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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?.
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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? 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. Processing Instructions Input Output
For example… …an abacus is a kind of computer…
…and a Burrough’s Adding Machine… Advertisement from 1954
However, we’re concerned with just 3 types of computers that are used for business information systems: • Mainframes • Minicomputers • Microcomputers
Mainframe Computers • modularized to reduce overhead • used in centralized computing environments • large-scale computing server • used as large database servers Mainframes typically cost hundreds of thousands of dollars and are manufactured by companies such as Hitachi, IBM, and Amdahl.
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
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 Monitor Computer Case (CPU) Keyboard Mouse
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… Mouse Keyboard 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 four major units as shown 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 some • reserved space for certain functions • Clock Unit - generates pulses that determine the • speed of instruction processing, the rate is measured in megahertz (Mhz)
System Memory • A PC has three basic types of memory: • Cache memory that is built into the CPU (not the CPU 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 • 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 • Tape drives
Computer 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. • Two general types of software: • System software • Application software
System Software Systems software is the program that controls the computer and manages its resources. Acts as an intermediary between user and 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 (XP, 2000, ME, 98, 95, 3.1) • DOS (MS-DOS, DR-DOS, PC-DOS) • Mac OS X • Unix • Linux • Palm OS • Characteristics of OS: • Multi-User • Multi-Processing • Multi-Tasking • Real-Time Operating systems are written to run on specific processors (platforms).
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 • 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. • Common Network Architecture: • Peer-to-Peer • Client/Server
Computer Networks • Two the main types of computer networks are: • LAN - Local 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.
A peer-to-peer network requires the computers to be connected to each other by a network cable, usually an “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.
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.
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 or • physical 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.
All nodes on a Bus topology are connected to a central line or backbone.
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.
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.
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 • Linux
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 a “network of networks.”
The Internet is very large and diverse, there is no • one method of access and there are many protocols • used 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.