1 - overview of computers

8/12/2019 1 - Overview of Computers

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Computer Concepts

Introduction to ComputersMr. John Oliver P. Brioso

IAS - IT Department

Far Eastern University


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Data Processing

datainformation

processing

storage


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Data Processing

Data- raw fact, e.g. name, age, sex, score

Information - process data, e.g. number of students,average age,

number of male students, highest score in a quiz

Data Processing

The manipulation of raw data into a more useful form

called information.The modern name of paperwork and involvescollection, processing and distributing of facts andfigures to achieve a desired result.


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Data Processing Cycle

1. Input- initial data is entered.

2. Processing- input data is changed and is

usually combined with other information.3. Store- input data and results are stored forfuture use

4. Output- Results are collected


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Basic Data ProcessingActivities

Recording

Storing

retrievingselecting/classifying

sorting

computing


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Types of Data Processing

1. Manual Data Processing.The processing ofdata manually or through mechanical devices.

2. Electronic Data Processing.The processingof data through the use of computers.


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Methods of Data Processing

1. Batch Processing

2. On-Line Processing3. Real-Time Processing

4. Distributed Processing


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1. Batch Processing. Data are collected by

groups to permit convenient, efficient andserial processing.

2. On-Line Processing. Uses device directlyconnected to the CPU either for data entry or

inquiry purposes.


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3. Real-Time Processing. Has a capability of fast response toobtain data from an activity or aphysical process, performcomputations and return a response fast enough to affect the

outcome of the activity or process.

4. Distributed Processing. Generally consists of remote terinalslinked to a large central computer systems to help the userconduct inquiries about accounts, process jobs or other dataprocessing operations.


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is an electronic device designed to manipulatedata so that useful information can begenerated.

What is a Computer?

is an electronic device designed to acceptdata, process data based on stored instructions,store data so that useful information can be

generated.


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Characteristics of a Computer

1. It is a machine.

2. It is electronic.

3. It is automatic.

4. It can manipulate data.

5. It has a memory.

6. It has logic functions.


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Capabilities of a Computer

1. Speed

2. Repetitiveness

3. Accuracy

4. Logical operations

5. Store and recall information

6. Self-checking

7. Self-operating


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Limitations of a Computer

1. The computer cannot generate information on itsown.

2. A computer cannot correct wrong instructions.

3. A computer cannot come out with an originaldecision.

4. A computer cannot derive meanings from objects

5. Dependence on prepared instructions


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Classification of Computers

oAccording to purposeGeneral PurposeSpecific Purpose

o According to data handledAnalogDigitalHybrid

oAccording to capacitySuper computersMainframeMidrangeMini-computersMicrocomputers


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General Purpose.Handles variety of different problems and to meet different needs(e.g. varied business applications such as payroll, accounts receivable,inventory control, budgeting and sales analysis)

Specific Purpose.Handles specific problem or to perform a specific task. (e.g. thoseused for collecting highway tolls, airline reservations, satellitetracking, air traffic control and industrial process control).


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Analog computersComputers commonly used for scientific and engineering problems,

particularly in chemical industries, electric power plants, and petroleumrefineries.

Digital computers

Digital computers are computers that specialize in counting or discretevalues such as business systems.

Hybrid computersMachines that incorporate in a single computer both the analog and digital

features. These computers are used in working out special types of

problems in science and various areas of engineering, such as spacevehicle simulations and training of astronauts.


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Super ComputersThese are the biggest and fastest machines today where numerical

computations are carried out at speeds of up to 50 million operationsper second.

Mainframes These computers are the ultimate in sophistication, flexibility and

speed. These are very expensive machines and their main concern is to prove

their cost effectiveness. These computers are valuable to the larger firms which can provide

both skilled programmers and continuous applications, involvingthousands of employees and hundreds of thousands of customeraccounts on a daily basis.


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Midrange computersThese computers provide greater operating speed, larger memorycapacity, and high-speed input-output devices than the mini-computers and microcomputers.

