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UNIT 1 Introduction to Computer Organization and Architecture
Introduction
In this unit you shall be introduced to the concept of a computer. The unit explores the definition and parts of the computer. It puts emphasis on the input, process, storage and output parts of the computer. The unit emphasises the concept of a computer as a system rather than a simple entity of processing. The difference between data and information shall also be covered.
Learning objectives
By the end of the unit the student should be able to:
(a) Define the term computer(b) Explain the concept of a computer as a system(c) Describe the functions of different parts of the computer system(d) Name various input and output devices.(e) Give the functions of various storage devices.
What is a Computer?
A computer is an electronic device that stores, accepts data, retrieves data, processes data and gives output according to a set of instructions. Business dictionary defined a computer as a general purpose machine, commonly consisting of digital circuitry, that accepts (inputs), stores, manipulates, and generates (outputs) data as numbers, text, graphics, voice, video files, or electrical signals, in accordance with instructions called a program
http://www.businessdictionary.com/definition/computer.html#ixzz3yNEZwJhN Accessed 26/01/2016
Elements of a computer
Hardware is the collection of physical elements that constitutes a computer system. Computer hardware is the physical parts or components of a computer you can touch and see, examples of computer hard ware include monitor/screen, mouse, keyboard, hard disk drive (HDD), graphic cards, sound cards, memory, motherboard, and so on. All these are physical objects that are tangible.
Software: Software is any set of machine-readable instructions that directs a computer's processor to perform specific operations. Software refers to instructions that can be stored and run by hardware. A combination of hardware and software constitutes a usable computer system
User: An individual who uses a computer. This includes expert programmers as well as novices. An end user is any individual who runs an application program. Users generally use a system or a software product without the technical expertise required to fully understand it.
Main Hardware Components of the computer
Figure 1 a: The structure of the computer
(Adapted from http://ourjobs123.blogspot.com/2014/10/Computer-Basics-for-Bank-online-Aptitude-Tests.html)
Hardware
• This is the equipment that makes up a computer system (physical components).
• Many of these parts are contained within the computer’s case.
• Other parts are external but connected to the computer (peripheral devices). These allow data to be entered (input) and retrieved (output) and stored.
Internal hardware components CPU Mother Board RAM Sound Card Video Card Hard Drive DVD
External Hardware components Keyboard Mouse Printer Scanner Monitor Speakers
Input devices:
These are devices which help you to interact with the computer by entering data and commands into the computer system. Examples of input devices are mouse and keyboard.
• Processing devices (processor)
• Output devices (monitor, speakers and printer) display data
• Storage devices (memory sticks and disks) hold data
The processing device: Central Processing Unit (CPU)
• The part of the computer performs the bulk of data processing operations is called the central processing unit
• “Brain” as well as “heart” of computer system
• The chip or chips at the heart of a computer that enable it to process data.
• It is very easy to replace because it is inserted into the socket and is not soldered onto the motherboard
A computer may contain more than one CPU and is called a MULTIPROCESSOR.
CPU Components
• The CPU is made up of four major parts:
– Register set
– ALU
– Control unit
– Main memory
• Memory: An area within a computer system that holds data waiting to be processed.
• Control unit
Control unit: supervises the transfer of information among the registers and instructs the ALU as to which operation to perform by generating control signals.
• Arithmetic logic unit (ALU)
Performs computation and comparison operations
• Set of registers
Storage locations that hold inputs and outputs for the ALU
Stores intermediate data during the execution of instructions;
CPU Registers
• Primary functions
Hold data for currently executing program that is needed quickly or frequently (general-purpose registers)
Store information about currently executing program and about status of CPU (special-purpose registers)
Computer Input
• Input is any data entered into the computer’s memory.
• input devices : the devices that allow data and instructions to enter a computer (such as a keyboard, mouse, scanner)
• Each type of input device has an INTERFACE i.e. a means of communication between the human user and the electronic computer.
Types of input include:
Data – Unorganized information (words, numbers, images, or sounds) that the computer converts to meaningful information
Software – Programs transferred from storage devices to the computer’s memory
Commands – Instructions that tell the computer what to do
Responses – Prompts requiring user feedback
Modern data capture Methods
Data may be keyed in from source documents by keyboard operators• Computer Keyboard• Numeric keypad
The source documents may be read directly by a document reader. Document readers capture information in the form of pictures or text already printed on paper.
• Image Scanners
• Optical Character reader (OCR)
• Optical Mark reader (OMR)
• Magnetic ink character reader (MICR)
• Bar code readers
Data may be captured directly without the need for any source document
• Magnetic strip on a plastic card,
• Smart card
• Graphic input devices may be used to translate drawings or photographs into digital form that can be processed by a computer
• Mouse
• Track ball
• Touch screen
• Digitizing tablet
• Light pen
Sound Input
• A microphone can be attached to a sound card to provide audio input and also to issue commands and crate files
• Speech recognition is a type of input in which the computer recognizes words spoken into a microphone.
