Outside Intel There is now an alternative to Intel that offers more speed and a smaller form factor for Linux users. By Dan Burcaw Sunday, August 15th, 1999 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. feedback mail to a friend printer-friendly version        page 1 2 3 4   next >>   Linux Magazine / August 1999 / FEATURES Outside Intel

How the Mac Was Won

The PowerPC microprocessor has been around since 1993, when
Motorola, Apple Computer, and IBM decided they’d band together and
create a RISC-based rival to Intel’s x86 chips. Motorola and IBM were to
sell high-end PowerPC systems, while Apple was to sell the consumer
flavors.

(Not So) Old Yeller: Nowadays, even Apple’s iMac can be seen running Yellow Dog Linux.

In late 1994, three years after Linus Torvalds unleashed his first
build of Linux, developer Gary Thomas began toying with the idea of a
PowerPC port. Initially, Thomas says he started the port for “purely
selfish” reasons. “The best PCs of that day were 486 machines,” he
explains, “and the PowerMac was simply better and faster.” At the time,
Linux ranonly on Intel computers, though there was a port to Digital’s
Alpha architecture in the works. Thomas posted to a few mailing lists,
to see if anyone was interested in helping him with the port. Nobody
was. So he began the work himself.

By mid-1995, Thomas had some working Linux applications, an OS that
booted, and most importantly, he had help. Victor Yodaiken and Cort
Dougan of New Mexico Tech signed on to work on the development effort,
and PowerPC hardware vendors began to notice. Motorola, IBM, and Be Inc.
all provided test systems. Withno place to run the donated machines,
Thomas wired up a test network of Linux/PPC machines in his bedroom and
literally began sleeping with his work. Though the PowerPC vendors were
now holding round-table discussions about the port, one company remained
conspicuously absent from the project; the company selling the vast
majority of all PowerPC machines: Apple.

It turned out that Apple had its own plans for Linux, and they
revolved around the Mach microkernel — the same kernel architecture
that is at the heart of Apple’s soon-to-be-released Mac OS X. At a Free
Software symposium held in early 1996 in Cambridge, MA, Apple unveiled a
prototype of its Mach-based Linux port, developed in partnership with
the Open Software Foundation (today known as the Open Group). This
eventually came to be known as MkLinux.

One of the most interesting things about the Mach microkernel is
that its modular architecture is designed to let other operating systems
– Linux for example — run on top of it. Mach itself is very small, and
it handles only the most basic of system functions. MkLinux is
essentially a Mach microkernel, with a slightly modified version of the
Linux kernel plugged into it.

To the surprise and delight of Linux devotees around the world,
Apple gave away over 20,000 MkLinux Developers Release 1 (DR1) CDs a few
months later at its worldwide Developers Conference. MkLinux was
distributed at MacWorld Boston that yeartoo. The future of Linux on the
PowerPC looked bright.

By the summer of 1996 a very complete PowerPC Linux system had been
developed. Six months later, JeffCarr, now president of LinuxPPC,
Inc.,offered to provide the PowerPC Linux developers with resources such
as a Web page, e-mail, mailing lists, and development systems. The
domain linuxPPC.org was registered and the Linux/PPC Project gained a
home.

While Apple’s endorsement of the MkLinux project gave Linux on
PowerPC a boost, the Linux/PPC and MkLinux community began to drift
apart. MkLinux did not run on the latest PCI-based Macintosh computers
and the Linux/PPC development was stuntedby Apple’s refusal to release
hardware specifications for its new machines — a frustrating experience
for Linux/ PPC users and developers.

Fortunately for PowerMac owners, Paul Mackerras of Australia soon
began developing a new Linux OS for the PowerPC. Paul combined resources
from the PCI architecture with code from Open Firmware (the BIOS of
PowerPCs), MkLinux, and a few pieces of reverse-engineered code to
create a Linux kernel that ran on Apple’s PCI systems. The PowerPC Linux
community gained a third branch: Linux-pmac.

In the fall of 1997, Mike Meissner worked with Gary Thomas to
implement shared library support for Linux/PPC, putting the PowerPC port
onpar with other Linux ports. Up to this point, Linux/PPC applications
were unable to share libraries, which wasted resources whenever two
applications ran on the same system. After trying libc and various other
alternatives, a “snapshot” of Linux’s glibc was used as the basis of
PowerPC Linux shared libraries.

MkLinux, too, supported shared libraries, which led developers to do
a direct port of the popular Red Hat Linux distribution. This was an
excellent means of unifying the ongoing development of PowerPC Linux.
Implementing shared library support allowed both PowerPC ports to be
takendirectly from the Red Hat distribution, with no major patches.

Boot Me Up Scotty: A look at the MacOS BootX Control Panel.

