Joined: Dec. 2004
||Posted: Jan. 02 2005,15:42
Caspar_s, there are four partitions, called primary partitions, on any bootable disk because the structure of the master boot record, aka MBR, has remained basically unchanged since the IBM DOS 2.0 design from 1983, and it was designed to accommodate four partitions. The structure of the MBR has become an OS-independent de facto standard that allows for booting any operating system on x86 PC hardware.
You'll always be using the first partition. You can subdivide your space and allocate some to one or more of the other partitions if you want.
This page Simple Guide to Hard Disk Partitions gives a very good basic explanation of partitions and the MBR.
An extensive compilation of historical information about the MBR, drive geometries, changes introduced at different versions of DOS and Windows, and even original FDISK assembler code, can be found at The Starman's Realm.
Also, see this thread Pendrive geometry started by JohnS on this forum for an explanation of how to calculate the partition sizes you want if you decide to use more than one partition, and a simple procedure for creating them using sfdisk and mkdosfs. I carved my pendrive up into two partitions, sda1 for 125MB, and sda2 with the remainder of the space. I didn't allocate any space to partitions 3 or 4.