Red Hat Linux 7.2: The Official Red Hat Linux Alpha Installation Guide
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# Partitioning with fdisk

This section applies only if you chose to use fdisk to partition your system.

To partition your system without using fdisk, please skip to the section called Automatic Partitioning for automatic partitioning or the section called Partitioning Your System for partitioning with Disk Druid.

| Caution
| Unless you have previously used fdisk and understand how it works, we do not recommend that you use it. Disk Druid is easier to understand than fdisk. To exit fdisk, click Back to return to the previous screen, deselect fdisk, and then click Next.

If you have chosen to use fdisk, the next screen will prompt you to select a drive to partition using fdisk. Once you have chosen which drive to partition, you will be presented with the fdisk command screen. If you do not know what command to use, type [m] at the prompt for help.

When you are finished making partitions, type [w] to save your changes and quit. You will be taken back to the original fdisk screen where you can choose to partition another drive or continue with your installation.

| Note
| None of the changes you make take effect until you save them and exit fdisk using the `w` command. You can quit fdisk at any time without saving changes using the `q` command.

After you have partitioned your drive(s), click Next. You will need to use Disk Druid to assign mount points to the partitions you just created with fdisk.

You will not be able to add new partitions using Disk Druid, but you will be able to edit mount points for the partitions you have already created. For each partition created with fdisk, click on the Edit button, choose the appropriate mount point for that partition from the pulldown menu, and click on OK.

## SRM Partitioning Requirements

When you allow the Red Hat Linux installation program to partition for you (automatic partitioning), the installation program will handle certain special partitioning requirements for SRM. Disk Druid is also aware of SRM's partitioning requirements and will partition your system accordingly. If you use fdisk to partition manually, however, you will need to be aware of these issues, since you will need to take care of them yourself. Special partitioning issues for SRM include the following:

1. You will need to use BSD-style disklabels. When you use fdisk in the graphical installation program, it will start in BSD disklabel mode.

2. You will need to leave unallocated space at the beginning of your hard drive.

You will need to use BSD-style disklabels because of `aboot`'s partitioning requirements. When you are using the SRM firmware to boot Linux, you are using the `aboot` boot loader. The `aboot` program supports the creation of bootable block devices and contains a program which can load Linux kernels from a filesystem that is bootable by SRM.

The `aboot` program does not understand DOS-style partition tables. You will need to use BSD-style disklabels, which `aboot` does understand.

BSD-style disk labeling is different in certain ways from standard `fdisk`-style partitioning (used on x86 installations) in the following ways:

- The partitions are identified by letters (a, b, c...) instead of numbers.

- The partition types are different. For example, instead of using "83" and "82" to correspond to "Linux" and "Linux Swap," respectively, ext2 partitions are identified as "8"; the swap partition is "1".

- You can have a maximum of eight partitions (a to h) per drive.

- Partition types must be explicitly set after creation. The BSD disklabel program uses a default partition type of unknown which causes the Disk Setup portion of the installation program not to see the partitions.

Another requirement for partitioning is that you provide initial unallocated space at the beginning of the hard drive. The initial unallocated space is unallocated disk space that is not explicitly allocated to any label other than the "whole disk" label. This space should be approximately 1 MB to 10 MB (2048 to 20480 sectors), depending on exactly what configuration of `aboot` you are using.

The unallocated disk space provides space at the very beginning of the hard drive for `aboot` to write the boot block and object file that allows booting to kernels located within the disk labels. For more information on the process `aboot` uses to boot, please see the SRM Firmware HOWTO at the following URL:

    http://www.redhat.com/docs/manuals/linux/RHL-5.1-Manual/alpha/manual/doc022.html

| Warning
| To provide the initial unallocated space, you will need to start your partitions at cylinder 2. If you do a workstation- or server-class installation and allow the installation program to partition for you, the installation program will provide the initial unallocated space. If you are using Disk Druid, Disk Druid knows about this requirement, and it will not allow you to start the partitions at cylinder 1 during manual partitioning. If you are using fdisk, however, you will need to remember to start your partitions at cylinder 2.

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