Computer program
A computer program is a list of instructions that tell a computer what to do. Everything a computer does is done by the instructions of a program. The first computers were made with only one built-in program, but today's computers have memory, which can be used to store many different programs. John von Neumann, a mathematician born in Hungary, came up with this idea in the late 1940s.
Some common examples of computer programs:
- Web browsers, like Mozilla Firefox or Chrome
- Word processors, like Microsoft Word or Google Docs
- Video games
- Operating systems, like Microsoft Windows or iOS
A computer program is usually stored as a file on the computer's hard drive. The file contains a list of instructions. When the user runs the program, the computer reads the file does what the instructions tell it to do. These instructions can be very simple, like "add these numbers together" or "save these letters". A computer program is written by a programmer, who combines many of these simple instructions to do complicated things, like talking to the computer's screen and telling it to show a video.
The main part of the computer, the processor, is built to understand instructions written in machine code, meaning very long patterns of ones and zeroes. This is hard for humans to understand, so computer programmers write in a programming language, such as BASIC, C, or Java. Once the program is written, the programmer uses a compiler to turn it into machine code so the computer can read it.
There are also bad programs, called malware, written by people who want to do bad things to a computer. Some are spyware, trying to steal information from the computer. Some try to damage the data stored on the hard drive. Some others send users to web sites that offer to sell them things. Some are computer viruses or ransomware.
Computer Program Media
Source code for a computer program written in the JavaScript language
"Hello, World!" program by Brian Kernighan (1978)
Lovelace's description from Note G
A Universal Turing machine U. U consists of a set of instructions in the table that can “execute” the correctly-formulated “code number” of any arbitrary Turing machine M
Glenn A. Beck changing a tube in ENIAC
Switches for manual input on a Data General Nova 3, manufactured in the mid-1970s
A VLSI integrated-circuit die
IBM's System/360 (1964) CPU was not a microprocessor.
Artist's depiction of Sacramento State University's Intel 8008 microcomputer (1972)
The original IBM Personal Computer (1981) used an Intel 8088 microprocessor.
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Related pages
Other websites
- Computer program Citizendium
