According to Hoyle...

Alternative Macintosh Operating Systems

March 2008

By Jonathan Hoyle

macCompanion

http://www.jonhoyle.com

This month, we examine the various operating system alternatives that are available to the Macintosh user. Although Mac OS X and Microsoft Windows represent the operating systems that run on over 99% of all Macintoshes, there are numerous others which are simply a download click away. The vast majority of these are essentially different flavors of the same operating system: Linux. In addition to Linux, there are other Unix-like operating systems, as well as others which are unique onto themselves. There are literally dozens of these options, although many are tied to very specific hardware, so the choices for your particular Macintosh computer may be limited. For this discussion, we will consider any operating system which is not a version of Mac OS or Windows.

Alternatives for the Intel-based Mac

For Intel-based Macs, there are two ways one can run Microsoft Windows: either by dual-booting via Apple's Boot Camp, or by running virtualization software (such as Parallels Desktop or VMWare Fusion). But can these avenues be used for non-Windows OS's as well?

Apple's Boot Camp is specified to run Windows XP or Vista only. Apple has not specified Linux as a possible choice for Boot Camp, but that doesn't mean it can't be used. Users who wish to include Linux as an additional Boot Camp option should visit this article, which details the procedure for triple-booting your Intel-Mac. It's a bit involved, and there are the usual device driver issues, but after several hours, you can eventually reach your goal.

The far easier approach to running an alternative operating system on your Intel-based Mac is through the aforementioned virtualization software approach. Parallels opens the door to just about any modern Intel-based operating system, including virtually all Linux distributions, any version of Windows (from 3.1 to Vista Enterprise), FreeBSD, Solaris, MS DOS, and even the forgotten OS/2, just to name a few. VMWare Fusion boasts an equally impressive list of supported operating systems.

Essentially, the world is your oyster if you are a promiscuous operating systems junkie with a modern Intel Mac.

What you cannot do (at least not on an Intel Mac) though is run most 68K- or PowerPC-based operating systems, such as Yellow Dog Linux. You might be fooled into thinking that the PowerPC emulator Rosetta would assist in this endeavor, but Rosetta is a part of the Mac OS X operating system and is not available when booting into another OS. If you are truly intent on guest-hosting a PowerPC-based operating system on your Intel-based Mac, your best chance is to check out PearPC, a Windows-based PowerPC emulator which supports Mac OS X 10.3, Mandrake Linux PPC, NetBSD/PPC and AIX. Neither the SheepShaver nor the Basilisk emulators will run these operating systems, as they fail to emulate the needed PMMU processor. However, both SheepShaver and Basilisk can support guest operating systems within Classic Mac OS (see the Guest Operating Systems for the Mac section below).

Alternatives for the PowerPC-based Mac

Despite the strong Intel partiality that predominates the Linux world, there is a surprising number of PowerPC-based Linux solutions available. Many of these are simply PowerPC rebuilds of preexisting Intel distributions, including: Debian, Gentoo, Mandriva (formerly Mandrake), SUSE, Fedora, Slackintosh (a PPC version of Slackware), and the ever popular Yellow Dog Linux (a PowerPC packaging of Red Hat Linux). In addition, there are PowerPC ports of OpenBSD, NetBSD and CRUX as well. Each of these runs on more recent PowerPC-based Macs (G4's or G5's), although many also have prior versions still available to download which will run on earlier hardware.

With Apple's abandonment of the PowerPC platform, there are already signs that some of these Linux distributions are no longer being supported. For example, Ubuntu Linux had supported G3 Macs and later, but announced that support was ending after version 6.10 (early 2007). Other distributions appear to have only half-hearted support for the Mac, such as Rock Linux, which tested against an older iMac, but no serious development since.

Going back further, LinuxPPC was a version written for PCI-based CHRP models, including Mac clones. This initiative began in 1996 but eventually died in 2002. Much of this initiative is now in the hands of PenguinPPC. LinuxPPC has also been ported to Nubus-based Power Macs. However, the most popular Linux available on these Nubus machines is MkLinux.

One very powerful and rather exciting operating system for pre-G3 Macintoshes was BeOS. At the failure of the Copland project in 1997, Apple seriously considered acquiring BeOS as the foundation to its next generation operating system, but the decision was instead made to adopt NeXT as this foundation of the future. Although officially defunct, BeOS lives on in the hands of many enthusiasts.

