COMPUTER ARCHITECTURE JC Harambearachchi

Recommended Text 1Computer Organization and Architecture by William Stallings 2Structured Computer Organisation Andrew S. Tanenbaum

A Computer is A programmable machine. It can execute or run a pre- recorded list of instructions which follow certain rules (a program). Modern computers are electronic and digital. The actual machinery -- wires, transistors, and circuits -- is called hardware; the instructions and data are called software.

fig computer Input process output

Computer System Hardware Software –OS –Application SW Live ware

1input operation 2processing operation-cpu 3storage operation-primary / secondry 4output operation 5Communication operations What are basic operations of a Computer ?

Components of a Computer System Computer hardware provides the physical mechanisms to process, store, and input /output data. Includes CPU, memory, I/O devices Software provides instructions to tell the hardware what tasks to perform. It includes system (eg Windows XP) and application (eg Excel) software Data in the computer may be representing numbers, characters, graphics etc but is always kept in a form that the hardware and software can manipulate.

central processing unit primary memory secondary storage input devices output devices communications devices I/O cards System Bus What are the major Hardware components of the computer ?

Keyboard pic mouse Input Hardware

cpu pic Memory chips pic Motherboard pic Process and memory Hardware

Hard drive Floppy Cd/dvd Storage Hardware

Monitor Speaker Printer Video card Sound card output Hardware

Modems pic Communication Hardware

System Software –Windows pic –Linux pic Device drivers Application softwaere –Word –Exel –ppt Software

Entertainment PERSONAL Education Productivty Specality –Word processing pic –Spread sheets –Database –Ppt –Quicken microsoft money Application Software types

Drawing Web page desin cad Application Software types

Block Diagram of a Computer Main Memory IOD IO Modules CPU

Computer Hardware

1Hardware- the CPU CPU performs actual processing of data, according to instructions from programs. Data and programs are stored in primary and secondary memory, and moved to and from CPU as required. Signals representing data and instructions travel between system components along electronic pathways, called buses. Capacity of bus is critical to system performance.

Central Processing Unit ( CPU) 1.Acting as the brain of the computer’ 2.Currently the Intel-Pentium microprocessor is the most common CPU though there are many types

Hardware - The Processor The CPU is a general purpose processor that performs data manipulation and/or transformation functions including computations, comparisons and data movement. The CPU consists of 3 main parts: –ALU - where arithmetic and logical operations performed –Control Unit - controls data movement and execution of instructions –Registers - small high speed storage areas

Components of a computer system

Computer Hardware

2Hardware - memory Memory - Purpose of memory is data storage. Two major types of memory : Primary memory - to hold data and instructions during processing –eg RAM. Relatively limited capacity and volatile Secondary memory - to provide permanent long term storage –eg hard disk. High capacity and non-volatile

Main Memory (RAM) 1.Different from disk storage 2.used to temporarily store Data 3.in modern computers memory is 512 MB.

Hardware- memory Digital computers deal with data in binary form - all data is represented using just two digits - 1 or 0. Letters and other symbols are assigned unique binary codes. Primary memory consists of a set of locations defined by sequentially numbered addresses. Each location contains a binary number that can be interpreted as data or an instruction.

Memory locations, using an 8 bit word  Memory locations are called words. Words are 8 bits (one byte) in size, or a multiple of 8. Common word sizes are 16, 32 and 64 bits.

Hardware - memory Memory is commonly measured in multiples of bits and bytes. 1 bit = 1 binary digit (0 or 1) byte = 8 bits 2.1KB = 1024 bytes = MB = 1024 KB= GB = 1024 MB = TB = 1024 GB = 2 40

Hardware - memory Secondary storage consists of non-volatile high-capacity devices to store programs and data not currently required by CPU. Hard and floppy disks, and tapes store data as magnetized spots. CD’s and DVD’s store data as pits or surface marks detectable by laser light.

3Hardware – I/O Input Devices collect & translate raw data into form useable by computer. e.g keyboard accepts letters and numbers and converts them to a binary code such as Unicode. Output devices produce results in useable form for user (or another device). e.g. monitor converts binary codes to characters and images, whilst modem converts digital data to analog form for transmission over telephone lines.

Hardware – I/O Peripherals 1Input Devices Mouse Keyboard 2Output Devices Monitor (VDU) Printer 3Secondary Storage Devices Hard Disk CD / DVD / Floppy

I/O Hardware

4Hardware - I/O Modules Interface between System Bus and other Peripherals example –Sound cards –Video cards –Network cards –PCI cards

5Hardware - System Bus series of electronic path ways and connecting other components of the computer.

Computer Main Memory Input Output Systems Interconnection Peripherals Communication lines Central Processing Unit Computer Structure - Top Level

Structure - The CPU Computer Arithmetic and Login Unit Control Unit Internal CPU Interconnection Registers CPU I/O Memory System Bus CPU

Types of computers Personal Computer –Microprocessor Mini computer Main frame Super computer

Types of computers supercomputer : An extremely fast computer that can perform hundreds of millions of instructions per second.supercomputer –IBM ASCI pic mainframe : A powerful multi-user computer capable of supporting many hundreds or thousands of users simultaneously.mainframe –Banks air lines vp2400 pic Work stations minicomputer : A multi-user computer capable of supporting from 10 to hundreds of users simultaneously.minicomputermulti-user –Designing, movies, Sun ws pic Microcomputers personal computer : A small, single-user computer based on a microprocessor.personal computeruser microprocessor –Desktop PC pic –Notebook pc (laptop) –PDAs palmtops Microcontrollers embeded computers

Server and client

What are Computer Ports ? Connection point examples 1.Serial port (Com) 2.Parallel Port 3.USB port 4.Ethernet Port

Basic concepts - communication Most modern computers no longer operate in isolation - they connect to other computers via modem or a network. To enable this communication, specialized hardware and software must be added to computers. In combination with other devices such as telephones, cabling, satellites, microwaves etc., a communications network is created

1Data processing 2Data storage 3Data movement 4Control What are Major functions of a Computer ?

Functional view Data Movement Apparatus Control Mechanism Data Storage Facility Data Processing Facility

Operations (1) Data movement –e.g. keyboard to screen Data Movement Apparatus Control Mechanism Data Storage Facility Data Processing Facility

Operations (2) Storage –e.g. Internet download to disk Data Movement Apparatus Control Mechanism Data Storage Facility Data Processing Facility

Operation (3) Processing from/to storage –e.g. updating bank statement Data Movement Apparatus Control Mechanism Data Storage Facility Data Processing Facility

Operation (4) Processing from storage to I/O –e.g. printing a bank statement Data Movement Apparatus Control Mechanism Data Storage Facility Data Processing Facility