Chapter 1- components and types of a computer system

Hardware

the physical parts of a computer

Software

the programs and other operating information used by a computer.

Motherboard

A circuit board that contains all of the computer system's main components.

RAM (Random Access Memory)

is a memory chip in a computer which holds all programs and data when they are in use.

ROM (Read Only Memory)

Chips that contain programming code and cannot be erased.

Internal hard disk drive

Stores data that is not instantly needed for an indefinite time. It also stores programmes and is used commonly to back up data.

CPU (central processing unit)

The central processing unit that is generally made from a single integrated circuit that performs all the processing and calculations.

Fetch-Execute cycle

• Fetch (retrieve) next instruction from memory • Decode (translate) instruction to work out what it is • Execute (carry out) the instruction

BIOS (basic input/output system)

Firmware that can control much of a computer's input/output functions, such as communication with the keyboard and the monitor.

CMOS (complementary metal-oxide semiconductor)

A type of non-volatile RAM that holds information about the most basic parts of your PC

OS (Operating System)

An operating system is a system software that manages the general operation of a computer system.

Roles of the OS

● Provides security and prevents unauthorised access to a system ● Allows users to load, run and store applications. Also resolve errors occurring applications ● Decided what should be loaded and deleted from memory ● Helping save, organise, find and delete files ● Manages input, output and backing devices ● Helps the user interact with the computer through a user interface.

CLI (Command Line Interface)

is a user interface to a computer's operating system or an application in which the user responds to a visual prompt by typing in a command on a specified line, receives a response back from the system, and then enters another command, and so forth.

GUI (Graphical User Interface)

A type of interface that allows users to interact with electronic devices through graphical icons and visual indicators such as secondary notation, as opposed to text-based interfaces, typed command labels or text navigation.

phablet

A device that combines the features of a smartphone with a tablet.

mainframe computer

A large, multi-user computer commonly used in large businesses and government agencies; more powerful than a minicomputer.

CAT (computer assisted translation)

a type of language translator that uses software in the translation process

Holography

technique used to make a 3-D image

Input device examples

Keyboard, mouse, speaker, touchscreen, storage device, scanner, microphone

Output device examples

Monitor, printer, storage device, speakers, projector

Keyboard Examples

QWERTY, concept, numeric

Trackerball

A pointing device where a ball on top of the device moves the cursor. Ideal for environments with little space. Users are less likely to suffer injuries such as RSI.

DDE

Direct Data Entry

Magnetic Stripe Reader

Reads data from a special magnetic stripe on a card when it is swiped

Contactless card reader

debit or credit cards that allow customers to pay for items without entering a PIN; a small chip emits radio waves

Chip and PIN readers

Reads the chip inserted in a card which contains information. The user then is asked to input a PIN to access the information.

Optical Mark Recognition (OMR)

Input devices that reads simple multiple-choice style answers by looking for marks on the paper.

Optical Character Recognition (OCR)

scanning text printed on paper and translating the images into words

barcode reader

An input device that reads barcodes.

Quick Response (QR)

a type of barcode made up of a matrix of filled in dark squares on a lighter background

CRT Monitor (Cathode Ray Tube)

desktop monitor that contains a cathode-ray tube

Thin Film Transistor (TFT)

A technology for LCD displays in which transistors are positioned at each pixel.

LCD monitor

A computer monitor that takes advantage of the polarizing properties of liquid crystals to produce images on a screen

LED monitor

Type of monitor which uses LED backlighting to illuminate the colours on the screen.

OLED (Organic Light-emitting Diode) monitor

A type of monitor that uses a thin LED layer or film between two grids of electrodes and does not use backlighting.

laser printer

A printer that produces images using the same technology as copier machines.

inkjet printer

A type of printer that uses a nonimpact process. Ink is squirted from nozzles as they pass over the media.

dot-matrix printer

A type of impact printer that uses small pins to strike an inked ribbon to produce tiny dots on the paper.

3-D printers

A printer that creates objects by adding layers of material onto one another. Also known as additive manufacturing.