Partition Computing

Dennis Faas's picture

In computer engineering, hard disk drive partitioning is the creation of logical divisions upon a hard disk that allows one to apply operating system-specific logical formatting. Disk partitioning is a simple technique which can be viewed as a precursor of logical volume management. The purpose of partitioning is to allow a user to have multiple file systems on a single hard disk.

Active partition

The Bootable Flag determines the active partition. Only one partition can normally be active at a time. The active marker is used during boot: after the BIOS loads the MBR into memory and executes it, the MBR checks the partition table at its end, and locates the active partition. Then it proceeds to load the boot sector of that partition into memory and runs it. Usually a boot loader such as GRUB or NTLDR is contained in there. Some operating systems require being installed on active partitions. For example, Microsoft Windows 2000 Professional marks its own partition active when it starts up. Thus NTLDR will run next time the system boots, even if the user intended to use another boot loader on a different partition.

Logical partitions

Logical partitions are a way to extend the Master Boot Record's limitation of four partitions. One partition can be designated as an extended partition. This can contain up to 24 logical partitions, whose details are listed in the extended partition's own partition table, the Extended MBR or EMBR. Modern operating systems treat these the same as primary partitions.

Partitioning Schemes: Microsoft Windows

With Windows the standard partitioning scheme is to create a single partition, the C: drive, where the operating system, data, and programs all reside. It is recommended, however, to create multiple partitions or use multiple hard drives with the operating system stored on one partition and with the rest of the partitions and/or drives allocated to applications and data. This makes it easier to locate and backup user data.

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