It have a unique feature called virtual memory by which the mainmemory capacity is made to appear larger than the actual size.

Mini-ComputersThese are increasingly powerful and do almost anything that large

computers do, only more slowly and at much lower cost.

This makes it ideal for small companies where capacity and speed ofoperations is not highly critical.


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MicrocomputersSometimes called a SINGLE-CHIP PROCESSOR or a

SYSTEM-ON-A-CHIP, the microcomputers is a digitalcomputer system that uses a microprocessor (the CPU

on a chip), a programmable ROM and a RAM. Basicallydesigned for hobbyist.

notebook computerslow-end functional computers (cheap PCs)fully-powered PCs

workstations


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Computer Description

A mainframe is a big, powerful, expensive computer that can support manyusers at the same time. Large businesses and organizations use mainframes.

Capacity: Enormous - the capacity of several hundred or even thousands ofPCs

Speed: Very fast - much, much faster than a PC

Cost: Very, very expensive - can usually only be afforded by large organizations

Users: Only used by large businesses and organizations


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A PC is apersonal computer, originally designed by IBM way back in

1981. Many different companies make PCs, but all of them are IBM-compatible. What this means, according to Bill Gates, is that they will allrun Microsoft Windows.

Capacity:Average hard disk size is 20 GB to 80 GB

Speed: Fast. Average speed is from 1 GHz to 3 GHz

Cost: Fairly inexpensive - under $1,000 - and getting cheaper every day!

Users: Just about everyone uses a PC! Homes, offices, schools


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Developed by Apple, a Macintosh is a computer, but it is NOT a PC.Macs have a

different operating system and use their own software andhardware.

Capacity:Average hard disk size is 20 GB to 80 GB

Speed: Fast. Average speed is from 500 MHz to 2 GHz

Cost: Fairly inexpensive, but usually more than an equivalent PC

Users: Just about everyone, especially in the education and design

fields


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A network is a group of computers that are connected so that they can shareequipment and information. Most people on a network use workstations, which aresimply PCs that are connected to the network. A server is a central computer whereusers on the network can save their files and information.

Capacity: (Workstation) Same as a PC, only needs an inexpensive network card(Server) Greater than a PC, often more than 100 GE

Speed: (Workstation) Same as a PC (Server) Generally faster than a PC, may usemultiple CPUs

Cost: (Workstation) Same as a PC (Server) More expensive than a PC but not ascostly as a mainframe

Users: (Workstation) People in a networked office or organization (Server) Generally a

network administrator or engineer


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A laptop, or notebook, is a lighter and more portable version of

a PC or Mac that can run on batteries.Capacity:Average hard disk size is 10 GB to 40 GB

Speed: Fast, but slightly less than a PC. Average speed is from700 MHz to 2 GHz

Cost: Fairly inexpensive, but more than an equivalent PC

Users: People on the move, especially business people and

students


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A PDA (Personal Data Assistant) is a handheld computer that is

generally used tokeep track of appointments and addresses.

Capacity: Much smaller than a PC - 8 MB to 64 MB of storagespace

Speed: Much slower than a PC - 8 MHz to 266 MHz

Cost: Expensive when compared to the capacities of a PC

Users: Business people and others who need to be organized


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Parts of a Computer

Component Description

Case or System Unit The main computer box, technically known as the system unit, is the mostimportant part of a computer. It contains the guts and brains of the computer.The system unit contains a lot of holes or ports where you plug in the rest of thecomputer system.

Monitor The monitor resembles a television set, and is where the computer displaysinformation.

Keyboard The keyboard is the thing you type on to tell your computer what to do.

Mouse Like the keyboard, the mouse is another input device that you use tocommunicate with your computer.

Speakers Most computers can make sounds, just like a stereo system. In fact, you caneven listen to audio CDs on most computers or watch DVDs.

Printer A printer is where a computer writes down information or output, onto paper, ora hardcopy.

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The Front of a Computer Case

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Item Description

System Unit or Computer

Case

A plastic or metal case with slots, buttons, and lights in the front andholes in the back. This is the most important part of a computerbecause it contains the Central Processing Unit (CPU). The system unitdirects the computer, performs calculations, and stores information.

