Booting - Knowledge (XXG)

169: 708:(released first in 1975) and an even earlier, similar machine (based on the Intel 8008 CPU) had no bootstrapping hardware as such. When powered-up, the CPU would see memory that would contain random data. The front panels of these machines carried toggle switches for entering addresses and data, one switch per bit of the computer memory word and address bus. Simple additions to the hardware permitted one memory location at a time to be loaded from those switches to store bootstrap code. Meanwhile, the CPU was kept from attempting to execute memory content. Once correctly loaded, the CPU was enabled to execute the bootstrapping code. This process, similar to that used for several earlier minicomputers, was tedious and had to be error-free. 2043:

problems, relating to project organization, project control and product quality. Many processes will become distributed as well. The defect detection process, so important for measuring and eventually achieving product quality, is typically one of the first to experience problems caused by the distributed nature of the project. The distribution of defect detection activities over several parties introduces risks like the inadequate review of work products, occurrence of "blind spots" with respect to test coverage or over-testing of components. Lifecycle-wide coordination of defect detection is therefore needed to ensure effectiveness and efficiency of defect detection activities. —J.J.M. Trienekens; R.J. Kusters. (2004)

1878:. Such an interface may be used to write the boot loader program into bootable non-volatile memory (e.g. flash) by instructing the processor core to perform the necessary actions to program non-volatile memory. Alternatively, the debug interface may be used to upload some diagnostic or boot code into RAM, and then to start the processor core and instruct it to execute the uploaded code. This allows, for example, the recovery of embedded systems where no software remains on any supported boot device, and where the processor does not have any integrated boot ROM. JTAG is a standard and popular interface; many CPUs, microcontrollers and other devices are manufactured with JTAG interfaces (as of 2009). 888:. Retrieval of the OS from secondary or tertiary store was thus eliminated as one of the characteristic operations for bootstrapping. To allow system customizations, accessories, and other support software to be loaded automatically, the Atari's floppy drive was read for additional components during the boot process. There was a timeout delay that provided time to manually insert a floppy as the system searched for the extra components. This could be avoided by inserting a blank disk. The Atari ST hardware was also designed so the cartridge slot could provide native program execution for gaming purposes as a holdover from Atari's legacy making electronic games; by inserting the 782:, included an (external) ROM. Gruppi Speciali was, starting from 1975, a fully single-button machine booting into the operating system from a ROM memory composed from semiconductors, not from ferrite cores. Although the ROM device was not natively embedded in the computer of Gruppi Speciali, due to the design of the machine, it also allowed the single-button ROM booting in machines not designed for that (therefore, this "bootstrap device" was architecture-independent), e.g. the PDP-11. Storing the state of the machine after the switch-off was also in place, which was another critical feature in the telephone switching contest. 5533: 1050:

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 boot loader instructions into memory; a completion signal from the I/O device may then be used to start execution of the instructions by the CPU.

54: 866:, are so closely interwoven with their hardware that it is impossible to natively boot an operating system other than the standard one. This is the opposite extreme of the scenario 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 boot loader 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 771:(1971) had a program load switch that, in combination with options that provided two ROM chips, loaded a program into main memory from those ROM chips and jumped to it. Digital Equipment Corporation introduced the integrated-circuit-ROM-based BM873 (1974), M9301 (1977), M9312 (1978), REV11-A and REV11-C, MRV11-C, and MRV11-D ROM memories, all usable as bootstrap ROMs. The PDP-11/34 (1976), PDP-11/60 (1977), PDP-11/24 (1979), and most later models include boot ROM modules. 1988: 1838:(DSPs) may have boot ROM integrated directly into their silicon, so such a processor can perform a simple boot sequence on its own and load boot programs (firmware or software) from boot sources such as NAND flash or eMMC. It is difficult to hardwire all the required logic for handling such devices, so an integrated boot ROM is used instead in such scenarios. Also, a boot ROM may be able to load a boot loader or diagnostic program via serial interfaces like 1812: 1906:, since it usually boots first from its own memories and then controls overall system behavior, including booting of the DSP, and then further controlling the DSP's behavior. The DSP often lacks its own boot memories and relies on the host processor to supply the required code instead. The most notable systems with such a design are cell phones, modems, audio and video players and so on, where a DSP and a CPU/microcontroller are co-existing. 1293: 330:(1953), a decimal machine, which had a group of ten 10-position switches on its operator panel which were addressable as a memory word (address 8000) and could be executed as an instruction. Thus setting the switches to 7004000400 and pressing the appropriate button would read the first card in the card reader into memory (op code 70), starting at address 400 and then jump to 400 to begin executing the program on that card. The 1459: 1475: 717: 311: 261: 513: 323:

the information in these first 80 memory locations to an assembly area where the information in punched cards 2, 3, 4, and so on, could be combined to form the stored program. Once this information was moved to the assembly area, the machine would branch to an instruction in location 080 (read a card) and the next card would be read and its information processed.

295:, or a magnetic drum unit, depending on the position of the Load Selector switch. The left 18-bit half-word was then executed as an instruction, which usually read additional words into memory. The loaded boot program was then executed, which, in turn, loaded a larger program from that medium into memory without further help from the human operator. The 1207:). Some boot loaders can also load other boot loaders; for example, GRUB loads BOOTMGR instead of loading Windows directly. Usually a default choice is preselected with a time delay during which a user can press a key to change the choice; after this delay, the default choice is automatically run so normal booting can occur without interaction. 156:. The usage calls attention to the requirement that, if most software is loaded onto a computer by other software already running on the computer, some mechanism must exist to load the initial software onto the computer. Early computers used a variety of ad-hoc methods to get a small program into memory to solve this problem. The invention of 1271:(PXE) image. No drivers are required, but the system functionality is limited until the operating system kernel and drivers are transferred and started. As a result, once the ROM-based booting has completed it is entirely possible to network boot into an operating system that itself does not have the ability to use the network interface. 696:

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 relatively low-cost, "part-time-duty" hardware, such as the Teletype Model 33 ASR. (Friden Flexowriters were far more reliable, but also comparatively costly.)

424:, revived it for the design of the System/360, and continues to use it in those environments today. In the System/360 processors, an IPL is initiated by the computer operator by selecting the three hexadecimal digit device address (CUU; C=I/O Channel address, UU=Control unit and Device address) followed by pressing the 4800:), and as soon as the boot sector is a DR-DOS sector, it will find and load them. Of course, it is difficult to put all this into just 512 bytes, the size of a single sector, but this is a major convenience improvement if you have to set up a DR-DOS system, and it is also the key for the DR-DOS multi-OS 835:

introduced in 1976, featured PROM chips that eliminated the need for a front panel for the boot process (as was the case with the Altair 8800) in a commercial computer. According to Apple's ad announcing it "No More Switches, No More Lights ... the firmware in PROMS enables you to enter, display and

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where there is neither a bootstrap ROM nor a hardwired IPL operation. Instead, after the system is reset it reads and executes microinstructions sequentially from a cassette tape drive mounted on the front panel; this sets up a boot loader in RAM which is then executed. However, since this makes few

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file, which is loaded by IBMBIO.COM. The DR-DOS boot sector will find the kernel files as long as they are logically stored in the root directory. Their physical location on the disk, and if they are fragmented or not, is don't care for the DR-DOS boot sector. Hence, you can just copy the kernel

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An erroneous state can trigger bootloops; this state can be caused by misconfiguration from previously known-good operations. Recovery attempts from that erroneous state then enter a reboot, in an attempt to return to a known-good state. In Windows OS operations, for example, the recovery procedure

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As the complexity of today's products increases, single projects, single departments or even single companies can no longer develop total products, causing concurrent and distributed development. Today and worldwide, industries are facing complex product development and its vast array of associated

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EBPB introduced with DOS 7.1 requires even 87 bytes, leaving only 423 bytes for the boot loader when assuming a sector size of 512 bytes. Microsoft boot sectors therefore traditionally imposed certain restrictions on the boot process, for example, the boot file had to be located at a fixed position

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Typically, a microprocessor will, after a reset or power-on condition, perform a start-up process that usually takes the form of "begin execution of the code that is found starting at a specific address" or "look for a multibyte code at a specific address and jump to the indicated location to begin

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The length of the second stage loader is such that the final byte overwrites location 7. After the instruction in location 6 executes, location 7 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

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and held a 32 by 16 array of semiconductor diodes. With all 512 diodes in place, the memory contained all "one" bits; the card was programmed by cutting off each diode whose bit was to be "zero". DEC also sold versions of the card, the BM792-Yx series, pre-programmed for many standard input devices

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had a "READ IN" button that, when pressed, reset the processor and started an I/O operation on a device specified by switches on the control panel, reading in a 36-bit word giving a target address and count for subsequent word reads; when the read completed, the processor started executing the code

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VBR would only load the first 29 KB of the file into memory, relying on another loader embedded into the first part of IBMBIO.COM to check for this condition and load the remainder of the file into memory by itself if necessary. This does not cause compatibility problems, as IBMBIO.COM's size

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have a similar mechanism, in which the Load button causes the instruction set up in the entry keys on the front panel is executed, and the channel that instruction sets up is given a command to transfer data to memory starting at address 00100; when that transfer finishes, the CPU jumps to address

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system (c. 1958) used a card reader to load a program from a punched card. The 80 characters stored in the punched card were read into memory locations 001 to 080, then the computer would branch to memory location 001 to read its first stored instruction. This instruction was always the same: move

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Some microcontrollers provide special hardware interfaces which cannot be used to take arbitrary control of a system or directly run code, but instead they allow the insertion of boot code into bootable non-volatile memory (like flash memory) via simple protocols. Then at the manufacturing phase,

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If there is no active partition, or the active partition's boot sector is invalid, the MBR may load a secondary boot loader which will select a partition (often via user input) and load its boot sector, which usually loads the corresponding operating system kernel. In some cases, the MBR may also

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physical sectors and using 386 instructions for size reasons. At the same time other vendors managed to squeeze much more functionality into a single boot sector without relaxing the original constraints on only minimal available memory (32 KB) and processor support (8088/8086). For example,

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Large and complex systems may have boot procedures that proceed in multiple phases until finally the operating system and other programs are loaded and ready to execute. Because operating systems are designed as if they never start or stop, a boot loader might load the operating system, configure

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On systems with those constraints, the first program loaded into RAM may not be sufficiently large to load the operating system and, instead, must load another, larger program. The first program loaded into RAM is called a first-stage boot loader, and the program it loads is called a second-stage

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Smaller computers often use less flexible but more automatic boot loader 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

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Some earlier 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

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In case of DSPs there is often a second microprocessor or microcontroller present in the system design, and this is responsible for overall system behavior, interrupt handling, dealing with external events, user interface, etc. while the DSP is dedicated to signal processing tasks only. In such

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such interfaces are used to inject boot code (and possibly other code) into non-volatile memory. After system reset, the microcontroller begins to execute code programmed into its non-volatile memory, just like usual processors are using ROMs for booting. Most notably this technique is used by

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The disk, tape or card deck must contain a special program to load the actual operating system or standalone utility into main storage, and for this specific purpose "IPL Text" is placed on the disk by the stand-alone DASDI (Direct Access Storage Device Initialization) program or an equivalent

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read-type command, but exactly the same procedure is also used to IPL from other input-type devices, such as tape drives, or even card readers, in a device-independent manner, allowing, for example, the installation of an operating system on a brand-new computer from an OS initial distribution

4877:, DR-DOS has "smart" boot sectors which will actually "mount" the file-system to search for and load the system files in the root directory instead of expecting them to be placed at a certain location. Physically, the system files can be located anywhere and also can be fragmented. 4808:

kernel files must reside on specific locations, but the DR-DOS files can be anywhere, so you don't have to physically swap them around each time you boot the other OS. Also, it allows to upgrade a DR-DOS system simply by copying the kernel files over the old ones, no need for

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The first instruction that is fetched and executed following a hardware reset is located at physical address FFFFFFF0h. This address is 16 bytes below the processor's uppermost physical address. The EPROM containing the software-initialization code must be located at this

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command and slightly relaxed in later versions of DOS. The boot loader was then able to load the first three sectors of the file into memory, which happened to contain another embedded boot loader able to load the remainder of the file into memory. When Microsoft added

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and so on. This feature is often used for system recovery purposes, or it could also be used for initial non-volatile memory programming when there is no software available in the non-volatile memory yet. Many modern microcontrollers (e.g. flash memory controller on

1377:. If the boot order is set to "first, the DVD drive; second, the hard disk drive", then the firmware 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 disk drive. 1870:

initialization using CPU cache as RAM) and load the larger, fully featured version of U-Boot. Some CPUs and SoCs may not use CPU cache as RAM on boot process, they use an integrated boot processor to do some hardware configuration, to reduce cost.