At the same time, the Linux/PPC and Linux-pmac ports merged their
code into a single, more capable PowerPC Linux kernel source. This left
two branches of Linux for the PowerPC: Linux/PPC, with its monolithic
kernel, and MkLinux, with its Mach-based microkernel. After a few years’
concerted effort at standardizing the two distributions MkLinux and
Linux/PPC today share binary compatibility. You can run most
applications on either branch of Linux for the PowerPC.

In May of 1996, Gary Thomas took a job with the Open Software
Foundation’s (OSF) Research Institute and became an advisor to the
MkLinux project, but it took over a year for him to convince the OSF to
let him work on the port full-time.

But by this time, Apple’s days of funding freewheeling R&D
efforts like MkLinux were numbered. The company was struggling for its
survival, and under the leadership of Steve Jobs, Apple’s focus shifted
back to its core competencies. It redirected its MkLinux engineers to
work on its own Mach-based operating systems — first the ill-fated
Rhapsody OS, later Mac OS X — and in the spring of 1998, it stopped
supporting the MkLinux effort. A few months later, the OSF merged with
the Open Group and MkLinux development was left to the Linux community,
which has picked it up handily and kept the distribution very much
alive. One solitary engineer remained on staff at Apple until early this
year, doing what he could for MkLinux developers.

While MkLinux remains a starting point for thousands of new PowerPC
Linux users, Linux/PPC has become a more complete system. It runs on a
wider variety of PowerPC machines and is fast becoming the standard
Linux distribution for the PowerPC. Recently, rumors of the demise of
MkLinux have been circulating in the Macintosh world. The MkLinux folks
insist that they are complete nonsense.

While MkLinux remains a starting point for thousands of new PowerPC
Linux users, Linux/PPC has become a more complete system. It runs on a
wider variety of PowerPC machines and is fast becoming the standard
Linux distribution for the PowerPC. Recently, rumors of the demise of
MkLinux have been circulating in the Macintosh world. The MkLinux folks
insist that they are complete nonsense.

PowerPC Linux Distributions

If your PowerPC system is not a Macintosh, you’re best off
with Linux/ PPC. Should you happen to own a NuBus-based PowerMac (the
6100, 7100, 8100 series PowerMacs, for example) then choosing your
distribution is easy: Go with MkLinux; Linux/ PPC doesn’t work on these
systems. If you’ve got an iMac, Linux/PPC is the only choice. But if you
have another type of PCI bus Macintosh, then you must choose between the
speed of a Linux/PPC distribution, orthe coolness of Mach-based MkLinux.

Linux does not yet support the FireWire peripheral ports
that come with the new Blue and White G3 systems, but both Linux/PPC and
MkLinux developers hope to change this situation in the near future.

The most prominent Linux/PPC distributions are LinuxPPC 1999,
released by LinuxPPC, Inc.; Terra Soft Solutions Inc.’s Yellow Dog
Linux; and Pacific Hi-Tech TurboLinux PPC.

The Debian team is working on a PowerPC port of its distribution.
This port is based, in part, on both the MkLinux and Linux/PPC code,
however, to date it does not have a working installation method.

MkLinux is available from Prime Time Freeware. It runs on virtually
all the same Macintosh hardware as Linux/PPC, with the notable exception
of the iMac — this is currently a “work in progress” according to the
MkLinux documentation — and the NuBus systems I mentioned earlier.

Each distribution has a target audience. Yellow Dog Linux’s Champion
Server, with its advanced security features is directed toward Internet
service providers and developers. LinuxPPC Inc.’s distribution provides
a complete port of Red Hat Linux appealing to a wide variety of users.
For those preferring the Mach microkernel design, MkLinux is a
particularly well-developed distribution.

With the exception of the Debian port, these distributions are all
on a par with the latest Intel distributions. In fact, PowerPC Linux is
even ahead in some areas. If you want to plug in Universal Serial Bus
(USB) keyboards or mice to a Linux box, for example, it had better be
running Linux/PPC, since Linux on Intel doesn’t yet support USB.

BootXing Linux

Apple’s constant and buggy Open Firmware (Apple’s version of BIOS)
revisions have long been a headache for Power Mac Linux users. Broken
Open Firmware on the latest Blue & Whites and iMacs has made booting
Linux a next-to-impossible task. To solve this problem, Ben
Herrenschmidt wrote a MacOS program, called BootX, that lets you boot
Linux/PPC straight from MacOS. So evenif your Linux distribution cannot
handle the buggy Open Firmware, you canboot Linux/PPC right from the
MacOS.

BootX has made installing Linux/ PPC a floppy-less experience. It
loads a mini-Linux system (called ramdisk) containing the installation
program directly into RAM, circumventing the need to boot Linux off a
floppy. By using the Open Firmware video settings and the Mac OS video
driver, BootX also helps Linux users get around unsupported video cards
– the ATI Rage 128 video card that comes with the new Apple Blue and
White G3s, for example.