Output Devices
• Output devices are peripheral devices that enable us to view or hear the computer’s processed data. E.g. a display screen or printer)
• Output: The product of the transformation of inputs by a process.
Computer output
Computer output refers to that which is output by the computer to the outside world e.g. sound.
• Types of output
– Visual output – Text, graphics, and video
– Audio output – Sounds, music, and synthesized speech
Output Devices
These are the devices that provide the output.
The devices send back the information to you from the computer e.g. Monitor and Printer.
Monitors
• A monitor is a peripheral device which displays computer output on a screen.
• Screen output is referred to as soft copy.
• Types of monitors:
– Cathode-ray tube (CRT)
– Liquid Crystal Display (LCD or flat-panel)
Printers
• A printer is a peripheral device that produces a physical copy or hard copy of the computer’s output.
Types of Printers
Laser
• Laser printer works like a copier
• Quality determined by dots per inch (dpi) produced
• Color printers available
• Expensive initial costs but cheaper to operate per page
• Inkjet printer
• Inkjet, is also called a bubble-jet, it makes characters by inserting dots of ink onto paper.
• Letter-quality printouts
• Cost of printer is inexpensive but ink is costly
Plotter
• A plotter is a printer that uses a pen that moves over a large revolving sheet of paper.
• It is used in engineering, drafting, map making, and seismology.
Audio Output: Sound Cards and Speakers
• Audio output is the ability of the computer to output sound.
• Two components are needed:
– Sound card – Plays contents of digitized recordings
– Speakers – Attach to sound card
Computer Storage
• Storage device:
– The place where a computer puts data.
– The area within a computer system where data can be left on a longer term basis while it is not needed for processing.
Why Is Storage Necessary?
• Storage devices:
– Retain data when the computer is turned off
– Are cheaper than memory
– Play an important role during startup
– Are needed for output
Storage Technologies: Magnetic and Optical
Magnetic Storage
Optical Storage – CD/DVD drive
• Magnetic – Storage devices use disks or tapes that are coated with magnetically sensitive material
• Optical – Storage devices that use laser beams to read patterns etched into plastic disks
CD-ROM Discs and Drives
• CD-ROM stands for Compact Disc-Read Only Memory.
• CD-ROM drives cannot write data to discs.
• They are capable of storing 650 MB of data.
• They are used for storing operating systems, large application programs, and multimedia programs.
CD-R and CD-RW Discs
CD-R
CD-RW
• Discs can be read and written to
• Discs are erasable
• Discs can be written to many times
• CD-RW drives are capable of reading, writing, and erasing data
DVD-ROM Discs and Drives
• DVD stands for Digital Video Disc.
• DVD technology is similar to CD-ROM technology.
• DVDs are capable of storing up to 17GB of data.
• The data transfer rate of DVD drives is comparable to that of hard disk drives.
• DVD-R and DVD-RW drives have the ability to read/write data.
Solid State Storage Devices
• Solid state storage devices use nonvolatile memory chips to retain data.
• They do not have moving parts.
• They are small, lightweight, reliable, and portable.
Examples of Solid State Storage Devices
Smart Card
Flash Memory
PC Card
Figure 1 b: Solid State Storage Devices
Memory Stick
Compact Flash Memory
Micro Drive
UNIT 2: The windows environment
Before you work with different computer applications you need to be familiar with the windows environment. It is this environment that you will be using in performing different tasks with your computer. For simplicity and standardisation, this module shall use windows 7 operating system environment as well as Microsoft Office 2007 applications. Please note that this work is not to promote a certain software producer but to impart knowledge and skills to students. After going through explanations and examples in this module, the student is advised to try exploring the same concepts in different hardware and software environments.
The windows aspects that you shall learn in this section include the desktop, the general office window and its sections, folder management and basic windows tools.
The desktop
Figure 2b: The windows desktop
Figure 2b shows how the desktop looks like. Note that the background differs according to the individual user preferences, so expect to see different desktop backgrounds whenever you encounter a different desktop. The desktop is what you see when the computer has finished booting up. It is equivalent to the top of your desk when are working in your office. You may remember that on your desk there are all tools that you need to do your daily tasks. On one’s desk we would expect to see pens, rulers, calculators, diaries, trays and so on. On the sides of the desk you may have a dust bin to throw unwanted papers.
The emergence of the electronic office resulted in converting all those functions into electronic form. We now have pens, rulers, recycle bin and other tools that we need to use in our electronic office that makes minimum or no use of papers. Next we are going to explore the different tools that we have on our desktop.
