A computer program is a set of instructions for a machine to follow, usually to perform a task for humans.
The earliest computers were literally mechanical, and the instructions caused their gears and wheels to take various courses.
With the invention of electronic computers, computational speed increased and the complexity of the tasks assigned them could be higher.
Where once a program consisted of a stack of punchcards or a roll of punched tape, modern programs are written, stored and run from various digital media, chief among them CD-ROMs and magnetic disks. Programs are now usually called "software," as distinct from the machines that run them, the "hardware".
Computer programs are broadly broken down by the functional level they work at:
- Bootup programs, which operate when a computer is switched on, and ready the machine for further instructions.
- Operating systems, which create a platform on which applications can be run, and manage the interface with data reading devices and peripherals such as printers, video monitors, etc.
- Applications, which are programs that accomplish specific tasks, such as spreadsheets, word processors, CAD programs, web browsers, etc.
A "computer program" is a set of statements or instructions to be used directly or indirectly in a computer in order to bring about a certain result.