A partition editor is a kind of utility software

Utility software

Utility software is system software designed to help analyze, configure, optimize or maintain a computer. A single piece of utility software is usually called a utility or tool....

 designed to view, create, alter and delete disk partitions on a computer storage device, most commonly a hard disk

Hard disk

A hard disk drive is a non-volatile, random access digital magnetic data storage device. It features rotating rigid platters on a motor-driven spindle within a protective enclosure. Data is magnetically read from and written to the platter by read/write heads that float on a film of air above the...

, but often a USB flash drive

USB flash drive

A flash drive is a data storage device that consists of flash memory with an integrated Universal Serial Bus interface. flash drives are typically removable and rewritable, and physically much smaller than a floppy disk. Most weigh less than 30 g...

 or other storage medium.

A partition is a section or segment of the storage space on a storage device. By partitioning a large device into several partitions it is possible to isolate various types of data from one another, and allow the coexistence of two or more operating systems simultaneously.

A drive can be partitioned into multiple partitions, or have many combined into one. Partition editing programs can be used to shrink a single partition to make room for more or combine two to increase the space on one.

Resources

• Parted Magic - Bootable OS on CD with an emphasis on partition editing.
• GParted - Gnome Partition Editor. Available for Linux, or as standalone bootable CD/USB flash versions.
• Partition Table Editor (included with PartitionMagic
  PartitionMagic
  PartitionMagic was a computer program for hard disk drive partitioning originally made by the PowerQuest corporation but now owned by Symantec. As of December 8, 2009, the Symantec website stated that they no longer offer Partition Magic. The program runs on Microsoft Windows operating systems...
  
  ) available as [ftp://ftp.symantec.com/public/english_us_canada/tools/pq/utilities/PTEDIT32.zip PTEDIT32.zip] from Symantec's FTP site.