On standard widows desktop there are icons which are there and are expected to be there. On figure there are two standard desktop icons namely Computer and Recycle bin. As a user you can also create your own folders on the desktop in which you save your work. In figure we have two folders named, All others and ITCA work. A user can create as many desktop icons as required. However, it is advisable to have very few icons on your desktop so as to avoid cluttering it. You need to plan how your work needs to be organised carefully. You may need to have as few as five main folders on your desktop possibly corresponding to all the modules you are doing that semester. If you are doing communication, introduction to computers, Statistics,
Standard desktop icons
User created folders
Saved document
Other icons
Entrepreneurship and Life skills; you may need to create a folder for each of the five. Then in each folder you can create more folders e.g. tutorials, lecture notes, self notes, exercises and assignments. The subfolders may also be subdivided into sub-sub folders. If you practice this you will notice that it will be a lot easier for you to locate anything of interest.
One can also save documents on the desktop be it word, spreadsheet, database, presentation etc. On figure the word document Automatic gate system was saved on the desktop. Note that it is not good computing practice to save documents directly on the desktop.
The desktop can also carry certain icons that are often used for example in figure there is Google chrome and Skype. Some software when installed on your computer will automatically put a desktop icon for easy access to it.
At the bottom of Windows 7 desktop window there is a series of icons corresponding to major applications running on the computer as well as active program icons. Figure shows such icons.
Basic operations in the Windows environment
Before you proceed to the next sections of this module, you have to acquaint yourself with the following basic operations:
Opening a document Saving a document Backing up a file Print previewing a document.
Word processing
Word processing involves creating textual documents using your computer as well as saving and printing those documents. The documents may be letters, memos, reports, assignments, etc. In your studies you will be required to write many of such documents. It is therefore critical that you are competent in word processing. The skills you will acquire in this area will be useful in writing your assignments and projects in your programme, at home and at work.
This module will not cover everything in word processing but limited to the structure of word processing window and a few word processing activities enough for building a base for your work.
Start button Folders Mozilla Firefox
Word
Internet explorer
Media player
Skype
The word processing window
Figure shows the main elements of the word processing window.
The grey area at the center of the window is called the work space or working area. You type all your work in this area. Let us explore the various parts of this window in the following sections.
The office button
The office button is found on the top left corner of the window. Clicking on the office button will produce the drop down menu as shown in figure below:
Minimise, maximise and closeOffice
buttonTool bars Title bar
Main menu bar
The drop down menu is comprised of new, open, save, save as, print, prepare, send, publish and close. These are the standard actions that you can perform while working on your documents. In your practical session you will familiarise with all these actions. You use the new action when you intend to create a new document e.g. a memo or a letter. The open action is used to open an existing document that has been saved either in the computer hard disk or any external storage device e.g. a memory card or memory stick.
The office button can also help you access any recently opened documents without bothering you with remembering where you saved the document. In this case the recent documents are listed thus ITCA module, Farai CV Telecel etc.
Tool bar
The tool bar contains standard tools that you can use to do several things while working with your document e.g. copying, pasting, indenting changing font colour and so on.
Title bar
As the name implies this is the position where the name or title of the document name is located. Once you save your document the name that you give to the document is the once that is written in this bar. Figure shows that the document I was working on is called ITCA Module which is a Microsoft word document.
Main Menu bar
The main menu contains several menu items that are used in working with your documents. Every action starts here. These are called main menu items because once you click on each of them a different set of sub items are displayed allowing you to perform certain specific actions. Figure shows the main menu and its menu items.
The main menu items are the Home, Insert, Page layout, references, mailings, Review and View. Each of these menu items has several submenus corresponding to it. If you click on any of these items a different set of submenus will be displayed. Figure and figure show the submenus of Home and Insert respectively. You shall learn the use of each of the items in the submenus in your practical sessions.
The submenus of Home are Clipboard, Font, Paragraphs, styles and Editing.
The insert menu option has the submenus Pages, Tables, Illustrations, Links, Header and footer, Text and symbols. Each of these submenus has a set of tools that you shall use to perform small tasks in when working with your documents.
UNIT 3 Role of ICT in Business
ICT definition
Information and communications technology (ICT) is often used as an extended synonym for information technology (IT), but is a more specific term that stresses the role of unified communications and the telecommunications (telephone lines and wireless signals), computers as well as necessary enterprise software, storage, and audio-visual systems, which enable users to access, store, transmit, and manipulate information.
Information Communication Technology (ICT) is a generic name used to describe a range of technologies for gathering, storing, retrieving, processing, analysing, and transmitting information.
ICT in Business
ICT in a business environment can be used for:
• Recording Data,
• Storing data,
• Manipulating data and
• Retrieving data
ICT is used in
• Administration- For Invoicing, Communication, Emailing.
• Business, Finance and Accounting- for Business Plans, Financial forecasting, Auditing, Market Analysis, Research, Recording Transactions.
• Communications- For email, instant messages, mobile phones.
• Engineering and Creative Art- for 2D and 3D Drawing, Modelling, Simulation.
• Wildlife and Tourism and Hospitality- Animal Tracking, Hotel booking, GIS.
