Mach wave Mach wave In fluid dynamics, a Mach wave is a pressure wave traveling with the speed of sound caused by a slight change of pressure added to a compressible flow. These weak waves can combine in supersonic flow to become a shock wave if sufficient Mach waves are present at any location. Such a shock wave is called a Mach stem or Mach front. Thus, it is possible to have shockless compression or expansion in a supersonic flow by having the production of Mach waves sufficiently spaced ("cf." isentropic compression in supersonic flows). A Mach wave is the weak limit
Mach (kernel) team had built Mach and ported it to a number of platforms, including complex multiprocessor systems which were causing serious problems for older-style kernels. This generated considerable interest in the commercial market, where a number of companies were in the midst of considering changing hardware platforms. If the existing system could be ported to run on Mach, it would seem it would then be easy to change the platform underneath. Mach received a major boost in visibility when the Open Software Foundation (OSF) announced they would be hosting future versions of OSF/1 on Mach 2.5, and were investigating Mach 3