Internal hardware of a computer Learning Objectives Learn

Internal hardware of a computer Learning Objectives • Learn how the processor works • Learn about the different types of memory and what memory is used for. • Learn how buses ae used to pass data and instructions • Learn the difference between von Neumann and Harvard Architecture

Internal hardware of a computer Components Animation link https: //prezi. com/sb 5 cg_6 wybtn/the-parts-of-a-computer-andwhich-one-you-should-choose/ Main components are: • Processor (CPU) • Main Memory (RAM) • ROM • Buses • Input/output controllers • Hard Drive • Sound card • Graphics Card

Internal hardware of a computer Components Central Processing unit Bus Processor Main Memory Input/Output

Internal hardware of a computer Components Central Processing unit • • • The brain of the system Executes programs A big finite state machine Typical processor contains 100, 000 transistors Moore’s law – number of components integrated into a single chip doubles every 18 -24 months • Synced by clock speek of up to billions of instructions per second • Can have multiple cores • Prime manufacturers are Intel and AMD

Internal hardware of a computer Components Main Memory • • • Also known as ROM, RAM or IAS (Immediate access store) Mainly used to store program instructions and data Integrated onto bigger boards to store up to 16 gig in 64 bit computers ROM – Read only memory RAM – Random Access Memory EEPROM – Electrically erasable programmable read only memory RAM has fast accesss via memory addresses All programs and data is loaded into RAM before execution RAM is volatile.

Internal hardware of a computer Components Main Memory - RAM • • • RAM has fast access via memory addresses Made of millions of cells which each has its own address All programs and data is loaded into RAM before execution More RAM means more applications can be loaded in. RAM is volatile. APPLICATIONS LIBRARY PROGRAMS UTILITY PROGRAMS OPERATING SYSTEM

Internal hardware of a computer Components Main Memory - ROM • • Read only memory Non-Volatile Contains the boot up instructions of a PC Contains the BIOS

Internal hardware of a computer Components Main Memory – Addressable Memory • All memory cells are addressable. • Memory map shows allocation of data and applications to memory. • Memory addresses usually shown in Hexadecimal. APPLICATIONS LIBRARY PROGRAMS UTILITY PROGRAMS OPERATING SYSTEM 87 FF 83 FF 8200 8000

Internal hardware of a computer Components Buses • Microscopic parallel wires connecting up componenets • Data Bus • Bi-direction bus consisting of 32 -64 wires (depending on the word length of the computer) • Carries data to and fro memory, processor and the I/O controllers • Address bus • One directional bus consisting of 32 -64 wires • Carries addresses of instructions or location of data in the memory. • Word length determines how many addressable cells you can access – modern computers could have 264 addresses

Internal hardware of a computer Components Buses • Microscopic parallel wires connecting up componenets • Control Bus • Bi-directional bus that sends control signals to all the registers, data and address buses • Controls access to the data and address buses. Making sure that the data is going the right way. • Sends the clock pulse round the system.

Internal hardware of a computer Components I/O Controllers • • Linked to the ports on the back of the motherboard. Acts as an intermediary between the CPU and the IO Devices Handles data flow between CPU and device. Translates signals from device into ones understood by the processor • Responds slowly so buffers data in order so that the processor does not have to wait for device.

Internal hardware of a computer Computer architectures Stored program concept Ø Proposed by John von Neumann and Alan Turing Ø A program must be resident in main memory to be executed Ø machine code instructions are fetched, one after another, from main memory in sequence and are executed, one at a time in the processor.

Internal hardware of a computer Computer architectures Von Neumann stored program computer Ø A serial machine Ø Instructions are fetched one after anaother Ø Single memory shared between program instructions and data. Ø Data and instructions travel along a shared data bus. Harvard stored program computer Ø Separate instruction and data memories Ø Separate instruction and data buses Ø Still functions as a serial computer ØUse more in mobile devices Harvard Vs Von Neumann No sharing resources with accessing data and instructions so the performance speed of a Harvard infrastructure is better.

Exercises 1) You have a budget of £ 2000. What is the best computer you can buy with that money. 2) In your research you need to talked about the individual component and what some of the figures mean – for instance clock speed, RAM, etc and how they affect the performance. 3) Come up with a couple of choices and justify the best one. 4) What purpose have you built your computer for? 5) Present your findings to the class in a Power Point.