Reboot

For other uses, see Reboot (disambiguation).

In computing, rebooting is the process by which a running computer system is restarted, either intentionally or unintentionally. Reboots can be either a cold reboot (alternatively known as a hard reboot) in which the power to the system is physically turned off and back on again (causing an initial boot of the machine); or a warm reboot (or soft reboot) in which the system restarts while still powered up. The term restart (as a system command) is used to refer to a reboot when the operating system closes all programs and finalizes all pending input and output operations before initiating a soft reboot.

Terminology

Etymology

Early electronic computers (like the IBM 1401) had no operating system and little internal memory. The input was often a stack of punch cards or via a switch register. On systems with cards, the computer was initiated by pressing a start button that performed a single command - "read a card". This first card then instructed the machine to read more cards that eventually loaded a user program. This process was likened to an old saying, "picking yourself up by the bootstraps", referring to a horseman who lifts himself off the ground by pulling on the straps of his boots. This set of initiating punch cards was called "bootstrap cards". Thus a cold start was called booting the computer up. If the computer crashed, it was rebooted. The boot reference carried over to all subsequent types of computers.

Cold versus warm reboot

"Cold boot" redirects here. For the attack called a "cold boot attack", see Cold boot attack.

For IBM PC compatible computers, a cold boot is a boot process in which the computer starts from a powerless state, in which the system performs a complete power-on self-test (POST).[1][2][3][4] Both the operating system and third-party software can initiate a cold boot; the restart command in Windows 9x initiates a cold reboot, unless Shift key is held.[1]: 509 

A warm boot is initiated by the BIOS, either as a result of the Control-Alt-Delete key combination[1][2][3][4] or directly through BIOS interrupt INT 19h.[5] It may not perform a complete POST - for example, it may skip the memory test - and may not perform a POST at all.[1][2][4] Malware may prevent or subvert a warm boot by intercepting the Ctrl + Alt + Delete key combination and prevent it from reaching BIOS.[6] The Windows NT family of operating systems also does the same and reserves the key combination for its own use.[7][8]

Operating systems based on Linux support an alternative to warm boot; the Linux kernel has optional support for kexec, a system call which transfers execution to a new kernel and skips hardware or firmware reset. The entire process occurs independently of the system firmware. The kernel being executed does not have to be a Linux kernel.[citation needed]

Outside the domain of IBM PC compatible computers, the types of boot may not be as clear. According to Sue Loh of Windows CE Base Team, Windows CE devices support three types of boots: Warm, cold and clean.[9] A warm boot discards program memory. A cold boot additionally discards storage memory (also known as the "object store"), while a clean boot erases all forms of memory storage from the device. However, since these areas do not exist on all Windows CE devices, users are only concerned with two forms of reboot: one that resets the volatile memory and one that wipes the device clean and restores factory settings. For example, for a Windows Mobile 5.0 device, the former is a cold boot and the latter is a clean boot.[9]

Hard reboot

A hard reboot means that the system is not shut down in an orderly manner, skipping file system synchronisation and other activities that would occur on an orderly shutdown. This can be achieved by either applying a reset, by cycling power, by issuing the halt -q command in most Unix-like systems, or by triggering a kernel panic.

Hard reboots are used in the cold boot attack.

Restart

The term "restart" is used by the Microsoft Windows and Linux families of operating systems to denote an operating system-assisted reboot. In a restart, the operating system ensures that all pending I/O operations are gracefully ended before commencing a reboot.

Causes

Deliberate

Redundant power supplies in a computer system reduce the risk of an unexpected loss of power.

Users may deliberately initiate a reboot. Rationale for such action may include:

  • Troubleshooting: Rebooting may be used by users, support staff or system administrators as a technique to work around bugs in software,[10] for example memory leaks or processes that hog resources to the detriment of the overall system, or to terminate malware. While this approach does not address the root cause of the issue, resetting a system back to a good, known state may allow it to be used again for some period until the issue next occurs.
  • Switching operating systems: On a multi-boot system without a hypervisor, a reboot is required to switch between installed operating systems.
  • Offensive: As stated earlier, components lose power during a cold reboot; therefore, components such as RAM that require power lose the data they hold. However, in a cold boot attack, special configurations may allow for part of the system state, like a RAM disk, to be preserved through the reboot.[11]

The means of performing a deliberate reboot also vary and may include:

  • Manual, hardware-based: A power switch or reset button can cause the system to reboot.[2] Doing so, however, may cause the loss of all unsaved data.[12]
  • Manual, software-based: Computer software and operating system can trigger a reboot as well; both Microsoft Windows and several Unix-like operating systems can be shut down from the command line[1]: 509 [13][14][15][16][17][18][19][20][21] or through the GUI.
  • Automated: Software can be scheduled to run at a certain time and date; therefore, it is possible to schedule a reboot.[22]

Power failure

Unexpected loss of power for any reason (including power outage, power supply failure or depletion of battery on a mobile device) forces the system user to perform a cold boot once the power is restored. Some BIOSes have an option to automatically boot the system after a power failure.[23][24] An uninterruptible power supply (UPS), backup battery or redundant power supply can prevent such circumstances.

Random reboot

"Random reboot" is a non-technical term referring to an unintended (and often undesired) reboot following a system crash, whose root cause may not immediately be evident to the user. Such crashes may occur due to a multitude of software and hardware problems, such as triple faults. They are generally symptomatic of an error in ring 0 that is not trapped by an error handler in an operating system or a hardware-triggered non-maskable interrupt.

Systems may be configured to reboot automatically after a power failure, or a fatal system error or kernel panic. The method by which this is done varies depending on whether the reboot can be handled via software or must be handled at the firmware or hardware level. Operating systems in the Windows NT family (from Windows NT 3.1 through Windows 7) have an option to modify the behavior of the error handler so that a computer immediately restarts rather than displaying a Blue Screen of Death (BSOD) error message. This option is enabled by default in some editions.

Hibernation

Main article: Hibernation (computing)

The introduction of advanced power management allowed operating systems greater control of hardware power management features. With Advanced Configuration and Power Interface (ACPI), newer operating systems are able to manage different power states and thereby sleep and/or hibernate. While hibernation also involves turning a system off then subsequently back on again, the operating system does not start from scratch, thereby differentiating this process from rebooting.

Simulated reboot

A reboot may be simulated by software running on an operating system. For example: the Sysinternals BlueScreen utility, which is used for pranking; or some modes of the bsod XScreenSaver "hack", for entertainment (albeit possibly concerning at first glance). Malware may also simulate a reboot, and thereby deceive a computer user for some nefarious purpose.[6]

Microsoft App-V sequencing tool captures all the file system operations of an installer in order to create a virtualized software package for users. As part of the sequencing process, it will detect when an installer requires a reboot, interrupt the triggered reboot, and instead simulate the required reboot by restarting services and loading/unloading libraries.[25]

Windows deviations and labeling criticism

Windows 8 & 10 enable (by default) a hibernation-like "Fast Startup" (a.k.a. "Fast Boot") which can cause problems (including confusion) for users accustomed to turning off computers to (cold) reboot them.[26][27][28]