Characteristics of today’s business environment
Today’s business is very different from the traditional business environment. Figure shows the four main aspects that characterise the modern day business environment. These aspects are the nature of business, technology, customers and the market.
The nature of business
Technology
The term “global”includes: global markets, global customers, global suppliers, globalshareholders, and global opportunities. Highly competitive withcompanies competing across national boundaries
Global reach of Internet Technology: mobile phones can handle Internet communicationsPervasive Computing- idea of putting powerful computer chips and functions into everyday things such as cars or household appliances. Fridges can now scan itself and inform you to procure goods online using GPS and location technologies
Three Spheres of Web Strategy
Figure 3a
When we talk of the web strategy we refer to how a business would deal with the issues that affect the way they appear to the outside world through their websites. Nowadays people know about an organisation mainly through visiting their website on the Internet. So, the business managers need to constantly update their information on these websites. The nature of your website and its content determine largely how your business will fare.
A good website should balance the three elements shown in figure 3a (community, technology and business)
Consider a website that focuses only on the community and the business. In this case the website takes into account the expectations of the community first and fuse them into their website. You realise that every business operates in a certain environment and serves a
specific community. It is paramount to note that each community has its own norms and values that shape its people’s expectations from the business. So a wise business manager has to make a thorough investigation into these norms, values and expectations. On the other hand the business has to be understood in terms of its processes and procedures.
The website now has to reflect the community expectations and the business processes and procedures. As figure 3a shows, this type of website will be inefficient for the success of the business. The website needs to be hosted on the Internet hence technology tools are required.
A business that ignores the community and focuses on the business processes, operations and expectations taking into consideration the modern IT technology is likely to fail again. As indicated in figure 3a users will be frustrated and may not even come onto the website. In this case the business will eventually collapse. Clearly no business can survive when it does not recognise the norms, values and expectations of the community that it serves. So make sure that pictures, logos, icons and everything that you use on your business is in line with the community if you want your products to do well. Imagine someone with a UK background where an owl is considered a lucky bird comes to Zimbabwe and puts pictures of an owl on every page of the website as well as banners to advertise the products!!!!!!!!!!!!!!!!!!!!!!!!!!! Pakaipa pakaipa. People will run away. The reason is simply that an owl in Zimbabwe is associated with witchcraft. So take the people’s culture seriously when branding your products.
Another approach may be taking only the society and the technology seriously. Clearly this does not work because the business functions and processes themselves are left out which should be the main reason of existence. Only a fool will ignore the business since the result is monetisation issues where no transitioning will occur. Actually there will be no business to talk about.
Finally, the proper way of doing it is considering the community, the business and the technology equally and inculcates them into the website development and maintenance always. When this is adequately done we now talk of web strategy balance. This is the optimal way of running a business properly online.
Internet, Email and E-Commerce
Internet
The Internet connected every part of the globe. The globalisation of business resulted in us having the following
Global Market Place E-Commerce Market Performance Price Comparison Sites
Messages can be sent to individuals and groups Quick Information Transfer
E-Commerce
Electronic commerce came also as a result of doing business on the Internet. The benefits that accrued to business following this include the following;
Shopping 24/7 Low Overheads Global Market E-Marketing
How software improves efficiency
• Speed- Quicker processing times save the business time and money. Transactions are processed on quicker on real-time
• Accuracy- with the use of verification and validation, data can be inputted more accurately. This can help with decision making.
• Data Handling- Can be inputted and manipulated anywhere on the market
• User friendly- Easy to use
• Capacity- Large quantity of data can be held with very little physical space
Computer Network
A computer network is a group of computers connected to each other electronically.
This means that the computers can "talk" to each other and that every computer in the network can send information to the others.
The components of a computer network include: a computer, the router, the gateway, the bridge networking device, the switch for networking and the hub. Most of these are data terminal equipment and components of networking that are tasked with receiving or generating data.
A virtual private Network (VPN) extends a private network across a public network, such as the Internet.
Definition of terms
• A database is an organized collection of data.
• A computer is a general purpose device that can be programmed to carry out a set of arithmetic or logical operations
• A router is a device that forwards data packets between computer networks, creating an overlay internetwork.
• A network switch (sometimes known as a switching hub) is a computer networking device that is used to connect devices together on a computer network.
E-Business
• It is the transformation of an organization’s processes to deliver additional customer value through the application of technologies, philosophies and computing paradigm of the new economy
• Three primary processes are enhanced in e-business:
1. Production processes, which include procurement, ordering and replenishment of stocks; processing of payments; electronic links with suppliers; and production control processes, among others;
2. Customer-focused processes, which include promotional and marketing efforts, selling over the Internet, processing of customers’ purchase orders and payments, and customer support, among others; and
3. Internal management processes, which include employee services, training, internal information-sharing, video-conferencing, and recruiting.
E-Business
The major different types of e-Business are:
Business -to- business (B2B);
Business to-consumer (B2C);
Business -to- government (B2G);
Consumer -to- consumer (C2C);
Mobile commerce (m-commerce).
