Chapter 1 Components of Your Computer What is a Computer Types of Computers Components of a Computer Computer Software Communication Networks The Internet.

Chapter 1

Components of Your Computer

• What is a Computer• Types of Computers• Components of a Computer• Computer Software• Communication Networks• The Internet and the World Wide Web

What is a Computer?

Input ProcessingInstructions

Output

A computer is a device that accepts input, manipulates it under a sequence of instructions (a program) and produces an output. This process is called the “Information Processing Cycle.”

The output can be the result of a calculation or just an acknowledgement of the input.

For example…

…an abacus is a kind of computer…

…so is a Slide Rule…

…and a

Burrough’s

Adding

Machine…

Advertisement from 1954

Handheld devices such as these are also computers…

However, we’re concerned with just 3 types of computers that are used for business information systems:

• Mainframes

• Minicomputers

• Microcomputers

Mainframe Computers

• industry term for a large computer“big iron”

• modularized to reduce overhead• used in centralized computing environments• large-scale computing server

• high volume• high overhead processing

• used as large database servers

Mainframes typically cost hundreds of thousands of dollars and are manufactured by companies such as Hitachi, IBM and Amdahl.

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P C W o r k s ta tio n so r te r m in a ls F r o n t- E n d

P r o c es s o r( F E P )

M ain f r am e

C lu s te rC o n tr o lle r

Diagram of a Simple Mainframe Configuration

Minicomputers

• smaller than a Mainframe• larger than a PC (Microcomputer)• have become the “mid-range” server

• IBM’s AS/400 is an example

IBM AS/400

Microcomputers

• Personal Computers (PCs)• desktop computing and client-server applications• can serve both as a client and a server

Microcomputers are what we think of as PCs. Although they cross the line at times, Sun Microsystems generally is thought to manufacture high-end PCs.

Microcomputers

• Microcomputers are generally categorized by the Central Processing Unit (CPU) type:– Intel-IBM compatible (Wintel)– Motorola – Apple/Macintosh/Power PC– Sun Microsystems - SPARC

Micro Computers

• Forms of Micro-Computers:– Workstations

• High processing speed and performance• Used for Engineering applications i.e. CAD, graphical

simulations and desktop publishing– Personal computers

• Less powerful than workstations• Categorized as either a desktop or portable computer

i.e. laptops or notebooks– Handheld Computers and PDAs

• Smallest personal computers• Increased power to perform word processing and

complex spreadsheet and database functions• Mobile connectivity with wireless telephone, internet

and email.

Basic Parts of a PC

MouseKeyboard

Computer Case (CPU)

Monitor

Components of a Computer

A computer needs the following devices to function:

• Input device(s)• Processing Unit• Output device(s)• Storage device(s)

This is the computer’s hardware…it is tangible.

Input Devices

Accept data for the computer to work with and Send it on to the processing unit…

MouseKeyboard

Microphone

Scanner

Processing Unit

The Central Processing Unit, or CPU, is the brains of the computer. It controls all activity and performs operations on data based on its instruction set. The CPU is made up of several major units as diagrammed below.

Processing Unit

The CPU consists of these main elements:

• Control Unit - executes the instructions as interpreted• Arithmetic / Logic Unit - performs mathematical and

logical operations• Registers - serve as the short term memory for

the ALU’s computations and provides somereserved space for certain functions

• Clock Unit - generates pulses that determine the speed of instruction processing, the rate is

measured in megahertz (Mhz)

Processing Unit

The CPU has two main features:

• Its speed measured in millions of instructions per second, or MIPS

• Its word size is the number of bits the CPU can process at a time. An 32-bit processor

manipulates 32 bits simultaneously.

System Memory• Computer’s memory stores data on

electrical devices called ‘Chips’.

• Data stored on memory chips is considered volatile - exception is FRAM (Ferroelectric RAM used in PDAs and Handheld computers.

• Many other places within a PC where memory chips are used i.e. Video and Sound Cards, Modems, Hard-disks, CD/DVD drives use them to increase their access speed and efficiency.

System Memory

A PC has three basic types of memory:

• Cache memory that is built into the CPU (not theCPU registers) called L1 or L2 cache – exists mainly to help CPU in its processing and system administration tasks.

• Read Only Memory (ROM) that is used to “boot” the system (among other applications)

• Random Access Memory (RAM) which is the main memory that acts like the workshop or

desktop of the CPU

Output Devices

The purpose of an output device is to present electronic data (and the results of our work) in a form that can be understood and used. For example, think how hard it would be to use a computer without a monitor.

Typical output devices on a PC are:• Monitor• Printer or Plotter• Speakers

Output Devices

Monitors:• CRT – Cathode Ray Tube, like a Television• LCD – Liquid Crystal Display• TFT – Thin-Film Transistor

Printers:• Laser printers• Inkjet• Thermal Wax• Dot-Matrix

Auxiliary Storage Devices

These devices, also known as secondary storage, are where the PC stores data that must last from session to session. Basically speaking this is the permanent data storage.

Though they differ in their technologies and methods of storage, the result is the same; the PC can easily retrieve the stored data for use at a later time.

These components are many times referred to as Mass Storage devices.

Auxiliary Storage Devices

Types of Auxiliary or Mass Storage devices are:

• Floppy disk drive • Hard disk drive • Optical disks (Compact discs, DVD)• Zip drives• Jazz or Bernoulli drives• Tape drives• Flash memory

Computer Software

Two general types of software:• System software• Application software

Software is computer instructions (Programs) and data. Anything that is electronically stored on a computer storage device is considered software.

