In computing, booting (booting up) is a bootstrapping process that starts operating systems when the user turns on a computer system. Computing is usually defined like the activity of using and developing Computer technology Computer hardware and software. In computing bootstrapping ("to pull oneself up by one's bootstraps" refers to techniques that allow a simple system to activate a more complicated system An operating system (commonly abbreviated OS and O/S) is the software component of a Computer system that is responsible for the management and coordination A computer is a Machine that manipulates data according to a list of instructions. A boot sequence is the initial set of operations that the computer performs when it is switched on. The bootloader typically loads the main operating system for the computer. An operating system (commonly abbreviated OS and O/S) is the software component of a Computer system that is responsible for the management and coordination

Contents 1 Boot loader 1.1 Second-stage boot loader 1.2 Flash boot loader 1.3 Network booting 2 Boot devices 3 Boot sequence on standard PC (IBM-PC compatible) 4 Other kinds of boot sequence 4.1 Initial Program Load 5 Rebooting 5.1 Hard reboot 5.2 Soft reboot 5.3 Random reboot 5.4 Errors 6 History 7 References 8 See also 9 Further reading

Boot loader

Computing systems powered by the central processor (or a set of processors), can only execute code found in the operating memory also known as systems memory that may be implemented in several technologies covered by the general types of: Read-Only Memory or ROM, and Random Access Memory or RAM. Modern operating systems and application program code and data are stored on nonvolatile or persistent local or remote peripheral memories or mass storage devices. Typical examples of such persistent storage devices are: hard disk, CD, USB flash drive, and Floppy drive. When a computer is first powered on, it must initially rely only on the code and data stored in nonvolatile portion of the systems memory map, such as ROM, NVRAM or CMOS RAM. Persistent code and data residing in the systems memory map represent the bare minimum needed to access peripheral persistent devices and load into the systems memory all of the missing parts of the operating system. Truly speaking at power-on time the computing system does not have an operating system in memory. Among many things, the computer's hardware alone,(processor and systems memory), cannot perform many complex systems actions of which loading program files from the disk based file systems is one of the most important tasks.

The program that starts the "chain reaction" which ends with the entire operating system being loaded is known as bootstrap loader. Early computer designers have creatively imagined that before being ready to "run" a computer had to have it's "boots" in order or strapped. Subsequently, to get the computing system in the ready to run state, a special small program, called a bootstrap loader, bootstrap or boot loader had to start first. Computer programs (also software programs, or just programs) are instructions for a Computer. In computing bootstrapping ("to pull oneself up by one's bootstraps" refers to techniques that allow a simple system to activate a more complicated system This program's only job is to load other software for the operating system to start. Often, multiple-stage boot loaders are used, in which several small programs of increasing complexity sequentially summon one after the other, until the last of them loads the operating system. The name bootstrap loader comes from the image of one pulling oneself up by one's boot straps. A boot is a type of Shoe that covers at least the Foot and the Ankle and sometimes extends up to the Knee or even the Hip. Serine/threonine kinase receptor associated protein, also known as STRAP, is a human Gene.

Early computers had a row of toggle switches on the front panel to allow the operator to manually enter the binary boot instructions into memory before transferring control to the CPU. A toggle switch is a class of Electrical switches that are actuated by a mechanical Lever, handle or rocking mechanism The binary numeral system, or base-2 number system, is a Numeral system that represents numeric values using two symbols usually 0 and 1. The boot loader would then read the operating system in from an outside storage medium such as paper tape, punched card, or a disk drive. Punched tape or paper tape is a largely obsolete form of Data storage, consisting of a long strip of paper in which holes are punched to store data Disk storage is a general category of a Computer storage mechanisms in which data is recorded on planar round and rotating surfaces ( disks, discs, or

Pseudo-assembly code for the bootloader might be as simple as the following eight instructions:

0: set the P register to 8
1: check paper tape reader ready
2: if not ready, jump to 1
3: read a byte from paper tape reader to accumulator
4: if end of tape, jump to 8
5: store accumulator to address in P register
6: increment the P register
7: jump to 1

A related example is based on a loader for a 1970's Nicolet Instrument Corporation minicomputer. Pseudocode is a compact and informal high-level description of a Computer programming Algorithm that uses the structural conventions of some Programming language See the terminology section below for information regarding inconsistent use of the terms assembly and assembler A minicomputer (colloquially mini) is a class of multi-user Computers that lies in the middle range of the computing spectrum in between the largest Multi-user Note that the bytes of the second-stage loader are read from paper tape in reverse order.