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are designed to execute this software after reset without outside help). 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

4558:; Rubin, Darryl; Ryan, Ralph; Schulmeisters, Karl; Shah, Rajen; Shaw, Barry; Short, Anthony; Slivka, Ben; Smirl, Jon; Stillmaker, Betty; Stoddard, John; Tillman, Dennis; Whitten, Greg; Yount, Natalie; Zeck, Steve (1988). "Technical advisors". 197:, had no program stored in memory, but was set up for each problem by a configuration of interconnecting cables. Bootstrapping did not apply to ENIAC, whose hardware configuration was ready for solving problems as soon as power was applied. 4703:

so you don't have to worry about leaving the first cluster free on a disk that you want to make bootable. The DR DOS system files can be located anywhere on the disk, so any disk with enough free space can be set to boot your system.

1941:, which might or might not be approved by the manufacturer. Modern boot loaders make use of concurrency, meaning they can run multiple processor cores, and threads at the same time, which add extra layers of complexity to secure booting. 547:, which did not lose its information when power was off, these bootstrap loaders would remain in place unless they were erased. Erasure sometimes happened accidentally when a program bug caused a loop that overwrote all of memory. 160:(ROM) of various types solved this paradox by allowing computers to be shipped with a start up program that could not be erased. Growth in the capacity of ROM has allowed ever more elaborate start up procedures to be implemented. 4018: 1189:

Many boot loaders (like GNU GRUB, rEFInd, Windows's BOOTMGR, Syslinux, and Windows NT/2000/XP's NTLDR) can be configured to give the user multiple booting choices. These choices can include different operating systems (for

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manual incorrectly states that the system files no longer need to be contiguous. However, for the boot process to work the system files still need to occupy the first two directory entries and the first three sectors of

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Since the CS register contains F000 (thus specifying a code segment starting at physical address F0000) and the instruction pointer contains FFF0, the processor will execute its first instruction at physical address

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UU was often of the form Uu, U=Control unit address, u=Device address, but some control units attached only 8 devices; some attached more than 16. Indeed, the 3830 DASD controller offered 32-drive-addressing as an

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representation. Since this has been mixed up numerous times in books and even in original Microsoft reference documents, this article uses the offset-based byte-wise on-disk representation to avoid any possible

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microcontrollers, and by others as well. In many cases such interfaces are implemented by hardwired logic. In other cases such interfaces could be created by software running in integrated on-chip boot ROM from

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from different partitions or drives), different versions of the same operating system (in case a new version has unexpected problems), different operating system loading options (e.g., booting into a rescue or

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After RESET, address lines A31–20 are automatically asserted for instruction fetches. This fact, together with the initial values of CS:IP, causes instruction execution to begin at physical address FFFFFFF0H.

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As the I/O operations needed to cause a read operation on a minicomputer I/O device were typically different for different device controllers, different bootstrap programs were needed for different devices.

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470V/6 and related CPUs supported four hexadecimal digits on those CPUs which had the optional second channel unit installed, for a total of 32 channels. Later, IBM would also support more than 16 channels.

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included features to make their operation simpler. They typically included instructions that performed a complete input or output operation. The same hardware logic could be used to load the contents of a

1027:(especially on x86 systems), to access the nonvolatile device (usually block-addressed device, e.g. NAND flash, SSD) or devices from which the operating system programs and data can be loaded into RAM. 535:(1965) simplified design by using the CPU to assist input and output operations. This saved cost but made booting more complicated than pressing a single button. Minicomputers typically had some way to 444:-like device. For example, on the System/370 Model 158, the keyboard sequence 0-7-X (zero, seven and X, in that order) results in an IPL from the device address which was keyed into the input area. The 4861:

does not only partition a disk, but can also format the freshly created volumes and initialize their boot sectors in one go, so there's no risk to accidentally mess up the wrong volume and no need for

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may be split into two stages: the platform would load a small SPL (Secondary Program Loader), which is a stripped-down version of U-Boot, and the SPL would do some initial hardware configuration (e.g.

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execution". A system built using that microprocessor will have the permanent ROM occupying these special locations so that the system always begins operating without operator assistance. For example,

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Early computers in the 1940s and 1950s were one-of-a-kind engineering efforts that could take weeks to program and program loading was one of many problems that had to be solved. An early computer,

4534:; Borman, Reuben; Borman, Rob; Butler, John; Carroll, Chuck; Chamberlain, Mark; Chell, David; Colee, Mike; Courtney, Mike; Dryfoos, Mike; Duncan, Rachel; Eckhardt, Kurt; Evans, Eric; Farmer, Rick; 456:, and its compatibles such as Amdahl's, reads 24 bytes from an operator-specified device into main storage starting at real address zero. The second and third groups of eight bytes are treated as 180:

There are many different methods available to load a short initial program into a computer. These methods reach from simple, physical input to removable media that can hold more complex programs.

4123: 1403:(POST). In this example of dual booting, the user chooses by inserting or removing the DVD from the computer, but it is more common to choose which operating system to boot by selecting from a 464:, with command chaining and suppress incorrect length indication being enforced). When the I/O channel commands are complete, the first group of eight bytes is then loaded into the processor's 1178:, are not themselves operating systems, but are able to load an operating system properly and transfer execution to it; the operating system subsequently initializes itself and may load extra 504:

IBM introduced some evolutionary changes in the IPL process, changing some details for System/370 Extended Architecture (S/370-XA) and later, and adding a new type of IPL for z/Architecture.

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In a minicomputer with a paper tape reader, the first program to run in the boot process, the boot loader, would read into core memory either the second-stage boot loader (often called a

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The boot process can be considered complete when the computer is ready to interact with the user, or the operating system is capable of running system programs or application programs.

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used front panel switches to cause the computer to automatically load instructions into memory from a device specified by the front panel's data switches, and then jump to loaded code.

4009: 1182:. The second-stage boot loader does not need drivers for its own operation, but may instead use generic storage access methods provided by system firmware such as the BIOS, UEFI or 4817:. You can even have multiple DR-DOS kernel files under different file names stored on the same drive, and LOADER will switch between them according to the file names listed in the 4653: 4707:(NB. The source attributes this to the SYS utility while in fact this is a feature of the advanced bootstrap loader in the boot sector. SYS just plants this sector onto the disk.) 100:, which can be "hard", e.g. after electrical power to the CPU is switched from off to on, or "soft", where the power is not cut. On some systems, a soft boot may optionally clear 3278: 360:) 0 and initiated the load sequence by causing PP 0 to execute the code loaded into memory. PP 0 loaded the necessary code into its own memory and then initialized the other PPs. 3915: 1238:

itself as a mere process within that system, and then irrevocably transfer control to the operating system. The boot loader then terminates normally as any other process would.

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booted its disk operating systems using a series of very small incremental steps, each passing control onward to the next phase of the gradually more complex boot process. (See

4457: 3945: 3783: 4542:; McKinney, Bruce; Martin, Pascal; Mathers, Estelle; Matthews, Bob; Melin, David; Mergentime, Charles; Nevin, Randy; Newell, Dan; Newell, Tani; Norris, David; O'Leary, Mike; 1267:

As with the second-stage boot loader, network booting begins by using generic network access methods provided by the network interface's boot ROM, which typically contains a

4538:; Geary, Michael; Griffin, Bob; Hogarth, Doug; Johnson, James W.; Kermaani, Kaamel; King, Adrian; Koch, Reed; Landowski, James; Larson, Chris; Lennon, Thomas; Lipkie, Dan; 3885: 4771: 4662: 4422: 4726: 4660: 1234:

so the device can begin functioning immediately; little or no loading is necessary, because the loading can be precomputed and stored on the ROM when the device is made.

1667:, which the BIOS requires for a proper boot loader — or even less, when additional features like more than four partition entries (up to 16 with 16 bytes each), a 134:

In addition to loading an operating system or stand-alone utility, the boot process can also load a storage dump program for diagnosing problems in an operating system.

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when the machine was powered up, and then to read software from a boot device and execute it. Firmware compatible with the BIOS on the IBM Personal Computer is used in

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do not require a noticeable boot sequence to begin functioning and when turned on may simply run operational programs that are stored in ROM. All computing systems are

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processor, initialization begins by reading a two-byte vector address at $ FFFD (MS byte) and $ FFFC (LS byte) and jumping to that location to run the bootstrap code.

805:-based console processor, and the VAX-11/730 had an 8085-based console processor. These console processors could boot the main processor from various storage devices. 468:(PSW) and the startup program begins execution at the location designated by that PSW. The IPL device is usually a disk drive, hence the special significance of the 3527: 1758:(followed by an INT 19h just in case INT 18h would return) in order to give back control to the BIOS, which would then attempt to boot off other devices, attempt a 892:

cartridge with the Macintosh system ROM in the game slot and turning the Atari on, it could "natively boot" the Macintosh operating system rather than Atari's own

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and some later systems, the functions of the switches and the LOAD button are simulated using selectable areas on the screen of a graphics console, often an

4570:; Rabinowitz, Chip; Tomlin, Jim; Wilton, Richard; Wolverton, Van; Wong, William; Woodcock, JoAnne (Completely reworked ed.). Redmond, Washington, USA: 3444: 4612: 501:

program running under an operating system, e.g., ICKDSF, but IPL-able tapes and card decks are usually distributed with this "IPL Text" already present.

497:; seeks and searches are not simulated by tape and card controllers, as for these device classes a Read IPL command is simply a sequential read command. 104:

to zero. Both hard and soft booting can be initiated by hardware such as a button press or by a software command. Booting is complete when the operative

5045: 3144: 847:). Because so little of the disk operating system relied on ROM, the hardware was also extremely flexible and supported a wide range of customized disk 3321: 2572:

never exceeded this limit in previous versions without this loader. Combined with a dual entry structure this also allows the system to be loaded by a

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assumptions about the system it can equally well be used to load diagnostic (Maintenance Test Routine) tapes which display an intelligible code on the

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file into memory: If the IBMBIO.COM file is larger than some 29 KB, trying to load the whole file into memory would result in the boot loader to

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for the PDP-11 that stored a bootstrap program of up to 32 words (64 bytes). It consisted of a printed circuit card, the M792, that plugged into the

4234: 1513:) entry point inside the ROM. This memory location typically contains a jump instruction that transfers execution to the location of the firmware ( 1138:(PBR) was coded to require at least 32 KB (later expanded to 64 KB) of system memory and only use instructions supported by the original 661:

A related example is based on a loader for a Nicolet Instrument Corporation minicomputer of the 1970s, using the paper tape reader-punch unit on a

4062: 367:(c. 1965) had a "SYSTEM BOOTLOAD" button that, when pressed, caused one of the I/O controllers to load a 64-word program into memory from a diode 307:

had similar mechanisms, but with different load buttons for different devices. The term "boot" has been used in this sense since at least 1958.

5191: 3740: 2665: 1042:. Often, multiple-stage boot loaders are used, during which several programs of increasing complexity load one after the other in a process of 3465: 2978: 5245: 4645: 3493: 1545: 1514: 1506: 4869:. Afterwards, you could just copy over the remaining DR-DOS files, including the system files. It is important to know that, in contrast to 4107: 808:

Some other superminicomputers, such as the VAX-11/750, implement console functions, including the first stage of booting, in CPU microcode.

