The same hardware logic could be used to load the contents of a punch card (the most typical ones) or other input media, such as a magnetic drum or magnetic tape, that contained a bootstrap program by pressing a single button. They typically included instructions that performed a complete input or output operation. The first programmable computers for commercial sale, such as the UNIVAC I and the IBM 701 included features to make their operation simpler. The program stored on this device, which David Wheeler completed in late 1948, loaded further instructions from punched tape and then executed them. The EDSAC system, the second stored-program computer to be built, used stepping switches to transfer a fixed program into memory when its start button was pressed.
Bootstrapping did not apply to ENIAC, whose hardware configuration was ready for solving problems as soon as power was applied. An early computer, ENIAC, had no program stored in memory, but was set up for each problem by a configuration of interconnecting cables. Pre integrated-circuit-ROM examples Early computers Įarly 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. These methods reach from simple, physical input to removable media that can hold more complex programs. There are many different methods available to load a short initial program into a computer. History Switches and cables used to program ENIAC (1946) Growth in the capacity of ROM has allowed ever more elaborate start up procedures to be implemented. The invention of read-only memory (ROM) of various types solved this paradox by allowing computers to be shipped with a start up program that could not be erased. Early computers used a variety of ad-hoc methods to get a small program into memory to solve this problem.
Active boot disk creator registration software#
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. 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.īoot is short for bootstrap or bootstrap load and derives from the phrase to pull oneself up by one's bootstraps. All computing systems are state machines, and a reboot may be the only method to return to a designated zero-state from an unintended, locked state. Minimally, some embedded systems do not require a noticeable boot sequence to begin functioning and when turned on may simply run operational programs that are stored in ROM. The process of returning a computer from a state of sleep (suspension) does not involve booting however, restoring it from a state of hibernation does. Booting is complete when the operative runtime system, typically the operating system and some applications, is attained. Both hard and soft booting can be initiated by hardware such as a button press or by a software command. On some systems, a soft boot may optionally clear RAM to zero. after electrical power to the CPU is switched from off to on, or "soft", where the power is not cut. Restarting a computer also is called rebooting, which can be "hard", e.g.
This may be done by hardware or firmware in the CPU, or by a separate processor in the computer system. After it is switched on, a computer's central processing unit (CPU) has no software in its main memory, so some process must load software into memory before it can be executed. In computing, booting is the process of starting a computer as initiated via hardware such as a button or by a software command.
For other uses, see Boot (disambiguation).
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