Computer Hardware

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Hardware Designed to Meet Your Needs

(r7/19/07 rdm)

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Objectives

Identify different types of memory and storage media, and understand the unique properties of each

Identify different types of input and output devices and how they are used to meet a variety of personal and professional needs

Understand the decision-making process involved in purchasing a computer system

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201 Jeopardy

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Integrated Circuits Transistor

– Composed of semi conducting material that opens or closes a circuit

Integrate circuits– Used to store and process bits and bytes in today’s

computers

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Inside the Computer Central processing unit

– Group of integrated circuits that perform processing

Motherboard– Primary circuit board of a computing device

Random access memory– Temporary, or volatile, storage

System bus (aka front side bus)

– Parallel pathways between the CPU and RAM

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The Central Processing Unit (CPU)Manipulating data as defined by programmed

instructions Arithmetic/logic unit (ALU)

– Contains the circuitry to carry out instructions

Control unit

– Sequentially accesses and decodes program instructions

– Coordinates flow of data in and out of ALU

Processor Registers– Small amount of very fast memory

(different than cache memory)

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The Machine Cycle

Execution of an instruction involves two phases:

Instruction phase

– Step 1: Fetch instruction

– Step 2: Decode instruction

Execution Phase

– Step 3: Execute instruction

– Step 4: Store results

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CPU Characteristics System clock

– Produces a series of electronic pulses at a predetermined rate called clock speed

Clock speed

– Measured in megahertz (MHz) or gigahertz (GHz)

Wordlength

– Number of bits that a CPU can process at once

Millions of instructions per second (MIPS)

– Amount of time it takes to execute an instruction

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Multiprocessing and Parallel Processing

Multiprocessing – Uses two or more CPUs in a single computer

Dual-core– Two independent processors inside a single CPU core

(a single integrated circuit)

Coprocessors– Special-purpose processors that speed processing

(i.e. math or graphics coprocessor)

Parallel processing– Links several microprocessors to operate in parallel

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Storage on the Motherboard

RAM (now mostly DIMMs)

– Set of chips grouped together on a circuit board

– Many types: DRAM, SDRAM, DDR-SDRAM, etc.

Cache Memory

– Highspeed memory that can be accessed more rapidly than RAM

– Three levels of cache: L1, L2, and L3

Video RAM (VRAM)

– Used to store image data for a computer display

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Storage on the Motherboard (Continued)

Read-only memory (ROM)

– Provides permanent storage for data and instructions

BIOS

– Stores hardware configuration information and boot program

Flash BIOS

– Intended to store data permanently

– Can be updated

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Secondary Storage Technologies Storage device

– Drive that reads and writes data

Storage media

– Objects that hold the data (disks)

Storage capacity

– Maximum amount of bytes medium can hold

Access time

– Time it takes for a request for data to be fulfilled by the device

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Magnetic Media: Disks and Tapes

Magnetic storage devices – Store bits and bytes more permanently than

RAM

Microdrives– Tiny hard drives that store gigabytes of data

on a disk one or two inches in size

Floppy disks – Portable, low-capacity (1.44 MB) storage

medium

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Magnetic Media: Disks and Tapes (continued) High capacity diskettes

– Stores up to 83 times more data

Storage area network or SAN– Links together many storage devices over a

network and treats them as one large disk.

RAID or redundant array of independent disks– Uses a multiple system of disks that can

reconstruct the data if any disk were to go bad

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Optical Storage Uses optical laser to burn pits into the surface of a

highly reflective disk surface

Compact disk read-only memory (CD-ROM)

– First optical media to be mass-marketed to the general public

Digital video disk (DVD)

– Backward-compatible with CD-ROMs

CD-RW

– Most popular format for rewritable CDs

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Flash Drives and Cards Flash memory card

– A chip that is nonvolatile

– Small and can be easily modified and reprogrammed

– Sometimes referred to as media cards

USB flash drive

– Small, flash memory modules

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Output Devices

Display resolution

– Measure of the amount of pixels on the screen

Liquid crystal display (LCD), or flat panel display

– Quickly displacing CRT (cathode-ray tube) displays

LCD projectors

– Used for projecting presentations from your computer onto a larger screen

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Special-Purpose I/O Devices

Many designed to support scientific and medical research

Computer scientists and musicians at the MIT Media Lab

– Experimenting with special input devices

Virtual reality headset

– Can project output in the form of three-dimensional color images

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Expansion

USB – Provides connection to computer for data

transfer– Provides power line

Firewire – Competes with USB as standard for connecting

devices to PCs

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So you need to buy a computer!

Where do you begin?

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Researching a Computer Purchase

To learn about computer type and platform

– www.cnet.com– www.zdnet.com

To learn about manufacturers

– Computer shopper magazine

– MacWorld magazine

– www.gateway.com

– www.dell.com

– www.apple.com

– www.lenovo.com/us/en

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Portability versus Power When planning the purchase of a computer system

– Consider portability

– Analyze your own computer style and needs

– Balance portability with power and capacity

Interoperability

– Consider how your device will interact with other computer systems

– Will you be connecting to a corporate network

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Choosing a Manufacturer and Model Apple computer users have it easy

– Only decision is model

IBM-compatible users

– Need to compare specifications and prices from different manufacturers

– Need to choose a processor, and the amount of memory and storage

Very important

– Warranty

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Choosing Peripherals What types best suit your needs?

If preference is keyboard for text input

– Consider an ergonomic design

What type of printing will you be doing?

Do you need professional quality output?

Will you be printing digital photos?

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Making the Purchase Computer systems

– Can be purchased online, over the phone, or in a local computer store

Purchasing online from the manufacturer

– Provides custom configuration options

Computer store shoppers

– Can take the unit home

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Summary

When selecting a computer system

– Analyze your specific computing needs

– Select a computer type and platform that will support those needs