Computer programmable machine. The two principal characteristics of a computer are:
- It can execute a prerecorded list of instructions (a program).
Modern computers are electronic and digital. The actual machinery -- wires, transistors, and circuits -- is called hardware; the instructions and data are called software.
All general-purpose computers require the following hardware components:
In addition to these components, many others make it possible for the basic components to work together efficiently. For example, every computer requires a bus that transmits data from one part of the computer to another.
Computers can be generally classified by size and power as follows, though there is considerable overlap:
What is Software?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.
The term includes:
- Application software such as word processors which perform productive tasks for users.
- Firmware which is software programmed resident to electrically programmable memory devices on board mainboards or other types of integrated hardware carriers.
- Middleware which controls and co-ordinates distributed systems.
- System software such as operating systems, which interface with hardware to provide the necessary services for application software.
- Software testing is a domain independent of development and programming. It consists of various methods to test and declare a software product fit before it can be launched for use by either an individual or a group. Many tests on functionality, performance and appearance are conducted by modern testers with various tools such as QTP, Load runner, Black box testing etc to edit a checklist of requirements against the developed code. ISTQB is a certification that is in demand for engineers who want to pursue a career in testing.
- Testware which is an umbrella term or container term for all utilities and application software that serve in combination for testing a software package but not necessarily may optionally contribute to operational purposes. As such, testware is not a standing configuration but merely a working environment for application software or subsets thereof.
Software includes websites, programs, video games, etc. that are coded by programming languages like C, C++, etc.
"Software" is sometimes used in a broader context to mean anything which is not hardware but which is used with hardware, such as film, tapes and records.Relationship to computer hardware:
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 that 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.
The term "software" was first used in this sense by John W. Tukey in 1958. In computer science and software engineering, computer software is all computer programs. The theory that is the basis for most modern software was first proposed by Alan Turing in his 1935 essay Computable numbers with an application to the Entscheidungsproblem.
Types of software:
Practical computer systems divide software systems into three major classes: system software, programming software and application software, although the distinction is arbitrary, and often blurred.System software
System software helps run the computer hardware and computer system. It includes:
- device drivers,
- operating systems,
- servers,
- utilities,
- windowing systems,
The purpose of systems software is to unburden the applications programmer from the details of the particular computer complex being used, including such accessory devices as communications, printers, readers, displays, keyboards, etc. And also to partition the computer's resources such as memory and processor time in a safe and stable manner.
Programming software
Programming software usually provides tools to assist a programmer in writing computer programs, and software using different programming languages in a more convenient way. The tools include:
- compilers,
- debuggers,
- interpreters,
- linkers,
- text editors,
An Integrated development environment (IDE) is a single application that attempts to manage all these functions.
Application software
Application software allows end users to accomplish one or more specific (not directly computer development related) tasks. Typical applications include:
- industrial automation,
- business software,
- computer games,
- telecommunications, (i.e., the internet and everything that flows on it)
- databases,
- educational software,
- medical software,
computer hardware as the electronic, magnetic, and electric devices that carry out the computing functions. Hardware is the physical components of the computer like microprocessor, hard disks, RAM, and motherboard. The peripheral devices such as monitor, mouse, keyboard, printer, and speakers can also be included in the list of hardware parts.
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