04-introduction to hw_view

8/13/2019 04-Introduction to HW_view

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Introduction toComputer Hardware

DCS201- Computer Science

By:Dilum Bandara


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Dilum Bandara - CSE 2

Outline

p Parts of a computer

p The Traditional view of a computer system

n Single User

n Multi User

p Von Neumann's architecture

p Components in detail

n CPU, Motherboard, Memory, Input/Output,Storage


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What is a computer

p Its a machine

p Able to execute a finite set of Instructions.

p Able to process data according to those

instructions.


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Courtesy by Microsoft Encarta Encyclopaedia


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Courtesy by Upgrading & Repairing a PC by Scott Mueller


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The Traditional View - Single UserComputer System

PrintersPrinters

KeyboardKeyboard

VDU(Display)

VDU(Display)

CPUCPU

Disk DriveDisk Drive

TapeDrive

TapeDrive

Input / OutputInput / Output StorageStorage

RAM ROM

MemoryMemory

Communicates witheveryone & manage

the system


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TheTraditional View - Multi UserComputer System

PrintersPrinters

KeyboardKeyboard

VDUVDU


TapeDrive

TapeDrive

Several terminalsSeveral terminals

KeyboardKeyboard

VDUVDU

KeyboardKeyboard

VDUVDU

CPUCPU

RAM ROM

MemoryMemory


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Major components of a computersystem

p With the introduction of personalcomputers & miniaturization, some ofthese devices went inside a single box


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Evolution

PrintersPrinters

KeyboardKeyboard

VDU

(Display)

VDU

(Display)

CPUCPU


Tape

Drive

Tape

Drive

Input / OutputInput / Output StorageStorage

RAM ROM

MemoryMemory

What we usually callas the CPU in a

personal computer


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Types of computers

p Super computers

p Mainframes

p Personal computers

p Laptops

p PDAs - Personal Digital Assistants


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Main frames

Courtesy by IBM


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Super computers


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Modern Computer Systems

p Include many more devices thantraditional computers

n Video sub-system (Graphic adapters)

n Multimedia devices

p Sound cards

p CD-ROM/DVD-ROM, etc.

n MODEMS

n NETWORK adaptors

n Communication port (Serial port)n Printer interface (parallel port)


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System components

p Motherboard

p CPU

p Memory

p VGA cardp Display

p Hard disk

p Floppy drive

p CD-ROM Drive

p Case/Chassis

p Power supply

p Keyboard

p Mousep Sound card

p Speakers

p Modem

p Printer

p Scanner


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The Motherboard

p The most important component in a PC

p Also called the main board

p Is a large circuit board that the processor,

memory & other electronic componentsare attached

p It provides the path through which theprocessor communicates with memory,

disks, expansion cards, keyboard & othercomponents attached to the motherboard


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Memory

p Memory is the workspace for theprocessor

p Is a temporary storage area whereprogram & data being operated

p Consist of an array of consecutiveMemory locations

p Each location can store one piece of data

p Each location has a unique address


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0002

0001

0000

FFFF

FFFE

FFFD

12

01

04

Memory cont


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Memory cont

p The CPU uses memory to store Instructions(programs) &Data (characters & digits)

p The CPU access (read or write) only a single

memory location at a time

p It is practically not possible to connect eachmemory location directly to the CPU using a

separate set of electrical connections

p Therefore all memory locations are connected

using the same set of shared electricalconnections called the Memory Bus


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Buses in computers


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Buses

p Bus is a set of electrical connections(parallel set of wires)

p 3 types

1. Address Bus

2. Control Bus

3. Data Bus

n All these 3 types of buses are enclosedwithin the memory bus


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Communicating with memory

MemoryMemory

Address BusAddress Bus

Control BusControl Bus

RD/ WR signalsRD/ WR signals

Data BusData Bus


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Types of Memories

1. ROM Read only memory2. PROM Programmable Read Only Memory

3. UVEPROM - UV Erasable PROM

4. EEPROM Electrical Erasable PROM5. FLASH ROM

6. RWM (Read Write Memory)

7. SRAM (Static RAM)

8. DRAM (Dynamic RAM)


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Types of Memories cont..

1. ROM Read only memoryn Can only be read, cannot be written to..

n Contents are written at the time ofmanufacture

n Stores initial start-up programsn Not economical to produce in small quantities


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Types of Memories cont.

2. PROM Programmable Read OnlyMemories

n Same as ROMS, but contents can be writtenonce, using special equipment.

