Hardware

Basic Computer System Central Processing Unit Input Devices Output Devices Backing Storage Devices

Basic Computer System Processor Processor –to process data Memory Memory –RAM stores programs and data when in use –ROM stores essential programs and data permanently Input devices Input devices –a way of getting data into the computer Output devices Output devices –so the computer can show us what it has done Backing storage devices Backing storage devices –to store programs and data when not in use

Central Processing Unit Input Device Output Device Backing Storage memory processor

Memory Central Processing Unit Memory Processor RAMROM RAM is random access memory RAM memory is used to store the programs being run and the files being used. RAM memory is lost when power is switched off. ROM is read only memory ROM memory is fixed memory which is placed there by the manufacturer and is used to store programs which are involved in the running of the computer system. ROM memory is not lost when power is switched off.

Memory The memory is split up into memory locations which store the data. Each memory location is like a pigeon hole where the data will be stored as bits. Each memory location has its own memory address. The number of bits stored in each memory location is called the memory word size. This can be 16, 24 or 32 bits. This is also the number of bits that are transferred at a time between the memory and the processor. Processor Memory Central Processing Unit

Processor The processor has 3 parts ALU The Arithmetic And Logic Unit, as its name suggests carries out the calculations and decision making Control Unit The Control Unit is in charge of the flow of data and the order and timing of processing instructions Registers Registers are temporary memory locations within the processor which hold data and information while it is being processed. Processor Memory Central Processing Unit ALU Control Unit Registers

Central Processing Unit Processor Memory ALU Control Unit Registers RAMROM

Input Devices Computers are digital devices which work with numbers - binary numbers. Computers are digital devices which work with numbers - binary numbers. All information used by a computer is held as a pattern of ones and zeros. All information used by a computer is held as a pattern of ones and zeros. Input devices are used to change information we understand into data the computer can process - binary numbers. Input devices are used to change information we understand into data the computer can process - binary numbers.

Input KeyBoard

Input Keyboard

Input Concept Keyboard

Input Mouse

Input Touch Pad

Input Tracker Ball

Input Joystick

Input Devices Keyboard Keyboard Concept Keyboard Concept Keyboard Mouse Mouse Touch Pad Touch Pad Tracker Ball Tracker Ball Joystick Joystick

Input Graphics Tablet

Input Touch Sensitive Screen

Input Touch Screen

Input Digital Camera

Input Digital Video Camera

Input Web Camera

Input Microphone

Input Sound Card

Input Scanner

Input Hand Held Scanner

Input Devices Graphics Tablet Graphics Tablet Touch Sensitive Screen Touch Sensitive Screen Digital Camera Digital Camera Microphone Microphone Sound Card Sound Card Scanner Scanner

Input Bar Code

Input OMR

Input OCR

Input MICR

Input Punched Card

Input Punched Tape

Input Magnetic Stripe

Input Devices Bar Code Reader Bar Code Reader Optical Mark Reader Optical Mark Reader Optical Character Reader Optical Character Reader Magnetic Ink Character Reader Magnetic Ink Character Reader Punched Card Reader Punched Card Reader Punched Tape Reader Punched Tape Reader Magnetic Stripe Reader Magnetic Stripe Reader

Output Devices Computers are digital devices which work with numbers - binary numbers. Computers are digital devices which work with numbers - binary numbers. All information used by a computer is held as a pattern of ones and zeros. All information used by a computer is held as a pattern of ones and zeros. Output devices are used to change data the computer has processed - binary numbers into information we can understand. Output devices are used to change data the computer has processed - binary numbers into information we can understand.

Output Monitor

Output Cathode Ray Tube

Output Liquid Crystal Display

Output Thin Film Transistor

Output Graphics Card

Output Ink Jet Printer

Output Laser Printer

Output Drum Plotter

Output Flat Bed Plotter

Output Sound Card

Output Speakers

Output Headphones

Output Robot Arm

Output Devices Monitor Monitor –CRT cathode ray tube –LCD liquid crystal display –TFT thin film transistor Graphics Card Graphics Card Printer Printer –Ink Jet Printer –Laser Printer Plotter Plotter –Drum –Flat bed

Output Devices Sound Card Sound Card Speakers Speakers Headphones Headphones Robot Arm Robot Arm

Backing Storage Devices Computers are digital devices which work with numbers - binary numbers. Computers are digital devices which work with numbers - binary numbers. All information used by a computer is held as a pattern of ones and zeros. All information used by a computer is held as a pattern of ones and zeros. Backing storage devices are used to permanently store computer data - binary numbers. Backing storage devices are used to permanently store computer data - binary numbers.

