February 1999
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Apple's position: No Linux Apple appears to have no interest in supporting Linux, but the penguin can do a lot for the Mac Summary Though most people think of the Intel platform when they think of Linux, Apple and Linux have a history that goes back to 1995. Rick Cook analyzes Apple's interest in Linux -- past and present -- and answers the question: What can Linux do for the Mac? (2,300 words) By Rick Cook

No such luck. Macworld came and went, and the Mac-Linux machines, rumored to target such specialized markets as education, never materialized.

Today, Apple's official position on Linux is simple: The company has nothing to do with Linux, doesn't want anything to do with Linux, and won't offer Linux on its machines.

Instead, Apple is pushing Mac OS X ("Mac ten"), the developed version of the Mac operating system built around the Mach microkernel architecture. The first version of Mac OS X, the server edition, will be out sometime this quarter. It will fill the role others have envisioned for Linux.

Dueling POVs
From Apple's point of view, this decision makes excellent sense. After all, Apple's product is essentially a nifty user interface and the operating system that supports it. The Macintosh hardware exists only to run the Mac operating system. Why offer another operating system that can't match the user interface of the Mac?

From the customer's standpoint things aren't quite so clear. "Basically our customers are looking for speed and flexibility," says Jason Haas, marketing director for LinuxPPC, a Milwaukee-based enterprise that markets the LinuxPPC distribution of Linux for the Macintosh. "Linux is fast and it can do a lot of things the Mac OS can't do."

Better networking
For one thing, Apple has traditionally lacked a server operating system to support the Mac in networked environments. Mac OS X Server is supposed to fill that hole when it arrives, but it hasn't yet arrived, and no one knows how well it will work when it does.

For another thing, networking is better with Linux than with the Mac. And it's cheaper too. "We have a lot of people who are interested in replacing the Apple server software with LinuxPPC and leaving the Macintosh clients to do what they do best, which is run applications," Haas says. He also cites a product called Netatalk Server which is an AppleShare IP-compatible server. "It can do the functions of AppleShare IP for hundreds or thousands of dollars less than AppleShare IP," he says. "Plus, you've got the power of Linux behind it, which makes it a win-win for system administrators."

A better architecture
Another thing in Linux's favor is the PowerPC chip, a powerful processor with a modern architecture. Exactly the sort of processor that will do an excellent job supporting Linux. In fact, if you want a Unix system built around a 64-bit processor, a G3-based Macintosh is by far the cheapest option. Systems using the Compaq (formerly DEC) Alpha or the Sun UltraSPARC chip are more expensive, and Intel's next-generation Merced chip (which promises only mediocre performance gains) isn't here.

"One group I know of ported some medical-imaging applications from [an] SGI [Unix-based workstation] to LinuxPPC," Haas says. "The fellow said they were relatively easy to port and they got a big performance gain. And that's just moving to a standard Power Macintosh G3." What Haas didn't add was that the Power Macintosh probably cost one-quarter the price of the SGI workstation.

And even better performance
If you have Macintosh hardware and you need a lot more performance, Linux can give it to you. As an example, Haas cited his former employer, which used a total of six G3s running AppleShare IP to support 32 people. "With Linux, you could easily turn five or six servers into two," he says.

As a result there are several versions of Linux for Apple in active development. None of them has the level of commercial features (i.e., support and ease of installation) as, say, the Red Hat or Caldera distributions for the Intel architecture. But they are full-featured and available. (See my current Linux 101 column for more info on the Mac distributions.)

Education
If it doesn't make corporate sense for Apple to offer a Macintosh with Linux to the general public, there is still one market where such a product makes a lot of sense. Compelling sense, in fact. That market is education.

Apple has traditionally had a strong relationship with schools and colleges, stretching back to the days of the Apple II. While Apple lost ground during its slump, there are still a lot of teachers whose primary computer training was on Apple, and who still have a soft spot for the Mac GUI, which makes it easy for children as young as five or six to use a computer. (I've seen this phenomenon first-hand, since I volunteer at my local Boys and Girls Club running their Macintosh lab for a few hours a week.)

Colleges and high schools, however, want to teach beyond point-and-click. Specifically, they want to teach their students the nitty-gritty of using a modern operating system, and much of the time that operating system is Unix.

A dual-boot Macintosh running Mac OS and Linux offers an ideal combination for educational institutions. Educators can capitalize on their familiarity with the Mac and still offer students an advanced Unix-like operating system. As the Linux kernel evolves further, adding better support for symmetrical multiprocessing, these features can be added. Such evolution may never be possible on the Mac operating system.

Economically, the Mac-Linux combination is attractive as well. Linux distributions range from free to cheap, and so do most Linux-based applications. There aren't many native applications for the Mac on Linux, but since open source applications come with source code, that's fairly easy to remedy. Even if a particular school doesn't have the skill to rework an application for the Mac, someone else will, and the results will be made freely available.

Education was the target market of the rumored Linux Macintosh back before January's Macworld show. The rumor seems to have spread -- and go to print -- less on the strength of evidence (though some Apple dealers were reportedly told about the project by Apple) than on the popularity of the concept.

The Apple-Linux connection
Still, Apple has flirted with Linux, albeit in a tentative fashion. Apple has even positioned booths at Linux-based tradeshows. Perhaps the most tangible outgrowth of that "across a crowded room" flirtation was the MKLinux project, jointly sponsored by the Open Group (then the Open Systems Foundation) and Apple to port a version of Linux to the Mach microkernel for the PowerPC.

"It's kind of amazing to me, given Apple's troubles, that they were willing to support MKLinux at all," says Rich Morin, president of Prime Time Freeware, a Mountain View, CA company that handles distribution of the current developer release of MKLinux. Yet, in spite of the company's well-publicized pre-1998 misstep and loss, Apple kept the MKLinux project alive.