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Boot loaders may face peculiar constraints, especially in size; for instance, on the IBM PC and compatibles, the boot code must fit in the

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identification, authorization, and authentication are separable concerns in an SSO session. When recovery of a site is indicated (viz. a

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DR-DOS boot sectors are able to locate the boot file in the FAT12, FAT16 and FAT32 file system, and load it into memory as a whole via

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When a computer is turned off, its software‍—‌including operating systems, application code, and data‍—‌remains stored on

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The VBR is often OS-specific; however, its main function is to load and execute the operating system boot loader file (such as

4108:"Caldera OpenDOS 7.01/7.02 Update Alpha 3 IBMBIO.COM - README.TXT and BOOT.TXT - A short description of how OpenDOS is booted" 3966: 3101: 3071: 2509: 1261: 2796: 2723: 1618:

A bootable MBR device is defined as one that can be read from, and where the last two bytes of the first sector contain the

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successors to the PDP-4 have an added Read-In button to read a program in from paper tape and jump to it. The Data General

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attempt to load secondary boot loaders before trying to boot the active partition. If all else fails, it should issue an

928: 245:, that contained a bootstrap program by pressing a single button. This booting concept was called a variety of names for 5627: 5321: 5134: 4893: 4281: 2694: 2636: 946: 350:

panel with 144 toggle switches; the dead start switch entered 12 12-bit words from the toggle switches to the memory of

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Intel 64 and IA-32 Architectures Software Developer's Manual Volume 3 (3A, 3B, 3C & 3D): System Programming Guide

3673: 3635: 1264:(TFTP). After these parts have been transferred, the operating system takes over the control of the booting process. 4763: 314:

IBM System/3 console from the 1970s. Program load selector switch is lower left; Program load switch is lower right.

208:

to transfer a fixed program into memory when its start button was pressed. The program stored on this device, which

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Chappell, Geoff (January 1994). "Chapter 2: The System Footprint". In Schulman, Andrew; Pedersen, Amorette (eds.).

4332: 2211: 1948: 1820: 990: 5836: 5662: 5634: 2169: 2086: 1835: 1676: 1573: 3431: 2093:

is displayed on an airport terminal screen) personal site visits might be required to remediate the situation.

1354:, USB hard disk drive, USB optical disc drive, USB solid-state drive, etc.), or a network interface card (using 5512: 3110: 2481: 2357: 2340: 2336: 1719: 4918: 4604: 3131: 53: 5394: 5120: 3308: 1199:), and some standalone programs that can function without an operating system, such as memory testers (e.g., 131:, and a reboot may be the only method to return to a designated zero-state from an unintended, locked state. 3168: 2821: 2513: 2332: 2251: 1711:

in the root directory of the file system and stored as consecutive sectors, conditions taken care of by the

1569: 1204: 966: 120: 89:, so some process must load software into memory before it can be executed. This may be done by hardware or 82: 3208: 4252: 2597: 2564: 2561: 2521: 2038:

before a boot sequence is finished, a restart might prevent a user from accessing the regular interface.

1538: 978: 4947: 1894:

Most DSPs have a serial mode boot, and a parallel mode boot, such as the host port interface (HPI boot).

1384:

installed on the hard drive, the user could set the boot order to the one given above, and then insert a

5173: 3217: 2744: 2216: 1751: 1227: 1135: 1083: 900: 725: 384: 45: 5345: 5218: 1442:

into what is usually a variant of Linux for various simple tasks such as Internet access; examples are

6043: 6009: 5959: 5829: 5724: 5641: 5565: 5558: 4862: 2090: 2053: 1938: 1798: 1728: 1340: 1324: 1004: 544: 457: 2965: 2657: 6050: 6023: 5854: 5694: 5648: 4858: 3461: 2631: 2497: 1816: 1755: 1742:), which is the second-stage boot loader, from an active partition. Then the boot loader loads the 1591:) and transfers execution to the boot code. In the case of a hard disk, this is referred to as the 1553: 1003:. When the computer is powered on, it typically does not have an operating system or its loader in 1000: 465: 288: 5075:(conference 19-21 September 2003) Workshop: defect detection in distributed software development 1987: 1929:

of the booting process. Some of them are made mandatory, others can be disabled or enabled by the

1640:), or where it is otherwise established that the code inside the sector is executable on x86 PCs. 6311: 6082: 6016: 4834: 4797: 4484: 4390: 3842: 3828: 3799: 3045: 2995: 2935: 2545: 2457: 2453: 2300: 1691: 1672: 1668: 1664: 1656: 1637: 1612: 1592: 1522: 1400: 1399:, in which the user chooses which operating system to start after the computer has performed its 1351: 1332: 1328: 1257: 1131: 1079: 908: 775: 445: 97: 5001: 3338: 5119:

Eye Security update: the Breaking Change, 4:09 AM UTC on July 19th 2024, reverted 05:27 AM UTC

3710: 1307:

The boot device is the storage device from which the operating system is loaded. A modern PC's

789:

include a separate console processor that bootstraps the main processor. The PDP-11/44 had an

6318: 5987: 5980: 5766: 5370: 5140: 4976: 4866: 4810: 4696: 4674: 4641: 4593: 4585: 4575: 4562:. By Duncan, Ray; Bostwick, Steve; Burgoyne, Keith; Byers, Robert A.; Hogan, Thom; Kyle, Jim; 4555: 4491: 4043: 3975: 3031: 2919: 2883: 2473: 2469: 2437: 2246: 2221: 2173: 2011: 1926: 1828: 1811: 1775: 1713: 1381: 1316: 970: 912: 852: 786: 768: 764: 662: 609: 592:

has a hardware loader, such that an operator need only push the "load" switch to instruct the

555: 249:

computers of the 1950s and early 1960s, but IBM used the term "Initial Program Load" with the

74: 2857: 6340: 6283: 6230: 6223: 5809: 5731: 5196: 5050: 3574: 3140: 2756: 2520:

techniques to squeeze everything into a single physical sector, as it was a requirement for

2505: 2353: 2144: 1874:

It is also possible to take control of a system by using a hardware debug interface such as

1622: 1604: 1260:, and certain parts of it are transferred to the client using a simple protocol such as the 1253: 1230:

to start is generally unacceptable. Therefore, such devices have software systems in ROM or

1020: 1008: 938: 934: 885: 732: 577: 421: 368: 250: 157: 124: 109: 31: 4968: 1102:, sometimes called the zero-stage boot loader, can find and load first-stage boot loaders. 6159: 5717: 5572: 4571: 4567: 4551: 4353: 3368: 2817: 2517: 2236: 2136: 1944: 1859: 1852: 1759: 1660: 1648: 1347: 1320: 1247: 1219: 949:

interpreter, with much of the firmware being written in Forth. It was standardized by the

848: 821:

processors always start by running the instructions beginning at F000:FFF0, while for the

351: 284: 205: 1595:(MBR). The conventional MBR code checks the MBR's partition table for a partition set as 1395:

without having to install an operating system onto the hard drive. This is an example of

5109:(20 Jul 2024) CrowdStrike IT outage affected 8.5 million Windows devices, Microsoft says 4170: 3241: 1898:

systems the DSP could be booted by another processor which is sometimes referred as the

1474: 1458: 5687: 5223: 4523: 4169:

Compaq Computer Corporation; Phoenix Technologies Ltd; Intel Corporation (1996-01-11).

4111: 3025: 2792: 2774: 2112: 2102: 2082: 1731:

or LBA, even if the file is not stored in a fixed location and in consecutive sectors.

1478: 1223: 1087: 828: 774:

An Italian telephone switching computer, called "Gruppi Speciali", patented in 1975 by

408: 404: 254: 105: 5078:

Eleventh Annual International Workshop on Software Technology and Engineering Practice

3825:

Alberto Ciaramella discusses the patent for bootstrapping computers conceived at CSELT

6334: 5882: 5875: 5613: 4563: 4543: 4539: 4531: 3398: 2394: 2281: 2196: 2191: 2177: 2030:

that occurs on computing devices; when those devices repeatedly fail to complete the

1619: 1564:

Once the BIOS has found a bootable device it loads the boot sector to linear address

1296: 1292: 1183: 1179: 1043: 881: 364: 242: 238: 152: 141: 128: 38: 5322:"Google Nest Hub gets a new UI that's so fresh it could bootloop your smart display" 3820:

Alberto Ciaramella racconta il brevetto del boostrap dei computer concepito in CSELT

2276:

CrowdStrike reverted the content update at 05:27 UTC, This left machines stuck in a

716: 310: 37:

This article is about bootstrapping operating systems. For the general concept, see

30:"Quick boot" redirects here. For the feature of the Quarterdeck memory manager, see 6137: 5903: 5655: 4750:) file and then loads the *whole* file into memory before it passes control to it. 4547: 4035: 3962: 3440: 2782: 2107: 2057: 1934: 1494: 1443: 1404: 1396: 1343: 1231: 1091: 748: 574: 520: 260: 213: 669:. The bytes of its second-stage loader are read from paper tape in reverse order. 5108: 2786: 2715: 1902:(giving name to a Host Port). Such a processor is also sometimes referred as the 1373:

Typically, the system firmware (UEFI or BIOS) will allow the user to configure a

1200: 1186:, though typically with restricted hardware functionality and lower performance. 6269: 6205: 5868: 5820: 5177: 4679: 3884:. February 1979. 2.3 BOOTSTRAPPING and 3.6.1 Boot Command (B). EK-11780-UG-001. 2568: 2493: 2477: 2322:

Excluding the 370/145 and 370/155, which used a 3210 or 3215 console typewriter.

2226: 2162: 2150: 1688: 1608: 1526: 1447: 1359: 1072: 1068: 889: 705: 666: 540: 392: 86: 17: 5097:(23 Jul 2024) Inside the 78 minutes that took down millions of Windows machines 5074: 4303:"How to Enter the BIOS on Any PC: Access Keys by Manufacturer | Tom's Hardware" 969:

specification defined another firmware standard, which was implemented on some

953:

as IEEE standard 1275-1994; firmware that implements that standard was used in

550:

Other minicomputers with such simple form of booting include Hewlett-Packard's

6304: 6290: 6130: 5802: 5604: 4792: 4788: 4747: 4743: 4700: 4535: 4527: 4386: 4273: 3818: 3804: 3487: 2557: 2549: 2529: 2525: 2433: 2428: 2414: 2231: 2128: 2117: 2056:, before recovery is indicated. Detection of an erroneous state may require a 1947:

argued that booting security serves a legitimate goal but in doing so chooses

1863: 1680: 1644: 1615:(VBR), and executes it. The MBR boot code is often operating-system specific. 1534: 1424: 1127: 1063: 994: 863: 794: 790: 629: 593: 512: 433: 429: 292: 234: 116: 5297:"Google thinks it has solved the mystery of the cursed bootlooping wallpaper" 5161: 4889: 2686: 2626: 2069:

was to reboot three times, the reboots needed to return to a usable menu.

2052:

The system might exhibit its erroneous state, say in an explicit bootloop or

1969:

Measured boot with the Trusted Platform Module, also known as "trusted boot".

1541:, further complicated by the fact that at this point memory is very limited. 1407:

menu on the selected device, by using the computer keyboard to select from a

1110:

Examples of first-stage (Hardware initialization stage) boot loaders include

276:

computer (1952–1956) had a "Load" button that initiated reading of the first

119:(suspension) does not involve booting; however, restoring it from a state of 6276: 5924: 5759: 5752: 5708: 5419:"Botched security update breaks Windows worldwide, causing BSOD and crashes" 5250: 4597: 3805:

Device for automatically loading the central memory of electronic processors

2760: 2409:

processors (note the swapped order), whereas it would have to be written as

2406: 2201: 2132: 2007: 1883: 1771: 1743: 1490: 1363: 1196: 1191: 1123: 1016: 974: 958: 893: 859: 844: 818: 632:

for the boot loader might be as simple as the following eight instructions:

62: 4135: 2576:

VBR, which would load only the first three sectors of the file into memory.

1789:

via CSM) does not rely on boot sectors, UEFI system loads the boot loader (

516:

PDP-8/E front panel showing the switches used to load the bootstrap program

5021: 4791:

file into memory before it executes it. It does not care at all about the

1862:

designs may also include an intermediary boot sequence step. For example,

6297: 6262: 6096: 5952: 5889: 5745: 5738: 5542: 5470: 4818: 4361: 2277: 2123: 1930: 1794: 1463: 1300: 1167: 1155: 1119: 1099: 942: 878: 870:

Unix implementation and copied by various freeware operating systems and

840: 822: 752: 736: 625: 441: 437: 343: 331: 319: 304: 300: 265: 225: 90: 78: 70: 4074: 1505:

on 32-bit and 64-bit x86 processors), usually pointing to the firmware (

1007:(RAM). The computer first executes a relatively small program stored in 6191: 5931: 5910: 5861: 5701: 5680: 5439: 5081: 5046:"Microsoft blocks UEFI bootloaders enabling Windows Secure Boot bypass" 4636:. The Andrew Schulman Programming Series (1st printing, 1st ed.). 2241: 2206: 1999: 1995: 1467: 1388: 1163: 954: 920: 832: 551: 327: 318:

Other IBM computers of that era had similar features. For example, the

296: 273: 229: 1643:

The boot sector code is the first-stage boot loader. It is located on

923:-based machines, and later also used as an alternative to the BIOS in 6244: 5973: 5938: 4874: 4870: 4855: 4835:"The continuing saga of Windows 3.1 in enhanced mode on OmniBook 300" 4814: 4805: 4801: 4784: 4739: 3752:. February 1979. pp. 1–10, 2-29–2-34, 3-1–3-6. EK-11060-OP-003. 2573: 2542: 2501: 2489: 2465: 2461: 2398: 2035: 1914: 1722:

and FAT32 support, they even switched to a boot loader reaching over

1684: 1367: 1159: 1059: 1012: 802: 605: 581: 563: 375: 277: 5272:"'It was unintentional,' says creator of 'cursed' Android wallpaper" 5133:

Ruley, John D.; David Methvin; Tom Henderson; Martin Heller (1997).