Alternatives for the 68K-based Mac

Do you have an old 68K Mac sitting up in the attic somewhere? If so, you may be surprised to find that you can dust it off and turn it into a Linux server with relative ease. The Linux/Mac68K project (formerly MacLinux) has as its primary goal to allow Linux to run on as many 68K Macs as possible. Linux requires a PMMU (Paged Memory Management Unit) processor, which is not found on some of the earliest Macs. No 68000-based Mac has one, nor does the 68020-based Mac LC. Fortunately, the 68030 processor has one built in, so any 68030 or better Macintosh can be used. Even the 68060 is supported, for those Macs with 060 accelerator boards.

If you have the original 68020-based Mac II, you have the potential to run MacLinux, as this machine includes a socket for an optional 68851 PMMU to be installed. If you are one of the lucky few with this already pre-installed, you are good to go. Otherwise, you will have to purchase a 68851 and install it yourself. In addition, you will want to have a minimum of 4 MB of RAM on board, but maxing out your RAM is the recommendation for MacLinux. The latest version of MacLinux updated the kernel to version 2.2.25 (Fall 2003), and an OS X cross-compiler was made available in 2005 for developers interested in contributing.

Of similar vintage is NetBSD/mac68K, the 68K equivalent to NetBSD/macppc project referred to above. There are also 68K Mac ports of Debian Linux and OpenBSD (formerly MacBSD). If that's not enough, true Unix thrill-seekers may try to locate MacMach, a 4.3 BSD / 3.0 Mach Microkernel project that was hot and heavy in the early 1990's, but I have been unable to find where it is today.

Many people think of Mac OS X as Apple's first and only attempt to put the ease of a Macintosh interface on top of a powerful Unix operating system. This is untrue, as Apple had its first Unix implementation in the late 1980's with A/UX. This wonderful operating system was essentially an SVR4 implementation with a System 7-like Finder and a compatibility layer to run standard Mac OS apps as well as Unix ones. It even included a command line Terminal shell for those more comfortable in that environment. This was a direct analog of Mac OS X for 68K Macs! Unfortunately, A/UX did not survive Apple's move to the PowerPC, as IBM's RISC-based AIX was considered its replacement. The final release of A/UX was version 3.1.1 from 1995, and with a little luck, perhaps you may be able to find it on Ebay or Craig's List.

Guest Operating Systems for the Mac

In each of the operating systems discussed above, we examined those which essentially replace the Mac's standard OS. However, there are operating systems that may coexist with the native Mac OS as guest operating systems. These live and operate within application space, thereby not removing the standard Mac OS, into which the user is accustomed to booting. Essentially, these guest OS's are viewed as just applications by the host Mac OS, whilst being an operating system onto themselves within their own domains. The benefits to this approach include an easy installation procedure, simplicity to launch (double-click like any other app), and the ability to coexist with other Macintosh programs.

Guest hosting as an application, such as the 68000-based Mac Plus or Mac Classic. The downside is pretty severe though: although these guest OS's can be preememptive multitasking and memory-protected in themselves, they are vulnerable to the limitations of the host OS. For example, a guest operating system running as a Classic application is itself multitasked only cooperatively, and the entire environment may be breached by a single errant Classic Mac program. Although this may appear as the worst of both worlds, it does buy you the greatest simplicity of running a separate operating system.

With all of the free Unixes (Unices?) for the Macintosh, you might understandably think that none could be sold commercially by a 3rd party. If so, prepare to be surprised by MachTen by Tenon Systems, a 4.4 BSD implementation that lives inside the Classic application space. After A/UX, this was one of the more popular and well-supported Unix implementations available back in the day. Versions 2.2 and 2.3 were the last to support 68K, whilst version 4.1.4 was the end of the line for PowerPC. None of the product literature indicates if MachTen will run in the Classic Environment under Mac OS X; I emailed Tenon about this and was told that they remember having had success in testing under Classic. In late 2002, Tenon announced their discontinuance of MachTen, marking it down from its high of $695 to a mere $99 "while supplies last".

Apparently supplies were in quite abundance at the time, since more than 5 years later, MachTen remains available on their web site for the same $99.

There are a couple of other alternative 68K Mac operating systems which live inside application space. One is the rather famous MacMinix, a 68K Mac distribution of Minix, the Unix-like operating system well known to computer science students of the 1980's using Andrew Tanenbaum's textbook Operating Systems Design and Implementation.

Whether or not you believe that Linus Torvalds stole Minix from Andy Tanenbaum to create Linux, MacMinix is still worth a look. Another is MacMint, a Mac OS port of the Atari ST operating system MiNT, an OS written to be a TOS / Multi-TOS compatible replacement. MiNT is an acronym for MiNT Is Not TOS.

Coming Up Next Month: We look back at the face of Basic development environments in 2008. See you in 30!

Read all of the According to Hoyle columns.

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