Archive for the 'Kernelthread.com' Category

The Apple Motion Sensor As A Human Interface Device

Sunday, March 20th, 2005

AMS2HID is software that allows you to use a PowerBook with a motion sensor in new ways. You can play games such as Neverball and driving simulators by using the PowerBook itself as an input controller. The motion of the PowerBook in physical space provides input to such games through AMS2HID. You can also use [...]

"Blue Screen of Death" Rescues With Personal Devices

Friday, March 4th, 2005

Now that the cat’s out of the bag, I can point people to something cool we did in our group at IBM Research. What I am referring to was demonstrated at IBM PartnerWorld 2005 a couple of days ago in Las Vegas, calling it a “personal jumper cable” to counter the “Blue Screen of Death” [...]

The PowerBook Sudden Motion Sensor

Wednesday, March 2nd, 2005

I recently looked at the motion sensor based disk drive protection feature added to Apple’s PowerBook line. Here is a discussion along with some examples of using the orientation data provided by the sensor.

UNIX on the Nintendo Game Boy Advance

Tuesday, September 7th, 2004

gbaunix is a rather contrived experiment in which we run an ancient version of the UNIX operating system on a popular hand-held game system using a simulator. Specifically, it is 5th edition UNIX (1974) running on Nintendo’s Game Boy Advance, with SIMH as the core simulator.

A Taste of Computer Security

Wednesday, July 28th, 2004

Given the nature and scope of the field of Computer Security, it would require one or more books to even briefly touch upon all that is known in the area. A Taste of Computer Security gives you, well, a taste of (a subset of) the subject. The contents are not uniform in their depth or [...]

More Power to Firmware

Wednesday, June 16th, 2004

My original intent with More Power to Firmware was to put up some sample Forth code for doing graphics with mouse input in the Open Firmware implementation that Apple uses. I have included a discussion of the Extensible Firmware Interface (EFI), broadening the document’s scope. Three complete (though prototypical) examples are included: Towers of Hanoi [...]

10 Things Apple Did To Make Mac OS X Faster

Tuesday, June 1st, 2004

The performance of computer hardware typically increases monotonically with time. Even if the same could be said of software, the rate at which software performance improves is usually very slow compared to that of hardware. In fact, many might opine that there is plenty of software whose performance has deteriorated consistently with time. Moreover, it [...]

URL-based Security Holes in Mac OS X

Wednesday, May 26th, 2004

There has been great hue and cry over the recently found “URL exploits” in Mac OS X. I briefly looked at this issue today. While it’s certainly a worrisome situation, in my opinion there seems to be more confusion than necessary (which amounts to a very normal situation in such cases!) I have a few [...]

Determining Free Space Fragmentation with hfsdebug

Sunday, May 23rd, 2004

hfsdebug can go through the volume allocation bitmap and calculate a list of free extents, along with their sizes, on a volume. Thus, you could determine the size(s) of the largest free space chunk(s) on your volume. A popular name for this appears to be “free space fragmentation”. Although hsfdebug could quantify free space fragmentation [...]

Resistance of HFS Plus to Fragmentation

Tuesday, May 18th, 2004

I had been wondering for a while as to how well the combination of Panther and HFS+ stands up to fragmentation. According to Apple, there should be so little fragmentation in a typical use-case scenario that you don’t even need to worry about it. I have seen several discussions on this topic in the Mac [...]


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