Chapter 10. Dual-Boot and Beyond
Mac OS X isn't the only operating system you can run on your Mac. Right about now, some of you are probably saying to yourself, "Huh?", but stay with me here. There are many PowerPC-based operating systems that run great on Apple hardware, including Linux, NetBSD, BeOS, and many others. But who says you have to run one operating system at a time? And who says it has to be a PowerPC-based operating system?
There is an array of bewildering choices when it comes to mixing and matching operating systems. Do you need run Linux on your PowerBook so you can write code for a client? Sure, no problem. How about running Linux under Mac OS X? Also, no problem. Do you want to run Mac OS X on an x86 Linux machine? You can even do that, if you are patient. Here are some of the combinations we'll look at in this chapter:
Running on the Bare Metal
If you want to run an alternative operating system on your Mac, there are many choices available. Linux and NetBSD will run on just about any kind of Mac, all the way back to the 68k-based Macintoshes. BeOS can run on many of the pre-G3 Power Macs, but most of the current BeOS development is on the x86 version, so this might be of curiosity value only. To boot into another operating system on your Mac, you'll need to erase or repartition your drive. We'll talk about this in the "Linux on Mac Hardware" section of this chapter; much of what you read in that section will apply to other operating systems as well.
Running on Mac OS X
There is a good selection of emulators that run on Mac OS X. With Microsoft's Virtual PC ($99 and up; http://www.microsoft.com/mac/products/virtualpc/virtualpc.aspx), you can run x86-based operating systems. Amit Singh's legendary "Many Systems on a PowerBook" article (http://kernelthread.com/mac/vpc) documents dozens of operating systems that run under Virtual PC. In addition to Virtual PC, there are two open source x86 emulators of note: Bochs, a portable (but very slow) x86 emulator and QEMU, a highly tuned x86 emulator that comes close to Virtual PC in speed. We'll discuss Virtual PC and QEMU in the "Emulators on Mac OS X" section.
Running Mac OS X under Another OS
This is probably the oddest one of the bunch. Although it may sound like some sort of sick fantasy, you can run Mac OS X on PC hardware using PearPC (http://pearpc.sourceforge.net). You'll need a fairly fast computer to even approximate the speed of entry-level Macs. Running Mac OS X Tiger on my PC (a 2.4GHz Prescott-core Pentium IV with 512MB of PC3200 RAM and a Radeon 9600 graphics adapter) felt a lot like my first Mac OS X machine (a PowerMac 7500 with a Sonnet G3 add-in card, 128 MB of RAM, Radeon MAC Edition, and XPostFacto, which allowed me to even install Mac OS X on the unsupported hardware). In other words, the system was just barely usable, and constantly pushed the limits of my patience. But with a fast enough PC and some more time for PearPC to mature, it could become a very interesting way to run Mac OS X. Read all about it in the "Emulating the Mac" section of this chapter.
All of these operating systems wouldn't be very useful if they didn't talk to the outside world. Whether you're running an alternative operating system on the bare hardware or under an emulator, getting the network up and running can be tricky in some cases. When it gets tricky, we'll cover this essential configuration step in detail in this chapter.