Most computer users have had some contact (or a run in) with Unix, long the dominant operating system for universities, research labs, and the Internet. However, hardware requirements, software costs, and Unix's inherently cryptic nature usually put this OS beyond the reach of home users. In the early 1990s, Linus Torvalds at the University of Helsinki in Finland and an international group of volunteers developed a freeware Unix clone called Linux. Linux has since become widely available to PC owners, with several thick book/CD-ROM packages on the shelves of most computer book stores. In 1997, similar versions of Linux were released for PowerPC-based Macs; this article discusses my non-expert experience installing and using one of them: MkLinux.
Why Bother? Why would anyone want to run Unix on a Mac? You can't use Mac applications, and the complicated command-line interface is as far from the Mac OS as one can get. Isn't Unix the antithesis of Macintosh? I installed MkLinux to educate myself about an important OS, and to learn how a true multi-user system with preemptive multitasking and protected memory works.
Folks with deeper technical knowledge may find other aspects attractive. For example, Linux can be used to run an Internet server, with all the usual services and some functions the Mac OS can't yet provide, like true multihoming. Programmers - many of whom used Unix in school - will appreciate that powerful compilers, editors, and other tools are readily available for Linux, plus the source code for the whole system (and many applications) is available so you can experiment and customize. Someone who uses Unix at the office can use Linux to do the same on a Mac at home. Finally, let's not forget that Rhapsody, Apple's forthcoming operating system based on NeXT technology, includes a full Unix implementation, although it'll be hidden unless users specifically access it.
Choices -- There are two easily accessible versions of Linux for the Macintosh Power PC. MkLinux, sponsored by Apple, is a port of Linux running on top of a Mach microkernel. A CD-ROM/book combination with Developer Release 2.1 (DR2.1) is sold by Prime Time Freeware for $50. MkLinux generally runs on PowerPC 601-based NuBus Macs and PowerPC 604-based PCI machines, but not (yet) on 603 boxes or (reportedly) on Apple's new G3 systems. You need at least 500 MB of disk space (on a separate disk or drive partition from the Mac OS startup disk) and a bare minimum of 8 MB of RAM.
Since DR2.1 was issued early in 1997, six updates have been produced, available only by downloading from the Internet; altogether, the updates are more than 200 MB. For this article, I've stuck with version 2.1. The one major deficiency I've found in MkLinux is that it cannot print over the serial port. Users with PCI machines also report PPP does not work, except possibly under the fifth update.
The second option is Linux for PowerPC (linux-pmac), a conventional, non-Mach port produced by a group of volunteers led by Paul Mackerras at Australian National University. A $32 CD-ROM recently became available for this system, which is supposed to work on all Macs that use Open Firmware, a process that controls hardware initialization and diagnostics before an operating system loads. This excludes PowerPC-based 601 NuBus machines and apparently some Performas, but does include PowerPC 604-based machines and many PowerPC 603-based Macs.
I have a Mac with a PowerPC 601 processor, so I haven't tried linux-pmac. Linux for 68K Macs is currently under development.
If neither MkLinux nor linux-pmac capture your fancy, two other non-commercial Unix-like operating systems are available for the Mac, NetBSD (formerly MacBSD) and OpenBSD. These work on some Mac models and are available on CD-ROM for $35 and $30 respectively. If you'd like to consider a commercial alternative, check out the highly regarded MachTen from Tenon Intersystems. [Tenon also recently created WebTen, a Mac application combining Tenon's Unix technology with the popular Apache Web server. -Adam]
All these ports are sensitive to the type and model of machine they are installed on, so double-check with FAQs, mailing lists, and vendors to make sure your particular Mac or clone will work with a particular Unix offering. The rest of this article refers to MkLinux DR2.1, which works fine on my Performa 6116.
Installation -- Installing MkLinux DR2.1 was easy and straightforward using the CD-ROMs and book from Prime Time Freeware (PTF). The most difficult part was formatting my hard disk with the correct partitions. I have an external 1 GB hard disk from APS, and its formatting software could not set up Unix drive partitions. Using ResEdit to modify Apple's HD SC Setup program (as described in the PTF book) did the trick, however. I also had a little trouble setting up networking; MkLinux includes a command called setnet to facilitate setting up PPP and LAN connections. I also had to edit the default chat script to make MkLinux dial my modem and connect to my ISP.
After installing DR2.1, I found a new control panel in the Mac OS, which can be set so that when the computer starts you get a dialog box enabling you to start MkLinux. Virtual Memory and RAM Doubler must be disabled for it to work (although this has been remedied in recent updates).
If you need help, you can count on a sympathetic attitude from lots of other folks running MkLinux on a wide variety of machines. At least ten mailing lists covering MkLinux topics are hosted by Apple, and traffic is substantial on most of them. There are also a number of FAQs and help pages on the Web, including the Linux on the PowerPC FAQ-O-Matic.
Learning the Ropes -- If you don't know or remember much about Unix commands, there will be some learning required before you can do anything. The PTF book is of only modest assistance; the best approach is to borrow or buy one of the several tomes available on Linux for PCs. I used a copy of Linux Unleashed which I found on sale.
Most important to master are the procedures for booting up and shutting down; setting up user accounts; moving around the file system; copying, moving, and renaming files; modifying file permissions; accessing the hard disk; reading and editing text files using the program vi (not easy to get used to!); downloading via FTP (although you can use FTP in the Mac OS if you want); and decompressing, building, and installing new programs.
These tasks are non-intuitive and seem daunting at first, though they turned out to be easier than I expected. Neat graphical programs are available that enable you to bypass much of the command maze, but you are unlikely to install and run them correctly unless you can deal with the basics.
Running X Windows -- Unix is not a completely text-based world. MkLinux duplicates X Windows, a graphical interface which you start by typing the command X11. In its most basic form, X provides you with independent windows within which you can execute the usual commands. The system can, however, be made more elaborate through the use of window managers that allow you to customize the desktop.
MkLinux DR2.1 comes with two free window managers, the bare-bones Tab Window Manager (twm) plus the Freeware Window Manager (fvwm2). The latter has nice 3-D borders and enables the user to create scrolling windows, multiple "pages" or desktops, and all sorts of buttons for initiating action without typing commands.
X Windows has plenty of applications, many of which are free and look and work like their analogues for the Mac or Windows. On my MkLinux setup I was able to install attractive graphical programs to manage files (TkDesk), edit text (Nedit), read news (Knews), get email (Xfmail), transfer files (Xftp) and browse the Web (Mosaic) without excessive difficulty. Netscape Communications has also begun compiling Communicator and Navigator for MkLinux. Several games are also available, including one called XBill, where you try to stop a familiar-looking man from installing Windows on a bunch of computers. A basic source for MkLinux applications is the MkArchive.
Conclusion -- Working in X Windows brings you full circle, recreating the sort of interface for which you purchased your Mac in the first place, although it is quite different in look, feel, and capabilities. Building, improving, and maintaining an MkLinux machine is guaranteed to keep boredom at bay for some time. It's also nice knowing that there's more power with which to experiment, especially as Rhapsody nears completion. A major update, MkLinux DR3, is expected before the end of 1997, which promises better performance and more possibilities.