1256:. In this scenario, the operating system is stored on the disk of a 5219:"Windows 10 update sending PCs into endless boot cycle: What to do" 4914: 3546:

M9301 bootstrap/terminator module maintenance and operator's manual

1925:

There are various measures have been implemented which enhance the

1415:

Boot Menu, or both; the Boot Menu is typically entered by pressing

1154:

Second-stage (OS initialization stage) boot loaders, such as shim,

6237: 6089: 5945: 5917: 5896: 4418: 3944:. December 1982. pp. 1-2–1-4, B-1–B-8, C-1–C-2. AA-K410C-TE. 2485: 1986: 1810: 1707: 1703: 1699: 1652: 1473: 1457: 1392: 1385: 1315:

firmware supports booting from various devices, typically a local

1291: 1175: 1171: 962: 779: 744: 721: 715: 601: 597: 589: 559: 532: 528: 511: 453: 387: 309: 259: 224:

The first programmable computers for commercial sale, such as the

201: 194: 173: 167: 52: 4202: 6182: 6175: 6144: 5966: 5620: 5597: 5590: 4589: 3426: 3424: 2140: 1991: 1910: 1888: 1875: 1867: 1839: 1831: 1779: 1549: 1530: 1518: 1510: 1412: 1408: 1312: 1308: 1143: 1139: 1115: 1111: 1055: 1024: 950: 916: 904: 884:, were "instant-on", with the operating system executing from a 871: 867: 371:

and deliver an interrupt to cause that program to start running.

5443: 5192:"New Windows Server updates cause DC boot loops, break Hyper-V" 4494:. May 2012. Section 9.1.4 First Instruction Executed, p. 2611. 4248: 1533:), the PCI bus and the PCI devices (including running embedded 452:

The IPL function in the System/360 and its successors prior to

253:

and later used it for their mainframe lines, starting with the

93:

in the CPU, or by a separate processor in the computer system.

5371:"CrowdStrike Update Pushing Windows Machines Into a BSOD Loop" 4939: 4627: 4625: 4623: 4485:"Intel 64 and IA-32 Architectures Software Developer's Manual" 3250: 3080: 3004: 2974: 2944: 2788:

The Preparation of Programs for an Electronic Digital Computer

1847: 1683:

loaders have to be supported as well in some environments. In

1556:("boot device sequence") until it finds one that is bootable. 1486: 1071:) of the most promising device, typically starting at a fixed 924: 798: 246: 101: 4546:; Olsson, Mike; Osterman, Larry; Ostling, Ridge; Pai, Sunil; 3047:

650 magnetic drum data-processing machine manual of operation

204:

system, the second stored-program computer to be built, used

4683:. Vol. 10, no. 3. p. 241–246, 257, 264, 266. 2468:

counterparts could still be achieved utilizing conventional

2343:

used a keyboard/display device compatible with nothing else.

1855:) have firmware ROM integrated directly into their silicon. 1801:) directly, and the OS kernel is loaded by the boot loader. 1086:(PBR), which in turn are limited to a single sector; on the 961:

and some other PowerPC-based machines, as well as Sun's own

477:

command also causes the selected device to seek to cylinder

4456:. Intel. 1986. Section 10.2.3 First Instructions, p. 10-3. 1222:

must boot immediately. For example, waiting a minute for a

539:

short programs by manipulating an array of switches on the

338:

IBM's competitors also offered single button program load.

5162:"Disabling automatic reboot prevents possible reboot loop" 3808:

U.S. Patent No. 4,117,974. 1978-10-03. (submitted in 1975)

2937:

704 Electronic Data-Processing Machine Manual of Operation

2524:- and cross-compatibility with other operating systems in 2452:

As an example, while the extended functionality of DR-DOS

2135:

value exceeded the maximum of 255 which happened due to a

1827:

Many modern CPUs, SoCs and microcontrollers (for example,

1537:). One of the most involved steps is setting up DRAM over 1062:) at a predefined address (some CPUs, including the Intel 1030:

The small program that starts this sequence is known as a

751:, reduced the physical size and cost of ROM. This allowed 5246:"Google has tried everything but building the best phone" 2885:

Principles of Operation Type 701 And Associated Equipment

2147:. This then crashed the SystemUI component on every boot. 907:; one of the functions of that firmware was to perform a 212:

completed in late 1948, loaded further instructions from

3904:

VAX-11/730 Central Processing Unit Technical Description

2401:

compatible machines, this can be written as 16-bit word

2284:. and devices booted after the revert were not affected. 1525:(POST) to check and initialize required devices such as 839:

Due to the expense of read-only memory at the time, the

628:

or the operating system from an outside storage medium.

596:

reader to load a program directly into core memory. The

237:(the most typical ones) or other input media, such as a 5022:"mjg59 | Boot Guard and PSB have user-hostile defaults" 4813:, no difficult setup procedures as required for MS-DOS/ 4227:"Chapter 6 - Troubleshooting Startup and Disk Problems" 1913:

chips load their configuration from an external serial

755:

boot programs to be included as part of the computer.

5346:"Statement on Falcon Content Update for Windows Hosts" 5069: 5067: 3722:. July 1977. pp. 1–5, 2-1–2-12. EK-11034-UG-001. 3672:"11 MRVll·D Universal Programmable Read.Only Memory". 2272: 2270: 2268: 2058:

distributed event store and stream-processing platform

1438:

Several devices are available that enable the user to

1203:), a basic shell (as in GNU GRUB), or even games (see 5121:(19 Jul 2024) BSOD error in latest CrowdStrike update 4387:"Voodoo Envy's Instant-On IOS (powered by Splashtop)" 4274:"List of PC brands with their corresponding hot-keys" 1485:

Upon starting, an IBM-compatible personal computer's

1098:

boot loader. On many embedded CPUs, the CPU built-in

945:, later known as Open Firmware, which incorporated a 3854:. February 1979. p. 6-57. EK-KD11Z-TM-001. 2967:

Operator's Guide for IBM 7090 Data Processing System

2027: 1933:. Traditionally, booting did not involve the use of 1544:

After initializing required hardware, the firmware (

1358:). Older, less common BIOS-bootable devices include 115:

The process of returning a computer from a state of

6254: 6215: 6158: 6122: 6074: 6067: 6033: 6001: 5846: 5819: 5787: 5672: 5582: 5550: 5540: 5481: 4421:. 1983. Section 5.3 SYSTEM INITIALIZATION, p. 5-7. 4333:"MontaVista Linux drives Dell's quick-boot feature" 3280:

BM792 read-only-memory and MR11~DB bootstrap loader

1023:, to initialize CPU and motherboard, to initialize 937:originally had vendor-specific ROM-based firmware. 4101: 4099: 4097: 4095: 4093: 3576:M9312 bootstrap/terminator module technical manual 3103:CONTROL DATA 6600 Computer System Reference Manual 2865:. IBM. August 1961. pp. 125–127. A22-6530-2. 2131:: when setting a specific image as wallpaper, the 1252:Most computers are also capable of booting over a 5136:Networking Windows NT 4.0: Workstation and Server 4560:The MS-DOS Encyclopedia: versions 1.0 through 3.2 2397:representation must be assumed in the context of 2060:for real-time operation of a distributed system. 682:Read a byte from paper tape reader to accumulator 645:Read a byte from paper tape reader to accumulator 2822:"The System Design of the IBM Type 701 Computer" 2448: 2446: 2413:in programs for other CPU architectures using a 836:debug programs (all in hex) from the keyboard." 3782:. June 1981. p. 1-6. EK-11024-TM-001. 2040: 1659:in order to leave room for the default 64-byte 1090:, the size is limited by the IPL medium, e.g., 485:, simulating a Seek cylinder and head command, 383:A noteworthy variation of this is found on the 81:command. After it is switched on, a computer's 5395:"CrowdStrike Falcon blue screen issue updates" 5091: 5089: 3914:. May 1982. p. 1-9. EK-KA730-TD-001. 2851: 2849: 858:Some operating systems, most notably pre-1995 5455: 4890:"Intel Platform Innovation Framework for EFI" 2602:Computer Dictionary of Information Technology 2440:continues to take care of these requirements. 2360:, e.g., OS/2 Boot Manager, rather than an OS. 1663:with four partition entries and the two-byte 8: 5002:"The boot process rxos 1.0rc1 documentation" 2859:Reference Manual 7030 Data Processing System 1823:device, showing additional available options 379:read in by jumping to the last word read in. 4675:"DR DOS 5.0 - The better operating system?" 4040:Osborne 4&8-Bit Microprocessor Handbook 3742:PDP-11/60 installation and operation manual 6071: 6057: 5843: 5547: 5462: 5448: 5440: 4164: 4162: 4160: 3489:Altair 8800 loads 4K BASIC from paper tape 3340:Programmed Data Processor-7 Users Handbook 3073:Operator's Guide for IBM 7040-7044 Systems 801:line of 32-bit superminicomputers, had an 685:Store accumulator to address in P register 648:Store accumulator to address in P register 588:Following the older approach, the earlier 407:and its successors, including the current 264:Initial program load punched card for the 5073:J.J.M. Trienekens; R.J. Kusters. (2004) 3210:Burroughs B 1700 Systems Reference Manual 2508:, controlled utilization of (documented) 735:(ROM), with its many variants, including 704:The earliest microcomputers, such as the 585:by simply omitting the unneeded diodes. 473:magnetic tape. For disk controllers, the 77:such as a button on the computer or by a 4412:"iAPX 286 Programmer's Reference Manual" 4358:"SplashTop Linux On HP, Dell Notebooks?" 3236: 3234: 2541:There is one exception to the rule that 2176:systems worldwide stuck in bootloops or 1552:) goes through a pre-configured list of 1521:) start-up program. This program runs a 1432: 1428: 1420: 1416: 1130:. On the IBM PC, the boot loader in the 493:, simulating a Search ID Equal command, 4969:"Overview – The four bootloader stages" 4136:"Why BIOS loads MBR into 7C00h in x86?" 4042:. Osborne/McGraw-Hill. pp. 10–20. 3253:. September 2005. pp. Chapter 17. 2749:IEEE Annals of the History of Computing 2589: 2292: 2264: 919:was developed by Intel, originally for 903:included ROM-based firmware called the 731:The introduction of integrated circuit 712:Integrated circuit read-only memory era 616:Early minicomputer boot loader examples 411:machines, the boot process is known as 4796:files to the disk (even with a simply 3974:. OSBORNE/McGraw-Hill. pp. 5–27. 3968:Osborne 16-Bit Microprocessor Handbook 3934:VAX-11/750 Software Installation Guide 3634:"10 MRV11-C Read-Only Memory Module". 3243:z/Architecture Principles of Operation 3203: 3201: 3170:PDP-10 System Reference Manual, Part 1 2436:still need to be stored contiguously. 1694:, up to 59 bytes are occupied for the 1275:IBM-compatible personal computers (PC) 573:DEC later added, in 1971, an optional 153:to pull oneself up by one's bootstraps 4451:"80386 Programmer's Reference Manual" 4075:"An Introduction to RISC-V Boot flow" 4063:Apple Ad, Interface Age, October 1976 2716:"Pull yourself up by your bootstraps" 1214:Embedded and multi-stage boot loaders 543:. Since the early minicomputers used 96:Restarting a computer also is called 7: 4839:MoHPC - the Museum of HP Calculators 2918:, Jeremy M. Norman, 2005, page 436, 2085:(SSO) for some applications; in the 395:even in cases of gross CPU failure. 172:Switches and cables used to program 112:and some applications, is attained. 57:A flow diagram of a computer booting 3220:. November 1973. p. 1-14. 2553: 1917:("configuration ROM") on power-up. 1706:volumes since DOS 4.0, whereas the 1611:code from that partition, known as 1288:System partition and boot partition 184:Pre integrated-circuit-ROM examples 3380:. January 1968. p. 10-3. 3290:. January 1974. DEC-II-HBMAA-E-D. 2331:Only the S/360 used the 2250; the 2079:Security Assertion Markup Language 2026:) is a diagnostic condition of an 1937:. The security can be bypassed by 1651:, and must fit into the first 446 1583:, but some BIOSes erroneously use 1331:(MBR) on such a drive or disk, an 812:Microprocessors and microcomputers 624:) that could read paper tape with 25: 5160:Shultz, Gregory (February 2001). 4833:Paul, Matthias R. (2017-08-14) . 4638:Addison Wesley Publishing Company 4134:Sakamoto, Masahiko (2010-05-13). 4106:Paul, Matthias R. (1997-10-02) . 3844:PDP-11/44 System Technical Manual 3772:PDP-11/24 System Technical Manual 3606:Microcomputer Interfaces Handbook 3410:. August 1969. p. 10-3. 3053:. IBM. 1955. pp. 49, 53–54. 2747:(1980). "Programming the EDSAC". 2081:(SAML), which can also implement 1607:is found, the MBR code loads the 1427:is typically entered by pressing 1075:such as the start of the sector. 929:Apple Macs using Intel processors 554:series (mid-1960s), the original 5531: 4762:Paul, Matthias R. (2002-02-20). 4717:Paul, Matthias R. (2001-01-17). 4652:(xxvi+738+iv pages, 3.5"-floppy 4615:from the original on 2018-10-14. 4605:"The MS-DOS Encyclopedia (1988)" 4024:from the original on 2022-10-09. 3951:from the original on 2022-10-09. 3921:from the original on 2022-10-09. 3891:from the original on 2022-10-09. 3874:VAX-11/780 Hardware User's Guide 3861:from the original on 2022-10-09. 3831:from the original on 2021-11-13. 3789:from the original on 2022-10-09. 3759:from the original on 2022-10-09. 3729:from the original on 2022-10-09. 3623:from the original on 2022-10-09. 3593:from the original on 2022-10-09. 3563:from the original on 2022-10-09. 3533:from the original on 2022-10-09. 3526:. April 1974. DEC-11-H873A-B-D. 3450:from the original on 2022-10-09. 3443:. April 1971. p. 2-30. 3417:from the original on 2022-10-09. 3387:from the original on 2022-10-09. 3357:from the original on 2022-10-09. 3327:from the original on 2022-10-09. 3297:from the original on 2022-10-09. 3227:from the original on 2022-10-09. 3120:from the original on 2022-10-09. 3090:from the original on 2022-10-09. 3060:from the original on 2022-10-09. 3014:from the original on 2022-10-09. 2997:IBM 7094 Principles of Operation 2984:from the original on 2022-10-09. 2954:from the original on 2022-10-09. 2872:from the original on 2022-10-09. 2842:from the original on 2022-10-09. 2077:Recovery might be specified via 2064:Recovery from an erroneous state 797:, the first member of Digital's 700:Booting the first microcomputers 4983:from the original on 2014-12-23 4950:from the original on 2020-11-12 4921:from the original on 2013-03-18 4896:from the original on 2011-08-21 4845:from the original on 2017-10-06 4774:from the original on 2017-10-06 4729:from the original on 2017-10-06 4687:from the original on 2019-07-25 4501:from the original on 2022-10-09 4463:from the original on 2022-10-09 4428:from the original on 2022-10-09 4393:from the original on 2021-11-13 4368:from the original on 2016-10-05 4313:from the original on 2023-02-20 4284:from the original on 2020-11-11 4255:from the original on 2010-12-28 4183:from the original on 2022-10-09 4146:from the original on 2017-08-24 3991:from the original on 2022-10-09 3692:from the original on 2022-10-24 3675:Microcomputer Products Handbook 3654:from the original on 2022-10-24 3637:Microcomputer Products Handbook 3586:. March 1981. EK-M9312-TM-OO3. 3496:from the original on 2019-07-30 3468:from the original on 2020-01-03 3400:PDP-15 Systems Reference Manual 3260:from the original on 2022-10-09 3187:from the original on 2022-10-09 3150:from the original on 2022-10-09 2898:from the original on 2022-10-09 2799:from the original on 2023-02-20 2726:from the original on 2012-04-17 2697:from the original on 2020-05-10 2668:from the original on 2018-10-05 2658:"Pull oneself up by bootstraps" 2639:from the original on 2006-08-27 2608:from the original on 2019-08-05 2048:Detection of an erroneous state 5244:Hollister, Sean (2021-10-19). 4742:boot sector searches for the 4550:; Perez, Gary; Peters, Chris; 4231:Windows NT Server Resource Kit 4171:"BIOS Boot Specification 1.01" 3712:PDP-11/34 system user's manual 3556:. June 1977. EK-M9301-TM-OO1. 2916:From Gutenberg to the Internet 2192:Bootstrapping § Computing 2161:On 19 July 2024, an update of 1262:Trivial File Transfer Protocol 27:Process of starting a computer 1: 6169:Preboot Execution Environment 5774:Run-Time Abstraction Services 5320:Peckham, James (2022-03-29). 5217:Paul Wagenseil (2021-01-21). 5123:Reddit update, 20 000 replies 5082:IEEE Xplore: 27 December 2004 4673:Rosch, Winn L. (1991-02-12). 