Software for PowerPC Linux

Wolf in Sheep’s Clothing: SheepShaver allows MacOS applications to work on a PowerPC running Linux by creating a MacOS runtime environment.

Most Intel-based Linux applications will run on PowerPC Linux with a
simple recompile, though not all code — programs that depend on the
little-endian nature of Intel programs, for example — is easily ported.
So PowerPC Linux users have access to the majority of Open Source Linux
applications. Virtually all of the key components of the modern Linux
distribution are available to PowerPC Linux users, including XFree86,
the modern GNU C 2.1 Library (glibc 2.1), egcs 1.1 (the modern compiler
which will be the basis of the GCC 2 compiler), and as I write this,
Linux kernels up to 2.2.7.

Popular Open Source software such as the GIMP (the GNU Image
Manipulation Tool), KDesktop Environment (KDE), GNOME (GNU Network
Object Model Environment), Apache, KOffice, Mozilla, Emacs, GDB (GNU
debugger), Lesstif, PHP: Hypertext Preprocessor, RPM (Red Hat Package
Manager), Samba, BIND (Berkeley Internet Name Domain), Sendmail, Pine,
and Perl work great under Power-PC Linux. Virtually any other Open
Source application for Linux will work smoothly under PPC Linux.

The PowerPC architecture is officially supported in the Linux
kernel. This means that the PowerPC port is in the main kernel branch.
It’s not some port done on the side that never finds its way into
Linus’s tree. Linus will accept patches for the PowerPC and they will
get merged into the main Linux tree.

Right now there is virtually no commercial software available for
Linux on the PowerPC, but ISVs are beginning to take a long, hard look
at the platform and this should change in the coming year.

One commercial product you can buy today is Applixware, an office
suite with full support for Microsoft Office format files. Applixware
contains all the components you’d expect to find in an office suite
including a word processor, spreadsheet, database, drawing and charting
tool, presentation tool, mail client, and an HTML authoring tool.

And in the personal unproductivity software realm, Loki
Entertainment Software will soon release a Linux/ PPC version of its
Civilization III: Call to Power strategy game. Loki recently
announced plans to bring other blockbuster game titles (including
Myth II: Soulblighter and Railroad Tycoon II: The Second
Century) to Linux, so with any luck we’ll see these titles on
Linux/PPC as well.

SheepShaver for Linux/PPC is also in the works. Based on a BeOS
program, it will let Linux/PPC users run MacOS applications from within
Linux/PPC, by creating a MacOS runtime environment within Linux/PPC.
It’s expected to be released any day.

The Code Ahead

Though Apple’s early work on the MkLinux port raised hopes in the
PowerPC Linux community, it appears that the MkLinux work was more of a
testing ground for the Mach kernel than a concerted effort on Apple’s
part to support Linux. However, changes are afoot. In the last few
months, Apple has hired a Linux Technology Manager, whose job is to help
Linux developers get access to Apple’s hardware specifications. Apple
now says it plans to open up the specifications to its older products.
When this will happen, and how much information will actually be
released is unclear, but it is a sure sign that Apple is interested in
reversing its history of shutting out the Linux community.

And though some in the Linux community have criticized it as a
cynical attempt to get free PR from the Open Source buzz, Apple’s
Community Source license is, at least, a step in the right direction.
And Darwin — an Open Source subset of Apple’s Mac OS X server — is
another positive sign. At the very least, Linux developers can now look
at Darwin’s device drivers to get the specifications on Apple’s current
hardware.

One area where help from Apple could make a real difference is with
its next-generation PowerPC chip, the G4, which is expected later this
year. When Apple’s latest machines, the G3s were introduced, developers
had Linux running on them in less then a month. With Apple’s
cooperation, Linux users could be enjoying the benefits of G4 systems as
soon as they ship.

Like the rest of the Linux community, the PowerPC ports have gained
a great deal of momentum in the last two years. There are now hundreds
of thousands of Mac owners booting up Linux, and commercial companies
are just beginning to notice. So are some computer resellers. Terra
Soft, the company I work for, is presently negotiating distribution
deals with value added resellers (VARs) that will make preinstalled,
fully configured PowerPC Linux systems available to those who want them.
No doubtother such deals will materialize as the year progresses.

System administrators now have an alternative to Intel that not only
offers more speed and a smaller form factor, but the same Linux
operating system that they already know and love. As Linux enters the
desktop market, PowerPC Linux is sure to make the powerful Macintosh
personal computers and Linux a winning combination.

Dan Burcaw is Director of Research and Development at Terra Soft
Solutions, Inc. of Loveland, Colorado. He can be reached at
dburcaw@terraplex.com. Linux Magazine’s Robert McMillan also
contributed to this story.