The Apple disk partitioning scheme was developed in 1986. It attempted to be forward thinking as it was intended to handle drives of sizes up to several hundred megabytes. While the original intent was to handle various block sizes, in practice only 512 byte blocks are supported. Since the various address fields are 32 bits unsigned this means the format can handle disks up to 2 Terabytes in size.
Under GNU/Linux mac-fdisk and pdisk can be used to manipulate an Apple partition map.
For Linux installation on PowerPC you need an additional special bootstrap partition where the boot-loader will resist (the Macintosh Open-Firmware only boots from HFS partitions). The partitions can be really tiny, 800kB is the minimal size of an Macintosh partition.
The basic commands in mac-fdisk are 'p' (print), 'd' (delete), 'c' (create), 'b' (bootstrap parition), 'w' (write) and 'q' (quit).
When you install T2 Linux for the first time, you first need to delete the empty partition created MacOS X with 'd number'. Usually this is the last partitions before some possibly present free-space.
First you should use 'p' (print) to get a list of the currently available partitions:
/dev/hda
Command (? for help): p
/dev/hda
# type name length base ( size ) system
part1 Apple_partition_map Apple 63 @ 1 ( 31.5k) Partition map
part2 Apple_HFS Mac OS X 16777216 @ 64 ( 8.0G) HFS
part3 Apple_HFS Untitled 2 1600 @ 16777280 ( 20.G) HFS
Block size=512, Number of Blocks=58605120
DeviceType=0x0, DeviceId=0x0
The 'Untitled 2' partition must be deleted using the 'd' command:
Command (? for help): d Partition number: 3
The next step is to create the special bootstrap partitions with the minmal possible size mac-fdisk has a special command 'b'. So you only need to run the command 'b' and specify its start.
As with all the create commands you need to specify a start. For such start and length specifications of partitions some different possibilities are available: either enter the real block number (difficult since you need to compute all the indexes yourself ...), the size in kB, MB, GB (only really useful to specify the length) or by using the boundaries of existing partitions using 'number P'. 'Number' is usually the last partition containing the currently 'free-space'.
So for the bootstrap partition you usually need 'b 3P' to create the bootstrap partition at the beginning of the free-space partition 3:
Command (? for help): b First block: 3P
Now you can create the other 'normal' partitions for the swap-space, the '/' (root) file-system and optionally '/home', '/usr', ... partitions. You need the command 'c' (create) for this which asks for the start and length as well as a name. A possible scenario creating 128 MB swap-space, a 5GB '/' and all the rest as '/home' partition:
Command (? for help): c First block: 4P Length (in blocks, kB (k), MB (M) or GB (G)): 128M Name of partition: 'Linux swap' Command (? for help): c First block: 5P Length (in blocks, kB (k), MB (M) or GB (G)): 5GB Name of partition: 'Linux root' Command (? for help): c First block: 6P Length (in blocks, kB (k), MB (M) or GB (G)): 6P Name of partition: 'Linux home'
The partition table now should look like:
Command (? for help): p
# type name length base ( size ) system
part1 Apple_partition_map Apple 63 @ 1 ( 31.5k) Partition map
part2 Apple_HFS Mac OS X 16777216 @ 64 ( 8.0G) HFS
part3 Apple_Bootstrap bootstrap 1600 @ 16777280 (800.0k) NewWorld bootblock
part4 Apple_UNIX_SVR2 Linux swap 262144 @ 16778880 (128.0M) Linux native
part5 Apple_UNIX_SVR2 Linux root 10485760 @ 17041024 ( 5.0G) Linux native
part6 Apple_UNIX_SVR2 Linux home 31078336 @ 27526784 ( 14.8G) Linux native
Block size=512, Number of Blocks=58605120
DeviceType=0x0, DeviceId=0x0
Now you should - if you are sure everything is ok - save the modified partition to the disk using 'w' (write) command and quit the program with 'q' to continue the installation.
Command (? for help): w The partition map has been saved successfully! Calling ioctl() to re-read partition table. Syncing disks. Command (? for help): q