Slice (disk) - PC Partition Types - Primary Partition

Primary Partition

A primary partition contains one file system. In DOS and all versions of Microsoft Windows systems, what Microsoft calls the system partition was required to be the first partition. All Windows operating systems from Windows 95 onwards can be located on ( almost ) any partition, but the boot files (io.sys, bootmgr, ntldr, etc.) must be on a primary partition. However, other factors, such as a PC's BIOS (see Boot sequence on standard PC) may also impart specific requirements as to which partition must contain the primary OS.

The partition type code for a primary partition can either correspond to a file system contained within (e.g. 0x07 means either an NTFS or an OS/2 HPFS file system) or indicate that the partition has a special use (e.g. code 0x82 usually indicates a Linux swap partition). The FAT16 and FAT32 file systems have made use of a number of partition type codes due to the limits of various DOS and Windows OS versions. Though a Linux operating system may recognize a number of different file systems (ext4, ext3, ext2, ReiserFS, etc.), they have all consistently used the same partition type code: 0x83 (Linux native file system).