What tells a computer what to do input or output

Unit 7. Evolution of computers

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Computer Hardware Basics

– any physical device or equipment used in or with a computer system (anything you can see and touch).

External hardware

• – any hardware device that is located outside the computer.
• – a piece of hardware device which is used to enter information to a computer for processing.
• Examples: keyboard, mouse, trackpad (or touchpad), touchscreen, joystick, microphone, light pen, webcam, speech input, etc.
  
• – a piece of hardware device that receives information from a computer.
• Examples: monitor, printer, scanner, speaker, display screen (tablet, smartphone …), projector, head phone, etc.

Internal hardware

• – any piece of hardware device that is located inside the computer.
• Examples: CPU, hard disk drive, ROM, RAM, etc.

Computer Software Basics

Computer software

• – a set of instructions or programs that tells a computer what to do or how to perform a specific task (computer software runs on hardware).
• Main types of software – systems software and application software.

Application software

• – a computer program that provides users with tools to accomplish a specific task.
• Examples of application software: word processing, spreadsheets, presentation, database management, Internet browsers, email programs, media players, accounting, pronunciation, translation, desktop publishing, enterprise, etc.

System Software

– it is designed to run a computer’s hardware and application software, and make the computer system available for use. It serves as the interface between hardware, application software, and the user.

• Main functions of system software – allocating system resources, managing storage space, storing and retrieval of files, providing security, etc.
• Main types of systems software – operating system, device driver, utility software, programming software, etc.

– a software that controls and coordinates the computer hardware devices and runs other software and applications on a computer. It is the main part of system software and a computer will not function without it.

• Main functions of an operating system – booting the computer, managing system resources (CPU, memory, storage devices, printer, etc.), managing files, handling input and output, executing and providing services for application software, etc.
• Examples of operating system: Microsoft Windows, Apple iOS, Android OS, macOS, Linux, etc.

– a software program that is designed to control a particular hardware device that is attached to a computer.

• The main purpose of device driver – it acts as a translator between the hardware device and operating systems or applications that use it.
• It instructs computer on how to communicate with the device by translating the operating system’s instructions into a language that a device can understand in order to perform the necessary task.
• Examples of device driver: printer driver, display driver, USB driver, sound card driver, motherboard driver, ROM driver, etc.

– a type of system software that helps set up, analyze, configure, strengthen, maintain a computer and performs a very specific task (e.g. antivirus software, backup software, memory tester, screen saver, etc.).

Quick revise

A computer is an information processing machine. Computers process data to produce information.

The sets of instructions that humans give computers are called programs or software.

Software that carries out a particular type of task for a user is often called applications software.

There are many reasons for using computers:

• Computers can work much faster than humans;
• Computers never get tired or need a rest;
• Computers can do jobs that it would be dangerous for a human to do;
• Computers can store large amounts of information in a very small space;
• Computers can find information very quickly;
• Computers never lose or misplace information.

The three stages of computing are input, processing and output.

A computer works through these stages by ‘running’ a program. A program is a set of step-by-step instructions which tells the computer exactly what to do with input in order to produce the required output.

Input

• This stage of computing is concerned with getting the data needed by the program into the computer.
• Input devices are used to do this.
• The most commonly used input devices are the mouse and the keyboard.

Processing

• The instructions about what to do with the input are contained in a program.
• During the processing stage the computer follows these instructions using the data which has just been input.
• What the computer produces at the end of this stage is called output.

Output

• This stage of computing is concerned with producing the processed data as information in a form that is useful to the user.
• Output devices are used to do this.
• The most commonly used output devices are the screen, which is also called a monitor or visual display unit (VDU) and the printer.

Data & Information

• Data is any collection of numbers, characters or other symbols that has been coded into a format that can be input into a computer and processed.
• Data on its own has no meaning, or context.
• It is only after processing by a computer that data takes on a context and becomes information.
• There are many types of data
• All data ends up being stored as a series of numbers inside the computer.
• Data can be input to the computer by the user in many different ways.
• The main types of data that can be input into a computer and processed are numeric, text, dates, graphics and sound.

Computer Systems

• Hardware is the name that is given to any part of a computer that you can actually touch.
• An individual piece of hardware is called a device.
• The basic hardware of any computer consists of a central processing unit (CPU) along with input, output and backing storage devices.

The central processing unit (CPU)

• This is the part of the computer where the searching and sorting of data, calculating and decision-making goes on.
• The CPU contains the Main Memory, the Control Unit and the Arithmetic and Logic Unit (ALU).

An introduction to processors

This video provides an explanation of the parts within a processor and the functions of each part. The Central Processing Unit contains the Arithmetic Logic Unit, which carries out all arithmetic operations plus AND/OR functions, and the Control Unit, where decisions are made about collecting and sending data.

What device tells the computer what to do?

What controls the input and output in computer?