E-Business Components
Content & User Experience
Content Strategy
User Experience (UX) & Design
Information Architecture (IA)
Usability & QA Testing
Application & Development
Web development
Data Warehousing & ETL
Product data management
Integration with business partners
Operations (Order placement, order processing, & supply chain management)
E-Marketing & Demand Creation
Direct Marketing
Email Marketing
E-Business Model
Application and Development
E-Marketing & Demand Creation
Online Merchandising &
Conversion
Content & User Experience
CRM, BI & Analytics, ERP
Completed Interface
KPIs
Functional S
pecificationDeliver Insights
Traf
fic
Search Engine Marketing, Search Engine Optimisation, Online Advertising
Social Media management & monitoring
Online Merchandising & Conversion
Internal Site Search (searches performed on the website, not in a public search engine like Google)
A/B & Multivariate Testing
Online Merchandising
CRM, BI, & Analytics
Customer Relationship Management & Database management
Business Intelligence
Competitive Intelligence and Web Analytics
UNIT 4 SOFTWARE
Definition
• Software are the instructions given to a computer in the form of a program.
• Software is the set of programs, which are used for different purposes.
• Software are all the programs used in a computer to perform certain tasks.
Categories of Computer Software
Types of Software
Software is divided into two broad categories:
1) Systems software and
2) Application software.
Systems Software
• Systems software is the term used to describe programs that enable the computer to function, improve its performance and access the functionality of the hardware.
• Function of systems software is the control of the operation of the computer. • Systems software provides the foundation for applications software.
Operating System Software
Systems software is further subdivided into operating systems and utilities.
• The operating system is the program that actually makes the computer operate.
Examples: Windows 7, 8, Linux
Operating System Software
• It is the basic minimum software needed for a computer to be functional.
• It constitutes the greater part of Systems software.
• Its major function is to control the hardware
Functions of an Operating System
Functions of an Operating System
ResourceManagement
TaskManagement
UserInterface
FileManagement
• Boot-up the computer.
• Control the hard drives: This includes such features as formatting and defragmenting disks as well as saving files to and retrieving files from disk.
• Control input devices such as keyboards, mice and scanners.
• Control output devices such as the video display and printer.
Control the external ports: Ports are the external connections that enable peripheral devices to be connected to a computer. Common types of ports are serial, parallel, USB. Of these the USB ports are the most important.
• Provide the functionality for computers to be linked in a network.
• Provide the foundation for application software to be launched.
• Enable application software to access and use the hardware.
Utilities Software
Utilities Software are programs which either improve the functioning of the operating system or supply missing or additional functionality.
Examples: Windows Explorer (File/Folder Management), Windows Media Player,, WinZip, WinRAR for compressing files
Applications software
• Application software is used in real-world tasks to solve user problems
• Application software is used in real-world tasks to solve user problems
Applications software
Types of applications software
1) Off the shelf
General applications that can be purchased from vendors. E.g. Microsoft Office
2) Custom software
Software specially designed for a particular industry or organization E.g. Galileo/Worldspan (Travelling Agents) , ASCUDA for ZIMRA border clearance, POSware for supermarkets etc
Versions of software
• The new releases of software products are called versions.
• The versions use a numbering system such as
Windows 7, Windows 8, MS Office 2010.
Why …. Versions of software
• Software developers continually strive to improve the performance of their products and add new features.
• Especially in a world of competing products, each developer needs to make their product perform better, have fewer problems and have more features.
Relationship btwn s/w, h/w and users
Software Licensing
Basically in two forms i.e.
a) Proprietary software
b) Open source software
Proprietary Software:
• Also called non-free software, is software with restrictions on using, copying and modifying as enforced by the proprietor(owner).
• Restrictions on use, modification and copying is achieved by either legal or technical means and sometimes both.
• Examples of proprietary software are Microsoft Windows, Microsoft Office, Norton Antivirus etc.,
Open Source Software:
• Open source software (OSS) is computer software whose source code is available under a license that permits users to use, change, and improve the software, and to redistribute it in modified or unmodified form.
• It is often developed in a public, collaborative manner.
• Common OSS products are Linux, Netscape, Apache, etc.,
Freeware
• It is copyrighted software given away for free by the author.
• You are unable to view the source code
• Although it is available for free, the author retains the copyright, which means one cannot do anything with it that is not expressly allowed by the author.
Users
Applicationsoftware
Operatingandsystemssoftware
Hardware
• Usually, the author allows people to use the software, but not sell it.
• Examples: Adobe PDF, Google Talk, Yahoo Messenger
Shareware
• Freely distributed for a trial period
• You can only enjoy a free trial of it for a short period e.g. 14 days after which you are required to pay for a license
• The author usually requests that you pay a small fee if you want to use the program regularly.
• By so doing, you become registered with the producer so that you can receive service assistance and updates.