Floppy Drive Reads and writes to 3 - inch floppy disks. A floppy disk can storeabout 1.5 MB of informationabout as much as a novel.

Hard Drive The computers main, long-term storing device. Unlike floppy disks andCD-ROMs, you typically cannot remove a hard disk.

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CDROM or DVD Drive CD-ROMs and DVDs for your computer can store lots of information and look exactly likeCDs for your stereo and DVDs for your home DVD player.

The only read difference between a CD-ROM and a DVD is how much information theycan store. A CD-ROM and a DVD can store at least 700 MB of information, while a DVDcan store much moreup to 4.7 GB or 9.4 GB on a dual-layer DVD.

Zip Drive A special type of disk drive that can read and write to Zip disks. A Zip disk is a lot like afloppy disk, although they are faster and can store more informationfrom 100 to 250MB.

Tape Backup A device that you can use to store backups, or copies, of the information on a computers

hard drive.

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Keyboard The keyboard is the thing you type on to tell your computer what to do.

Mouse Like the keyboard, the mouse is another input device that you use tocommunicate with your computer.

Scanner Scanners work like photocopiers, except the image is translated into a digitalimage in your computer rather than copied onto paper.

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Monitor The monitor resembles a television set, and is where the computer displaysinformation.

Speakers If visible, your computer speakers are similar to those on a stereo system (or at

least a cheap stereo system). They allow your computer to play sounds.

Printer A printer is where a computer writes down information or output, onto paper, ora hardcopy.

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Whats Inside a Computer Case?

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Motherboard

Central Processing

Unit (CPU)

Random Access

Memory (RAM)

ROM-BIOSExpansion Slot

Expansion Card

PCMCIA Cards

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Item Description

Motherboard The main piece of circuitry in a computer. Everything connects to or is wired to themotherboard.

Central Processing

Unit (CPU)

The computers brain or heart, the CPU is a computers main chip. The CPU is

really nothing more than an incredibly fast and powerful calculator.

Random Access

Memory (RAM)

A computers temporary storage place, where it gets its work done. For example,

when you use a word processor to type a letter, the letter is stored in thecomputers memory.

ROM-BIOS A computers ROM-BIOS (stands for Read Only MemoryBasic Input/OutputSystem) is a special chip with instructions for the computer to communicate withother hardware parts.

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Expansion Slot An expansion slot lets you add more features and capabilities to acomputer by plugging in expansion cards.

Expansion Card A card that allows you to expand your computers capabilities, such as

modem card, a network card, a video card, or a sound card.

PCMCIA Cards Notebook computers are too small to use expansion cards, so they usespecial credit-card sized PCMCIA cards instead. You plug in a PCMCIAcard, or PC Card, into a notebook computer to give it more features andcapabilities. Nobodys getting tested o this, but PCMCIA stands for

Present Computer Memory Card International Association.

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The Back of a Computer (Ports)

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Port Icon Description

The keyboard and mouse jacks look identical on most PCs, solook for colors and icons to help you with plugging in thesedevices.

Serial (or COM) ports are a very versatile type of port. Some ofthe things you can plug into a serial port include: a mouse,modem, scanner, or digital camera. Most computers have twoserial ports: COM1 and COM2.

You plug your printer into the parallel, or printer, port. Manynewer printers may use a USB port.

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Designed to replace older Serial and Parallel ports, the USB(Universal Serial Bus) can connect computers with a number ofdevices, such as printers, keyboards, mice, scanners, digitalcameras, PDAs, and more. Better yet, the USB port supportsplug-and-play, so you can simply plug in a USB device and startusing it. USB 1 ports can transfer information at a speed up to12 Mbps (Megabytes per Second). Newer USB 2 ports cantransfer information at a speed up to 480 Mbps. Mostcomputers come with two USB ports.

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You plug your monitor into the video port.

Plug in your speakers or headphone into the

Line Out jack.

