D.3.1. Getting the Mac Ready for Linux

Before you can see how fast your Mac really is, you have to do some work. You'll need a hard disk or removable disk, preferably a gigabyte or larger, that you can repartition. If you have only one hard disk, you'll need to get either an external hard drive or additional internal drive (if your machine has room for one) or erase the internal hard disk and repartition it! Unfortunately, there isn't any non-destructive partition software for the Macintosh.

Table D-1. pdisk Partitioning Commands

When you use pdisk, you're actually editing your hard disk's partition map. The partition map is a scary sounding name for a file that contains a list of all the partitions on your hard disk. The partition map is stored on a partition all its own.

When you're in the Mac OS, you see only one partition, which you think of as your hard disk. The other four partitions are invisible, and you don't have any reason to directly interact with them. (Unless you've decided to go and install Linux.) The first partition holds the partition map. The next three are device drivers, pieces of software that tells the Mac how to use the hard disk and where to look for the Mac OS partition. Your Mac OS software and the OS are stored on the fifth partition, which is an Apple HFS or HFS Plus partition.

If you have SCSI drives in your computer, pdisk will first display their names with "fake" SCSI names in the format /dev/scsibus.scsi_id, such as /dev/sdc1.5. Fortunately, it also lists their device name in proper /dev/sdletter format. Linux refers to SCSI devices with the /dev/sdletter scheme, so use that format when working with the device.

A hard disk on an Adaptec card will be at /dev/sda. Devices on the regular internal SCSI bus will follow at /dev/sdb and /dev/sdc. If your machine has only one device on the SCSI card, you're in the clear. If you have other devices attached to it, the naming game can get a little hairy.

And now, we partition:

When creating the root partition, instead of typing the length in megabytes, use the free-space partition's length in blocks. In this example, the Apple_Free partition is 4,195,504 blocks long, which is roughly 2 GB. By typing the partition's exact length in blocks, you will use up all the available disk space and not have wasted space left over after partitioning:

Command (? for help): c
First block: 9p
Length in blocks: 4195504
Name of partition: root
Command (? for help): p

Partition map (with 512 byte blocks) on '/dev/hda'
 #:                type name             length   base    ( size )
 1: Apple_partition_map Apple                63 @ 1
 2:      Apple_Driver43*Macintosh            54 @ 64
 3:      Apple_Driver43*Macintosh            74 @ 118
 4:    Apple_Driver_ATA*Macintosh            54 @ 192
 5:    Apple_Driver_ATA*Macintosh            74 @ 246
 6:       Apple_Patches Patch Partition     512 @ 320
 7:           Apple_HFS untitled        4194304 @ 832     (  2.0G)
 8:     Apple_UNIX_SVR2 swap              61440 @ 4195136 ( 30.0M)
 9:     Apple_UNIX_SVR2 root            4195504 @ 4256576 (  2.0G)

In this example, partition /dev/hda9 will become your root device. Write down which partition is your root device. You will need to know that later. If you have a SCSI hard disk, it would be /dev/sda7. Also note that if you are planning on installing Linux on a drive other than your startup disk, you don't have to have the Apple_HFS partition on the disk. You can devote the entire drive to Linux.

When you're done partitioning, type w:

Command (? for help): w
Writing the partition map will permanently save changes.
Save changes? (y/N): y

Tips for partitioning include the following:

• If you make a mistake, it's not fatal. You can quit pdisk at any time without saving changes.

• Changes are not final until you tell pdisk to write the new partition map with the w command.

D.3.3. Installing BootX

After you have placed the vmlinux file and BootX Extension in their respective places, double-click the BootX application. Make sure that the No Video Driver and Use RAM Disk boxes are checked. You don't need to enter anything in the Root Device or More Kernel Arguments field.

Make sure that the LinuxPPC CD-ROM is in the CD-ROM drive, and click the Linux button, and LinuxPPC will boot into the Red Hat installer.