One can purchase a complete set of computer hardware components-hard disks, CPU, memory modules, motherboards, video display unit, keyboard etc-and interconnect them to produce a computer. This computer would show evidence of life such as a blinking cursor on its screen, but no meaningful work e.g banks transactions, examination processing, checking email, browsing the internet, playing music, etc can be done with the computer. To power the computer hardware to do useful work, one must add to it another layer of resources known as computer software. To introduce computer software to the beginning is the aim of this article.
What is Computer Program?
A computer software is a sequence of instructions written to be followed by the CPU to perform a specific task. The writer of the program is called a computer programmer.
The same program may be expressed in several equivalent forms or languages. A program in the form it was written by the programmer is called a source code or a source program. For the CPU to follow the program, the program must be in the native language of the CPU. This native language is called the machine languages of the particular CPU.
What is Computer Software?
A computer software is a set of computer programs and possibly data held in computer storage, such that the processor may execute the programs to serve some specific purpose.
Hierarchy of languages for expressing software:
MICROCODE
MACHINE LANGUAGE
ASSEMBLY LANGUAGE
HIGH LEVEL PROGRAMMING LANGUAGE
EXECUTION MODELS