Boot Disk

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What Does Boot Disk Mean?

A boot disk is a removable data storage medium used to load and boot an operating system or utility program. Typically, a boot disc is a read-only medium that stores temporary files on a CD-ROM or floppy disc drive. Other boot disk mediums include USB drives, zip drives, and paper tape drives.


One of the most common uses of a boot disk is to start the computer when the operating on the internal hard drive does not load. Generally, a boot disk contains a full-scale operating system, and may include a small utility operating system as well. In recent years, boot disks have become less common as original equipment manufacturers turn to using hard drive partitions to store recovery data.

A boot disk may also be referred to as a bootable diskette, startup disk, bootable disk or bootable rescue disk.

Techopedia Explains Boot Disk

The boot disk is generally used to repair damage by restoring system files to a last effort or reinstalling the operating system to its original factory condition.

The boot disk is used for a variety of functions, including:

  • Customizing an operating system environment
  • Anti-virus and anti-spyware scans
  • Installing a full-scale operating system
  • Software and hardware troubleshooting
  • Accessing the operating system when passwords are lost
  • Data purging to remove old and unneeded data
  • Data recovery to restore damaged, corrupted or inaccessible data

In order for a boot disk to operate, a computer needs to have a built-in program to load and execute the instructions. All boot disks need to be compatible with the personal computers they are intended for. Some computers have a basic input/output system (BIOS) that supports booting from a device such as a CD-ROM or USB. Other systems may require a boot floppy to run software on a CD-ROM and do not support booting from just a CD-ROM.

If recovery data is not stored on a PC’s hard drive, an operating system generally provides the tools to create a boot disk.


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Margaret Rouse
Senior Editor
Margaret Rouse
Senior Editor

Margaret is an award-winning technical writer and teacher known for her ability to explain complex technical subjects to a non-technical business audience. Over the past twenty years, her IT definitions have been published by Que in an encyclopedia of technology terms and cited in articles by the New York Times, Time Magazine, USA Today, ZDNet, PC Magazine, and Discovery Magazine. She joined Techopedia in 2011. Margaret's idea of a fun day is helping IT and business professionals learn to speak each other’s highly specialized languages.