The Line In jack allows you to listen to yourcomputer using a stereo system.

You plug a microphone into this jack torecord sounds on your computer.

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Port Icon DescriptionIf you have a joystick, musical (MIDIMusicalInstrument Digital Interface) keyboard, or othergaming device, this is where you plug it in.

The phone or modem jack is where you plug yourcomputer into a phone line.

You can connect your computer to a network byplugging in an Ethernet cable in this port.

An SCSI port is one of the fastest ways to connecta hard drive, CD-ROM drive, or other device to acomputer.

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Firewire A FireWire (IEEE 1394 or i.LINK) port lets you connect such devices as hard disks anddigital camcorders to a computer. It can transfer information at a speed of up to 400 Mbps.


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How a computer works

Input

You communicatewith the computer via

an input device suchas a mouse, akeyboard, or a

joystick.

Process/Storage

The computerprocesses data, makes

calculations, directs thework of the hardware,and stores your files.

Output

The computercommunicates itsresults to you via an

output device such asa monitor, a printer, orspeakers.

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Computer System Components

1. Hardware

2. Software3. Peopleware

4. Data / information

5. Procedures


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Hardware

Refers to the physical component of the computer system.

1. Input devices e.g. keyboard & mouse2. Output devices e.g. monitor & speaker3. Data storage and Media devices e.g. floppy disks & hard

disks4. Processing devices these are internal or electronic devices

which process the data and produce an output. (CPU)

It includes:


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Input Devices

Keyboard

Mouse

Digital cameraWebcam

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The Keyboard

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The Mouse

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The Mouse

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The optical mouse, operates by using an infrared sensor.You can identify an optical mouse by the telltale red glowemanating from its underside.

The wireless mouse (and keyboard). A wireless mouseand keyboard run on batteries and communicate with thecomputer the same way a remote control communicateswith a television.


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Digital camera and Webcam

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Other Input Devices

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Output Devices

Monitor

Printer

Speakers

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Monitor

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Printers

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Types of Printers

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Speakers

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Storage Devices

Primary Storage DeviceThe computers main memory.

Secondary Storage DevicesThe physical devices (also called auxiliary devices) are physicallyseparated but connected directly to the CPU through acommunication line so that programs or data can be accessed withalmost no intervention from human operator


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Two types of computer memory

inside the computer

1. RAM (Random Access Memory) a place where

the programs and software we load gets stored.2. ROM (Read Only Memory) it is where the CPU

fetches or reads instructions.


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Examples of Secondary

MemoryMagnetic Disk

Magnetic TapesFloppy Disk

Hard Disk

CD-ROM


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Hard Disk

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Floppy Disks

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CD-ROM and DVD Drives

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Types of CD

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Types of DVD

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Magnetic Tapes

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Other Storage Devices

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Central Processing Unit (CPU)

This is the brain of the computer.

All operations performed by the computersystem are controlled by this physical device.

This is sometimes referred to as the processor

or central processor. This is the most important element of a

computer system.


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The Central Processing Unit

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Typical component of the CPU

1. Control unit it acts as a supervisor that controls andsupervises the operation in the CPU.

2. Arithmetic logic unit (ALU) it performs themathematical and logical operations of the computersystem.

3. Memory unit it is the storage device of the computer.


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Measurements used in

Computer

1. Bit (binary) either ON (1) or OFF (0)

2. Nibble group of 4 bits.

3. Byte group of 8 bits.

4. Kilobyte (KB) 1024 or 210bytes

5. Megabyte (MB) a million bytes or 1,048,576bytes


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6. Gigabyte (GB) a billion bytes or1,073,744,824 bytes

7. Terabyte (TB)

a trillion bytes or1,009,511,627,776 bytes

easurements continued

BPS (bytes per second) is used to measuremodem speeds.


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Clock Speed it is how fast a computerprocesses

1. Hertz (Hz) a single clock cycle per second.

2. Kilohertz (kHz) 1000 cycles per second.

3. Megahertz (MHz) 1 million cycles persecond.

Software instructions that tell the computer what to


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Softwareinstructions that tell the computer what todo.