3942:Digital Equipment Corporation 3912:Digital Equipment Corporation 3882:Digital Equipment Corporation 3852:Digital Equipment Corporation 3780:Digital Equipment Corporation 3750:Digital Equipment Corporation 3720:Digital Equipment Corporation 3683:Digital Equipment Corporation 3645:Digital Equipment Corporation 3614:Digital Equipment Corporation 3584:Digital Equipment Corporation 3554:Digital Equipment Corporation 3524:Digital Equipment Corporation 3433:How To Use The Nova Computers 3408:Digital Equipment Corporation 3378:Digital Equipment Corporation 3348:Digital Equipment Corporation 3318:Digital Equipment Corporation 3288:Digital Equipment Corporation 3178:Digital Equipment Corporation 2662:Idioms by The Free Dictionary 2168:s Falcon software caused the 2157:LG smartphone bootloop issues 2010:a concurrent and distributed 1805:Other kinds of boot sequences 1696:Extended BIOS Parameter Block 1501:on 16-bit x86 processors and 1497:(the physical memory address 1493:, the instruction located at 1481:BIOS from 2000 during booting 1269:Preboot Execution Environment 676:Check paper tape reader ready 639:Check paper tape reader ready 525:Digital Equipment Corporation 420:IBM coined this term for the 399:IBM System/360 and successors 85:(CPU) has no software in its 69:is the process of starting a 5628:MultiProcessor Specification 5172:(2). Element K Journals: 9. 4787:boot sector loads the whole 3462:"Oldcomputers: Altair 8800b" 1554:non-volatile storage devices 793:as a console processor; the 150:and derives from the phrase 6199:Remote Initial Program Load 5796:Common Firmware Environment 4233:. Microsoft. Archived from 3310:PDP-11 Peripherals Handbook 3113:. August 1963. p. 53. 2002:that is stuck in a bootloop 1951:that are hostile to users. 1636:on disk (also known as the 927:-based machines, including 489:, and to search for record 6357: 5788:Hybrid firmware bootloader 5529: 5369:Baran, Guru (2024-07-19). 5295:Hager, Ryne (2020-06-01). 4331:Brown, Eric (2008-10-02). 3320:. 1976. p. 4-25. 3083:. p. 10. A22-6741-1. 2212:Comparison of boot loaders 1423:keys during the POST; the 1380:For example, on a PC with 1285: 1245: 991:Comparison of boot loaders 988: 853:Software Cracking: History 745:erasable programmable ROMs 220:First commercial computers 43: 36: 29: 5837:Comparison of bootloaders 5149:– via Google Books. 4201:Red Hat Bootloader Team. 3027:Oxford English Dictionary 2891:. IBM. 1953. p. 26. 2567:(DPT/FDPB). Therefore, a 2496:sectors had to resort to 2170:2024 CrowdStrike incident 2087:zero trust security model 1939:unlocking the boot loader 1836:digital signal processors 1746:from the storage device. 1677:Advanced Active Partition 1628:, found as byte sequence 1150:Second-stage boot loaders 673:Set the P register to 106 651:If end of tape, jump to 9 287:from a punched card in a 4699:has been improved under 3111:Control Data Corporation 2829:Proceedings of the I.R.E 2512:, multi-level data/code 2369:The signature at offset 2358:Second-stage boot loader 1299:bootable flash drive, a 1106:First-stage boot loaders 981:x86-based workstations. 977:-based machines and the 877:Some machines, like the 688:Decrement the P register 654:Increment the P register 428:button. On the high end 326:Another example was the 216:and then executed them. 5725:Phoenix SecureCore UEFI 4389:. YouTube. 2008-07-16. 3180:. 1969. pp. 2–72. 2761:10.1109/mahc.1980.10009 2252:Windows startup process 2139:during conversion from 1785:Unlike BIOS, UEFI (not 1205:List of PC Booter games 967:Advanced RISC Computing 872:BeOS Personal Edition 5 831:'s first computer, the 785:Some minicomputers and 679:If not ready, jump to 2 642:If not ready, jump to 2 636:Set the P register to 9 374:The first model of the 291:, a magnetic tape in a 83:central processing unit 5139:. Wiley. p. 257. 5095:Tim Warren, The Verge 4038:; Kane, Gerry (1981). 3965:; Kane, Gerry (1981). 2745:Campbell-Kelly, Martin 2687:"Bootstrap Definition" 2504:-level programming in 2480:, for the addition of 2045: 2003: 1824: 1679:(18 bytes) or special 1482: 1471: 1435:keys during the POST. 1304: 979:SGI Visual Workstation 965:-based computers. The 845:Apple DOS: Boot loader 728: 517: 315: 269: 177: 123:does. Minimally, some 58: 5180:– via ProQuest. 4915:"OpenBIOS - coreboot" 4804:utility to work. The 3350:. 1965. p. 143. 3218:Burroughs Corporation 2856:"IBM 7619 Exchange". 2217:Linux startup process 1990: 1963:Android Verified boot 1814: 1770:Many modern systems ( 1477: 1461: 1295: 1228:GPS navigation device 1192:dual or multi-booting 1136:Partition Boot Record 1084:Partition Boot Record 901:IBM Personal Computer 719: 515: 458:Channel Command Words 313: 263: 171: 56: 46:Boot (disambiguation) 6044:EFI system partition 6010:GUID Partition Table 5960:Windows Boot Manager 5830:Bootloader unlocking 5642:Legacy Plug and Play 5566:Open-source firmware 5559:Proprietary firmware 5166:Windows Professional 5026:mjg59.dreamwidth.org 4307:www.tomshardware.com 3827:] (in Italian). 3616:. 1981. p. 17. 3516:BM873 restart/loader 3133:GE-645 System Manual 2565:Disk Parameter Table 2548:will load the whole 2429:PC DOS 5.0 2091:blue screen of death 2054:Blue screen of death 1834:) or sometimes even 1799:EFI System Partition 1391:in order to try out 1005:random-access memory 737:mask-programmed ROMs 545:magnetic-core memory 523:, starting with the 414:Initial Program Load 353:peripheral processor 44:For other uses, see 6051:BIOS boot partition 6024:Apple Partition Map 5855:Acronis OS Selector 5695:American Megatrends 5375:Cyber Security News 5107:Joe Tidy, BBC News 4940:"UEFI - OSDev Wiki" 4140:Glamenv-Septzen.net 3800:Ciaramella, Alberto 3370:PDP-9 User Handbook 3109:(Second ed.). 2632:The Free Dictionary 2498:self-modifying code 2373:in boot sectors is 1817:unlocked bootloader 1756:BIOS interrupt call 1692:Volume Boot Records 1001:non-volatile memory 985:Modern boot loaders 466:Program Status Word 440:-like device or an 6312:Power-on self-test 6017:Master boot record 4335:. linuxdevices.com 4278:www.disk-image.com 4203:"UEFI shim loader" 2947:. pp. 14–15. 2775:Wilkes, Maurice V. 2460:compared to their 2418:misinterpretation. 2004: 1978:Firmware passwords 1825: 1657:Master Boot Record 1638:MBR boot signature 1613:Volume Boot Record 1593:Master Boot Record 1523:power-on self-test 1483: 1472: 1401:Power-on self-test 1360:floppy disk drives 1352:memory card reader 1333:optical disc drive 1329:Master Boot Record 1305: 1224:digital television 1132:Master Boot Record 1094:size, track size. 1080:Master Boot Record 1054:(for example, the 909:power-on self test 787:superminicomputers 778:, a researcher at 776:Alberto Ciaramella 729: 558:(1969), and DEC's 518: 316: 270: 178: 59: 6328: 6327: 6154: 6153: 6002:Partition layouts 5997: 5996: 5981:Plop Boot Manager 5783: 5782: 4977:Texas Instruments 4719:"FAT32 in DR-DOS" 4647:978-0-201-60835-9 4554:; Pollock, John; 4492:Intel Corporation 3032:Oxford University 2779:Wheeler, David J. 2720:The Phrase Finder 2474:assembly language 2470:code optimization 2247:Self-booting disk 2222:Macintosh startup 2174:Microsoft Windows 2028:§ erroneous state 2012:system of systems 1603:flag set). If an 1489:CPU, executes in 1317:solid-state drive 935:Unix workstations 913:IBM PC compatible 851:mechanisms. (See 763:The Data General 741:programmable ROMs 663:Teletype Model 33 556:Data General Nova 332:IBM 7040 and 7044 206:stepping switches 73:as initiated via 16:(Redirected from 6348: 6321: 6314: 6307: 6300: 6293: 6286: 6284:Execute in place 6279: 6272: 6265: 6247: 6240: 6233: 6226: 6208: 6201: 6194: 6185: 6178: 6171: 6147: 6140: 6133: 6113: 6106: 6099: 6092: 6085: 6072: 6060: 6053: 6046: 6026: 6019: 6012: 5990: 5983: 5976: 5969: 5962: 5955: 5948: 5941: 5934: 5927: 5920: 5913: 5906: 5899: 5892: 5885: 5878: 5871: 5864: 5857: 5844: 5839: 5832: 5812: 5805: 5798: 5776: 5769: 5762: 5755: 5748: 5741: 5734: 5732:TianoCore EDK II 5727: 5720: 5711: 5704: 5697: 5690: 5683: 5665: 5658: 5651: 5644: 5637: 5630: 5623: 5616: 5607: 5600: 5593: 5575: 5568: 5561: 5548: 5535: 5522: 5515: 5506: 5499: 5492: 5464: 5457: 5450: 5441: 5434: 5433: 5431: 5430: 5415: 5409: 5408: 5406: 5405: 5399:www.eye.security 5391: 5385: 5384: 5382: 5381: 5366: 5360: 5359: 5357: 5356: 5342: 5336: 5335: 5333: 5332: 5317: 5311: 5310: 5308: 5307: 5292: 5286: 5285: 5283: 5282: 5268: 5262: 5261: 5259: 5258: 5241: 5235: 5234: 5232: 5231: 5214: 5208: 5207: 5205: 5204: 5197:BleepingComputer 5188: 5182: 5181: 5157: 5151: 5150: 5130: 5124: 5117: 5111: 5105: 5099: 5093: 5084: 5071: 5062: 5061: 5059: 5058: 5051:BleepingComputer 5042: 5036: 5035: 5033: 5032: 5018: 5012: 5011: 5009: 5008: 4998: 4992: 4991: 4989: 4988: 4965: 4959: 4958: 4956: 4955: 4936: 4930: 4929: 4927: 4926: 4917:. coreboot.org. 4911: 4905: 4904: 4902: 4901: 4886: 4880: 4879: 4851: 4850: 4830: 4824: 4823: 4780: 4779: 4759: 4753: 4752: 4735: 4734: 4714: 4708: 4706: 4693: 4692: 4670: 4664: 4651: 4629: 4618: 4616: 4601: 4568:Petzold, Charles 4552:Petzold, Charles 4520: 4514: 4513: 4507: 4506: 4500: 4489: 4481: 4475: 4474: 4469: 4468: 4462: 4455: 4447: 4441: 4440: 4434: 4433: 4427: 4416: 4408: 4402: 4401: 4399: 4398: 4383: 4377: 4376: 4374: 4373: 4354:Larabel, Michael 4350: 4344: 4343: 4341: 4340: 4328: 4322: 4321: 4319: 4318: 4299: 4293: 4292: 4290: 4289: 4270: 4264: 4263: 4261: 4260: 4245: 4239: 4238: 4223: 4217: 4216: 4214: 4213: 4198: 4192: 4191: 4189: 4188: 4182: 4175: 4166: 4155: 4154: 4152: 4151: 4131: 4125: 4122: 4120: 4119: 4110:. Archived from 4103: 4088: 4087: 4085: 4084: 4079: 4071: 4065: 4060: 4054: 4053: 4032: 4026: 4025: 4023: 4016: 4006: 4000: 3999: 3997: 3996: 3990: 3973: 3959: 3953: 3952: 3950: 3939: 3929: 3923: 3922: 3920: 3909: 3899: 3893: 3892: 3890: 3879: 3869: 3863: 3862: 3860: 3849: 3839: 3833: 3832: 3815: 3809: 3807: 3797: 3791: 3790: 3788: 3777: 3767: 3761: 3760: 3758: 3747: 3737: 3731: 3730: 3728: 3717: 3707: 3701: 3700: 3698: 3697: 3691: 3680: 3669: 3663: 3662: 3660: 3659: 3653: 3642: 3631: 3625: 3624: 3622: 3611: 3601: 3595: 3594: 3592: 3581: 3571: 3565: 3564: 3562: 3551: 3541: 3535: 3534: 3532: 3521: 3511: 3505: 3504: 3502: 3501: 3483: 3477: 3476: 3474: 3473: 3458: 3452: 3451: 3449: 3438: 3428: 3419: 3418: 3416: 3405: 3395: 3389: 3388: 3386: 3375: 3365: 3359: 3358: 3356: 3345: 3335: 3329: 3328: 3326: 3315: 3305: 3299: 3298: 3296: 3285: 3275: 3269: 3268: 3266: 3265: 3259: 3248: 3238: 3229: 3228: 3226: 3215: 3205: 3196: 3195: 3193: 3192: 3186: 3175: 3165: 3159: 3158: 3156: 3155: 3149: 3143:. January 1968. 