It is intangible and exists only electronically.

System Software

Systems software are the programs that controlthe computer and manage its resources. Such asoperating systems and system utilities. Acts as an Intermediary to act as a translator to interact with the Hardware.

Operating systems perform the basic tasks of computing like managing the input and output of data and interpreting the instructions of the programs.

System Utility software performs more basic functions such as file management or backup, but they must work under an operating system.

System Software

Examples of Operating systems:• Windows (2000, ME, 98, 95, 3.1, CE)• DOS (MS-DOS, DR-DOS, PC-DOS)• Mac OS X• Unix (Solaris, FreeBSD, SCO UNIX)• Linux• Palm OS• BeOS

Operating systems are written to run on specific processors (platforms).

Characteristics of OS:

•Multi-User

•Multi-Processing

•Multi-Tasking

•Real-Time

System Software

Examples of Utility software:• Anti-virus software

• Norton, McAfee, Sophos, Trend Micro• File Management

• PKZip, WinZip, Norton SystemWorks• Disk Utilities

• PartitionMagic, System Commander• Backup

• Retrospect, Backup MyPC

Utility software is written to run under specific operating systems.

Application Software

Application software consists of programs that help you work and play on the computer. This category includes word processors, games, spreadsheets, drawing and other “productivity”programs.

This is the bulk of all software written.

Application software is written to run under specific operating systems.

Application Software

Examples of Application software:• Document Processing

• Adobe Acrobat, WordPro, TextBridge• Graphics

• Flash, CorelDraw, PaintShop Pro• Games

• MS Flight Simulator, Tomb Raider• Programming

• Kylix, CodeWarrior• Suites

• StarOffice, WordPerfect Office, Office 2000• Database Management

• Oracle, SQL Server, MySQL

Communication Networks

Computer Networks

Two or more computers connected to share data and resources are “networked.” The simple idea behind computer networking is to allow users to access more information and give them access to devices not directly attached to their “local” system, such as printers or storage devices.

Computer Networks

Three of the main types of computer networks are:• LAN - Local Area Network• MAN – Metropolitan Area Network• WAN - Wide Area Network

A LAN is comprised of computers located within close proximity, such as in an office or building. A WAN is a network of computers that are situated further apart, but still connected. Such a network might be of computers within a single state agency or of a multi-national corporation worldwide.

Computer Networks

A PC must have a Network Interface Card installed to connect it to a network. The cards, frequently called “nics”, come installed in many new computers as they are also used for cable modem and DSL internet service.

The computers can be configured in several ways, the most popular of these “architectures” are peer-to-peer and client/server. The first is a looseconnection of local computers with no central authority, the later relies on a “server” to manage the network and its resources.

A peer-to-peer network requires the computers to be connected to each other by a network cable, usuallyan “unshielded twisted pair” cable known as “CAT 5”. Connecting more then two computers require the use of a network hub as transmission link as shown.

E th er n e t Hu b

P eer - to - P eer N etw o r k

A client/server network uses a computer known as the server to manage the network and control access to resources. The computers can be connected using various types of cable including CAT 5, coaxial and fiber optical.

C lien t/S er v er N etw o r k

N etw o r k S er v er

Hu b

Computer Networks• Network connections can also be made

using RADIO transmission – Wireless.• Allows user to stay connected to their

home/office network using portable PC or PDA or may be Cell phone.

• Two Technologies that use wireless networking – Bluetooth (for home or small office use) and wireless Ethernet.

Computer Networks

Local Area Networks are configured in 3 basic topologies. These are either the logical orphysical way the computers are connected. Each connection on the network is known as a node.

These topologies are:• Star• Bus• Ring

A Star topology connects all the nodes directly to the server or to a connecting device such as a hub.

S er v er

All nodes on a Bus topology are connected to acentral line or backbone.

S er v er

Nodes on a Ring topology are connected in a closed loop. This means that each node has two connections,one in and another out. Using this type of topology the data must travel through all the nodes.

S er v er

Computer Network-Hardware

• Servers– Used in client/server network.– Manages and Controls the network.

• Hubs & Routers – Manages traffic for a network.– Hubs connect the nodes to each other.– Routers direct the network traffic to other networks

(internet) or to other segments of the same network not located nearby.

• Cable or Connection Media– Cable i.e. shielded/unshielded twisted pair (CAT5), coaxial,

fiber optics etc.– Wireless media.

Computer Network Software

Computer networks use special operating systems and other system software to manage the network, its resources and its users. Network Operating Systems (NOS) should be very secure and robust to provide reliable network services.

Examples of such software are:• Windows 2000 Server• Novell NetWare• Unix…too many flavors• Linux

Extra functionality & enhancements in NOS:

•Communication and Connectivity

•Security & Encryption services

•Backup and Restoration

•Remote Network Administration

The World Wide Web/Internet

The World Wide Web is a collection of computers connected via the Internet that support the use of documents written in HyperText Markup Language(HTML). The “web” uses the HyperText Transfer Protocol (HTTP) as the standard for the formatting and transmission of these documents.

Internet is the network of networks.

Not every server on the ‘net uses HTTP, andtherefore is not part of the Web.

The Internet

T h e I n te r n e t

The Internet is very large and diverse, there is no one method of access and there are many protocolsused such as:

• NNTP - Network News Transfer Protocol for newsgroups

• SMTP - Simple Mail Transfer Protocol for sending e-mail

• FTP - File Transfer Protocol used for sending files• SNTP – Simple Network Time Protocol – used by

timeservers to synchronize the time of computers that connect to them.

It’s a wonder it works so well, much less at all.