Critical Mach number and slow down as it travels around the aircraft's structure. When the aircraft's airspeed reaches the critical Mach number, the speed of the airflow in some areas near the airframe reaches the speed of sound, even though the aircraft itself has an airspeed lower than Mach 1.0. This creates a weak shock wave. As the aircraft exceeds the critical Mach number, its drag coefficient increases suddenly, causing dramatically increased drag, and, in an aircraft not designed for transonic or supersonic speeds, changes to the airflow over the flight control surfaces lead to deterioration in control of the aircraft. In aircraft
GNU Mach by Thomas Bushnell (rather than by a Utah researcher) is from 16 December 1996. In 2002, Roland McGrath branched the OSKit-Mach branch from GNU Mach 1.2, intending to replace all the device drivers and some of the hardware support with code from OSKit. After the release of GNU Mach 1.3, this branch was intended to become the GNU Mach 2.0 main line; however, as of 2006, OSKit-Mach is not being developed. GNU Mach 1.4 was released on 27 September 2013, eleven years after 1.3. GNU Mach GNU Mach is an implementation of the Mach microkernel. It is the default microkernel