Stop The Presses

Apple was perhaps one of the last companies that most Linux developers and users expected to join the Linux effort—until Apple's recent joint announcement with the Open Software Foundation that they were supporting a port of Linux to the Mach microkernel running on PowerMac computers. This announcement was treated by Apple as if it were of equal importance to their announcement of a large price cut on most of their computers. The announcement was made on the fifth of February at the Freely Redistributable Software Conference, and made international news that day and the next.

Linux had already been ported to some PowerPC machines before Apple's work was started; see the Linux/PowerPC web page at http://www.linuxppc.org/linuxppc/ for the latest information. They have successfully run Linux/PPC on a Motorola PowerStack computer. The work that the OSF did is significantly different; instead of porting Linux directly to PowerMacs, they ported Linux to OSF MK, the Open Software Foundation Microkernel, based on Mach 3. In microkernel parlance, this is creating a Linux “server”. While they did that, they also ported OSF MK to the PowerMac. After completing those projects, porting their Linux server to OSF MK on the PowerMac took less than three weeks. That doesn't mean that it is production quality yet, but that is significantly faster progress than most ports of Linux.

The Linux server creates other potential advantages, besides making Linux quickly available on Apple PowerMacs. For instance, OSF MK has been ported to platforms that Linux has not yet been ported to, such as Intel i860 and HP PA-RISC. Developers wishing to port to such platforms may find it easier to port the Linux server to OSF MK on those platforms than to do a complete port of Linux to those platforms, or may find it easier to start their port by first porting the Linux server, and then working on porting the standard monolithic Linux kernel.

Just as at DEC, Linux support at Apple is a serious part of company strategy supported by corporate management. By maintaining close contact and a friendly relationship with the developers working on the other Linux/PPC ports (Motorola, Be, FirePower, and IBM), Apple has assured the Linux community that it is not attempting to take over Linux development, but instead has become a contributing member of the community.

The work has not only contributed to Linux, but also to OSF MK. Several performance improvements and extensions were made to OSF MK to improve the performance of the Linux server, which may also improve the performance of other servers on OSF MK.

Linux is designed as a monolithic operating system, the antithesis of a microkernel-based operating system. Many people have remembered that Linus has said that he is not interested in making Linux be a microkernel operating system. Doesn't creating a Linux server violate the whole idea of Linux?

Not in the least. First of all, the great majority of the source files were unmodified. Of 909 original files in the Linux source code, only 43 had to be modified. Second, the source code to everything, including the drivers in the microkernel, is freely available, and can be used to develop a monolithic Linux/PowerMac if there are sufficiently interested developers. Finally, no one is suggesting that the Linux server should replace the monolithic version of Linux as the official version.

For more information, see the web site: www.osf.org/mall/os/mklinux.html

Over several months, support for Linux/Sparc has progressed on the sun4c architecture to the point where it is now able to run all normal SunOS X-based binaries correctly, including Netscape, and work on the native user environment is proceeding at a rapid pace.

On February 17th, David Miller (the leader of the Linux/Sparc team) announced that he had achieved a shell prompt on the sun4m architecture; specifically a Sun SparcClassic. (if you don't know why that is significant, read the series of articles on porting Linux to the DEC Alpha in Linux Journal issues 18-21.) On the 20th, he “apologized” for that “lie,” announcing that it now “runs all the programs that work on the sun4c”.

Several other developers, including Miguel de Icaza, are hard at work developing a full user environment and distribution of Linux/Sparc. Keep an eye on Linux Journal and the comp.os.linux.announce newsgroup if this whets your appetite.