Disk cloning is the process of creating a 1-to-1 copy of a

hard disk drive A hard disk drive (HDD), hard disk, hard drive, or fixed disk is an electro-mechanical data storage device that stores and retrieves digital data using magnetic storage with one or more rigid rapidly rotating platters coated with magne ...

(HDD) or

solid-state drive A solid-state drive (SSD) is a solid-state storage device that uses integrated circuit assemblies to store data persistently, typically using flash memory, and functioning as secondary storage in the hierarchy of computer storage. It is a ...

(SSD), not just its files. Disk cloning may be used for upgrading a disk or replacing an aging disk with a fresh one. In this case, the clone can replace the original disk in its host computer. Disk cloning may also be used for disaster recovery or forensics. In the context of

backup software Backup software are computer programs used to perform a backup; they create supplementary exact copies of files, databases or entire computers. These programs may later use the supplementary copies to restore the original contents in the event of ...

, disk cloning is very similar to

disk imaging A disk image, in computing, is a computer file containing the contents and structure of a disk volume or of an entire data storage device, such as a hard disk drive, tape drive, floppy disk, optical disc, or USB flash drive. A disk image is usua ...

; in case of the latter, a 1-to-1 copy of a disk is created inside a disk image file. Disk cloning may be done with specialized cloning software, backup software, disk imaging software that has the necessary features, or specialized hardware.

Operating environment

A disk cloning program needs to be able to read even protected operating system files on the source disk, and must guarantee that the system is in a consistent state at the time of reading. It must also overwrite any operating system already present on the destination disk. To simplify these tasks, most disk cloning programs can run under an

operating system An operating system (OS) is system software that manages computer hardware, software resources, and provides common services for computer programs. Time-sharing operating systems schedule tasks for efficient use of the system and may also i ...

different from the native operating system of the host computer, for example,

MS-DOS MS-DOS ( ; acronym for Microsoft Disk Operating System, also known as Microsoft DOS) is an operating system for x86-based personal computers mostly developed by Microsoft. Collectively, MS-DOS, its rebranding as IBM PC DOS, and a few ope ...

or an equivalent such as

PC DOS PC or pc may refer to: Arts and entertainment * Player character or playable character, a fictional character controlled by a human player, usually in role-playing games or computer games * '' Port Charles'', an American daytime TV soap opera * ...

or DR-DOS, or

Linux Linux ( or ) is a family of open-source Unix-like operating systems based on the Linux kernel, an operating system kernel first released on September 17, 1991, by Linus Torvalds. Linux is typically packaged as a Linux distribution, w ...

. The computer is booted from this operating system, the cloning program is loaded and copies the computer's file system. Many programs can clone a disk, or make an image, from within the running system, with special provision for copying open files; but an image cannot be restored onto the Windows System Drive under Windows. A disk cloning program must have

device drivers In computing, a device driver is a computer program that operates or controls a particular type of device that is attached to a computer or automaton. A driver provides a software interface to hardware devices, enabling operating systems and ot ...

or equivalent for all devices used. The manufacturers of some devices do not provide suitable drivers, so the manufacturers of disk cloning software must write their own drivers, or include device access functionality in some other way. This applies to tape drives, CD and

DVD The DVD (common abbreviation for Digital Video Disc or Digital Versatile Disc) is a digital optical disc data storage format. It was invented and developed in 1995 and first released on November 1, 1996, in Japan. The medium can store any kind ...

readers and writers, and

USB Universal Serial Bus (USB) is an industry standard that establishes specifications for cables, connectors and protocols for connection, communication and power supply (interfacing) between computers, peripherals and other computers. A broad ...

and FireWire drives. Cloning software contains its own

TCP/IP stack The Internet protocol suite, commonly known as TCP/IP, is a framework for organizing the set of communication protocols used in the Internet and similar computer networks according to functional criteria. The foundational protocols in the suit ...

for multicast transfer of data where required.

Image transfer

The simplest method of cloning a disk is to have both the source and destination disks present in the same machine, but this is often not possible. Disk cloning programs can link two computers by a parallel cable, or save and load images to an external USB drive or network drive. As disk images tend to be very large (usually a minimum of several hundred MB), performing several clones at a time puts excessive stress on a network. The solution is to use

multicast In computer networking, multicast is group communication where data transmission is addressed to a group of destination computers simultaneously. Multicast can be one-to-many or many-to-many distribution. Multicast should not be confused with ...

technology. This allows a single image to be sent simultaneously to many machines without putting greater stress on the network than sending an image to a single machine.

Image manipulation

Although disk cloning programs are not primarily backup programs, they are sometimes used as such. A key feature of a backup program is to allow the retrieval of individual files without needing to restore the entire backup. Disk cloning programs either provide a Windows Explorer-like program to browse image files and extract individual files from them, or allow an image file to be mounted as a read-only filesystem within Windows Explorer.

Cloning software

This table highlights the common capabilities of disk cloning software.

Notes

References

{{Reflist, 30em, refs= Clonezilla home page
(includes supported filesystems and other info)
/ref> {{Cite web, url=http://www.mondorescue.org/docs/mondorescue-howto.html, title = MondoRescue HOWTO {{cite web, title=Norton Ghost, url=http://us.norton.com/ghost, publisher= Symantec, access-date=15 December 2012 About ntfsclone
{{webarchive, url=https://web.archive.org/web/20080221173134/http://www.linux-ntfs.org/doku.php?id=ntfsclone , date=2008-02-21
{{webarchive, url=https://web.archive.org/web/20080706133848/http://man.linux-ntfs.org/ntfsclone.8.html , date=2008-07-06 {{Cite web , url=http://www.partimage.org/Main_Page , title=Partimage home page , access-date=2008-05-26 , archive-url=https://web.archive.org/web/20170208121536/http://www.partimage.org/Main_Page , archive-date=2017-02-08 , url-status=dead Partimage supported filesystems
/ref>
/ref> {{Cite web, url=http://www.partimage.org/Supported-Filesystems, title = Partimage - Supported filesystems Clone a drive or partition with IsoBuster, Managed or otherwise
/ref> IsoBuster 4.3 Release notes
/ref> IsoBuster 4.8 Release notes
/ref> Storage software Backup Utility software types

Operating environment

Image transfer

Image manipulation

Cloning software

See also

Notes

References