Computer Chapter two - نسخة

7/23/2019 Computer Chapter two - نسخة

http://slidepdf.com/reader/full/computer-chapter-two- 1/65

Introduction to Computer Science

ByDr. Ahmed Taha

Lecturer, Computer Science Department,

Faculty of Computers & Informatics,

Benha University1



LOGO2



LOGO3



LOGO

Book Title:

New Perspectives on Computer Concepts,

2014, Comprehensive

Authors:

June Jamrich Parsons, Dan Oja

Publisher:

Course Technology;

Edition:

16 edition (January 30, 2013)

4



LOGO

Book Contents

# Chapter Title

1 Computers and Digital Basics

2 Computer Hardware

3 Computer Software

4 Operating Systems and File Management

5 Local Area Networks

6 The Internet

7 The Web and E-mail

8 Digital Media

9 The Computer Industry: History, Careers, and Ethics10 Information Systems Analysis and Design

11 Databases

12 Computer Programming

5



Computer Hardware

6


http://slidepdf.com/reader/full/computer-chapter-two- 7/65LOGO

Contents

Personal Computer Basics1

Microprocessors and Memory2

Storage Devices3

Input and Output Devices4

7



Personal ComputerBasics

8



Desktop Computer System Components

9



Desktop Computer System

10



The term peripheral device designates input, output, and

storage equipment that might be added to a computer

system to enhance its functionality.

Popular peripheral devices include printers, digital

cameras, scanners, game controllers, and speakers

Peripheral Devices

11



A desktop computer fits on a desk and runs on power

from an electrical wall outlet.

A portable computer is a small, lightweight personal

computer with input, output, storage, and processing

components integrated into a single unit that runs on

power supplied by an electrical outlet or a battery

Portable Computers

12



Portable Computers

13

Clamshell units are hinged with a

screen on top and a keyboard below.

The advantage of this form factor is

that the screen is protected when the

unit is closed.

Slate units have a screen, but no

physical keyboard. The screen accepts

touch input. These units are lighter and

smaller than their clamshell counterparts.



Microprocessorsand Memory

14



A microprocessor (simply a processor) is an integrated

circuit designed to process instructions.

It is the most important, and usually the most expensive,

component of a computer.

Microprocessor

15



It is the largest chip on the system board, although it

might be hidden under a cooling fan.

Microprocessor

16



A microprocessor ’s performance is affected by several factors:

Clock Speed

Bus Speed

Word Size

Cache Size

Instruction Set

Number of Cores

Processing Techniques

Microprocessor

17



Microprocessor Clock: a timing device that sets the pace for

executing instructions.

The speed of a microprocessor is specified in Gigahertz.

Gigahertz (GHz) means a billion cycles per second.

A cycle is the smallest unit of time in a microprocessor ’s

universe.

Every action a processor performs is measured by these

cycles.

Processor’ s Performance: Clock Speed

18

One Clock

Cycle



A microprocessor with 2.13 GHz means that the

microprocessor ’s clock operates at a speed of 2.13 billioncycles per second.

Clock speed comparisons are only valid when comparing

processors within the same chip family.

For example:

i7 1.87 GHz processor is faster than i7 1.6 GHz processor

i7 1.6 GHz processor is faster than the i5 2.4 GHz processor

Processor’ s Performance: Clock Speed

19



Processor’ s Performance: Number of Cores

A microprocessor that contains circuitry for more than one

processing unit is called a multi-core processor.

More cores usually produce faster performance.

20

The 2.4 GHz i5 processor has two

cores, giving it the equivalent of 4.8

GHz performance (2.4 x 2).

The 1.6 GHz i7 processor has four

cores, giving it the equivalent of 6.4

GHz performance (1.6 x 4).



LOGO

Processor’ s Performance: Front Side Bus

Front Side Bus (FSB) refers to the circuitry that

transports data to and from the microprocessor.

A fast FSB moves data quickly and allows the processor

to work at full capacity.

21

FSB speed is measured in

megahertz (one million cycles per

second).

Today’s computers have

FSB speeds ranging from 1000

MHz to 1800 MHz. Higher numbers

indicate faster FSB speeds.

Microprocessor

d a t a

FSB

Microprocessor

d a t a



LOGO

Processor’ s Performance: Cache Size

CPU cache is special high-speed memory that allows a

microprocessor to access data more rapidly than frommemory located elsewhere on the system board.

CPU cache is structured into several levels. Level 1 cache

(L1) is the fastest, whereas Level 2 (L2) and Level 3 (L3)are slightly slower.

Cache capacity is usually measured in megabytes.22



LOGO

Processor’ s Performance: Word Size

Word Size refers to the number of bits that a

microprocessor can manipulate at one time.

For example, a 64-bit processor has 64-bit registers and

processes 64 bits at a time.

A large word size gives processors the ability to handle

more data during each processing cycle.

Today’s personal computers typically contain 32-bit or 64-

bit processors

23



LOGO

Processor’ s Performance: Processing Techniques

Can a microprocessor execute more than one instruction

at a time?

