System partition and boot partition: Difference between revisions

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{{Short description|Computing terms for disk partitions}}

{{multiple issues|citations missing=June 2011|primarysources=June 2011}}

{{Redirect-distinguish|System partition|EFI system partition}}

In [[Microsoft Windows]], the '''system partition''' and '''boot partition''' refer to:

{{Redirect-distinguish|Boot partition|BIOS boot partition}}

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==Common definition==

*The '''boot partition''' is the disk partition that contains the Windows [[operating system]] files and its support files, but not any files responsible for [[booting]].

In context of every operating system, except those developed by [[Microsoft]], the system partition and the boot partition are defined as follows:

* The ''boot partition'' is a [[primary partition]] that contains the [[boot loader]], a piece of software responsible for [[booting]] the [[operating system]]. For example, in the standard [[Linux]] directory layout ([[Filesystem Hierarchy Standard]]), boot files (such as the [[Linux kernel|kernel]], [[initrd]], and boot loader [[GRUB]]) are mounted at <code>/boot/</code>.<ref>{{cite book|last=Petersen|first=Richard|title=Ubuntu The Complete Reference|year=2009|publisher=McGraw-Hill|___location=New York|isbn=978-0-07-164368-9|page=473|chapter=Chapter 21: Basic System Administration}}</ref> Despite Microsoft's radically different definition (see below), System Information, a utility app included in [[Windows NT]] family of operating systems, refers to it as "boot device".<ref>{{cite book |last1=Andrews |first1=Jean |first2=James |last2=Chellis |title=A+ Guide to Software |date=13 August 2012 |publisher=Cengage Learning |isbn=9781285414980 |page=21 |edition=6th}}</ref><ref>{{cite book |last=Donald |first=Lisa |title=MCSA / MCSE: Windows Server 2003 Environment Management and Maintenance Study Guide: Exam 70-290 |publisher=John Wiley & Sons |isbn=9780470327616 |pages=116–117 |edition=2nd |date=2008}}</ref>

* The ''system partition'' is the disk partition that contains the operating system folder, known as the ''system root''. By default, in Linux, operating system files are mounted at <code>/</code> (the [[root directory]]).

In Linux, a single partition can be both a boot and a system partition if both <code>/boot/</code> and the root directory are in the same partition.

The system partition can be different from the boot partition, although they are often on the same partition (drive C:). Windows setup places the initial system partition based on [[motherboard]] [[BIOS]] settings. [[Bitlocker]] requires a separate, unencrypted system partition for [[booting]].

==Microsoft definition==

The [[master boot record]] is located at physical sector 0, just before the [[partition table]], and is therefore not contained inside any of the logical partitions or volumes.

Since [[Windows NT 3.1]] (the first version of Windows NT),<ref>{{cite web|url=https://support.microsoft.com/en-us/kb/100525|title=Definition of System and Boot Partition|date=20 February 2007|website=Support|publisher=[[Microsoft]]|archive-url=https://web.archive.org/web/20160313090403/https://support.microsoft.com/en-us/kb/100525|archive-date=13 March 2016|url-status=dead}}</ref> Microsoft has defined the terms as follows:

* The ''system partition'' (or system volume)<ref name=":1">{{Cite web|url=https://support.microsoft.com/en-us/help/314470/definitions-for-system-volume-and-boot-volume|title=Definitions for system volume and boot volume|date=29 October 2009|website=Support|publisher=[[Microsoft]]|archive-url=https://web.archive.org/web/20170913184351/https://support.microsoft.com/en-us/help/314470/definitions-for-system-volume-and-boot-volume|archive-date=2017-09-13|url-status=dead}}</ref> is a primary partition that contains the boot loader, a piece of software responsible for booting the operating system.<ref name=":0">{{cite book|title=Microsoft Encyclopedia of Networking|last2=Tulloch|first2=Ingrid|publisher=[[Microsoft Press]]|year=2002|isbn=0-7356-1378-8|edition=2nd|___location=Redmond, WA|first1=Mitch|last1=Tulloch}}</ref>{{Rp|1087}} This partition holds the [[boot sector]] and is marked active.<ref name=winternals5>{{cite book|last1=Russinovich|first1=Mark E|last2=Ionescu|first2=Alex|last3=Solomon|first3=David A|title=Windows Internals|year=2008|publisher=Microsoft Press|___location=Redmond, WA|isbn=978-0-7356-2530-3|edition=5th}}</ref>{{rp|970}}