See also

References

  1. ^ a b c d e Jones, James G.; Landes, Craig; Tittel, Ed (2002). A+ Exam Cram 2 (Exam Cram 220-221, Exam Cram 220-222). Que Publishing. pp. 379–380, 509. ISBN 9780789728678.
  2. ^ a b c d Cooper, Jim (2002). Using MS-DOS 6.22. Que Publishing. pp. 24, 960, 964. ISBN 9780789725738.
  3. ^ a b Tulloch, Mitch; Tulloch, Ingrid (2002). Microsoft Encyclopedia of Networking (2nd ed.). Microsoft Press. p. 172. ISBN 0-7356-1378-8.
  4. ^ a b c Soper, Mark Edward (2004). Absolute Beginner's Guide to A+ Certification. Que Publishing. p. 188. ISBN 9780789730626.
  5. ^ "Hardware Troubleshooting: Cold Booting Versus Warm Booting". Support. Microsoft. 7 July 2005. Archived from the original on 21 February 2015.
  6. ^ a b Grimes, Roger (1 June 2001). "2". Malicious Mobile Code: Virus Protection for Windows. O'Reilly Media. p. 50. ISBN 9781565926820.
  7. ^ "Using CTRL+ALT+DEL key combination to open Windows Security opens Task Manager". Microsoft Support. Microsoft. 15 January 2006. Retrieved 19 January 2013.
  8. ^ Osterman, Larry (24 January 2005). "Why is Control-Alt-Delete the secure attention sequence (SAS)?". Larry Osterman's WebLog. MSDN Blogs. Retrieved 15 March 2007.
  9. ^ a b Loh, Sue (22 June 2005). "Boot Persistence Terminology". Windows CE Base Team Blog. Microsoft. Retrieved 3 March 2013.
  10. ^ Debogue, Jean. "Did you reboot". WeDebugYou.
  11. ^ Ken Freeze (28 October 1985), "Jram-3 Rivals Persyst Stretch In RAM Race of Add-On Boards", InfoWorld
  12. ^ Shelly, Gary B.; Vermaat, Misty E. (2012). Enhanced Discovering Computers, Complete: Your Interactive Guide to the Digital World, 2013 Edition. Cengage Learning. p. 400. ISBN 9781133598312.
  13. ^ "shutdown". Microsoft Learn. 5 October 2023.
  14. ^ "Stop-Computer". Microsoft Learn.
  15. ^ shutdown(8) – Darwin and macOS System Manager's Manual
  16. ^ shutdown(8) – DragonFly BSD System Maintenance and Operation Commands Manual
  17. ^ shutdown(8) – FreeBSD System Manager's Manual
  18. ^ shutdown(8) – Linux Programmer's Manual – Administration and Privileged Commands
  19. ^ shutdown(8) – NetBSD System Manager's Manual
  20. ^ shutdown(8) – OpenBSD System Manager's Manual
  21. ^ shutdown(8) – Solaris 11.4 System Administration Commands Reference Manual
  22. ^ Gary A. Donahue, Gary A. (2011). Network Warrior (2nd ed.). Sebastopol: O'Reilly Media. p. 698. ISBN 9781449309350.
  23. ^ "AsRock 775i65G User Manual" (PDF). p. 32.
  24. ^ "Supermicro C7Q67 User's Manual" (PDF). p. 69.[permanent dead link‍]
  25. ^ "Microsoft App-V 4.6 SP1 Sequencing Guide".
  26. ^ Walter Glenn (3 March 2016). "The Pros and Cons of Windows 10's "Fast Startup" Mode". How-To Geek.
  27. ^ Oliver Niehus (14 December 2012). "Windows 8: Fast Boot". MSDN - Oliver's Blog.
  28. ^ "Distinguishing Fast Startup from Wake-from-Hibernation". Microsoft Hardware Dev Center. 15 December 2021.

Read other articles:

Transalkilasi

Industri petrokimia Gazprom. Industri ini banyak menggunakan reaksi transalkilasi.[1] Transalkilasi adalah reaksi kimia yang melibatkan transfer gugus alkil dari satu senyawa organik kepada senyawa organik yang lain. Reaksi ini digunakan untuk mentransfer gugus metil dan etil antara cincin benzena. Reaksi ini merupakan nilai khusus dalam industri petrokimia[1] untuk memproduksi p-xilena, stirena,[2] dan senyawa aromatik lainnya. Motivasi untuk menggunakan reaksi transa...

 

 

Tupai kecil

Tupai kerdil[1] Tupaia minor Status konservasi Risiko Rendah (IUCN 3.1)[2] Klasifikasi ilmiah Kerajaan: Animalia Filum: Chordata Kelas: Mammalia Ordo: Scandentia Famili: Tupaiidae Genus: Tupaia Spesies: T. minor Nama binomial Tupaia minorMiller, 1903 Peta persebaran Tupai kecil atau disebut juga tupai kerdil (Tupaia minor) adalah salah satu spesies tupai yang berada dalam famili Tupaiidae.[1] Spesies ini adalah spesies asli yang berada di wilayah Thailand, M...

 

 

Clovis culture

Prehistoric culture in the Americas c. 11, 500 to 10,800 BCE ClovisGeographical rangeNorth AmericaPeriodLithicDatesc. 11,500 – 10,800 BCE[1][2]Type siteBlackwater DrawPreceded byPaleo-IndiansFollowed byFolsom tradition A Clovis point created using bifacial percussion flaking, (which flakes both edges with a percussor). The deep flake initiated from the base constitutes the flute characteristic of Clovis and some other early Paleoindian points. Clovis culture is a prehistoric...

Justin Hubner

Justin Hubner Justin Hubner pada tahun 2024Informasi pribadiNama lengkap Justin Quincy HubnerTanggal lahir 14 September 2003 (umur 20)Tempat lahir 's-Hertogenbosch, BelandaTinggi 187 m (613 ft 6 in)[1]Posisi bermain Gelandang bertahanInformasi klubKlub saat ini Cerezo OsakaNomor 67Karier junior Brabant United Willem II2017–2019 Den Bosch2020– Wolverhampton WanderersKarier senior*Tahun Tim Tampil (Gol)2023– Wolverhampton Wanderers 0 (0)2024– Cerezo Osaka (p...