Backing Storage Units Bit(binary digit)1 or 0 Bit(binary digit)1 or 0 Byte (by eight)8 bits Byte (by eight)8 bits Kilobyte (Kb)1024 bytes Kilobyte (Kb)1024 bytes almost a thousand bytes Megabyte (Mb)1024 kilobytes Megabyte (Mb)1024 kilobytes almost a million bytes Gigabyte (Gb)1024 megabytes Gigabyte (Gb)1024 megabytes almost a thousand, million bytes Terabyte (Tb)1024 gigabytes Terabyte (Tb)1024 gigabytes almost a million, million bytes

Backing Storage Units 10x10X10X10 = 10 4 = x10X10X10 = 10 4 = This is a nice round number in decimal. This is a nice round number in decimal. It is easy for us to work with. It is easy for us to work with. 2x2x2x2x2x2x2x2x2x2= 2 10 = x2x2x2x2x2x2x2x2x2= 2 10 = 1024 This is a nice round number in binary. This is a nice round number in binary. It is easy to arrange in a computer system. It is easy to arrange in a computer system.

Bits and Bytes We use binary to store: Numbers Numbers Text Text Graphics Graphics Video Video Sound Sound Programs Programs

Storing Numbers Numbers are converted to in binary. Numbers are converted to in binary. 1 Bin is 1 Dec 10 Bin is 2 Dec 1000 Bin is 8 Dec 1001 Bin is9 Dec 1111 Bin is15 Dec Bin is255 Dec

Binary to Decimal BinaryDecimal

Integers These are whole numbers which have no decimal part. These are whole numbers which have no decimal part. They can be easily converted to binary numbers. They can be easily converted to binary numbers. 1 byte can only store numbers up to byte can only store numbers up to 255. The computer can perform calculations on integers very quickly and efficiently. The computer can perform calculations on integers very quickly and efficiently.

Storing Text Text is stored using a special set of codes called ASCII. Text is stored using a special set of codes called ASCII. American Standard Code for Information Interchange American Standard Code for Information Interchange Each symbol (letter, number etc) has its own unique code Each symbol (letter, number etc) has its own unique code a is 97, A is 65, ? is 63, 3 is 51 a is 97, A is 65, ? is 63, 3 is 51 One ASCII code is one byte long (eight bits). One ASCII code is one byte long (eight bits).

Storing Graphics Black and White graphics are stored using pixels (Picture Elements). Black and White graphics are stored using pixels (Picture Elements). The image to be stored is broken up into dots, each dot is a pixel. The image to be stored is broken up into dots, each dot is a pixel. The pixels are 1 for black and 0 for white. The pixels are 1 for black and 0 for white.

Calculating Image Storage A black and white graphic uses 1 bit to store each pixel A black and white graphic uses 1 bit to store each pixel If the image is 300 pixels by 200 pixels then it is stored using a total of 300 x 200 bits i.e bits If the image is 300 pixels by 200 pixels then it is stored using a total of 300 x 200 bits i.e bits Divide this by 8 to give the number of bytes Divide this by 8 to give the number of bytes –60000/8 = 7500 Divide this by 1024 to give the number of kilobytes Divide this by 1024 to give the number of kilobytes –7500/1024 = Round up to ensure you have enough storage Round up to ensure you have enough storage –7.324 = 8 Kb

Storage Floppy Disc

Storage Magnetic Disc

Storage Magnetic Tape

Storage Smart Card

Storage CD ROM

Storage DVD

Storage USB Flash Drive

Backing Storage Devices Floppy Disc1.44Mb Floppy Disc1.44Mb Magnetic DiscSeveral Gb Magnetic DiscSeveral Gb Magnetic TapeSeveral Gb Magnetic TapeSeveral Gb Smart Card few Kb Smart Card few Kb Compact Disc 650 Mb Compact Disc 650 Mb –CD ROM CD R CD RW Digital Versatile Disc 4.2 Gb – 17 Gb Digital Versatile Disc 4.2 Gb – 17 Gb –DVD ROM DVD R DVD RW DVD RAM USB Flash Drive16 – 256 Mb USB Flash Drive16 – 256 Mb

Backing Storage Devices Magnetic Magnetic –Floppy Disc –Hard Disc –Tape Optical Optical –CDROM CDR CDRW –DVD DVD R DVD RW DVD RAM Flash Flash –USB drives

Hardware