BASIC COMPUTER ARCHITECTURE

INPUT DEVICES PRESENTED BY:

OUTPUT DEVICES PRESENTED BY:

MEMOMY PRESENTED BY:

CPU PRESENTED BY:

Introduction

In this presentation, we’ll discuss various input, output, and CPU(central processing unit),memory designed to meet the various needs and lifestyles of people.

What Peripheral Devices Suit Your Needs?

Input Devices Output Devices Storage Devices

Input Devices

• Input device captures information and translates it into a form that can be processed and used by other parts of your computer. KeyboardsPointing devicesGame controllersScannersStylusesMicrophonesDigital camerasWeb cams

Input Devices

The keyboard is the most common input device. Types of keyboards include:• Wireless• Multimedia and one-touch access• Portable keyboards for PDAs

                     

          

                     

          

Types of Input Devices

                     

          

                     

          

Pointing Devices

Pointing devices are mainly used to choose and enter commands

Pointing devices tend to have PS/2 connectors or USB connectors• PS/2 connector fits into a PS/2 port, which a small round

socket with small holes that fit the pins on the connector• USB connectors fit into USB ports, and these are small

rectangular openings on the back or front of your computer, or even on your keyboard or monitor

Pointing Devices

Various pointing devices are available Types of pointing devices:

• MouseMechanical mouseOptical mouseWireless mouse

• Trackball• Touchpad• Pointing stick

Game Controller

Game controllers are used mainly to play games Types of gaming devices

• Gamepads• Joysticks• Gaming wheels• Force feed

                     

          

Specialized Input Devices

Other types of input devices include:• Scanners• Styluses• Microphones• Digital cameras• Web cams

Scanner

•Scanner is a light sensitive device that helps you copy or capture images, photos, and artwork that exist on paper. Types of scanners include:Flatbed

                                                                   

Styluses

• Stylus is an input device consisting of a thin stick that uses pressure to enter information or to click and point

• Styluses are used with:PDAs Tablet PCsGraphics tablets

                                                                   

Microphones

• Microphones are used to input audio

• Three main types of microphones are:Desktop microphonesHeadsetsDirectional microphones

• Speech recognition is increasingly being included in application software

                     

          

                                                                   

                     

          

Digital Cameras

Digital cameras are used to: • Download images to a computer• Post pictures to the Web• Produce videos

Resolution is measured in megapixels Higher the resolution, better the

image quality, but the more expensive the camera

Web Cams

• Web cam is a video camera that can be used to take images for uploading to the Web

Output Devices

Output devices take information within your computer and present it to you in a form that you can understand

Main output devices: Monitors Printers Speakers

Flat Panel Display Devices

Devices with flat-panel displays• Tablet PCs

• PDAs

• Cellular phones

• Desktop computers

                     

          

Monitors

CRTs Flat-panel displays

Gas plasma LCD (liquid crystal display)

Passive matrix Active matrix

Called TFT (thin film transistor) Separate transistor for every pixel

Printers

Inkjet – most popular Makes images by forcing droplets

through nozzles Top speed is 20 pages per minute

Laser Forms images using an

electrostatic process Prints between 3 and 30 pages per

minute

                     

          

Printers - Cont

Resolution of a printer is the number of dots per inch (dpi) it produces.

Higher the resolution, better the image, and usually the more costly the printer

                     

          

Printers - Cont.

Multifunction printer:• Scan, copy, fax, and print

• Can be either inkjet or laser

• Cost less than buying individual units

• Take up less desk space

Speakers

A speaker is a device that produces computer output as sound

Speakers are common devices in computer systems Examples include:• Built-in speaker• Two-device set speakers• Surround sound speakers

                     

          

                     

          

CPU: 3 Major Components

ALU (arithmetic logic unit) Performs calculations and comparisons (data changed)

CU (control unit): performs fetch/execute cycle Functions:

Moves data to and from CPU registers and other hardware components (no change in data)

Accesses program instructions and issues commands to the ALU

Subparts: Memory management unit: supervises fetching instructions

and data I/O Interface: sometimes combined with memory

management unit as Bust Interface Unit Registers

Example: Program counter (PC) or instruction pointer determines next instruction for execution

System Block Diagram

Concept of Registers

Small, permanent storage locations within the CPU used for a particular purpose

Manipulated directly by the Control Unit Wired for specific function Size in bits or bytes (not MB like memory) Can hold data, an address or an

instruction How many registers does the LMC have?

Registers Use of Registers

Scratchpad for currently executing program Holds data needed quickly or frequently

Stores information about status of CPU and currently executing program Address of next program instruction Signals from external devices

General Purpose Registers User-visible registers Hold intermediate results or data values, e.g.,

loop counters Equivalent to LMC’s calculator Typically several dozen in current CPUs

Special-Purpose Registers

Program Count Register (PC) Also called instruction pointer

Instruction Register (IR) Stores instruction fetched from memory

Memory Address Register (MAR) Memory Data Register (MDR) Status Registers

Status of CPU and currently executing program

Flags (one bit Boolean variable) to track condition like arithmetic carry and overflow, power failure, internal computer error

Register Operations Stores values from other locations

(registers and memory) Addition and subtraction Shift or rotate data Test contents for conditions such as zero

or positive

Operation of Memory

Each memory location has a unique address

Address from an instruction is copied to the MAR which finds the location in memory

CPU determines if it is a store or retrieval Transfer takes place between the MDR

and memory MDR is a two way register

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Relationship between MAR,

MDR and MemoryAddress

Data

MAR-MDR Example

Visual Analogy of Memory

Individual Memory Cell

Memory Capacity Determined by two factors

1. Number of bits in the MAR LMC = 100 (00 to 99) 2K where K = width of the register in bits

2. Size of the address portion of the instruction 4 bits allows 16 locations 8 bits allows 256 locations 32 bits allows 4,294,967,296 or 4 GB

Important for performance Insufficient memory can cause a processor

to work at 50% below performance

RAM: Random Access Memory

DRAM (Dynamic RAM) Most common, cheap Volatile: must be refreshed (recharged

with power) 1000’s of times each second SRAM (static RAM)

Faster than DRAM and more expensive than DRAM

Volatile Frequently small amount used in cache

memory for high-speed access used

ROM - Read Only Memory

Non-volatile memory to hold software that is not expected to change over the life of the system

Magnetic core memory EEPROM

Electrically Erasable Programmable ROM

Slower and less flexible than Flash ROM Flash ROM

Faster than disks but more expensive Uses

BIOS: initial boot instructions and diagnostics

Digital cameras

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