3. UVEPROM - UV Erasable PROM

n Same as PROM but contents can be erased byshining an UV light on the IC

n Require special equipment to program


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4. EEPROM Electrical Erasable PROMn Same as UVEPROM except that contents can

be erased by applying a special high voltageto some of the signals

5. FLASH ROMn A special type of EEPROM that can be erased

or programmed while in the circuit.

n Once programmed the contents remains

unchanged even after a power failuren Commonly used in modern PCs


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6. RWM (Read Write Memory)n Traditionally known as RAM ( Random Access

Memory)

n Contents are erased when power is

disconnected.n Two major types SRAM and DRAM


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7. SRAM (Static RAM)n More reliable but expensive

n Typically used for cache memories.

n More expensive and consumes more electricalpower

8. DRAM (Dynamic RAM)n Contents are stored as charges in a small

capacitor

n Capacitor must be re-charged from time to

typen Bulk of the PC memory is made out of DRAM


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Memory Modules



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Connecting memory & microprocessor

CPU

ROM

RAM 1

RAM 2

MemoryController


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Memory Hierarchyp Modern CPUs are much faster than the

speed of memory

p The memory has to be organized in such away that its slowness does not reduce the

performance of the overall system

p Some memory types are fast but expensive

n Registers, SRAM

p Some other types are cheap but slow

n DRAM


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Memory Hierarchy contp The objective of having a memory

hierarchy is to have a memory system:

n with a sufficient speed

n with a sufficient capacity

n and as cheap as possible

p The main idea is to use:

n a limited capacity of the fast but expensive

memory types

n and a larger capacity of slow but cheap memorytypes


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Traditional memory hierarchy

Secondary storage

Mainmemory

Reg.Spe

ed

C

o

st

S

i

ze


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Modern memory hierarchy

Secondary storage

Mainmemory

Reg.S

pe

ed

C

o

st

S

i

ze

Cache

memory


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Cache Memory

p Consist of small amount of memory (fewKBs in size) which is faster than the mainmemory

p Cache is used by the CPU to store

frequently used instructions & datap Sometimes multiple levels of cache is used

n L1 Cache Very fast, usually within CPU itself

n L2 Cache Slower than L1, but faster than

main memory


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CPU - Central Processing Unit

p Also called the Microprocessor

p The brain or engine of the computer

p CPU performs both arithmetic operations

& logic operations plus controllingp Is the most expensive single component

of a PC


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Type of processors

p 1st generation 8080/8086/8088

p 2nd generation 80286

p 3rd generation 80386 (DX/SX)

p 4th generation 80486 (SX/DX/DX2/DX4)

p 5th generation Pentium/AMD K5

p 6th generation Pentium Pro/AMD K6

p 7th generation Pentium IV/AMD Athlon


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Heating & Cooling

p Modern processors generate excessiveheat

p It is not just enough to have a heat sink

p Therefore cooling fans are used

p The size of heat sink & fan is gettinglarger with each new microprocessor


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Passive heat sinks



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Active Heat sinks



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Components of the CPU

Registers

Controlunit

ALU

i h i & i i ( )


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Arithmetic & Logic Unit (ALU)

p is the data processing unit of the CPUp Arithmetic unit is capable of performing

arithmetic operations

p Logic unit performs logical operations

ALU


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Control Unit

p This unit controls the operation of the CPU

Control Unit

i


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Registers

p Is a type of memory located inside the CPUp Can hold a single piece of data

p This data is useful in both data processing& control functionalities.

p Several types of CPU register

n Program counter (PC)

n Instruction register (IR)

n Accumulator

n Flag register

n General purpose register

I l S f h CPU


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Internal Structure of the CPU

A

E

D

C

B

ALU

AddressBU

S

Control Unit

IR

FLAG

ALU

PC

+1

DataBUS

CTRLBUS

M ki th CPUf t


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Making the CPU faster

p Having an effective memory hierarchy.p There are several other methods of

making the CPU faster:

1. Instruction pre-fetching

2. Instruction Pipelining

I t ti f t hi


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Instruction pre-fetching

p When one instruction is in the executionstage, the next instruction is fetched tothe CPU.

I t ti f t hi


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Instruction pre-fetching

Fetch Execute

Fetch Execute

Fetch Execute

Instruction 1

Instruction 2

Instruction 3

time

Fetch Execute

Fetch Execute

FetchExecute

Instruction 1

Instruction 2

Instruction 3

I t ti Pi li i


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Instruction Pipelining

p Extends the idea of instruction pre-fetching

p The term pipelining is used because thisprocess is similar to an industrial

assembly line where output of one step isfed to the next step as input

I t ti Pi li i t


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Instruction Pipelining cont

p Pipelining divides the instruction cycle in toa series of sub-operations & a separatesegment of the CPU is dedicated to onesub-operation

p Therefore at any given moment, a numberof instructions are executed inside the CPU,each in a different stage or a sub-operation

I i th ll f


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Improving the overall performance

p Select a type of memory with compatiblespeed with the CPU.

n A slower memory will keep the CPU idling

p Some CPUs (e.g. the Pentium) usedifferent speeds for its internal operationsand for communication with memory.

n FSB (Front Side Bus) speed is related to

memory access.n Usual has the range from 133MHz to 533MHz

CPUsupportchips


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CPU support chips

p CPU support chips are used in suchoperations to improve overall performance

1. Direct Memory Access (DMA) controllers

2. Interrupt Controllers (PIC)

3. Real-Time Clock (RTC)

4. Other devices

n Disk controllers

n Communication controllers

n Display controllers

DirectMemoryAccess (DMA)


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Direct Memory Access (DMA)

p DMA controllern Provide a way of bypassing the CPU when

transferring data between memory and IO(Input/Output) devices.