24

Serial Processing Pipelining Processing Parallel Processing



LOGO

Companies producing Microprocessors

Today’s Popular Server, Desktop, and Mobile

Microprocessor Families

25



LOGO

Memory

RAM ROMRAM stands for Random AccessMemory

ROM stands for Read Only Memory

RAM is temporary memory (volatilememory)

ROM is permanent memory (non-volatile memory)

The data in RAM can be changed ordeleted

The instructions written in ROMcannot be changed or deleted

Instructions in Ram changecontinuously as different programs areexecuted and new data is processed

It is not possible to write newinformation or instructions in ROM

The instruction is written into the RAMat the time of execution The instructions written into ROM atmanufacturing time



LOGO

Random Access Memory

RAM (Random Access Memory) is a temporary holding

area for data, application program instructions, and theoperating system.

In a personal computer, RAM is usually several chips or

small circuit boards that plug into the system board within

the computer ’s system unit.

27

RAM is the “waiting room” for the

computer ’s processor.

Unlike disk storage, most RAM is

volatile, which means it requires

electrical power to hold data.



LOGO

Random Access Memory (RAM)

Dynamic RAM(DRAM)

• The main memory

in personal

computers is

DRAM.

• Dynamic indicates

that the memory

must be constantly

refreshed or it will

lose its contents

RAM

Static RAM(SRAM)

• It is typically used

for CPU caches.

• Static RAM is faster

and less volatilethan dynamic RAM,

but it requires more

power and is more

expensive



LOGO

Random Access Memory (RAM)

SRAM DRAM

SRAM stands for Static Random AccessMemory

DRAM stands for Dynamic Random Access Memory

It is typically used for CPU caches The main memory in personal

computers is DRAMIt is faster than DRAM It is slower than SRAM.

It is more expensive It is less expensive

It does not need to be power-refreshed

It has to be refreshed after each readoperation

It utilizes less power It utilizes more power



LOGO

Read Only Memory (ROM)

ROM (Read Only Memory) is a type of memory circuitry

that is housed in a single integrated circuit which isplugged into the system board.

The contents of ROM remain in place even when the

computer power is turned off .

30

Early ROM technologies were not

modifiable; updating ROM meant

physically replacing the chip



LOGO


ROM contains a small set of instructions and data called

the bootstrap loader

In a PC, the contents of ROM are sometimes referred to

as the BIOS (Basic Input/Output System)

31

The bootstrap loader ’s instructions

tell the computer how to access the

hard disk, find the operating

system, and load it into RAM.



LOGO


PROM EPROMPROM stands for Programmable Read-Only Memory

EPROM stands for Erasable Read-OnlyMemory

It is a programmable memory It is electronically programmablememory

The user can write instructions onPROM only once

The user can write instructions onEPROM many times.

The instructions written by the usercannot be erased from PROM

The instructions written by the usercan be erased from EPROM

If there is an error while writing on

PROM, it becomes unusable

If there is an error while writing on

EPROM, it can still be used againIt provides less usability asinstructions are written only once

It provides more usability asinstructions are written many times



LOGO

Virtual Memory

Virtual memory is a feature of an operating system (OS)

that allows a computer to compensate for shortages ofphysical memory by temporarily transferring pages of data

from random access memory (RAM) to disk storage.

33



LOGO

Storage Devices

34



LOGO

A data storage system has two main components: a

storage medium and a storage device.

Storage Basics

35

A storage medium is the disk,

tape, CD, DVD, paper, or othersubstance that contains data.

A storage device is the

mechanical device that records andretrieves data from a storage

medium.



LOGO

Three types of storage technologies are commonly used

for personal computers: magnetic, optical, and solid state

Each storage technology has its advantages and

disadvantages.

Storage Basics

36



LOGO

Magnetic storage stores data by magnetizing

microscopic particles on a disk or tape surface. Tape

The particles retain their magnetic orientation until that

orientation is changed, thereby making disks fairly

permanent but modifiable storage media.

Magnetic Storage Technology

37

Floppy diskHard disk Tape



LOGO

A hard disk drive contains one or more platters and their

associated read-write heads.

A hard disk platter is a flat, rigid disk made of aluminum or

glass and coated with magnetic iron oxide particles.

More platters mean more data storage capacity. The

platters rotate as a unit on a spindle, making thousands of

rotations per minute.

Hard disk platters are typically 3.5" in diameter , with

storage capacities ranging from 40 GB to 2 TB.

Hard Disks

38



LOGO

Hard Disks

39



LOGO

Hard Disks

40



LOGO

Hard Disks

41



LOGO

Hard Disks

42



LOGO

Each platter has a read-write head that hovers just a few

microinches above the surface.

A read-write head mechanism in the disk drive magnetizes

particles to write data, and senses the particles’ polarities to

read data.

Hard disk technology is the preferred type of main storage

for most personal computers because:

It provides lots of storage capacity.

It provides fast access to files.

A hard disk is economical.

Hard Disks

43



LOGO

Hard Disks

44



LOGO

External Hard Disks (Portable)

45

The storage capacity of your desktop or laptop computer

can be increased by adding a second hard disk drive.