• You can copy shareware and pass it along to friends and colleagues, but they too are expected to pay a fee if they use the product.
• Examples: Winzip
Shareware is inexpensive because it is usually produced by a single programmer and is offered directly to customers.
• Thus, there are practically no packaging or advertising expenses.
• Note that shareware differs from public-domain software in that shareware is copyrighted.
• This means that you cannot sell a shareware product as your own.
• Examples :
Legal issues of software
Software Piracy
• Making illegal copies of copyrighted software
• Why the fuss?
– Very easy to duplicate software
– Software company may lose hundreds of dollars per pirated copy
• Prosecution
– Possible: Small-medium sized business who purchase a few copies and distribute to many users
– Impossible: Individual users who probably would not have purchased software on their own anyway
Counterfeiting
• Software is copied onto CD-ROMS / DVD-ROMS
• Package duplicates the original
• Sold in flea markets or small stores
• Cheaper price
Copying Software
• Legitimate reasons
– Backup copy
– Copy to hard disk
• Illegitimate reasons
– Obtain software without paying for it
Software Suites
• Suites are a number of productivity packages bundled together. Examples:
– Microsoft Office has MS Word, Excel, Power point, Internet Explorer, Access etc
– Lotus SmartSuite
– Corel WordPerfect Office
– Sun StarOffice
Advantages of suites
• Cost
• Similar graphical user interface
• Share common tools
• Programs are designed to work together
Disadvantages of suites
• Large size
• Many features never used by many end users
Tutorial questions
1) Describe the factors to consider when purchasing software.
2) For each of the scenarios below, suggest the appropriate hardware and software needs:
a) Airline reservation
b) Biomedical imaging
c) Lecture theatre
d) Diamond mining
UNIT 5
COMPUTER VIRUSES
Definition Computer Virus
1. A set of computer instructions2. Deliberately created3. That propagates4. And does unwanted things.
Characteristics of Computer Viruses:
1. Cannot exist in a viable form, apart from another (usually legitimate) program.2. Propagates when the host program is executed.3. Has an incubation period, during which no damage is done.4. After incubation period, begins to manifest its behavior.
A Few Manifestations of Computer Viruses:
1. Sudden or periodic slowing of programs.2. Unexplained change in the size of any program.
o Files with extension .EXE.o Files with extension .COM.o Files with extension .BAT.o Files with extension .SYS.o Files with extension .OVL.
("Explanations" would be, for example, a new version of DOS, or re-installing a program with different options.)
3. Unusual behavior of the computer, especially during a program which you have been running regularly with no problems.
4. Failure of any program (such as a word processor) to install correctly from its distribution disks.
Programs which are NOT viruses:
1. Trojan horse: a standalone program which does its damage immediately, while you are running it for another purpose (usually a game!).
2. Bomb: a standalone program (like a Trojan horse) whose only effect is to destroy some part of your system (programs, data) but does not pretend to be another program while it runs.
3. Bug: a legitimate program with some logic error which causes accidental damage to your system even though everything was done according to the manual.
4. User error: a human error (which the human may deny!) which causes loss of data or programs, or damage to hardware, due to accident or entry of incorrect commands.
Virus-caused behavior:
1. Formats hard drive, destroying all data ("Dark Avenger").2. Causes random change in typed characters ("Teatime" virus).3. Presents a political or (false) advertising message every few times ("Stoned" virus:
Legalize Marijuana).4. Causes computer to act as though a monitor or disk drive is going bad ("Jerusalem-B"
virus).
Where viruses can hide:
1. In the "boot" sector of any floppy disk. This is a small program which runs whenever the computer is "booted" from the diskette, whether or not the diskette is "bootable." (This is the tiny program which puts the message "Non-system disk or disk error" on the screen if the disk is not bootable!)
2. Attached to any program: shareware, commercial or public domain.3. Embedded in the hidden system files IO.SYS and MSDOS.SYS on the boot disk or
drive.4. Same as #2, but pay SPECIAL ATTENTION to the file COMMAND.COM on the
boot disk or drive.5. The "partition table" on a hard drive. (This DOES contain executable information,
since it is attached to the "Master Boot Record" which is consulted at boot-up to determine whether to boot DOS, OS/2, UNIX, etc.)
How viruses are spread:
1. Trading, copying or pirating software on diskettes without knowing the source.2. Software salesmen giving demos on your computer from their diskettes.3. Computer repair personnel using diagnostic disks.4. Computer user groups and bulletin boards (BBS's). NOTE: #2 & #3 account for over
80% of all infections at business sites! #1 accounts for nearly all others, #4 LESS THAN 5%.
