> i don't see how mach is an improvement over linux. especially > early linux. mach kernels were three times the size of linux > kernels of the day and didn't do anything useful by themselves.
What the AT&T lawsuit blocked distribution of was Mach 2.5, which was BSD Unix with parts of the kernel replaced. One unified source tree ran on several architectures (VAX, 68k, MIPS, x86; later 88k, Sparc). Commercial multiprocessor Unix machines were sold running that code base (the Encore Multimax, and I *think* the Sequent Symmetry). As for utility, Mach on VAX and 68k Sun and DEC PMAX and PC hardware was the computing environment for hundreds of people at a time at CMU for a good chunk of a decade. Multiprocessor desktop workstations (4-way 88k "Luna" boxes made by Omron) were not uncommon in 1992. By no means was it perfect, and it was never really good at the distributed-computing thing, but I think it would have provided *very* stiff competition for Linux if it hadn't been embargoed. Dave Eckhardt