 

 

Préhistoire de l'Algérie

Peinture rupestre du Tassili n'Ajjer La Préhistoire de l'Algérie commence avec les premières traces d'occupation humaine trouvées sur le territoire actuel de l'Algérie, il y a environ 2 millions d'années, et s'achève avec les premiers textes libyques dits Tifinagh, puis les textes carthaginois et romains, dans la deuxième moitié du Ier millénaire av. J.-C.. Paléolithique archaïque Les sites préhistoriques de Guelta Zerka, dans la wilaya de Sétif, au centre-est du pays,...

 

 

Apollo 12

Second crewed Moon landing Apollo 12Commander Pete Conrad studies the Surveyor 3 spacecraft, which had landed two years previously; the Apollo Lunar Module, Intrepid, can be seen at top right.Mission typeCrewed lunar landing (H)OperatorNASACOSPAR IDCSM: 1969-099A[1]LM: 1969-099C[1]SATCAT no.CSM: 4225[2]LM: 4226[2]Mission duration10 days, 4 hours, 36 minutes, 24 seconds[3] Spacecraft propertiesSpacecraftCommand and service module CSM-...

S-75 Dvina

S-75 Dvina(Kode NATO: SA-2 Guideline) Rudal S-75 Dvina dipasang lengkap dengan dudukan misil Jenis Misil darat ke udara Negara asal  Uni Soviet Sejarah pemakaian Masa penggunaan 1957-sekarang Digunakan oleh Lihat daftar pemakai rudal (dulu dan sekarang) Pada perang Perang Vietnam, Perang Enam Hari, Perang Dingin, Perang Teluk, Perang di Abkhazia (1992–1993) Sejarah produksi Perancang Asosiasi Riset dan Produksi SA Lavochkin Tahun 1953-1957 Diproduksi 1957 Jumlah...

 

 

Legione Volontaria Italiana

Questa voce o sezione sull'argomento unità militari non cita le fonti necessarie o quelle presenti sono insufficienti. Puoi migliorare questa voce aggiungendo citazioni da fonti attendibili secondo le linee guida sull'uso delle fonti. Segui i suggerimenti del progetto di riferimento. Legione Volontaria Italiana(AF) Italiaansche Verkennings Corp  Sudafricatrad. Corpo di ricognizione italiano Il generale Louis Botha capo della Legione Volontaria Italiana nella seconda guerra boera D...

 

 

约翰斯顿环礁

此條目可参照英語維基百科相應條目来扩充。 (2021年5月6日)若您熟悉来源语言和主题，请协助参考外语维基百科扩充条目。请勿直接提交机械翻译，也不要翻译不可靠、低品质内容。依版权协议，译文需在编辑摘要注明来源，或于讨论页顶部标记{{Translated page}}标签。 约翰斯顿环礁Kalama Atoll 美國本土外小島嶼 Johnston Atoll 旗幟颂歌：《星條旗》The Star-Spangled Banner約翰斯頓環礁�...

List of United States fighter aircraft

S This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed.Find sources: List of United States fighter aircraft – news · newspapers · books · scholar · JSTOR (November 2023) (Learn how and when to remove this message) This list is incomplete; you can help by adding missing items. (March 2024) A U.S Air Force F-35A This is a list o...

 

 

Programmable calculator

This article uses bare URLs, which are uninformative and vulnerable to link rot. Please consider converting them to full citations to ensure the article remains verifiable and maintains a consistent citation style. Several templates and tools are available to assist in formatting, such as reFill (documentation) and Citation bot (documentation). (August 2022) (Learn how and when to remove this message) Programmable calculators are calculators that can automatically carry out a sequence of oper...

 

 

United States congressional delegations from Iowa

Since Iowa became a U.S. state in 1846, it has sent congressional delegations to the United States Senate and United States House of Representatives. Each state elects two senators to serve for six years, and members of the House to two-year terms. Before becoming a state, the Iowa Territory elected a non-voting delegate at-large to Congress from 1838 to 1846. These are tables of congressional delegations from Iowa to the United States Senate and the United States House of Representatives.&#...