When viruses activate:
1. Every few times the computer is booted up 2. On a certain day of the year 3. On a certain day of the week ("Sunday" virus).4. On a certain day of the month ("Friday the 13th", "Saturday the 14th" viruses).5. Every day EXCEPT one ("Israeli" or "Suriv03" virus, every day except Friday the
13th.)6. On a certain date only. (Jan. 1, 2000 "Century" will activate, write zeroes to all
connected disks, effectively destroying all data and programs, destroying all directories, file allocation tables, boot records and partition tables, possibly causing the disk to have to be returned to the dealer for repair. Finally, a message is presented to the user, "Welcome to the 21st Century.")
7. A certain period after infection ("Plastique" virus, one week).8. After infecting a certain number of files ("MIX/1" virus, six files).9. After a certain number of keystrokes ("Devil's Dance" virus, 2000 keystrokes; after
5000 destroys hard disk data and prints characteristic "Devil's Dance" message).10. At a particular time of day ("Teatime" virus, between 3:10 and 3:13 PM, trashes every
11th keystroke.)
11. Any combination of the above, plus anything you can probably think of!
Types of viruses, classified by how they spread ("vectors"):
Boot-sector viruses. Can NOT be transmitted from BBS's at all. Transmitted by floppy or tape cartridge (rare). Boot- up must be attempted from infected disk. Remains memory- resident during warm boot, infects boot sector of all other disks in system including hard and floppy disks.
Program viruses. May be transmitted by distribution of infected programs via floppy, BBS or network. Some infect ONLY COMMAND.COM; others avoid infecting COMMAND.COM, to avoid detection.
Types of viruses, classified by operating system:
DOS. Greatest variety of viruses due to widespread use. Amiga-DOS. Restricted to Commodore Amiga. Macintosh. Restricted to Macintosh computers. NOTE: Amiga(TM) and
Macintosh(TM) computers often have a DOS emulation mode. In this mode, some (but not all) DOS viruses can damage them as well.
OS/2. Relatively immune to viruses so far, due to rarity of systems. Most DOS viruses are rendered harmless by OS/2, although some may still survive since OS/2 can also run DOS programs.
UNIX. These viruses are relatively rare, but some have the potential of migrating to PC's running UNIX clones such as XENIX. Similar remarks apply to Amigas and Macintoshes running A/UX or other UNIX clones.
VMS, MVS, etc. (Minicomputers & mainframes). A few viruses spread over networks. More commonly affected by worms (RTM Internet worm, e.g.), logic bombs via e-mail, etc.
Conditions for propagation [1] (epidemiology):
Many computers in close proximity. "Proximity" may not be physical distance between computers, but between computer owners in the same class or job.
Frequent exchange of susceptible software. Long incubation period of virus. Proportionately few "immune" individuals in the community, i.e. those using
anti-viral software. Use of software brought from home, where "the kids" could bring home
viruses from school, etc.
Prevention of virus infections or attenuation of epidemics:
Remove any of the conditions above.
Isolate computers. This is seldom practical! But you can set aside one computer in an organization on which to try out disks and software before releasing disks for general use.
Don't be hasty to try every new program that comes down the pike. Use the computer set aside in #1 to set future dates and see if anything
happens.
Use anti-viral software on ALL computers, and keep it updated regularly. (The few users who don't use the software will be protected by "herd immunity" which is well known in disease control.)
Disallow use of any software not purchased by and for the corporation, or disinfected as in #1 and #3.
UNIT 6: Computer Generations
The development of electronic computers can be divided into five generations depending upon the technologies used. A computer generation is born when there is a departure in technology.
First Generation of Computers (1942-1955)The beginning of commercial computer age is from UNIVAC (Universal Automatic Computer). It was developed by two scientists Mauchly and Echert at the Census Department of United States in 1947. They were based on vacuum tubes. Examples of first generation computers are ENIVAC and UNIVAC-1
Advantages
Vacuum tubes were the only electronic component available during those days. Vacuum tube technology made possible to make electronic digital computers. These computers could calculate data in milliseconds.
Disadvantages
The computers were very large in size. They consumed a large amount of energy. They heated very soon due to thousands of vacuum tubes. Therefore needed air
conditioning hence they were not very reliable. Costly commercial production. Limited commercial use. Very slow speed. Limited programming capabilities. Used machine language only. Used magnetic drums which provide very less data storage. Used punch cards for input. Not versatile and very faulty so constant maintenance was required.
Second Generation Computers (1955-1964)
The second generation computers used transistors. The scientists at Bell laboratories developed transistor in 1947. The size of the computers was decreased by replacing vacuum tubes with transistors. The examples of second generation computers are IBM 7094 series and IBM 1400 series
Advantages
Smaller in size as compared to the first generation computers. More reliable Used less energy and were not heated. Wider commercial use Better portability as compared to the first generation computers. Better speed and could calculate data in microseconds
Used faster peripherals like tape drives, magnetic disks, printer etc. Used Assembly language instead of Machine language. Accuracy improved.
Disadvantages
Cooling system was still required Constant maintenance was required Commercial production was difficult Only used for specific purposes Costly and not versatile Punch cards were used for input.