Classification of Software:1. System softwareprograms which control and assist

in the computer operation. (e.g. operating system,compilers, utility programs, etc.)

2. Application softwareprograms which provide asolution to a specific operation or application. (e.g.business software, desktop publishing, Officeproductivity, etc.)


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Peopleware

Represent thepersonnel involve insystem analysis,programming,computer operation,system maintenance,the end user, and thelike.

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Users of IT

Librarians

catalog the processed disks and tapes and keepthem secure.

Computer programmers

design, write, test and implement the programsthat process data on the computer system; theyalso maintain and update programs.


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Users of IT

Systems analysts Knowledgeable in the programming area but have broader

responsibilities.

They plan and design not just individual programs but entirecomputer systems.

S.A. Maintain a working relationship with programmers and theusers of the organization.

The analysts work closely with the users to plan a new systems

that will the users needs.


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Users of IT

Network manager implements and maintains the organizations network.

Chief Information Officer (CIO) the department manager, must understand more than just

computer technology.

This person must understand the goals and operations of theentire organization and be able to make strategic decisions.


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Users of IT

End users The user of Information System.

Ordinary users

people who uses computer on day to day basis.

Note: There are some specific jobs and standard titles. There are manyothers, most specific to the organization.

D t


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Data

Facts which are processed to produce information. Data areprocessed using these four processing functions: Input,

process, output, storage

Information

Data that have been processed and presented in a form suitablefor the user or human to interpret or understand.

Procedures

Step-by-step instructions to be followed by a computer toproduce an output. E.g. users manual, system documentation,

policies, disclaimer, etc.


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Computers and Society

Computers: Can we live without them?

Controversy: another word for computer

The Misuse of Personal Computer

sources of personal data

Violating the privacy of personal information

Securing the integrity of Personal information

How are computers affecting our lives?

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Applications of Computers in Society

Health and medicine

Transportation

Law enforcement

Money and banking Industrial Factories

Communications

Agriculture Education

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Applications of IT

Computers speed up the check out process atsupermarkets

enable 24 hour banking

provide up-to-the-minute weather information

entertain us with video games and films

application using elevators, automobiles and vendingmachines.


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Applications of IT

Retailers query to determine which products areselling and which are not.

The use of word processing system to create memos

and to check spelling, grammar and style Banker and geologist use computer for their

convenience.

C t C i C t i


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Computer Crimes: Categories

1. Crimes that create havoc inside the computer

2. Crimes that involve the manipulation of computer systems and

their data

3. Crimes involve telecommunication

4. Crimes that involve the abuse of personal information

5. Crimes that involve negligence

6. Crimes that support criminal enterprises

7. Crimes that involve the theft of hardware or software

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C t C i E l


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Computer Crimes: Examples

Credit Card Fraud Data Communications Fraud

Unauthorized access to computer files

Unlawful copying of copyrighted software

Defrauding the System

Negligence and Incompetence

The Hacker Problem

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Ethics. refers to the rules and standardsgoverning the conduct of an individual withothers.

Computer ethics.A code of ethics providesdirection for computer professionals andusers so that they act responsibly in their

application of information technology.

Code of Ethics


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Code of Ethics

1. Maintain the highest standard of professional behavior.

2. Avoid situations that create a conflict of interest.

3. Do not violate the confidentiality of your employer or those you

service.4. Continue to learn so your knowledge keeps pace with the

technology.

5. Never misrepresent or withhold information that is germaneto a problem or situation of public concern.

Code of Ethics


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6. Use information judiciously and maintain system integrity at alltimes.

7. Do not violate the rights or privacy of others.

8. Take appropriate action when exposed to unethical or illegalpractices.

9. Do not exploit the shortcomings of an employers computer

system for personal gain.

