About the Authors

Ole Henry Halvorsen is currently a senior software engineer at a leading manufacturer of professional video equipment, where he works on drivers and software for high-end HD video hardware for Mac, Linux, and PC. He was part of the team that created some of the earliest video hardware devices for both USB 3.0 and Thunderbolt. He holds a bachelor's degree in network computing and a master's degree in information technology from Monash University, Australia. He formerly worked as an R&D engineer at Silicon Graphics (SGI) where he worked on NAS and SAN storage technologies and solutions for supercomputing and high-performance computing.

When not spending time with his family, he enjoys programming for the kernel, iOS, Linux, and the Web, as well as reading, watching movies, playing games, and keeping fit.

Douglas Clarke has been developing for the Macintosh professionally for 15 years. He has spent most of his career working with hardware and developing device drivers, and he has written drivers for Mac OS 9, Mac OS X, and Windows. His first exposure to the I/O Kit came a year before the initial release of Mac OS X, and he has been working with it continually since. He currently develops drivers to support real-time video applications. He graduated with a degree in computer science from Monash University in Australia.