0: set the P register to 106
1: check paper tape reader ready
2: if not ready, jump to 1
3: read a byte from paper tape reader to accumulator
4: store accumulator to address in P register
5: decrement the P register 
6: jump to 1

The length of the second stage loader is such that the final byte overwrites location 6. After the instruction in location 5 executes, location 6 starts the second stage loader executing. The second stage loader then waits for the much longer tape containing the operating system to be placed in the tape reader. The difference between the boot loader and second stage loader is the addition of checking code to trap paper tape read errors, a frequent occurrence with the hardware of the time, which in this case was an ASR-33 teletype. Introduced about 1963, Teletype Corporation 's ASR33 was a very popular model of Teleprinter. A teleprinter (

Some computer systems, upon receiving a boot signal from a human operator or a peripheral device, may load a very small number of fixed instructions into memory at a specific location, initialize at least one CPU, and then point the CPU to the instructions and start their execution. These instructions typically start an input operation from some peripheral device (which may be switch-selectable by the operator). Other systems may send hardware commands directly to peripheral devices or I/O controllers that cause an extremely simple input operation (such as "read sector zero of the system device into memory starting at location 1000") to be carried out, effectively loading a small number of bootload instructions into memory; a completion signal from the I/O device may then be used to start execution of the instructions by the CPU.

Smaller computers often use less flexible but more automatic bootload mechanisms to ensure that the computer starts quickly and with a predetermined software configuration. In many desktop computers, for example, the bootstrapping process begins with the CPU executing software contained in ROM (for example, the BIOS of an IBM PC) at a predefined address (the CPU is designed to execute this software after reset without outside help). In Computing, the BIOS (ˈbaɪoʊs This software contains rudimentary functionality to search for devices eligible to participate in booting, and load a small program from a special section (most commonly the boot sector) of the most promising device. A boot sector (sometimes called a bootblock) is a sector of a Hard disk, Floppy disk, or similar Data storage device that contains It is usually possible to configure the BIOS so that only a certain device can be booted from and/or to give priority to some devices over others (a CD or DVD drive is usually given priority over a hard disk, for instance).

Boot loaders may face peculiar constraints, especially in size; for instance, on the IBM PC and compatibles, the first stage of boot loaders located on hard drives must fit into the first 446 bytes of the Master Boot Record, in order to leave room for the 64-byte partition table and the 2-byte 0xAA55 'signature', which the BIOS requires for a proper boot loader. A byte (pronounced "bite" baɪt is the basic unit of measurement of information storage in Computer science. MBRs and disk partitioning MBRs and system bootstrapping On IA-32 IBM PC compatible machines using the MBR Partition Table scheme the bootstrapping Disk partitioning is the creation of separate divisions of a Hard disk drive using Partition editors Once a disk is divided into several partitions directories and

Some operating systems, most notably pre-1995 Macintosh systems from Apple, are so closely interwoven with their hardware that it is impossible to natively boot an operating system other than the standard one. Macintosh, commonly nicknamed Mac is a Brand name which covers several lines of Personal computers designed developed and marketed by Apple Inc Apple Inc, ( formerly Apple Computer Inc, is an American Multinational corporation with a focus on designing and manufacturing Consumer electronics This is the opposite extreme of the bootload using switches mentioned above; it is highly inflexible but relatively error-proof and foolproof as long as all hardware is working normally. A common solution in such situations is to design a bootloader that works as a program belonging to the standard OS that hijacks the system and loads the alternative OS. This technique was used by Apple for its A/UX Unix implementation and copied by various freeware operating systems and BeOS Personal Edition 5. A/UX (from A pple U ni' x') was Apple Computer 's implementation of the Unix Operating system for some of their Macintosh Unix (officially trademarked as UNIX, sometimes also written as Unix with Small caps) is a computer BeOS is an Operating system for Personal computers which began development by Be Inc

