15. Appendix: Using cfdisk to partition your harddisk

15.1. Hard disk names

SCSI harddisks are named with sdx, where x is a hardisk letter. The disk with the lowest SCSI ID on the first controller will become sda, the next lower sdb, an so on.

If you have IDE harddisks, they are called hda, hdb, hdc, and so on instead, where hda is the master disk on the first controller, hdb is the slave disk on the first controller, hdc is the master disk on the second controller, and so on.

15.2. Harddisk partitions

GNU/Linux systems often uses a partition scheme inherited from MS-DOS. With this, a harddisk can have up to four primary partitions. If you want more, you have to make one of these an extended partition where you can make several logical partitions. The partitions are named with the disk they belong to, and a number. The first primary partition on the first SCSI disk is therefore sda1, the second primary partition is sda2, and so on. The first and second logical partition on an extended partition on the first SCSI disk is sda5 and sda6, and so on. If this makes absolutely no sense to you at all, try to read Section 16.

15.3. Starting cfdisk

you start cfdisk from the command line with the command
        cfdisk /dev/sdx
where x is the SCSI hardisk letter, like a, b, c, d, etc. So if I want to partition the first harddisk on the SCSI controller, I'll enter the command
        cfdisk /dev/sda

15.4. Using cfdisk

15.4.1. The user interface

After you have started cfdisk you'll get an interface where the current partition table is listed with the names and some data about each partition, and some command buttons on the bottom of the screen. To change between partitions, use the up and down arrow keys. To change between commands, use the left and right arrow keys.

15.4.2. Deleting a partition

To delete an existing partition, highlight it with the up and down keys, select the Delete command with the left and right arrow keys, and press Enter.

15.4.3. Making a new partition

To make a new partition, select the New command with the left and right arrow keys, and press enter. You'll get the choice between a primary and a logical partition. If you want a logical partition, the program will automatically make an extended partition for you. Then you must choose the size of the partition (in MB). If you can't enter a value in MB, return to the main screen with the Esc key, and select MB with the Units command.

15.4.4. Set the type of a partition

To set the type of a partition, for bootable PReP, Linux swap or Linux ext2, highlight the actual partition, and select the Type command. You'll get a list over different types. Press space, and you'll get even more. Find what type you need, and enter the number at the prompt.

15.4.5. Make a partition bootable

To be able to boot from a primary partition, you need to make it bootable. Highlight the actual partition and select the Bootable command.

15.4.6. Write the result to disk and quit

When you are content with the layout of the disk, select the Write command. The partition table will be written to disk. Remember that this will destroy all data on partitions you have deleted or changed. You should therefore be very sure that you want to do this before actually press the Return key.

To exit the program, select the Quit command.