This isn't exactly common knowledge even within Apple. When asked about MKLinux, an Apple spokesman wasn't aware of Apple's sponsorship of the project and characterized MKLinux as the work of an independent third party with no Apple input.

In fact, the MKLinux project germinated within Apple, and at one time the company had a whole team of engineers working on it. That lasted until Apple shifted course on its operating systems, bought NeXT, and decided to use the Mach-based NeXT OS as the basis for its new operating system. "All of a sudden anyone who could spell 'Mach' was golden," Morin says. As a result, most of the team was shifted to the program for a new Mach-based Apple operating system.

So, if it's not interested in Linux, why has Apple supported MKLinux ?

Part of the answer is that the MKLinux project began in 1995 and Apple has changed considerably since then. Goals change, strategies shift, and what was once an inexpensive (for a company like Apple) bit of insurance may no longer be relevant to a rejuvenated, refocused Apple.

Another part of the answer is that having a version of Linux running the Mach microkernel on PowerPC hardware gives Apple a test bed for new ideas involving Mach on the PowerPC without stigmatizing Apple for any failures.

Then too, Apple's course toward a new operating system has been torturous and somewhat erratic. Originally, Apple tried to develop an object-oriented version of its operating system, first on its own and then later in partnership with IBM in an enterprise called Taligent. None of the projects was particularly successful.

Still later, after Apple bought NeXT, the company announced it was scrapping operating system projects code-named Pink, Copeland, and Gershwin, and would build a new operating system based on the NeXT OS, which was built on the Mach microkernel. What has finally emerged is Mac OS X.

This is where the insurance element of Macintosh Linux comes in. By having a Linux project in the works, Apple always had the option to shift to a Linux-based operating system if it had to, or of building a new OS on Unix. This was never likely, but for a company as big as Apple, keeping a few engineers working on a fallback position to the fallback position is a cheap enough insurance policy.

Of microkernels, Mach, and Linux
Mach isn't Mac OS X. Mach is a microkernel operating system developed at Carnegie-Mellon University as a research project. Mac OS X is based on Mach, via the NeXT OS, but they are completely different.

The kernel is, of course, the heart of the operating system. And a microkernel is the Jennie Craig version of the kernal. It's been slimmed, stripped, and pared until it contains only the absolute bare necessities of the operating system. Everything else, from the user interface to the filesystem, is kept outside the kernel.

Linux isn't a microkernel OS, but like most modern versions of Unix, it uses something of the same strategy. A lot of things (like drivers) can be loaded as modules rather than being compiled into the kernel.

The obvious advantage of a microkernel is flexibility without huge kernel size. A less-obvious advantage is comprehensibility. Microkernels are typically small enough to be understood by one person, an impossibility in most other modern versions of Unix (and never mind Microsoft's operating systems).

The concomitant disadvantage is speed. LinuxPPC claims to be about 20 percent faster than MKLinux because it doesn't use a microkernel architecture (remember, MKLinux is based on the Mach microkernel).

Although the underlying architecture is different (and the case of MKLinux, so is the underlying structure), all of the Macintosh Linux versions are designed to make porting software from other versions of Linux -- or other versions of Unix -- as easy as possible.

For example, Haas says that Applixware ported most of its Office Suite to LinuxPPC in about a month. "They said it went flawlessly," Haas says.

Linux on Macintosh
At press time, all the versions of Linux for the Mac are still works in progress. LinuxPPC and MKLinux are the furthest along. Both of them are built on the Red Hat 5.0 distribution and both offer all the usual compilers, servers, and other software that comes with Intel versions of Linux.

Of course, Linux on the Mac is still Linux. The various versions will happily share a hard disk with Mac OS, but they won't use its GUI. Once you've booted Linux, you're in Linux, complete with the windows managers and user interfaces of your choice. This comes as a shock to some Mac addicts, who subconsciously expect everything that runs on a Mac to look like a Mac.

Apple Linux on Macintosh?
So what are the chances that Apple will officially adopt Linux? At this point, probably nonexistent. Whatever may have gone before, today Apple seems to have a viable contender in Mac OS X and it is firmly committed to it.

What are the chances that a lot of Macintoshes will run Linux? Anywhere from good to excellent, depending primarily on how you define "a lot." According to some estimates, there are already more than 500,000 copies of Linux running on Macs of varying vintage. Haas says that "realistically," there are between 250,000 to 300,000 LinuxPPC users alone. (This is based on the 100,000 or so downloads of LinuxPPC.)

That may not be much compared to the millions of copies of Intel Linux in use, but it's still quite a substantial number of machines. And of course, the number of Linux-on-Mac installations will probably grow rapidly over the next couple of years. Haas says the LinuxPPC site is running about 500 downloads a day.

These won't be official Apple installations, but some Apple users are going to find it attractive to add Linux to their systems, especially since they can do it without losing the Mac operating system and user interface. As for the actual numbers, that will depend in part on how good Mac OS X Server is, particularly in its first iteration.

Since one team is only warming up and the other has yet to take the field, it's impossible to make that comparison. Apple has generally shown itself much better at producing effective, working operating systems the first time out of the box than say, Microsoft; but Linux benefits from the two decades of networking experience and development built into its Unix heritage.

It isn't unreasonable to suppose that Linux will be more effective as a server than Mac OS X Server. And if the difference is large enough, users will be encouraged to install Linux instead of Mac OS X Server.

At the very least, the existence of Macintosh versions of Linux gives Apple customers a fallback in case the Mac OS X Server turns out to be unattractive.

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About the author
Rick Cook has been covering computers and high technology for nearly 20 years for various publications. He is the author of a series of fantasy novels full of bad computer jokes.