Second-stage boot loader

The small program is most often not itself an operating system, but only a second-stage boot loader, such as GRUB, LILO or NTLDR. LILO redirects here for uses other than the boot loader see Lilo LILO ( LI nux LO ader is a generic Boot loader NTLDR ( Abbreviation of NT Loader) is the boot loader for all releases of Microsoft 's Windows NT It will then be able to load the operating system properly, and finally transfer execution to it. The system will initialize itself, and may load device drivers and other programs that are needed for the normal operation of the OS. In computing a device driver or software driver is a Computer program allowing higher-level computer programs to interact with a Hardware device

Many bootloaders (like GRUB, Bootmgr, LILO, and NTLDR) can be configured to give the user multiple booting choices. These choices can include different operating systems (for dual or multi-booting from different partitions or drives), different kernel versions of the same operating system (e. Multi boot or Multi booting (usually dual booting, but many OSes can be booted from the same computer is the act of installing multiple Operating g. , when a newer Linux kernel is installed, this gives one the option of using a known good kernel if problems arise), different kernel options (e. g. , booting into a rescue or safe mode) or some standalone program that can function without an operating system, such as memory testers (e. g. , memtest86+) or even games (e. Memtest86+ is Software designed to Stress test an 86-compatible computer's Random access memory (RAM for errors g. , Invaders). Usually a default choice is preselected with a time delay during which you can press a key to change the choice, after which the default choice is automatically run, so normal booting can occur without interaction.

The boot process is considered complete when the computer is ready to interact with the user, or the operating system is capable of running ordinary applications. An operating system (commonly abbreviated OS and O/S) is the software component of a Computer system that is responsible for the management and coordination Typical modern PCs boot in about one minute (of which about 15 seconds are taken by a power-on self test (POST) and a preliminary boot loader, and the rest by loading the operating system); whereas, large servers may take several minutes to boot and start all their services. A personal computer ( PC) is any Computer whose original sales price size and capabilities make it useful for individuals and which is intended to be operated Power-on self-test (POST is the common term for a computer router or printer's pre-boot sequence.

Many embedded systems must boot immediately. An embedded system is a special-purpose Computer system designed to perform one or a few dedicated functions often with Real-time computing constraints For example, waiting a minute for a digital television or sat-nav to start is generally unacceptable. Therefore such devices have their complete operating system in ROM or flash memory so the device can begin functioning immediately. Flash memory is non-volatile computer memory that can be electrically erased and reprogrammed For these types of embedded system little or no loading is necessary, since the loading can be precomputed and stored on the ROM when the device is made.

Large and complex systems may have boot procedures that proceed in multiple phases, each phase loading a more complex version of itself, until finally the actual operating system is loaded and ready to execute. Because most operating systems are designed as if they never start or stop, bootload processes sometimes construct a near-snapshot of a running operating system, configure themselves as a mere process within that operating system, and then irrevocably transfer control into the operating system; the bootload process then terminates normally as any other process would, and the operating system need not have any awareness of the bootload.

Flash boot loader

Embedded systems especially in automotive applications rely heavily on Flash Bootloaders to ensure that the ECU (Electronic Control Unit) is programmable either in production or in service. In automotive electronics an electronic control unit (ECU also called a Control unit, or Control module, is an Embedded system that controls one or more A Flash Bootloader resides in Flash memory, and is always the first application to run after a reset. The Flash bootloader decides whether an application is ready and thereby either stays in the ECU or jumps to the application to start execution. The benefit of having a Flash Bootloader on an ECU is mainly to allow erasing and programming new applications on a single ECU in case of application updates, a recall, or changing a configuration by downloading new calibration files. The most popular Flash Bootloaders are CAN based, i. e. use the Control Area Network protocol to download data to an ECU. These bootloaders use a Diagnostics protocol to communicate and download to an ECU.

Network booting

Main article: Network booting

Most computers are also capable of booting over a computer network. Network booting is the process of Booting a Computer from a network rather than a local drive A computer network is a group of interconnected Computers. Networks may be classified according to a wide variety of characteristics In this scenario, the operating system is stored on the disk of a server, and certain parts of it are transferred to the client using a simple protocol such as the Trivial File Transfer Protocol. A server is a Computer dedicated to providing one or more services over a computer network typically through a request-response routine Trivial File Transport Protocol ( TFTP) is a very simple file transfer protocol, with the functionality of a very basic form of FTP; it was After these parts have been transferred, the operating system then takes over control of the booting process.

