We have developed a series of benchmark programs to test the performance of the Mach operating system. A discussion of the philosophy of the benchmarks is given, and the individual benchmark programs are described. Results of the benchmarks on 386-based machines running Mach 2.5, Mach 3.0, and SCO System V/386 are given. Appeared in: Proceedings of the USENIX Mach Workshop, 1990, 83-100.

High Mach number astrophysical jets are simulated using a positive scheme, and are compared with WENO-LF simulations. A version of the positive scheme has allowed us to simulate astrophysical jets with radiative cooling up to Mach number 270 with respect to the heavy jet gas, a factor of two times higher than the maximum Mach number attained with the WENO schemes and ten times higher than with ...

Computers, the internet, and the larger communications network of which it is a part, provide an informational structure within which many of us spend a large part of our working day and a significant part of our leisure. We are, during those periods, “infonauts in cyberspace,” using the internet to get information from places near and remote, and acting in various ways through the internet to ...

Interprocess communication (IPC) provides the fundamental mechanism for the Mach microkernel to be extensible and exible. Mach IPC provides eecient communication mechanisms for many applications. However, it does not provide suucient functionality for real-time applications which have rigid timing constraints among threads. In Real-Time Mach (RT-Mach), we have extended Mach IPC to be priority i...

Mach bands are illusory bright am! da.rk bands seen where a lumin<lnce plateau meets <I ramp, as in half-shadows or penumbras. Ra.tliff, Milkman, and Kaufman (1983) showed that Mach bands are attenmtted by placing stimuli, such as bars, nemby. An experiment comparing Mach band attenuation for bar a.ncl Craik-O'Brien stimuli shows that they are equally effective in attenuating Mach bands. 'J'he ...

Direct numerical simulations are conducted to investigate in detail the effect of Mach number on vortex pairing in a mixing layer. The pairing process is found to be delayed at higher Mach numbers and the paths followed by the vortices change. To investigate the effect of the initial shape of the vortices a simple vortex dynamical model of pairing is constructed which accurately models pairing ...

The Breguet range equation indicates that to the first order of approximation range will be maximized by maximizing ML/D, where M is the Mach number and L/D is the lift/drag ratio. Since the drag coefficient increases very rapidly as the Mach number approaches one, this leads to the design of a long range aircraft which fly at high subsonic speeds, typically in the range Mach 0.8 to 0.85, just ...

SUMMARY An asymptotic analysis of the compressible Euler equations in the limit of vanishing Mach numbers is used as a guideline for the development of a low Mach number extension of an explicit higher order shock capturing scheme. For moderate and large Mach numbers the underlying explicit compressible ow solver is active without modiication. For low Mach numbers, the scheme employs an operato...