The Mach research project at CMU ended 10 years later, but it pioneered concepts still in use today. For example, it employed a machine-independent memory management system so it could be targeted at many different types of computers and computing -- uniprocessors, multiprocessors and distributed processors. "And the underlying idea of a microkernel became quite popular," Rashid says. "It spawned a variety of other efforts where operating systems were effectively layered on top of smaller, simpler systems."
Mach was the first 64-bit version of Unix, and it became the basis (along with BSD) for OSF/1, the operating system sponsored by the Open Software Foundation. From there it went on to become the basis for DEC/Compaq/HP Tru64 Unix, NeXTstep -- used by the NeXT computer -- and eventually Apple's Mac OS X.
Rashid says what to name the operating system was much debated among developers at CMU. One team member wanted to call it MUCK, for Multiprocessor Universal Communication Kernel, while another favored MOOSE, for Multiprocessor-Oriented Operating System Environment. Rashid says he was greatly relieved when his choice of Mach won by a coin toss. "I seriously doubt the system would have been very successful had it been named MOOSE," he observes.
Gordon Bell, from the bully pulpit
Bell, now a researcher at Microsoft, spent 23 years in R&D at Digital Equipment Corp., where he most famously led the development of the Vax, the most successful minicomputer ever built. He went on to co-found Encore Computer, whose parallel-processing machines ran Berkeley Unix, and then Ardent Computer, whose graphics super-workstations ran AT&T Unix. Along the way, he advised the U.S. Department of Defense on IT matters and created and headed the National Science Foundation's computer science and engineering arm.
Bell became a Unix evangelist, pushing for its broad adoption in scientific computing and supercomputing while at the NSF and urging the Defense Advanced Research Projects Agency (DARPA) to support the Berkeley and Mach versions of Unix with strong funding. He was on the board of the UniForum Association, which supports open technologies, and pushed for the adoption of the Posix standard.
Bell's enthusiasm for Unix was matched only by his disdain for the commercial vendors of the operating system's variants. He became an outspoken and acerbic critic of the parties in the Unix Wars. In an opinion column entitled "Unix's secret tax bills" (PDF) that appeared in the April 24, 1995 issue of Computerworld, Bell wrote, "'Standard Unix' is an oxymoron. Its backers claim that it's an undifferentiated, 'open' standard, yet vendors maintain differentiated products."
The competitive practices by what he called "the Unix cartel" increased the user's cost of products such as database management systems by 250%, he estimated, and warned that "uncertainty over the responsibility for its evolution" was Unix's most serious flaw.