Classe Type 053

Questa voce o sezione sull'argomento classi navali non cita le fonti necessarie o quelle presenti sono insufficienti. Puoi migliorare questa voce aggiungendo citazioni da fonti attendibili secondo le linee guida sull'uso delle fonti. Segui i suggerimenti del progetto di riferimento. Classe Type 053Classe JianghuDescrizione generale TipoFregata ProprietàCina Entrata in servizio1975 Caratteristiche generaliDislocamento1930 t Lunghezza103,2 m Larghezza10,2 m Pescaggio3,1...

 

 

Percy Brookfield

Australian politician Percy BrookfieldPercy Brookfield in 1915Member of the New South Wales Legislative Assembly for SturtIn office3 February 1917 – 22 March 1921Serving with Mat Davidson and Brian DoePreceded byJohn CannSucceeded byJabez Wright Personal detailsBornPercival Stanley Brookfield(1875-08-07)7 August 1875Wavertree, Lancashire, EnglandDied22 March 1921(1921-03-22) (aged 45)Adelaide, South Australia, AustraliaResting placeBroken Hill CemeteryPolitical partyLa...

 

 

Conseil national du patronat français

Conseil national du patronat françaisHistoireFondation 21 décembre 1945Dissolution 27 octobre 1998Prédécesseur Confédération générale du patronat français (CGPF)Successeur Mouvement des entreprises de France (Medef)CadreSigle CNPFType Organisation patronaleForme juridique Association loi de 1901Financement Cotisations des adhérentsSiège 31 avenue Pierre-Ier-de-Serbie 75016 ParisPays  FranceLangue françaisOrganisationPersonnes clés Georges Villiers, Paul Huvelin, François Ce...

Late Night (franchise)

American late-night talk show franchise Not to be confused with The Late Show (franchise). Late NightThe logo for Late Night with Seth Meyers, the current iteration of the Late Night franchise.GenreTalk showVariety showCreated byDavid LettermanPresented byDavid Letterman (1982–1993) Conan O'Brien (1993–2009) Jimmy Fallon (2009–2014) Seth Meyers (2014–present)Country of originUnited StatesNo. of episodes1,819 (under Letterman)2,725 (under O'Brien)969 (under Fallon)1,535 (under Meyers)T...

 

 

塞芒人

塞芒人Semang一位塞芒族男子總人口約4596人分佈地區馬來西亞（東南亞）泰國（東南亞） 马来西亚4296 泰國300語言巴特克语、拉诺语、嘉海語、明里克语、明蒂尔语、肯休语、金塔克语、湯加語、馬來語宗教信仰泛靈信仰、伊斯蘭教、基督教、佛教 塞芒人（Semang、Seemang、Siamang[註 1]），又譯賽孟人，是一支矮黑人民族，分布於馬來半島北部及泰國南部，被認為是...

 

 

Magnus Bäckstedt

Magnus Bäckstedt NamnMagnus Peter BäckstedtSmeknamnMagnus MaximusBig MaggieFödd30 januari 1975 (49 år)Hemland SverigeLängd193 cmVikt90 kgStallinformationNuvarande stallAvslutad karriärDisciplinLandsvägRollCyklistAmatörstall2002–2003Rabobank TT3Proffsstall19961997 1998 1998–2001 2002–2003 2004 2005–2007 2008Collstrop-LystexPalmans-LystexGANCrédit AgricoleTeam FaktaAlessio-BianchiTeam LiquigasGarmin-ChipotleViktiga segrarParis–Roubaix 2004Tour de France, 1 etapp Nationsm...

Up All Night (Take That song)

2009 single by Take ThatUp All NightSingle by Take Thatfrom the album The Circus B-side84Released2 March 2009Recorded2008GenrePop rockalternative rockLength3:21LabelPolydorSongwriter(s)Gary BarlowHoward DonaldJason OrangeMark OwenBen MarkJamie Norton[1]Producer(s)Take ThatJohn ShanksTake That singles chronology Greatest Day (2008) Up All Night (2009) The Garden (2009) Music videoUp All Night on YouTube Up All Night is the second single from English group Take That's fifth studio albu...

 

 

Perdana Global Peace Organization

Questa voce sull'argomento partiti politici è solo un abbozzo. Contribuisci a migliorarla secondo le convenzioni di Wikipedia. Segui i suggerimenti del progetto di riferimento. Perdana Global Peace OrganisationLeaderMahathir Mohamad, già primo ministro della Malaysia Stato Malaysia Ideologiapacifismo Affiliazione internazionaleinternazionale Sito webwww.perdana4peace.org/ Modifica dati su Wikidata · Manuale L'organizzazione Perdana Global Peace Organisation �...