DMAcontroller cont


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DMA controller cont

CPU

IO

device

Memory

DMACont..

CPU

IOdevice

Memory

EnhancementsinmodernCPUs


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Enhancements in modern CPUs

p Hyper Threading (HT)p Dual Core

HyperThreading (HT)


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Hyper Threading (HT)

p Was introduced with the Intel Pentium 4p Allows 2 threads to run at the same time

with limitations

n A single resource cant be used by the same

threadn Example:

n While 1st thread is working with integers(integer portion of ALU) 2nd thread can workon floating point numbers (floating point unit

in ALU)

HyperThreading(HT)cont


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Hyper Threading (HT) cont

p The operating Systems feels that there are2 logical CPUs

p Achieved through

n a mix of shared, replicated & partitioned chip

resources, such as registers, maths units &cache memory

HT Technology requires a computersystemwith:


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system with:

p A processor that supports HT technologyp HT technology enabled chipset HT

p HI technology enabled BIOS

p HT technology enabled/optimized

operating system

DualCore


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Dual Core

p Introduced by IBM Power4 how ever AMDbrought it to the consumer market

p Combines 2 independent processors &their respective caches onto a single

silicon chipp Provide better performance improvement

than HT

DualCorecont


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Dual Core cont

Courtesy by www.gen-x-pc.com

Commodity processor vendors &Products


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Products

p Intel x86, Pentiums, Xeon, Itaniump AMD K5/6, Athlon, Duron, Athlon XP,

Athlon Opteron

p Cyrix

p Apple G5

Other CPUs


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Other CPUs

p

SPARCp Motorola

p Z80

p Northstar

p Etc.

What is thebestCPU?


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What is the best CPU?

p

It depends on how you look at itp Need to consider the use of the system

p Cannot purely depend on the Clock Speedanymore

p Common CPUs

n Intel Pentium, AMD, Cyrix

Processor packaging


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Processor packaging

p

SIP Single Inline Package

p DIP Dual Inline package

p PGA Pin Grid Array

p SEG Single Edge Contact

PGA


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PGA


CPUsockets


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CPU sockets


Morecloserview


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More closer view


SEG


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SEG


VGA Card


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p

Video Graphics Arrayp is used to generate pictures & text that

you see on the displaying device.

p Either available as a separate expansion

card or integrated into the motherboard.p Enhancements

n VGA, SVGA, VESA SVGA

n VESA - Video Electronic Standards Association

Display (Video) Controller


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p y( )

VGA card classifications


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p

based on:n Video Processor

n Video memory

p Card type

n PCI Peripheral Component Interconnectn AGP Accelerated Graphics port

n PCIE - Peripheral Component InterconnectExpress


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Display


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p y

p

Produces the visible outputp Different types:

n CRT Cathode Ray Tube

n TFT Thin Film Transistor

n LCD - Liquid Crystal Displayp Categorized based on:

n Screen size

n Colour depth/Resolution


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Power supply


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ppy

p

Power supplyn Primary source of power for the system

n Provide different voltages

p+12V, -12V, +5V, -5V, +3.3 V, -3.3V


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UPS


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p

Stands for Uninterrupted Power Supplyp These devices would continue to provide

power in case of the power failure

p UPS can be find in different capacities &

typesp Capacity is give in VA

p 2 major types

n Standby UPS

n Online UPS

Standby UPS


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p Are the most common & used mainly withPCs

p Are cheaper as well

Online UPS


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p Are use for high end applications

p These are much more robust &can handle large capacity

Secondary storage


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p Includes Hard disks, floppy disks, CD-ROMs, ZIP disks, etc.

p Hard Disk

n Contains a rigid, disk shaped platter

n

Constructed using aluminium or glassp Then a magnetic coating is applied

n High capacity & high speed


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Types of hard disks connectors


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p IDE Integrated Device Electronics

p SCSI Small Computer System Interface

p Serial ATA Serial AT AttachmentInterface

IDE


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SCSI


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Platters, Tracks & Sectors


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Floppy Disk


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Courtesy by www.exploratorium.edu

Floppy Drive


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Optical Storage


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p Make use of light instead of magnetism.

p Different forms of optical storage:

n CD-ROM

n CD-R Recordable

n

CD-RW Rewritable

n DVD digital versatile/video disk

n DVD-R/DVD-RW


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Geometry of a CD


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Pit Land

0 1

Components of a CD-ROM drive


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Other Input/Output Devices


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p Keyboard

p Mouse

p Barcode readers

p Printers

Keyboard


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Mouse


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Other Readers

B d R d


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p Barcode Readers

p Optical Character Recognition (OCR)

p Magnetic Character Recognition (MCR)

Barcode Readers


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Printer

Diff t t


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pDifferent types

n Impact

pDot-matrix

pDaisy wheel

p

Tape/Ribbonn Non impact

pBubble jet

p Ink jet

pLaser

Impact Printers


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Laser Printer concept


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04-introduction to hw_view

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