can begin. I estimate I have a cubic meter of bat dropping to remove, probably by shovelling the industrial vacuums.

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Roof colours impact on temperature

These are some preliminary results for roof colour tests I am conducting. The setup is 8 equal sized pieces of roofing material, some painted with different coloured roof paints. They were left out in full 12noon summer sun (Lat 19 south), and the temperature of the under side of the material was measured after 30 minutes exposure. Results follow:

1. White Colour Bond 48C
2. Painted white Zincalume 45C
3. 2 coats painted white Zincalume 43C
4. 2 coats painted white Colour Bond 45C
5. Black painted Zincalume 70C
6. Silver painted Zincalume 63C
7. Gold painted Zincalume 60C
8. Unpainted Zincalume 50C

I’m going to conduct this again soon, with an 8 channel data logger, so more precise results can be presented. But for now, you can get the jist of what is happening.

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Personal flash video player

With this handy little util, flash video player, and ffmpeg to do the conversion it is easy to embed videos in your website, without having to use a video sharing site like youtube. This is of great importance to intranets, and protected sources. Why run the flash route? Easy, it’s the only working, embedded video player in Linux.

ffmpeg -i infile -t flv -ar 44100 outfile.flv

Just a note, you seem to have to have the whole thing on a webserver for it to work. It won’t work straight off your hard drive.

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PHP internal server error

I think my cpanel host recently upgraded some software on their server, and suddenly all my usual proceedures for rolling out web apps broke, with Internal server errors and this in the error log “error: directory is writable by others”. So, the obvious solution of going into the file manager and changing the permissions was tried, but the changes never stuck.

In the end I had to use FTP, and chmod 755 all the directories which were PHP entry points, ie held php files which the users accessed (index.php). Note group and other has no write access. If group has write access then you’ll get the same error message.

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Please vote for this

This is my partner’s work, and you help in voting for her would be greatly appreciated.

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My new home

Well, this may not be my only corner of cyberspace, but it is certainly
my newest. This blog, which is basically just a series of notes to
myself, has just been moved from LiveJournal.com. Basically because
LiveJournal didn’t support categories via XMLRPC, so Performancing couldn’t use it, and because LiveJournal didn’t support RSS feeds off indivitual categories.
To make the move I used ljdump to export my records, and then I used this XSLT to convert the records into TypePad format, for importing into WordPress.
xsltproc livejournal-to-typepad.xslt ljdump-1.1/simbiosis/L-* > typepadexport

My .bashrc

# ~/.bashrc# Make the prompt in the for user@host:directoryexport PS1='\u@\h:\w\$ '# Eliminate duplicates in your command historyexport HISTCONTROL=ignoredups# Make ls and ll colour, and ll show a complete list with human readable file sizes.alias ll='ls -lahi --color'alias ls='ls --color'

http://plone.jcu.edu.au/verg/resources/how-to/a-good-bashrc/view

Sometimes Java seems like a hack

I am using Java RMI to do the main IPC work for me, in a distributed number crunching application. Now the reason I’m using Java for this is another story, for another time. So, like any good developer I’ve got plenty of test cases, but one of them just never seemed to exit. So I fired it up in Eclipse and paused the execution when it should have been finished, and what did I find? 1/2 a dozen RMI related threads. But I unexported the objects, and cleaned everything up… Well according to this that isn’t enough. The only way to fully shutdown an RMI server is with System.exit(0).

Why? did the implementation get too tricky, and they decided to leave the cleanup to the operating system? Oh well, lets see if we can drop RMI now! I hear Jini is good. I just hope it doesn’t inherit this same problem.

Pet hates

Current pet hate. RSS feeds which have only the title, and the title again in the body, or even just the first sentence. What is the point?

Head set finally working

After much hearache my BlueAnt Bluetooth headset is working in linux. There is a couple of patches to the current a2play which are required (http://hpc-external.jcu.edu.au/~nigel/uploads/Main/a2play.diff.txt). Basically the codec detection fails the first time, so retry, and it needs the complete shutdown sequence, which apparently crashes iTech headsets.