Boot devices

The boot device is the device from which the operating system is loaded. A modern PC BIOS supports booting from various devices. In Computing, the BIOS (ˈbaɪoʊs These include the local hard disk drive (or partitions on a hard disk), floppy, optical disc drive, a SCSI device, Zip drive, LS-120, a network interface card using PXE and a USB device (USB-FDD, USB-ZIP, USB-CDROM, USB-HDD, USB flash drive). A hard disk drive ( HDD) commonly referred to as a hard drive, hard disk, or fixed disk drive, is a Non-volatile storage device Disk partitioning is the creation of separate divisions of a Hard disk drive using Partition editors Once a disk is divided into several partitions directories and A boot disk is a removable digital data storage medium from which a Computer can load and run ( boot) an Operating system or utility program In Computing, an optical disc drive ( ODD) is a Disk drive that uses Laser light or electromagnetic waves near the Light spectrum The Zip drive is a medium-capacity removable Disk storage system introduced by Iomega in late 1994 Also known as the LS-120 and the later variant LS-240, the SuperDisk was introduced by 3M 's storage products group (later known as Imation The Preboot eXecution Environment ( PXE, aka Pre-Execution Environment or 'pixie' is an environment to boot Computers using a network interface

Typically, the BIOS will allow the user to configure a boot order. If the boot order is set to "firstly, the DVD drive; secondly, the hard disk drive", then the BIOS will try to boot from the DVD drive, and if this fails (e. g. because there is no DVD in the drive), it will try to boot from the local hard drive.

For example, on a PC with Windows XP installed on the hard drive, the user could set the boot order to that given above, and then insert a Knoppix CD in order to try out Linux without having to install an operating system onto their hard drive. Windows XP is a family of 32-bit and 64-bit Operating systems produced by Microsoft for use on Personal computers including home and Knoppix, or KNOPPIX (nopɪks is a GNU/Linux Operating system based on Debian designed to be run directly from a CD / DVD Linux (commonly pronounced ˈlɪnəks This is an example of dual booting - the user choosing which operating system to start after the computer has performed its Power On Self Test. Power-on self-test (POST is the common term for a computer router or printer's pre-boot sequence. In this example of dual booting, the user chooses by inserting or removing the CD from the computer, but it is more common to choose which operating system to boot by selecting from a menu using the computer keyboard. (Typically, the boot loader which presents the menu will select a default option if the user does nothing for a configured number of seconds, e. g. 30 seconds - this facilitates unattended rebooting into a default environment. )

Boot sequence on standard PC (IBM-PC compatible)

Upon starting, a personal computer's x86 CPU runs the instruction located at the memory location F000:FFF0 (on 286s and 386SXs, the base of the code segment is actually 0xFF0000 and on 386s it is 0xFFFF0000) of the BIOS. A personal computer ( PC) is any Computer whose original sales price size and capabilities make it useful for individuals and which is intended to be operated See also X86 assembly language The generic term x86 refers to the most commercially successful Instruction set architecture in the history of Personal In Computing, the BIOS (ˈbaɪoʊs This memory location is close to the end of system memory. It contains a jump instruction that transfers execution to the location of the BIOS start-up program. This program runs a power-on self test (POST) to check that devices the computer will rely on are functioning; it also initializes these devices. Power-on self-test (POST is the common term for a computer router or printer's pre-boot sequence. Then, the BIOS goes through a preconfigured list of non-volatile storage devices until it finds one that is bootable. Non-volatile memory, nonvolatile memory, NVM or non-volatile storage, is Computer memory that can retain the stored information A bootable device is one such that it can be read from and the last two bytes of the first sector contain the word 0xAA55. In Computing, " word " is a term for the natural unit of data used by a particular computer design On IBM PCs and derivatives made by IBM, if it finds no such device, control is transferred to IBM Cassette BASIC. IBM Cassette BASIC was a version of the Microsoft BASIC programming language licensed by IBM for the IBM PC. On other IBM PC compatibles, an error message is generated and the boot process stops. IBM PC compatible computers are those generally similar to the original IBM PC, XT, and AT.