3141:General Electric 3138: 3128: 3122: 3121: 3119: 3108: 3098: 3092: 3091: 3089: 3078: 3068: 3062: 3061: 3059: 3052: 3042: 3036: 3035: 3022: 3016: 3015: 3013: 3002: 2992: 2986: 2985: 2983: 2972: 2962: 2956: 2955: 2953: 2942: 2932: 2926: 2913: 2907: 2906: 2904: 2903: 2897: 2890: 2880: 2874: 2873: 2871: 2864: 2853: 2844: 2843: 2841: 2826: 2818:Buchholz, Werner 2814: 2808: 2807: 2805: 2804: 2771: 2765: 2764: 2741: 2735: 2734: 2732: 2731: 2712: 2706: 2705: 2703: 2702: 2683: 2677: 2676: 2674: 2673: 2654: 2648: 2647: 2645: 2644: 2623: 2617: 2616: 2614: 2613: 2594: 2577: 2569:DR-DOS 7.07 2539: 2533: 2516:and algorithmic 2506:machine language 2450: 2441: 2425: 2419: 2412: 2405:in programs for 2404: 2392: 2388: 2384: 2380: 2376: 2372: 2367: 2361: 2354:active partition 2350: 2344: 2329: 2323: 2320: 2314: 2310: 2304: 2297: 2285: 2274: 2167: 1960:UEFI secure boot 1853:USB flash drives 1741: 1737: 1716: 1649:removable drives 1635: 1631: 1627: 1605:active partition 1590: 1586: 1582: 1578: 1567: 1504: 1500: 1254:computer network 1220:embedded systems 1032:bootstrap loader 1021:execute in place 1019:) which support 1011:(ROM, and later 1009:read-only memory 941:later developed 939:Sun Microsystems 733:read-only memory 578:read-only memory 496: 492: 488: 484: 480: 476: 471: 463: 369:read-only memory 346:(c. 1964) had a 251:IBM 7030 Stretch 158:read-only memory 125:embedded systems 110:operating system 108:, typically the 32:Quickboot (QEMM) 21: 18:Bootstrap loader 6356: 6355: 6351: 6350: 6349: 6347: 6346: 6345: 6331: 6330: 6329: 6324: 6317: 6310: 6303: 6296: 6289: 6282: 6275: 6268: 6261: 6250: 6243: 6236: 6229: 6222: 6211: 6204: 6197: 6190: 6181: 6174: 6167: 6150: 6143: 6136: 6129: 6118: 6109: 6102: 6095: 6088: 6081: 6063: 6056: 6049: 6042: 6029: 6022: 6015: 6008: 5993: 5986: 5979: 5972: 5965: 5958: 5951: 5944: 5937: 5930: 5923: 5916: 5909: 5902: 5895: 5888: 5881: 5874: 5867: 5860: 5853: 5847:Implementations 5842: 5835: 5828: 5815: 5808: 5801: 5794: 5779: 5772: 5765: 5758: 5751: 5744: 5737: 5730: 5723: 5716: 5707: 5700: 5693: 5686: 5679: 5673:Implementations 5668: 5661: 5654: 5647: 5640: 5633: 5626: 5619: 5612: 5603: 5596: 5589: 5578: 5573:Custom firmware 5571: 5564: 5557: 5536: 5527: 5518: 5511: 5502: 5495: 5488: 5477: 5468: 5438: 5437: 5428: 5426: 5417: 5416: 5412: 5403: 5401: 5393: 5392: 5388: 5379: 5377: 5368: 5367: 5363: 5354: 5352: 5350:crowdstrike.com 5344: 5343: 5339: 5330: 5328: 5319: 5318: 5314: 5305: 5303: 5294: 5293: 5289: 5280: 5278: 5270: 5269: 5265: 5256: 5254: 5243: 5242: 5238: 5229: 5227: 5216: 5215: 5211: 5202: 5200: 5190: 5189: 5185: 5159: 5158: 5154: 5147: 5132: 5131: 5127: 5118: 5114: 5106: 5102: 5094: 5087: 5072: 5065: 5056: 5054: 5044: 5043: 5039: 5030: 5028: 5020: 5019: 5015: 5006: 5004: 5000: 4999: 4995: 4986: 4984: 4967: 4966: 4962: 4953: 4951: 4938: 4937: 4933: 4924: 4922: 4913: 4912: 4908: 4899: 4897: 4888: 4887: 4883: 4848: 4846: 4832: 4831: 4827: 4777: 4775: 4768:opendos@delorie 4761: 4760: 4756: 4732: 4730: 4723:opendos@delorie 4716: 4715: 4711: 4701:DR DOS 5.0 4690: 4688: 4672: 4671: 4667: 4648: 4631: 4630: 4621: 4603: 4582: 4572:Microsoft Press 4556:Reynolds, Aaron 4524:Zbikowski, Mark 4522: 4521: 4517: 4504: 4502: 4498: 4487: 4483: 4482: 4478: 4466: 4464: 4460: 4453: 4449: 4448: 4444: 4431: 4429: 4425: 4414: 4410: 4409: 4405: 4396: 4394: 4385: 4384: 4380: 4371: 4369: 4352: 4351: 4347: 4338: 4336: 4330: 4329: 4325: 4316: 4314: 4301: 4300: 4296: 4287: 4285: 4272: 4271: 4267: 4258: 4256: 4247: 4246: 4242: 4225: 4224: 4220: 4211: 4209: 4200: 4199: 4195: 4186: 4184: 4180: 4173: 4168: 4167: 4158: 4149: 4147: 4133: 4132: 4128: 4117: 4115: 4105: 4104: 4091: 4082: 4080: 4077: 4073: 4072: 4068: 4061: 4057: 4050: 4034: 4033: 4029: 4021: 4014: 4008: 4007: 4003: 3994: 3992: 3988: 3982: 3971: 3961: 3960: 3956: 3948: 3937: 3931: 3930: 3926: 3918: 3907: 3901: 3900: 3896: 3888: 3877: 3871: 3870: 3866: 3858: 3847: 3841: 3840: 3836: 3817: 3816: 3812: 3803: 3798: 3794: 3786: 3775: 3769: 3768: 3764: 3756: 3745: 3739: 3738: 3734: 3726: 3715: 3709: 3708: 3704: 3695: 3693: 3689: 3678: 3671: 3670: 3666: 3657: 3655: 3651: 3640: 3633: 3632: 3628: 3620: 3609: 3603: 3602: 3598: 3590: 3579: 3573: 3572: 3568: 3560: 3549: 3543: 3542: 3538: 3530: 3519: 3513: 3512: 3508: 3499: 3497: 3486:Holmer, Glenn. 3485: 3484: 3480: 3471: 3469: 3460: 3459: 3455: 3447: 3436: 3430: 3429: 3422: 3414: 3403: 3397: 3396: 3392: 3384: 3373: 3367: 3366: 3362: 3354: 3343: 3337: 3336: 3332: 3324: 3313: 3307: 3306: 3302: 3294: 3283: 3277: 3276: 3272: 3263: 3261: 3257: 3246: 3240: 3239: 3232: 3224: 3213: 3207: 3206: 3199: 3190: 3188: 3184: 3173: 3167: 3166: 3162: 3153: 3151: 3147: 3136: 3130: 3129: 3125: 3117: 3106: 3100: 3099: 3095: 3087: 3076: 3070: 3069: 3065: 3057: 3050: 3044: 3043: 3039: 3024: 3023: 3019: 3011: 3007:. p. 146. 3000: 2994: 2993: 2989: 2981: 2970: 2964: 2963: 2959: 2951: 2940: 2934: 2933: 2929: 2914: 2910: 2901: 2899: 2895: 2888: 2882: 2881: 2877: 2869: 2862: 2855: 2854: 2847: 2839: 2824: 2816: 2815: 2811: 2802: 2800: 2773: 2772: 2768: 2743: 2742: 2738: 2729: 2727: 2714: 2713: 2709: 2700: 2698: 2685: 2684: 2680: 2671: 2669: 2656: 2655: 2651: 2642: 2640: 2625: 2624: 2620: 2611: 2609: 2596: 2595: 2591: 2586: 2581: 2580: 2540: 2536: 2451: 2444: 2426: 2422: 2410: 2402: 2390: 2386: 2382: 2378: 2374: 2370: 2368: 2364: 2351: 2347: 2330: 2326: 2321: 2317: 2311: 2307: 2298: 2294: 2289: 2288: 2275: 2266: 2261: 2256: 2237:Network booting 2187: 2165: 2099: 2075: 2073:Recovery policy 2066: 2050: 1985: 1975:Disk encryption 1972:Intel BootGuard 1957: 1945:Matthew Garrett 1923: 1860:embedded system 1807: 1791:EFI application 1768: 1739: 1735: 1712: 1661:partition table 1633: 1629: 1625: 1588: 1584: 1580: 1576: 1565: 1562: 1502: 1498: 1456: 1434: 1430: 1422: 1418: 1348:USB flash drive 1321:hard disk drive 1290: 1282: 1277: 1250: 1248:Network booting 1244: 1242:Network booting 1216: 1152: 1108: 997: 987: 915:computers. The 849:copy protection 814: 761: 714: 702: 618: 510: 494: 490: 486: 482: 478: 474: 469: 461: 401: 222: 191: 189:Early computers 186: 166: 49: 42: 35: 28: 23: 22: 15: 12: 11: 5: 6354: 6352: 6344: 6343: 6333: 6332: 6326: 6325: 6323: 6322: 6315: 6308: 6301: 6294: 6287: 6280: 6273: 6266: 6258: 6256: 6252: 6251: 6249: 6248: 6241: 6234: 6227: 6219: 6217: 6213: 6212: 6210: 6209: 6202: 6195: 6188: 6187: 6186: 6179: 6164: 6162: 6156: 6155: 6152: 6151: 6149: 6148: 6141: 6134: 6126: 6124: 6120: 6119: 6117: 6116: 6115: 6114: 6100: 6093: 6086: 6078: 6076: 6069: 6065: 6064: 6062: 6061: 6054: 6047: 6039: 6037: 6031: 6030: 6028: 6027: 6020: 6013: 6005: 6003: 5999: 5998: 5995: 5994: 5992: 5991: 5984: 5977: 5970: 5963: 5956: 5949: 5942: 5935: 5928: 5921: 5914: 5907: 5900: 5893: 5886: 5879: 5872: 5865: 5858: 5850: 5848: 5841: 5840: 5833: 5825: 5823: 5817: 5816: 5814: 5813: 5806: 5799: 5791: 5789: 5785: 5784: 5781: 5780: 5778: 5777: 5770: 5763: 5756: 5749: 5742: 5735: 5728: 5721: 5714: 5713: 5712: 5705: 5691: 5684: 5676: 5674: 5670: 5669: 5667: 5666: 5659: 5652: 5645: 5638: 5631: 5624: 5617: 5610: 5609: 5608: 5594: 5586: 5584: 5580: 5579: 5577: 5576: 5569: 5562: 5554: 5552: 5545: 5538: 5537: 5530: 5528: 5526: 5525: 5524: 5523: 5509: 5508: 5507: 5500: 5485: 5483: 5479: 5478: 5469: 5467: 5466: 5459: 5452: 5444: 5436: 5435: 5410: 5386: 5361: 5337: 5326:Android Police 5312: 5301:Android Police 5287: 5263: 5236: 5209: 5183: 5152: 5145: 5125: 5112: 5100: 5085: 5063: 5037: 5013: 4993: 4979:. 2013-12-05. 4960: 4944:wiki.osdev.org 4931: 4906: 4881: 4825: 4754: 4709: 4665: 4646: 4619: 4580: 4564:Letwin, Gordon 4540:McDonald, Marc 4532:Ballmer, Steve 4515: 4476: 4442: 4403: 4378: 4356:(2008-06-14). 4345: 4323: 4294: 4265: 4240: 4237:on 2007-05-15. 4218: 4193: 4156: 4126: 4089: 4066: 4055: 4048: 4027: 4001: 3980: 3954: 3924: 3894: 3864: 3834: 3810: 3792: 3762: 3732: 3702: 3664: 3626: 3596: 3566: 3536: 3506: 3478: 3453: 3420: 3390: 3360: 3330: 3300: 3270: 3230: 3197: 3160: 3123: 3093: 3063: 3037: 3017: 2987: 2977:. p. 34. 2957: 2927: 2908: 2875: 2845: 2809: 2793:Addison-Wesley 2766: 2736: 2707: 2678: 2649: 2618: 2588: 2587: 2585: 2582: 2579: 2578: 2534: 2472:techniques in 2442: 2420: 2362: 2356:may contain a 2345: 2324: 2315: 2305: 2291: 2290: 2287: 2286: 2263: 2262: 2260: 2257: 2255: 2254: 2249: 2244: 2239: 2234: 2229: 2224: 2219: 2214: 2209: 2204: 2199: 2194: 2188: 2186: 2183: 2182: 2181: 2159: 2154: 2148: 2137:rounding error 2126: 2120: 2115: 2113:Windows Server 2110: 2105: 2103:Windows NT 4.0 2098: 2095: 2083:Single sign-on 2074: 2071: 2065: 2062: 2049: 2046: 1984: 1981: 1980: 1979: 1976: 1973: 1970: 1967: 1964: 1961: 1956: 1953: 1922: 1919: 1900:host processor 1806: 1803: 1767: 1764: 1675:(6 bytes), an 1673:disk timestamp 1669:disk signature 1665:boot signature 1599:(the one with 1561: 1558: 1479:Award Software 1455: 1452: 1281: 1278: 1276: 1273: 1246:Main article: 1243: 1240: 1215: 1212: 1180:device drivers 1151: 1148: 1134:(MBR) and the 1107: 1104: 1088:IBM System/360 1082:(MBR) and the 986: 983: 829:Apple Computer 813: 810: 760: 757: 720:An Intel 2708 713: 710: 701: 698: 693: 692: 689: 686: 683: 680: 677: 674: 659: 658: 655: 652: 649: 646: 643: 640: 637: 617: 614: 509: 506: 422:7030 (Stretch) 409:z/Architecture 405:IBM System/360 400: 397: 381: 380: 372: 361: 221: 218: 190: 187: 185: 182: 165: 162: 148:bootstrap load 129:state machines 106:runtime system 26: 24: 14: 13: 10: 9: 6: 4: 3: 2: 6353: 6342: 6339: 6338: 6336: 6320: 6316: 6313: 6309: 6306: 6302: 6299: 6295: 6292: 6288: 6285: 6281: 6278: 6274: 6271: 6267: 6264: 6260: 6259: 6257: 6253: 6246: 6242: 6239: 6235: 6232: 6228: 6225: 6221: 6220: 6218: 6214: 6207: 6203: 