Storage and execution




Typically, computer programs are stored in non-volatile memory until requested either directly or indirectly to be executed by the computer user. Upon such a request, the program is loaded into random-access memory, by a computer program called an operating system, where it can be accessed directly by the central processor. The central processor then executes ("runs") the program, instruction by instruction, until termination. A program in execution is called a process. Termination is either by normal self-termination, by user intervention, or by error – software or hardware error.

Simultaneous executionedit

Many operating systems support multitasking which enables many computer programs to appear to run simultaneously on one computer. Operating systems may run multiple programs through process scheduling – a software mechanism to switch the CPU among processes often so users can interact with each program while it runs. Within hardware, modern day multiprocessor computers or computers with multicore processors may run multiple programs.

Self-modifying programsedit

A computer program in execution is normally treated as being different from the data the program operates on. However, in some cases, this distinction is blurred when a computer program modifies itself. The modified computer program is subsequently executed as part of the same program. Self-modifying code is possible for programs written in machine code, assembly language, Lisp, C, COBOL, PL/1, and Prolog.

Comments

Post a Comment

Popular posts from this blog

49)Discussed: What to expect on Republic Time 2021and what not to

India Republic Day -- Republic Day 2021: In 2020it was the agitation against the Citizenship Amendment Act (CAA). Nowthousands of farmersgenerally from Punjab and Haryanahave been camping at the borders of Delhi for more than 2 monthsdemanding the Centre repeal the three farm laws. For that second year in a lineRepublic Day celebrations from the national capital will be presented under the shadow of strong protests against laws approved by the Centre. In 2020it was the agitation against the Citizenship Amendment Act (CAA). This timethousands of farmersgenerally from Punjab and Haryanahave been camping at the borders of Delhi for more than 2 monthsdemanding the Centre repeal the three farm laws. This kind of years Republic Day attend will also be the first major open event in pandemic times. What is new this year The case will be pared down in terms of the number of spectatorsthe size of walking in line contingents and other side destinations. The spectator size have been reduced to
Read more

History

Image
Code-breaking algorithms have existed for centuries. In the 9th century, the Arab mathematician Al-Kindi described a cryptographic algorithm for deciphering encrypted code, in A Manuscript On Deciphering Cryptographic Messages . He gave the first description of cryptanalysis by frequency analysis, the earliest code-breaking algorithm. Early programmable machines edit The earliest programmable machines preceded the invention of the digital computer. As early as the 9th century, a programmable music sequencer was invented by the Persian Banu Musa brothers, who described an automated mechanical flute player in the Book of Ingenious Devices . In 1206, the Arab engineer Al-Jazari invented a programmable drum machine where musical mechanical automata could be made to play different rhythms and drum patterns. In 1801, Joseph-Marie Jacquard devised a loom that would weave a pattern by following a series of perforated cards. Patterns could be woven and repeated by arranging the cards. Analytica
Read more