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Linux Magazine / August 1999 / FEATURES
One of the great things about Linux is that it runs on just about anything. Sure, it sings on your Intel PC, but if you're so inclined, Linux can power your SparcStation, Amiga, or Alpha box. Heck, you can even run it on a PalmPilot.
And Linux has been ported to Apple's PowerPC hardware. Whether it's an Apple iMac, a G3 workstation, or an old Apple 7500 brought back to life, it can run Linux. Linux on the PowerPC microprocessor is as complete as Linux on any other chip, including Intel. And though Apple's Power Mac systems are far and away the most popular PowerPC-based computers, they are not the only ones. You can also run Linux on a variety of non-Apple PowerPC systems, including IBM's RS6000, Motorola's StarMax, and PowerStack systems, even Be Inc.'s BeBox.
But Why?
Why would you want to run Linux on your Macintosh? If you're thinking about things from an operating system perspective, you run Linux on the Mac to get Unix. From a hardware perspective, you run Linux on the PowerPC to get RISC.
The OS argument for Linux is simply made. Linux is a smart choice if you're looking for a stable operating system that doesn't require the fastest and most expensive Mac hardware on the market. Linux rarely crashes. If you're a MacOS user, tired of those little bombs, this may well be reason enough. But there's more: Linux is a true multi-user, multi-tasking operating system. It is designed so that no single application can monopolize the CPU, so you can run two programs at once without slowing down the whole system. Linux's leaner design is great for converting older PowerMacs into faster Web servers. And, unlike the current release of MacOS, you can run Linux with less then 32 megabytes of RAM. Though there are virtually no commercial applications for Linux on the PowerPC, there are a wide variety of Open Source Linux applications to choose from.
The hardware argument all comes down to RISC -- the Reduced Instruction Set Computer architecture that isat the heart of Apple's PowerPC microprocessor. The main difference between RISC chips and the Complex Instruction Set Computer (CISC) design that Intel uses for its x86 chips is that RISC processors have fewer instructions. This lower overhead means PowerPCs can complete some instructions more quickly than Intel chips.
You really notice the performance difference with any kind of number-crunching applications -- anything that uses a cryptographic algorithm, for example. Of course, there's a philosophical dimension to this argument as well. Long time MkLinux user, Fred Bacon puts it this way: "On the days I can't use Linux, I'd much rather use an Apple than a Microsoft system."
The marriage between Unix and RISC processors is a natural one. All of the major Unix vendors -- Sun, HP, IBM, and the former Digital -- ship their flagship Unix systems on RISC systems.
The PowerPC chip uses less power and runs cooler than a comparable Pentium processor. For the regular user, this translates into more compact computers and less overheating. The PowerPC is an appealing choice for anyone doing parallel computing, particularly supercomputer users, where lots of cheap processing units -- iMacs for example -- can be strung together in clusters. This clustered, low-cost architecture can give some applications near-supercomputer performance. At Australia's University of Adelaide, a team of researchers created a 38-node iMac cluster powered by the LinuxPPC Release 4 distribution for about one tenth the price of a real supercomputer.
Looking forward, the soon-to-be released G4 processor -- the next generation PowerPC -- is expected to have a clock rate above 400 MHz. It will feature copper interconnect design technology, which translates intomore, even tinier circuits on the same amount of real estate. The G4 will also have the much-anticipated AltiVec 128-bit vector processing capabilities. Similar to Intel's MMX, AltiVec will feature a number of new chip instructions designed to speed up things like image processing, sound, voice recognition, and networking.
