Computer Structure

Mr Arthur

Aims of Lesson 1

1. 5 Box Diagram of a Computer System

2. Main Memory V Backing Storage

5 Box Diagram

Main Memory

Random Access Memory Where programs are stored

temporarily while the computer is on

Volatile Memory = The contents of RAM is lost when the computer is switched off

Read Only Memory The contents of ROM are

stored permanently and cannot be edited

Programs are written to ROM during manufacture

Bootstrap Loader is stored in ROM and loads up the remainder of the OS

The Main Memory is required to store parts of programs whilst in use by the processor

Lesson Starter

1. I have an image that is 3 inches by 4 inches with a Resolution of 500dpi. Calculate the storage requirements.

2. What does RAM and ROM stand for?

3. What is the difference between RAM and ROM?

Aims of Lesson 2

Last Lesson

1. 5 Box Diagram of a Computer System

2. Main Memory V Backing Storage

Today’s Lesson

1. Backing Storage1. Magnetic

2. Optical

3. Serial Access

4. Direct Access

Backing Storage

A Backing Storage device is a piece of hardware that is used to store data permanently when the computer is switched off

Magnetic Hard Disk Magnetic Tape USB Memory Stick

Optical CDROM/R/RW DVDROM/R/RW

Sequential Access = This is Backing Storage where you access data in a particular order

Direct Access = This Backing Storage allows you to access data in any order

Lesson Starter

1. What is the purpose of Backing Storage?

2. List 4 examples of Backing Storage devices

3. What is the difference between Sequential and Direct data access?

Aims of Lesson 3

Last Lesson

1. 5 Box Diagram of a Computer System

2. Main Memory

3. Backing Storage

Today’s Lesson

1. The Processor

Lesson Starter

1. What is the purpose of purpose of the processor?

2. What is the measure of processor speed?

The Processor

The processor or Central Processing Unit is the brain of the computer where all the decision making, calculations etc are carried out

We send instructions (programs) to the processor to get the computer to do something

Processor speed (clock speed) is measure in how many millions of instructions the processor can process per second (typically 3-4Ghz)

Clock speed is one of the main measures of computer performance

Parts of the Processor Control Unit

Manages the fetching and executing of programs held in RAM

Makes sure programs are processed in the correct order

Arithmetic Logic Unit Performs + - X / calculations Makes AND, OR, NOT and IF decisions Handles FOR, loop untils

Registers Storage locations on the processor chip to

temporarily store instructions

Lesson Starter

1. List the 3 parts of the processor

2. Which part of the processor makes sure programs are processed in the correct order and manages the timing of processing?

Computer Comparison

Type RAM Hard Disk Processor Peripherals

Palmtop 256Mb 1Gb (Solid State) 500-800MHz StylusTouch SensitiveMonitor

Laptop 3Gb RAM 320GB 2.2 GHz possibly dual core

Touch PadLCD/TFT Monitor

Desktop 4Gb RAM 500Gb 3.2Ghz possibly quad core

Mouse, Keyboard, LCD Monitor

Mainframe Approx 32Gb RAM

8Tb or more 3.2Ghz possible 16 processors or more

EMBEDDED SYSTEM = A processor inside another device, for example, a microwave, sky + box.

Arrangements - Computer Structure Description of the purpose of a processor List the parts of a processor as ALU, control unit and registers Representation of the structure of a computer in the form of a simple

five box diagram representing: input devices, processor, main memory, output devices, and backing storage

Distinction between main memory and backing storage Description of the features and uses of RAM and ROM Description of the uses of embedded, palmtop, laptop, desktop and

mainframe computers Comparison of features of embedded, palmtop, laptop, desktop and

mainframe computers: type and speed of processor, size of main memory, backing storage, input and output devices

Description of clock speed as a simple indicator of system performance