Once BIOS has found a bootable device, BIOS loads the bootsector to hexadecimal Sector:Offset address 0000:7C00 and transfers execution to the boot sector. x86 memory segmentation refers to the implementation of Memory segmentation on the X86 architecture. This article describes the computer science term In Computer science, an offset within an Array or other Data structure object A boot sector (sometimes called a bootblock) is a sector of a Hard disk, Floppy disk, or similar Data storage device that contains In the case of a hard drive, this is referred to as the master boot record (MBR) and is often not operating system specific. MBRs and disk partitioning MBRs and system bootstrapping On IA-32 IBM PC compatible machines using the MBR Partition Table scheme the bootstrapping Usually, the MBR code checks the partition table for an active partition. Disk partitioning is the creation of separate divisions of a Hard disk drive using Partition editors Once a disk is divided into several partitions directories and If one is found, the MBR code loads that partition's boot sector and executes it. A boot sector (sometimes called a bootblock) is a sector of a Hard disk, Floppy disk, or similar Data storage device that contains The boot sector is often operating system specific, however in most operating systems its main function is to load and execute the operating system kernel, which continues startup. In Computer science, the kernel is the central component of most computer Operating systems (OS If there is no active partition or the active partition's boot sector is invalid, the MBR may load a secondary boot loader and pass control to it and this secondary boot loader will select a partition (often via user input) and load its boot sector, which usually loads the corresponding operating system kernel.

Newer systems that have EFI-compliant firmware can boot from that to either MBR or GPT drives. The Extensible Firmware Interface ( EFI) is a specification that defines a software Interface between an Operating system and platform Firmware In Computer hardware, GUID Partition Table ( GPT) is a standard for the layout of the Partition table on a physical Hard disk. Compatibility with x86 operating systems, such as 32-bit Windows XP and Vista, require “legacy BIOS” interfaces to operate, which is handled through a compatibility support module (CSM). The CSM includes a 16-bit binary (CSM16) supplied by BIOS vendors, like American Megatrends (AMI) and Insyde Software^[1] or Apple Inc. which offers it as a firmware update for Intel Macintosh computers. American Megatrends Incorporated ( AMI) is a hardware and Software company headquartered in unincorporated Gwinnett County, Apple Inc, ( formerly Apple Computer Inc, is an American Multinational corporation with a focus on designing and manufacturing Consumer electronics

Other kinds of boot sequence

Some other processors have other kinds of boot modes; most digital signal processors have the following boot modes:

• Serial mode boot
• Parallel mode boot
• HPI boot

Initial Program Load

In IBM mainframe systems, the boot process is known as IPL (Initial Program Load). A digital signal processor ( DSP or DSP micro) is a specialized Microprocessor designed specifically for Digital signal processing, generally The term was coined by IBM for the design of the System/360 and continues to be used in those environments today^[2]. The IBM System/360 ( S/360) is a Mainframe computer system family announced by IBM on April 7, 1964. In systems that share the System/360 heritage—and in some that have been inspired by it, including smaller systems such as the IBM 1130—IPL is a hardware function, not a program run on the system itself. The IBM 1130 Computing System was introduced in 1965. It was IBM 's least-expensive Computer to date and was aimed at price-sensitive computing-intensive In its basic form, an IPL is initiated by the computer operator by selecting the (three digit) device address using rotary switches on the computer console, followed by pressing the 'IPL' button. This starts a tiny (typically 24 byte) program entirely implemented in hardware, consisting merely of a few channel command words initiating a read operation from the designated device. In Computer science, channel I/O is a generic term that refers to a high-performance Input/output (I/O architecture that is implemented in various forms on a number Usually this is a disk drive, but exactly the same procedure is also used to boot from other devices, such as tape drives, or even card readers, in a device-independent manner, allowing e. A tape drive, which is also known as a streamer, is a data storage device that reads and writes data stored on a magnetic tape. A memory card reader is a device used for communication with a Smart card or a flash Memory card. g. the installation of an operating system on a pristine computer from a magnetic distribution tape. Of course, the disk, tape or card deck must contain a special program to load the actual operating system into memory, a multi-stage procedure similar to most booting procedures (see elsewhere in this article).

