Apple has once again surprised the computer industry with its recent decision to offer key parts of Mac OS X Server as publicly available source code. Leaders of the open-source movement have praised Apple as the first major computer company to adopt an open-source strategy–the same approach that’s made the Linux operating system a popular alternative to Windows NT. But what does this mean for Mac users and future versions of the Mac OS? Plenty, Apple says.
“It’s as if we had hired a huge bunch of programmers for free,” asserts Ernie Prabhakar, Apple’s product manager for Mac OS X Server. “We’ll have a final product with better performance and new features.”
How It Works
Apple has created a subset of Mac OS X Server called Darwin that includes Apple’s versions of the Mach 2.5 microkernel, the Berkeley Systems Distribution (BSD) 4.4 version of Unix, the Apache Web server, and such Mac-specific technologies as AppleTalk and the HFS+ file system (see “What’s in Mac OS X Server”). Apple has posted the Darwin source code (the underlying programming commands) on its Web site. Developers who agree to Apple’s license agreement can download the source code, modify it, and include it in their own products. They don’t have to pay royalties or license fees, but they do have to make their source-code modifications publicly available.
Apple is then free to incorporate any changes into future versions of Mac OS X Server–and Mac OS X, which uses the same Darwin components. Apple plans to release Mac OS X, its next-generation client operating system, later this year.
There are other benefits as well. Developers of G3 accelerators for older Macs could theoretically use Darwin to create drivers that would allow those Macs to run Mac OS X, which otherwise requires an Apple G3 Mac. Large Apple customers, especially universities, are now free to customize Mac OS X Server for their own needs. Developers who might otherwise turn to generic versions of Mach 2.5, Apache, and BSD 4.4 Unix–all available currently as open-source software–will have a chance to work with Apple’s versions of these components.
The move also makes Mac OS X Server a more viable competitor with Linux, the best-known open-source software. After all, it’s hard to compete with a free product unless yours is also available in a free version.
Darwin’s Limits
Although it is a fully functional modern operating system, Darwin lacks some of the differentiating features in Mac OS X Server, including NetBoot, which allows Mac clients to boot from a server partition (see “Apple Introduces OS X Server,” News, April 1999). Darwin also lacks a graphical user interface, but developers could theoretically port one of several freely available Linux windowing environments to the new OS. Apple interim CEO Steve Jobs says the company could move other Apple technologies to open source, but he has not announced specific plans.
Developers are free to modify Darwin in any way they choose. They can also create versions for Intel processors or other chips. But there’s no guarantee the modified software will even run on a Mac.
June 1999 page: 27