Computer software, or just software is a general term used to describe a collection of computer programs, procedures and documentation that perform some tasks on a computer system

Computer software is often regarded as anything but hardware, meaning that the "hard" are the parts that are tangible (able to hold) while the "soft" part is the intangible objects inside the computer.

Software encompasses an extremely wide array of products and technologies developed using different techniques like programming languages, scripting languages etc. The types of software include web pages developed by technologies like HTML, PHP, Perl, JSP, ASP.NET, XML, and desktop applications like Microsoft Word, OpenOffice developed by technologies like C, C++, Java, C#, etc.

Software usually runs on an underlying operating system (which is a software also) like Microsoft Windows, Linux (running GNOME and KDE), Sun Solaris etc. Software also includes video games like the Super Mario, Grand Theft Auto for personal computers or video game consoles.

Also a software usually runs on a software platform which can either be provided by the operating system or by operating system independent platforms like Java and .NET.

Software written for one platform is usually unable to run on other platforms so that for instance, Microsoft Windows software will not be able to run on Mac OS because of the differences relating to the platforms and their own standards. These applications can work using software porting, interpreters or re-writing the source code for the specific platform.

Computer software is so called to distinguish it from computer hardware, which encompasses the physical interconnections and devices required to store and execute (or run) the software. At the lowest level, software consists of a machine language specific to an individual processor.

A machine language consists of groups of binary values signifying processor instructions which change the state of the computer from its preceding state. Software is an ordered sequence of instructions for changing the state of the computer hardware in a particular sequence.

It is usually written in high-level programming languages that are easier and more efficient for humans to use (closer to natural language) than machine language. High-level languages are compiled or interpreted into machine language object code.

Software may also be written in an assembly language, essentially, a mnemonic representation of a machine language using a natural language alphabet. Assembly language must be assembled into object code via an assembler.