The System/360 IPL function reads 24 bytes from an operator-specified or pre-configured device into memory starting at location zero. The second and third groups of eight bytes are treated as Channel Command Words (CCWs) to continue loading the startup program. When the I/O channel commands are complete, the first group of eight bytes is then loaded into the Program Status Word (PSW) register and the startup program begins execution at the designated location. ^[2]

A noteworthy variation of this is found on the Burroughs B1700 where there is neither a bootstrap ROM nor a hardwired IPL operation. The Burroughs Corporation began in 1886 as the American Arithmometer Company in St The Burroughs B1000 Series machines consisted of three major generations Instead, after the system is reset it reads and executes opcodes sequentially from a tape drive mounted on the front panel, this sets up a boot loader in RAM which is then executed. However, since this makes few assumptions about the system it can equally well be used to load diagnostic (Maintenance Test Routine) tapes which display an intelligible code on the front panel even in cases of gross CPU failure. A front panel was used on early electronic computers to display and allow the alteration of the state of the machine's internal registers and memory.

Rebooting

Hard reboot

A hard reboot (also known as a cold reboot, cold boot or cold start) is when power to a computer is cycled (turned off and then on) or a special reset signal to the processor is triggered (from a front panel switch of some sort). Power cycling is the act of turning a piece of equipment usually a Computer, off and then on again This restarts the computer without first performing any shut-down procedure. (With many operating systems, especially those using disk caches, after a hard reboot the filesystem may be in an "unclean" state, and an automatic scan of on-disk filesystem structures will be done before normal operation can begin. An operating system (commonly abbreviated OS and O/S) is the software component of a Computer system that is responsible for the management and coordination In Computer science, a cache (kæʃ like "cash") is a collection of data duplicating original ) It may be caused by power failure, be done by accident, or be done deliberately as a last resort to forcibly retrieve the system from instances such as a critical error or virus-inflicted DoS attack. A computer virus is a Computer program that can copy itself and infect a computer without permission or knowledge of the user

Soft reboot

A soft reboot (also known as a warm reboot) is restarting a computer under software control, without removing power or (directly) triggering a reset line. Electric power is defined as the rate at which Electrical energy is transferred by an Electric circuit. It usually, though not always, refers to an orderly shutdown and restarting of the machine. To shutdown a computer is to turn its power off in a controlled way

The Control-Alt-Delete key combination on the original IBM PC was designed to allow a soft reboot for a quicker and more convenient (and, some argue, less stressful on system components) restart than powering the computer completely down then back up. Control-Alt-Delete (often abbreviated to Ctrl-Alt-Del, also known as the "three-finger salute" is a computer keyboard command on PC compatible systems

The Linux kernel has optional support for the kexec system call, which shuts down the currently running kernel and executes another one. In Computing, a system call is the mechanism used by an application program to request service from the Kernel. The entire process is done independent of the system firmware. Note that the kernel being executed does not have to be a Linux kernel.

Most Nintendo Game Boy games feature a soft reset feature when the A, B, Start, and Select buttons are pressed together. The line is a line of battery -powered Handheld game consoles sold by Nintendo. This was carried over to the Nintendo DS, with the sequence L, R, Start, and Select. The is a dual-screen Handheld game console developed and manufactured by Nintendo. Many Nintendo GameCube games have a similar feature, with the sequence Start, B, A, and X. The, often abbreviated as GCN, is Nintendo 's fourth home Video game console and is part of the sixth generation console era.