* The ''boot partition'' (or boot volume)<ref name=":1" /> is the disk partition that contains the operating system folder, known as the ''system root'' or <code>%systemroot%</code> in [[Windows NT]].<ref name=":0" />{{Rp|174}}

Before [[Windows 7]], the system and boot partitions were, by default, the same and were given the "C:" [[Drive letter assignment|drive letter]].<ref name=winternals5 />{{rp|971}} Since Windows 7, however, [[Windows Setup]] creates, by default, a separate system partition that is not given an identifier and therefore is hidden. The boot partition is still given "C:" as its identifier. This configuration is suitable for running [[BitLocker]], which requires a separate unencrypted system partition for booting. As of [[Windows 11]], this nomenclature is still used by the "Disk Management" utility.

Despite of [[Microsoft]]'s idiosyncratic terminology, it is possible to mark the ''boot partition'' as active and boot into it, if the partition is a primary partition, and the required files such as NTLDR and <tt>boot.ini</tt> for [[Windows XP]] or older [[Windows NT]] platforms exist on it. In a dual-boot scenario the ''system partition'' could be formatted with a [[File Allocation Table|FAT16]] file system and contain an [[MS DOS]] operating system and a [[Recovery Console]]. The old DOS boot sector of this partition is saved in a file <tt>bootsect.dos</tt> (or similar), and used as entry in the NTLDR <tt>boot.ini</tt> file. The new boot sector of this partition looks for and starts NTLDR, while the image of the old DOS boot sector looks for and starts DOS. Note that DOS boot sectors look for different files depending on the [[original equipment manufacturer]] such as [[IBM]] for [[PC DOS]] or [[Microsoft]] for [[MS DOS]].

== See also ==

Generally newer boot schemes support older schemes; this is the reason why [[Microsoft]] operating systems are typically installed in chronological order (oldest OS first, newest OS last), and why attempts to ''"repair"'' critical sectors with tools designed for older operating systems can cause havoc for newer operating systems.

* [[NTLDR]]

* [[Windows NTstartup Startup Processprocess]]

The new [[Windows Vista startup process]] supports the same and additional features; its boot sector looks for the new boot manager instead of NTLDR. Old <tt>fixmbr</tt> tools installing an NTLDR boot sector would destroy the newer boot sector, and therefore newer Windows versions typically use a separate ''system partition''. The recommended layout consists of a primary hidden recovery partition followed by the primary [[NTFS]] ''system partition'' (marked as ''active'' for booting), and a separate ''boot partition'' (in Microsoft terminology), the latter could be either a primary partition or a logical disk in an extended partition mounted as drive <code>C:</code>. More convoluted layouts with an OEM partition, or simpler layouts with ''system'' = ''boot'' partition, are possible.

* [[Windows VistaNT Startupstartup Processprocess]]

* [[Windows Vista startup process]]

== Other operating systems ==

* [[Windows To Go]]

It is interesting to note that in operating systems other than Windows and DOS the definitions of boot partition and system partition are just the opposite: the boot partition contains the boot files and the system partitions hold the operating system files.

For example, in the standard [[Linux]] directory layout ([[Filesystem Hierarchy Standard]]), boot files (such as the [[kernel]], [[initrd]], and boot loader [[GRUB]]) are mounted at <code>/boot/</code> while operating system files are mounted at <code>/</code> (the [[root directory]]); these may or may not be separate partitions, but they are mounted in the same hierarchy.

== See also ==

* [[Windows NT Startup Process]]

* [[Windows Vista Startup Process]]

* [[EFI System Partition]]

==External links==

*[http://support.microsoft.com/kb/100525 Definition of System and Boot Partition (NT)]

*[http://support.microsoft.com/kb/314470 Definition of System Partition and Boot Partition (XP)]

==References==

{{Reflist}}{{Firmware and booting}}

[[Category:Booting]]

[[Category:Disk partitions]]

[[Category:Windows administration]]

[[Category:Booting]]

{{Windows-stub}}