I just found a very nice post describing nice things to do with Bluetooth. By using the Proximity tool, my MacBook Pro can monitor the precense of my cell phone. Proximity will run an AppleScript when a selected device enters and/or leaves Bluetooth range. Most phones are class 2 Bluetooth devices, which gives a range of 10m (outdoors). This allows you to automatically lock your desktop when you leave and unlock when you come back.
Archive for the ‘Uncategorized’ Category
I just read an interesting article on how HFS+ deals with fragmentation. Not only will it take proactive steps to avoid fragmentation, apparently it will defragment some files on-the-fly.
This forensics-site has a very detailed article on the hex-dumps you can get from an HFS+ partition.
Our weather station has a serial connection and comes with Windows-software to view the weather data on your PC. The app is very eye-candy, but doesn’t do anything more than displaying the data. I’m more interested in long-term trending. So I wrote my own application to talk to the weather station and store the result in an rrdtool database.
Continue reading ‘Reverse engineering the Oregon WMR928NX weather station’ »
I’m again having problems with my new MacBook Pro (the late 2008 unibody one). The problem is most easily visible when BootCamping into Windows and running whatever 3D application (I use 3DMark06). Within 5 minutes, the machine crashes. After some trail-and-error, I found out that it appears to be a thermal problem.
Normally, when the load goes up, the fans kick in to keep the temperature down. Mine don’t… When stressing my CPU under MacOS, it happily goes up to 90ºC with the fans still idling at their standard 2000rpm. Needless to say, a bit of GPU-load increases the temperature beyond the safety-thresholds.
Resetting the SMC solves this problem only partially. On the first boot with a clean SMC, the same CPU-test brings the CPU to 70ºC with fans blazing at 4750rpm, as it should be. Once the machine goes through a sleep-wake cycle, the same test brings it straight up to 90ºC.
Just when I was about to call Apple Care, a software update pops in: SMC Firmware Update 1.2, looked promising, but the problem persisted… I’ll call Apple Care tomorrow.
Since PhotoShop is a bit too expensive, I’m sticking to The GIMP. When trying to get The GIMP to work under MacOSX (Leopard) I had two issues. The first one was a huge lag in the mouse pointer. Apparently this was caused by a specific version of X11. Since I’ve updated to 10.5.6, the problem disapeared by itself.
A second issue I was having is that (by default) the first mouse-click simply activates the window. The GIMP uses multiple windows, making this very anoying: to switch to another tool, I had to click twice. This blogpost gives the solution:
$ defaults write org.x.X11 wm_click_through -bool true
Recently I got a PowerBall. Needless to say, I wanted to know exactly how this thing works. Although the Wikipedia article gives some descritption, I found this post on Usenet (local copy) that goes into the dirty details of formulla’s.
My car has a CD player build-in that supports MP3 CDs. However, it’s fairly picky on the format of the disc. I tried to burn a CD using Burn Folder which comes with Leopard, which creates a multistandard disc containing a HFS+, an ISO-9660 with Rock Ridge, and a Joliet with Rock Ridge. While this looks very nice on paper, the car’s CD player was less satisfied: “Error CD”.
Another issue is that the player has no support for M3U-playlists. It does, however, support “albums” (directories), which can be used to emulate playlists. Just add a number prefix to each filename and it’ll work. Placing the same file in multiple playlists/albums/directories is possible, but wastes space. But this can be worked around.
Time Machine is the Mac way of doing backups. The concept is fairly similar to incremental rsync snapshots. Officially, Apple does not support Time Machine backups to a network volume: network drives don’t show up in the Time Machine user interface. The only way to get network-based Time Machine is by buying a Time Capsule.
When doing a Time Machine backup to a normal disk (I tried it with a LaCie 1TB USB disk), one can see the file structure created. Mine looked like this: Backups.backupdb/<hostname>/<date>/Macintosh HD/… Inside this directory is my full system (minus the parts I explicitly excluded in the Time Machine config).
Since we have more than 1 Mac, I’d like to have all of them back up to the same hard drive. I already have a Linux-based server serving files over AFP. This is where it gets more interesting…
I think I can skip the buildup on why backups are important and I’ll focus this post on the “how”. There are a lot of ways to make backups. Obviously some are better than others; in this post I’ll just explain how I do my backups.
The script I use was designed with the following items in mind:
- The storage medium is a hard drive. This has some advantages like random-access which can be used.
- Storage capacity should be as small as possible; differential and/or incremental backups are almost unavoidable in this.
- The backups should be pulled from the server. This way you know when a server is behaving strangely. If you push your backups and the server has a bad day, he won’t tell you that he forgot his backups!
- Since the backup contains sensitive data (eg SSL private keys, /etc/shadow), the network transfer should be encrypted.
- The backup needs to be taken as root. This is the only way to ensure that all files could be read. (Yes, technically you could use specific capabilities instead of root)
