Sugar Maple Software

As I’ve mentioned before, mailing lists are an excellent resource when looking for answers to your development questions. This is especially the case of the mailing lists hosted by Apple (at least those to which I subscribe). I frequently take advantage of this resource and also try to contribute. Often, I don’t have the answer or someone, who checks their mail much more frequently than I, has already answered the question, but, when the opportunity is there, I take the time to help. A couple of days ago, when I couldn’t remember the kernel equivalent of the gettimeofday function, I searched the Apple Mailing Lists and immediately found the answer (clock_get_calendar_value which lead me to kern/clock.h and the currently supported function clock_get_calendar_microtime). The signature of the reply to the original poster’s question caught my eye. It was mine. I had provided the answer exactly two years ago today. It’s like something out of a Sci-Fi movie… or maybe just good karma.

While I usually write about programming in the land of milk and honey (i.e., Cocoa), I spent most of the previous ten years writing kernel-level code. Recently, I’ve ventured back into the kernel and was reminded of the challenge of logging from an I/O Kit driver. When writing code in the kernel for an I/O Kit driver, you can’t invoke printf to log messages. Instead, you usually invoke IOLog. …