10. Accomplish each task to the best of your ability.

Code of Ethics

Ten Commandments of


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Computer Ethics

1. Thou shalt not use a computer to harm other people.

2. Thou shalt not interfere with other peoples computer work.

3. Thou shalt not snoop around in other peoples computer files.

4. Thou shalt not use a computer to steal.

5. Thou shalt not use a computer to bear false witness.

6. Thou shalt not copy or use proprietary software for which you

have not paid.

Ten Commandments of


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Computer Ethics

7. Thou shalt not use other peoples computer resources withoutauthorization or proper compensation.

8. Thou shalt not appropriate other peoples intellectual output.9. Thou shalt think about the social consequences of the

program you are writing or the system you are designing.

10. Thou shalt always use a computer in ways that ensureconsiderations and respect for your fellow humans


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The Hacker Problem

Hack - To modify a program, often in an unauthorizedmanner, by changing the code itself.

Software Piracy

The unauthorized copying of software.

What is a hacker?


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What is a hacker?

an enthusiastic, largely self-taught computer user

a person who gains access to computer systems illegally,usually from a personal computer.

Individuals who gain unauthorized access to computer systemsfor the purpose of stealing and corrupting data. (cracker)

A slang term for a computer enthusiast who enjoys learningprogramming languages and computer systems and can oftenbe considered an expert on the subject(s).


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Intellectual Property

Encompasses creations of the human intellectand their protection, usually by copyright.

literary, artistic, and scientific works

performances of performing artists,phonograms, and broadcasts

inventions in all fields of human endeavorscientific discoveries.


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Intellectual Property

World Intellectual Property Organization (WIPO). Thisorganization was founded in 1967 as one of the specializedagencies of the United Nations organizations, and it has sinceremained responsible for the protection of intellectual property.

Copyright

A form of protection provided by laws to the authorsof original works, otherwise known as the owners ofintellectual property.


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Security

Hardware Approaches

Closedcircuit TV monitorsAlarm systemsComputer-controlled devices that check employee badges,fingerprints or voice prints before unlocking doors at access

points.Computer centers should be isolated from pedestrian traffic.Machine-room fires should be extinguished by a specialchemical that douses the fire but does not destroy the files orequipment.

Continuous source of power (UPS)


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Viruses

[ Worm - a program that transfers itself from computer to

computer over a network and plants itself as a separate fileon the target computersdisks.

[ Virus - a set fo illicit instructions embedded in a file thatpasses itself onto other files with which it comes intocontact. This is the digita equivalent of vandalism.

[ Vaccine or antivirus- a computer program that stops thespread of a virus and often eradicates it.


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Y CodeRed - a worm that infects computers running icroSofts

IIS Server.

Y Nimda - a mass-mailing worm that utilizes mulitple methodsto spread itself.

Y SirCam - distributed as an e-mail attachment.

YForm - causes a clicking noise in the computerskeyboard on

the 18th day of the month.

Y Melissa - a macro virus distributed as an e-mail attachment thatwhen opened disables a number of safeguards in Word 97 or

Word 2000.

Viruses


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Some ad Guy Tricks

Bomb - causes a program to trigger damage under certainconditions; it is usually set to go off at a later date.Data diddling- refers to changing data before or as it entersthe system.

Denial of service (DoS) attack - occurs when hackersbombard a site with more requests for service that it canpossibly handle, preventing legitimate users from accessing thesite.

Piggybacking - an illicit user rides into the


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system on the back of another user.Salami technique - a technique that reflects the

small slices of money that may be squirreledaway undetected from a large financial system.Scavenging- a simple search to company trashcans and dumpsters for printouts containing no - for- distribution information.


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Ripper - corrupts data written to a hard disk approximately one time

out of a thousand.

MDMA - affects MSWord files; it can also delete files.

Concept - transferred from MSWord file to another if both are in

memory at the same time.

One_half - encrypts the disk so that only the virus can read the data

there.

Michaelangelo - destroys all data on the hard disk on March 6

ichaelangelosbirthday.

Cascade - picks random text characters and drops them to the

bottom of the screen.

Jerusalem - deletes any program executed on Friday the 13th.

Viruses

1 - overview of computers

Documents