Internal drives are inexpensive and can be easily installed

in a desktop computer ’s system unit.

External drives are slightly more expensive and connect

to a desktop or laptop computer using a cable.



LOGO

Floppy Disk

46

Floppy disks (also called floppies

or diskettes) is a type of diskstorage composed of a disk of thin

and flexible magnetic storage

medium, sealed in a rectangular

plastic carrier lined with fabric thatremoves dust particles.

This storage technology is no

longer used because a floppydisk’s 1.44 MB capacity is not

sufficient for today’s media-

intensive applications.



LOGO

Tapes

47

A tape is a magnetically coated strip of plastic on which

data can be encoded.

Tapes are similar to tapes used to store music.

Storing data on tapes is considerably cheaper than

storing data on disks.



LOGO

Tapes

48

Accessing data on tapes, however, is much slower than

accessing data on disks.

Tapes are sequential-access media, which means that to

get to a particular point on the tape, the tape must go

through all the preceding points



LOGO

CD, DVD, and Blu-ray technologies are classified as

optical storage, which stores data as microscopic lightand dark spots on the disc surface.

The dark spots are called pits. The lighter, non-pitted

surface areas of the disc are called lands.

Optical Storage Technology

49



LOGO

Optical drives contain a spindle that rotates the disc over

a laser lens.

The laser directs a beam of light toward the underside of

the disc.

The dark pits and light lands on the disc surface reflect

the light differently.

As the lens reads the disc, these differences are

translated into the 0s and 1s that represent Data


50



LOGO


51



LOGO


52



LOGO

Optical technologies are grouped into three categories:

read-only, recordable, and rewritable.


Recordable Rewritable

Read-only

Technology (ROM)

You cannot write to a

-ROM disc, which left

the factory with data

already on it. A -ROM

drive can read discs

but not write to them,

and has no use at all

for a blank disc.

Read-only

Recordable

Technology (R)

You can write to one

of these discs once

(provided you have

an -R drive). But

when you're done,

it's effectively a -

ROM disc

Rewritable

Technology (RW)

You can write to

these discs, erase

them, and write to

them again.

The term re-

recordable (RE) is

sometimes used

instead of rewritable



LOGO

CD (Compact Disc) technology was originally designed

to hold 74 minutes of recorded music.

The original CD standard was adapted for computer

storage with capacity for 650 MB of data.

Later improvements in CD standards increased the

capacity to 80 minutes of music or 700 MB of data.

CD (Compact Disc)

54



LOGO

DVD (Digital Video Disc or Digital Versatile Disc) is a

variation of CD technology that was originally designed asan alternative to VCRs, but was quickly adopted by the

computer industry to store data.

The initial DVD standard offered 4.7 GB (4,700 MB) ofdata storage.

A double layer DVD has two recordable layers on the

same side and can store 8.5 GB of data.

DVD (Digital Video Disc)

55



LOGO

Blu-ray is a high-capacity storage technology with a 25

GB capacity per layer.

The name Blu-ray is derived from the blue-violet colored

laser used to read data stored on Blu-ray discs.

DVD technology uses a red laser ; CD technology uses a

near infrared laser

Blu-ray

56



LOGO

Solid State Storage (sometimes called flash memory) is

a technology that stores data in erasable, rewritablecircuitry, rather than on spinning disks or streaming tape.

It is widely used in portable consumer devices, such as

digital cameras, portable media players, iPads, and cellphones.

It is also used as an alternative for hard disk storage in

some laptop computers.

Solid State Storage Technology

57



LOGO

Solid state storage contains a grid work of circuitry.

Each cell in the grid contains two transistors that act as

gates to hold the 1s and 0s that represent data

Very little power is required to open or close the gates,

which makes solid state storage ideal for battery-operated

devices, such as digital cameras and media players.


58



LOGO

Solid state storage has the following advantages:

Fast access to data because it includes no moving parts.

Very durable; it is virtually impervious to vibration, magnetic fields,

or extreme temperature fluctuations.

However, the capacity of solid state storage does notcurrently match that of hard disks.

The cost per megabyte of solid state storage is slightly

higher than for magnetic or optical storage.


59



LOGO

Several types of solid state storage are available to

today’s consumers: memory cards, solid state drives, andUSB flash drives.


60



LOGO

A memory card is a flat, solid state storage medium

commonly used to transfer files from digital cameras andmedia players to computers.

A card reader is a device that reads and writes data on

solid state storage.

Memory Cards

61



LOGO

A solid state drive (SSD) is a package of flash memory

that can be used as a substitute for a hard disk drive.

Some solid state drives are about the same size as a

microprocessor chip, whereas others are about the size of

a small hard disk drive.

Solid State Drive (SSD)

62



LOGO

A USB flash drive is a portable storage device that plugs

directly into a computer ’s system unit using a built-inconnector.

USB flash drives have capacities ranging from 16 MB to

256 GB.

Flash drives are slower than hard disk drives.

USB Flash Drives

63



LOGO

Advantages & Disadvantages of Different Storage Technology

64



Documents

Computer Chapter two - نسخة