Greg Kroah-Hartman has been writing Linux kernel drivers since 1999, and is currently the maintainer for the USB, PCI, I2C, driver core, and sysfs kernel subsystems. He is also the maintainer of the udev and hotplug userspace programs, as well as being a Gentoo kernel maintainer, ensuring that his email inbox is never empty. He is a contributing editor to Linux Journal Magazine, and works for IBM's Linux Technology Center, doing various Linux kernel related tasks.