6200: 6196: 6193: 6189: 6184: 6180: 6177: 6173: 6172: 6170: 6166: 6165: 6163: 6161: 6157: 6146: 6142: 6139: 6135: 6132: 6128: 6127: 6125: 6121: 6112: 6108: 6107: 6105: 6101: 6098: 6094: 6091: 6087: 6084: 6080: 6079: 6077: 6073: 6070: 6066: 6059: 6055: 6052: 6048: 6045: 6041: 6040: 6038: 6036: 6032: 6025: 6021: 6018: 6014: 6011: 6007: 6006: 6004: 6000: 5989: 5985: 5982: 5978: 5975: 5971: 5968: 5964: 5961: 5957: 5954: 5950: 5947: 5943: 5940: 5936: 5933: 5929: 5926: 5922: 5919: 5915: 5912: 5908: 5905: 5901: 5898: 5894: 5891: 5887: 5884: 5883:BootX (Linux) 5880: 5877: 5876:BootX (Apple) 5873: 5870: 5866: 5863: 5859: 5856: 5852: 5851: 5849: 5845: 5838: 5834: 5831: 5827: 5826: 5824: 5822: 5818: 5811: 5807: 5804: 5800: 5797: 5793: 5792: 5790: 5786: 5775: 5771: 5768: 5764: 5761: 5757: 5754: 5750: 5747: 5743: 5740: 5736: 5733: 5729: 5726: 5722: 5719: 5715: 5710: 5706: 5703: 5699: 5698: 5696: 5692: 5689: 5685: 5682: 5678: 5677: 5675: 5671: 5664: 5660: 5657: 5653: 5650: 5646: 5643: 5639: 5636: 5632: 5629: 5625: 5622: 5618: 5615: 5614:Open Firmware 5611: 5606: 5602: 5601: 5599: 5595: 5592: 5588: 5587: 5585: 5581: 5574: 5570: 5567: 5563: 5560: 5556: 5555: 5553: 5549: 5546: 5544: 5539: 5534: 5521: 5517: 5516: 5514: 5510: 5505: 5501: 5498: 5494: 5493: 5491: 5487: 5486: 5484: 5480: 5476: 5472: 5465: 5460: 5458: 5453: 5451: 5446: 5445: 5442: 5424: 5420: 5414: 5411: 5400: 5396: 5390: 5387: 5376: 5372: 5365: 5362: 5351: 5347: 5341: 5338: 5327: 5323: 5316: 5313: 5302: 5298: 5291: 5288: 5277: 5273: 5267: 5264: 5253: 5252: 5247: 5240: 5237: 5226: 5225: 5220: 5213: 5210: 5199: 5198: 5193: 5187: 5184: 5179: 5175: 5171: 5167: 5163: 5156: 5153: 5148: 5146:9780471175025 5142: 5138: 5137: 5129: 5126: 5122: 5116: 5113: 5110: 5104: 5101: 5098: 5092: 5090: 5086: 5083: 5079: 5076: 5070: 5068: 5064: 5053: 5052: 5047: 5041: 5038: 5027: 5023: 5017: 5014: 5003: 4997: 4994: 4982: 4978: 4974: 4970: 4964: 4961: 4949: 4945: 4941: 4935: 4932: 4920: 4916: 4910: 4907: 4895: 4891: 4885: 4882: 4878: 4876: 4872: 4868: 4864: 4860: 4857: 4844: 4840: 4836: 4829: 4826: 4822: 4820: 4816: 4812: 4807: 4803: 4799: 4794: 4790: 4786: 4773: 4769: 4765: 4758: 4755: 4751: 4749: 4745: 4741: 4728: 4724: 4720: 4713: 4710: 4705: 4702: 4698: 4686: 4682: 4681: 4676: 4669: 4666: 4663: 4661: 4659: 4656: 4654: 4649: 4643: 4639: 4635: 4634:DOS Internals 4628: 4626: 4624: 4620: 4614: 4610: 4609:PCjs Machines 4606: 4599: 4595: 4591: 4587: 4583: 4581:1-55615-049-0 4577: 4573: 4569: 4565: 4561: 4557: 4553: 4549: 4548:Paterson, Tim 4545: 4541: 4537: 4533: 4529: 4525: 4519: 4516: 4512: 4497: 4493: 4486: 4480: 4477: 4473: 4459: 4452: 4446: 4443: 4439: 4424: 4420: 4413: 4407: 4404: 4392: 4388: 4382: 4379: 4367: 4363: 4359: 4355: 4349: 4346: 4334: 4327: 4324: 4312: 4308: 4304: 4298: 4295: 4283: 4279: 4275: 4269: 4266: 4254: 4250: 4244: 4241: 4236: 4232: 4228: 4222: 4219: 4208: 4204: 4197: 4194: 4179: 4172: 4165: 4163: 4161: 4157: 4145: 4141: 4137: 4130: 4127: 4124: 4114:on 2003-10-04 4113: 4109: 4102: 4100: 4098: 4096: 4094: 4090: 4076: 4070: 4067: 4064: 4059: 4056: 4051: 4049:0-931988-42-X 4045: 4041: 4037: 4036:Osborne, Adam 4031: 4028: 4020: 4013: 4012: 4005: 4002: 3987: 3983: 3981:0-931988-43-8 3977: 3970: 3969: 3964: 3963:Osborne, Adam 3958: 3955: 3947: 3943: 3936: 3935: 3928: 3925: 3917: 3913: 3906: 3905: 3898: 3895: 3887: 3883: 3876: 3875: 3868: 3865: 3857: 3853: 3846: 3845: 3838: 3835: 3830: 3826: 3822: 3821: 3814: 3811: 3806: 3801: 3796: 3793: 3785: 3781: 3774: 3773: 3766: 3763: 3755: 3751: 3744: 3743: 3736: 3733: 3725: 3721: 3714: 3713: 3706: 3703: 3688: 3684: 3677: 3676: 3668: 3665: 3650: 3646: 3639: 3638: 3630: 3627: 3619: 3615: 3608: 3607: 3600: 3597: 3589: 3585: 3578: 3577: 3570: 3567: 3559: 3555: 3548: 3547: 3540: 3537: 3529: 3525: 3518: 3517: 3510: 3507: 3495: 3491: 3490: 3482: 3479: 3467: 3463: 3457: 3454: 3446: 3442: 3435: 3434: 3427: 3425: 3421: 3413: 3409: 3402: 3401: 3394: 3391: 3383: 3379: 3372: 3371: 3364: 3361: 3353: 3349: 3342: 3341: 3334: 3331: 3323: 3319: 3312: 3311: 3304: 3301: 3293: 3289: 3282: 3281: 3274: 3271: 3256: 3252: 3245: 3244: 3237: 3235: 3231: 3223: 3219: 3212: 3211: 3204: 3202: 3198: 3183: 3179: 3172: 3171: 3164: 3161: 3146: 3142: 3135: 3134: 3127: 3124: 3116: 3112: 3105: 3104: 3097: 3094: 3086: 3082: 3075: 3074: 3067: 3064: 3056: 3049: 3048: 3041: 3038: 3033: 3029: 3028: 3021: 3018: 3010: 3006: 2999: 2998: 2991: 2988: 2980: 2976: 2969: 2968: 2961: 2958: 2950: 2946: 2939: 2938: 2931: 2928: 2925: 2924:0-930405-87-0 2921: 2917: 2912: 2909: 2894: 2887: 2886: 2879: 2876: 2868: 2861: 2860: 2852: 2850: 2846: 2838: 2834: 2830: 2823: 2819: 2813: 2810: 2798: 2794: 2790: 2789: 2784: 2783:Gill, Stanley 2780: 2776: 2770: 2767: 2762: 2758: 2754: 2750: 2746: 2740: 2737: 2725: 2721: 2717: 2711: 2708: 2696: 2692: 2688: 2682: 2679: 2667: 2663: 2659: 2653: 2650: 2638: 2634: 2633: 2628: 2622: 2619: 2607: 2603: 2599: 2593: 2590: 2583: 2575: 2570: 2566: 2563: 2559: 2555: 2551: 2547: 2544: 2538: 2535: 2531: 2527: 2523: 2519: 2515: 2511: 2507: 2503: 2499: 2495: 2491: 2487: 2483: 2479: 2475: 2471: 2467: 2463: 2459: 2455: 2449: 2447: 2443: 2439: 2435: 2430: 2424: 2421: 2416: 2408: 2400: 2396: 2395:little-endian 2366: 2363: 2359: 2355: 2349: 2346: 2342: 2338: 2334: 2328: 2325: 2319: 2316: 2309: 2306: 2302: 2296: 2293: 2283: 2282:recovery mode 2279: 2273: 2271: 2269: 2265: 2258: 2253: 2250: 2248: 2245: 2243: 2240: 2238: 2235: 2233: 2230: 2228: 2225: 2223: 2220: 2218: 2215: 2213: 2210: 2208: 2205: 2203: 2200: 2198: 2197:Multi-booting 2195: 2193: 2190: 2189: 2184: 2179: 2178:recovery mode 2175: 2172:resulting in 2171: 2164: 2160: 2158: 2155: 2152: 2149: 2146: 2142: 2138: 2134: 2130: 2127: 2125: 2121: 2119: 2116: 2114: 2111: 2109: 2106: 2104: 2101: 2100: 2096: 2094: 2092: 2088: 2084: 2080: 2072: 2070: 2063: 2061: 2059: 2055: 2047: 2044: 2039: 2037: 2033: 2029: 2025: 2021: 2018:(also called 2017: 2013: 2009: 2001: 1997: 1994:console of a 1993: 1989: 1982: 1977: 1974: 1971: 1968: 1965: 1962: 1959: 1958: 1954: 1952: 1950: 1946: 1942: 1940: 1936: 1932: 1928: 1920: 1918: 1916: 1912: 1907: 1905: 1901: 1895: 1892: 1890: 1885: 1879: 1877: 1872: 1869: 1865: 1861: 1856: 1854: 1849: 1845: 1841: 1837: 1833: 1830: 1822: 1818: 1813: 1809: 1804: 1802: 1800: 1796: 1792: 1788: 1783: 1781: 1777: 1773: 1765: 1763: 1762:via network. 1761: 1757: 1753: 1747: 1745: 1732: 1730: 1725: 1721: 1715: 1709: 1705: 1701: 1697: 1693: 1690: 1686: 1682: 1678: 1674: 1671:(6 bytes), a 1670: 1666: 1662: 1658: 1654: 1650: 1646: 1641: 1639: 1624: 1621: 1620:little-endian 1616: 1614: 1610: 1606: 1602: 1598: 1594: 1575: 1571: 1559: 1557: 1555: 1551: 1547: 1542: 1540: 1536: 1532: 1528: 1524: 1520: 1516: 1512: 1508: 1496: 1492: 1488: 1480: 1476: 1469: 1465: 1460: 1454:Boot sequence 1453: 1451: 1449: 1445: 1441: 1436: 1426: 1414: 1410: 1406: 1402: 1398: 1394: 1390: 1387: 1383: 1378: 1376: 1371: 1369: 1365: 1361: 1357: 1353: 1349: 1345: 1342: 1338: 1334: 1330: 1326: 1322: 1318: 1314: 1310: 1302: 1298: 1297:Windows To Go 1294: 1289: 1284: 1279: 1274: 1272: 1270: 1265: 1263: 1259: 1255: 1249: 1241: 1239: 1235: 1233: 1229: 1225: 1221: 1213: 1211: 1208: 1206: 1202: 1198: 1193: 1187: 1185: 1184:Open Firmware 1181: 1177: 1173: 1169: 1165: 1161: 1157: 1149: 1147: 1146:processors. 1145: 1141: 1137: 1133: 1129: 1125: 1121: 1117: 1113: 1105: 1103: 1101: 1095: 1093: 1089: 1085: 1081: 1076: 1074: 1070: 1065: 1061: 1057: 1051: 1047: 1045: 1044:chain loading 1041: 1037: 1033: 1028: 1026: 1022: 1018: 1014: 1010: 1006: 1002: 996: 992: 984: 982: 980: 976: 972: 968: 964: 960: 956: 952: 948: 944: 940: 936: 932: 930: 926: 922: 918: 914: 910: 906: 902: 897: 895: 891: 887: 883: 882:microcomputer 880: 875: 873: 869: 865: 862:systems from 861: 856: 854: 850: 846: 842: 837: 834: 830: 826: 824: 820: 811: 809: 806: 804: 800: 796: 792: 788: 783: 781: 777: 772: 770: 766: 759:Minicomputers 758: 756: 754: 750: 747:(EPROM), and 746: 742: 738: 734: 727: 726:circuit board 723: 718: 711: 709: 707: 699: 697: 690: 687: 684: 681: 678: 675: 672: 671: 670: 668: 664: 656: 653: 650: 647: 644: 641: 638: 635: 634: 633: 631: 627: 623: 622:Binary Loader 615: 613: 611: 607: 603: 599: 595: 591: 586: 583: 579: 576: 571: 567: 565: 561: 557: 553: 548: 546: 542: 538: 534: 530: 526: 522: 521:Minicomputers 514: 508:Minicomputers 507: 505: 502: 498: 467: 459: 455: 450: 447: 443: 439: 435: 432:models, most 431: 427: 423: 418: 416: 415: 410: 406: 398: 396: 394: 389: 386: 377: 373: 370: 366: 362: 359: 355: 354: 349: 345: 341: 340: 339: 336: 333: 329: 324: 321: 312: 308: 306: 302: 298: 294: 290: 286: 282: 279: 275: 267: 262: 258: 256: 252: 248: 244: 243:magnetic tape 240: 239:magnetic drum 236: 231: 227: 219: 217: 215: 211: 210:David Wheeler 207: 203: 198: 196: 188: 183: 181: 175: 170: 163: 161: 159: 155: 154: 149: 145: 144: 140:is short for 139: 135: 132: 130: 126: 122: 118: 113: 111: 107: 103: 99: 94: 92: 88: 84: 80: 76: 72: 68: 64: 55: 51: 47: 40: 39:Bootstrapping 33: 19: 6216:ROM variants 6160:Network boot 6138:Raspberry Pi 5904:systemd-boot 5474: 5427:. Retrieved 5425:. 2024-07-19 5422: 5413: 5402:. Retrieved 5398: 5389: 5378:. Retrieved 5374: 5364: 5353:. Retrieved 5349: 5340: 5329:. Retrieved 5325: 5315: 5304:. Retrieved 5300: 5290: 5279:. Retrieved 5275: 5266: 5255:. Retrieved 5249: 5239: 5228:. Retrieved 5222: 5212: 5201:. Retrieved 5195: 5186: 5169: 5165: 5155: 5135: 5128: 5115: 5103: 5077: 5055:. Retrieved 5049: 5040: 5029:. Retrieved 5025: 5016: 5005:. Retrieved 4996: 4985:. Retrieved 4972: 4963: 4952:. Retrieved 4943: 4934: 4923:. Retrieved 4909: 4898:. Retrieved 4884: 4853: 4847:. Retrieved 4838: 4828: 4782: 4776:. Retrieved 4767: 4764:"Can't copy" 4757: 4737: 4731:. Retrieved 4722: 4712: 4695: 4689:. Retrieved 4678: 4668: 4633: 4608: 4559: 4518: 4509: 4503:. Retrieved 4479: 4471: 4465:. Retrieved 4445: 4436: 4430:. Retrieved 4406: 4395:. Retrieved 4381: 4370:. Retrieved 4348: 4337:. Retrieved 4326: 4315:. Retrieved 4306: 4297: 4286:. Retrieved 4277: 4268: 4257:. 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