A physical disk partition on which a series of logical drives can be created. You can create an extended partition on a disk to overcome the limitation of having only four partitions per disk.
Information about the various partitions on a disk is stored in a structure called the partition table. The partition table is 64 bytes in size and is located on cylinder 0, head 0, sector 1 of your hard drive, in the same sector as the Master Boot Record.
The partition table has the same format no matter what operating system is used on the disk. Up to four partitions can be created on a disk, but only one partition can be extended per disk.
In Microsoft Windows NT, you can create an extended partition using Disk Administrator. For earlier Windows platforms, use the fdisk utility.
In Windows 2000, extended partitions can be created only on basic disks.