Random reboot

Random reboot is a non-technical term referring to an unintended (and often undesired) reboot for which the cause is not immediately evident to the user. In Computing, booting ( booting up) is a bootstrapping process that starts Operating systems when the user turns on a Computer system Such reboots may occur due to a multitude of software and hardware problems, such as triple faults. A triple fault is a special kind of exception generated by the CPU when an exception occurs while the CPU is trying to invoke the Double fault exception

As Windows XP/Vista has an option to skip its Blue Screen of Death (Blue Screens of Death in Windows XP/Vista offer no option of pressing any key and seeing if the computer continues functioning) and immediately restarts the computer in the event of a fatal error, users can be mistaken in thinking a Windows XP/Vista computer suffers from random rebooting. The Blue Screen of Death (also known as a stop error, BSoD, bluescreen, or Blue Screen of Doom) is an Error screen displayed

Errors

In Windows, when an error occurs in the boot process, a Blue Screen of Death or a Black Screen of Death may occur. The Blue Screen of Death (also known as a stop error, BSoD, bluescreen, or Blue Screen of Doom) is an Error screen displayed The black screen of death (BlSoD, is one of three things a failure mode of Microsoft Windows 3 On Unix and Unix-like operating systems, like Linux, a fatal error in the boot process may cause a kernel panic. A kernel panic is an action taken by an Operating system upon detecting an internal Fatal error from which it cannot safely recover the term is largely specific

History

The word boot is derived from 'bootstrap' (short for 'bootstrap load', also: 'bootload'). This is the history of bootstrapping or booting which began in the 1880s as a leather strap and evolved into a group of metaphors that share a common meaning a self-sustaining In a computing context, that word has been used since at least 1958^[3].

The GE 645 (c. The GE-600 series was a family of 36-bit mainframe Computers originating in the 1960s built by General Electric (GE 1965) had a 'BOOT' button^[4] – it could be that the contraction started as a way to label the button with fewer letters than the full word.

The Multics operating system (c. Multics ( Mult iplexed I nformation and C omputing S ervice was an extremely influential early Time-sharing Operating system 1967) had a boot command. ^[5][6] Multics documents also refer to 'boot tapes', but it is hard to determine exactly when that term was first used.

In the Unix operating system, the earliest reference for 'boot' is probably in The Unix Programmer's Manual, first edition 1971. Unix (officially trademarked as UNIX, sometimes also written as Unix with Small caps) is a computer 11. 03^[7].

References

See also

• Boot disk, Live CD, Live USB
• Boot sector
• Comparison of boot loaders

• Extensible Firmware Interface (EFI)
• Linux startup process
• Microreboot

• Network booting
• RedBoot open source boot loader for embedded systems
• Windows NT Startup Process

Further reading

• How Computers Boot Up
• Pratical bootloader tutorial for ATmega microcontrollers
• How GRUB fits into the hardisk layout on a PC
• Booting with Grub at OSDEV Community
• A tutorial on dualbooting/multibooting with Windows NTLDR and Linux LILO/GRUB
• Booting From Scratch
  • Matthew Vea. A boot disk is a removable digital data storage medium from which a Computer can load and run ( boot) an Operating system or utility program A live CD or live distro is a computer Operating system that is executed upon boot, without installation to a Hard disk drive. A live USB or USB live distro is a USB flash drive or an External hard disk drive containing a full Operating system which can be booted A boot sector (sometimes called a bootblock) is a sector of a Hard disk, Floppy disk, or similar Data storage device that contains The following tables compare general and technical information for a number of available Bootloaders. The Extensible Firmware Interface ( EFI) is a specification that defines a software Interface between an Operating system and platform Firmware The Linux startup process is the process by which Linux -based Operating systems initialize Microrebooting is a technique used to recover from failures in software systems Network booting is the process of Booting a Computer from a network rather than a local drive RedBoot is an Open source application that uses the ECos Real-time operating system Hardware Abstraction Layer to provide bootstrap The Windows NT startup process is the process by which Microsoft 's Windows NT, Windows 2000, Windows XP and Windows Server 2003 x86 BootStrap Programming Tutorial.
• FreeBSD
  • Nathan Boeger and Mana Tominaga. Bootstrapping FreeBSD.
• Linux
  • Roberto Alsina. The Linux boot process unveiled.
  • Greg O'Keefe. From power up to Linux bash prompt HOWTO.
• Mac OS X
  • Amit Singh. Mac OS X Boot Process.
• Windows
  • Jonathan de Boyne Pollard (1996). The DOS and DOS/Windows boot processes. Frequently Given Answers.
  • Multi-booting, running different versions of Windows on your PC.
  • Windows Mobile 5.0 Soft Reset.
  • Pocket PC devices hard reset and soft reset.

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