Third Generation Computers (1964-1975)The Third generation computers used the integrated circuits (IC). Kilby developed the concept of integrated circuit in 1958. It was an important invention in the computer field. The first IC was invented and used in 1961. The size of an IC is about ¼ square inch. A single IC chip may contain thousands of transistors. The computer became smaller in size, faster, more reliable and less expensive. The examples of third generation computers are IBM 370 and UNIVAC AC 9000.
Advantages
Smaller in size as compared to previous generations. More reliable. Used less energy Produced less heat as compared to the previous two generations of computers. Better speed and could calculate data in nanoseconds. Used fan for heat discharge to prevent damage. Maintenance cost was low because hardware failure was rare. Totally general purpose Could be used for high-level languages. Good storage Versatile to an extent Less expensive Better accuracy Commercial production increased. Used mouse and keyboard for input.
Disadvantages
Air conditioning was required. Highly sophisticated technology required for the manufacturing of IC chips.
Fourth Generation Computers (1975-Present)
The fourth generation computers started with the invention of Microprocessor. The Microprocessor contains thousands of ICs. Ted Hoff produced the first microprocessor in 1971 for Intel. It was known as Intel 4004. The technology of integrated circuits improved rapidly. The LSI (Large Scale Integration) circuit and VLSI (Very Large Scale Integration) circuit was designed. It greatly reduced the size of computer. The size of modern Microprocessors is usually one square inch. It can contain millions of electronic circuits. The examples of fourth generation computers are Apple Macintosh & IBM PC.
UNIT 7: TYPES OF COMPUTERS
Types of Computer : Based on SizeDeep March 19, 2012 Types of Computer : Based on Size2012-04-09T18:59:47+00:00 IT Stuff
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The magic machine – Computers, are not only classified w.r.t their functions but are also differentiated by their size.
Primarily they are divided into four main types:
Super Computer Mainframe Computer Mini Computer Micro Computer
Super Computer:
They are focused on performing specific actions and follow heavy extremely intense and critical calculations like weather forecasting, fluid dynamics etc. They are generally used by scientists and are very powerful and expensive. The speed with which they operate is highly blazing.
Mainframe Computer:
They are the typical large computing machines which occupied extremely large space, more than the size of the rooms today. They were capable of operating multiple users via single interface and typically operated more than million instructions per second.
Mini Computer:
They are the intermediate solutions between Mainframe computers and Micro Computers. And they are also known as mid-range computers.
Micro Computer:
Microcomputers came into picture as computers having single chip micro processors. They are the most common computers being used for domestic / commercial purposes now a days. They also include solutions like Desktop Computers, Game Consoles, Tablet Computers, and Smart Phones etc. They are basically portable and carry very less space.
CLASSIFICATION BASED ON SIZE AND CAPABILITY
Classification digital Computer based on size and Capability
Based on size and capability, computers are broadly classified into
a. Microcomputers(Personal Computer) A microcomputer is the smallest general purpose processing system. The older pc started 8 bit processor with speed of 3.7MB and current pc 64 bit processor with speed of 4.66 GB.
Examples: - IBM PCs, APPLE computers
Microcomputer can be classified into 2 types :1. Desktops
2. Portables
The difference is portables can be used while travelling whereas desktops computers cannot be carried around.
The different portable computers are: -1) Laptop
2) Notebooks
3) Palmtop (hand held)
4) Wearable computers
Laptop: - this computer is similar to a desktop computers but the size is smaller. They are expensive than desktop. The weight of laptop is around 3 to 5 kg.
Notebook: - These computers are as powerful as desktop but size of these computers are comparatively smaller than laptop and desktop. They weigh 2 to 3 kg. They are more costly than laptop.
Palmtop (Hand held): - They are also called as personal Digital Assistant (PDA). These computers are small in size. They can be held in hands. It is capable of doing word processing, spreadsheets and hand writing recognition, game playing, faxing and paging. These computers are not as powerful as desktop computers. Ex: - 3com palmV.
Wearable computer: - The size of this computer is very small so that it can be worn on the body. It has smaller processing power. It is used in the field of medicine. For example pace maker to correct the heart beats. Insulin meter to find the levels of insulin in the blood.
b). Workstations:- It is used in large, high-resolution graphics screen built in network support, Engineering applications(CAD/CAM), software development desktop publishing
Ex: Unix and windows NT.
b) Minicomputer: - A minicomputer is a medium-sized computer. That is more powerful than a microcomputer. These computers are usually designed to serve multiple users simultaneously (Parallel Processing). They are more expensive than microcomputers. Examples: Digital Alpha, Sun Ultra.
c) Mainframe computers: - Computers with large storage capacities and very high speed of processing (compared to mini- or microcomputers) are known as mainframe computers. They
support a large number of terminals for simultaneous use by a number of users like ATM transactions. They are also used as central host computers in distributed data processing system.
Examples: - IBM 370, S/390.
d) Supercomputer: - Supercomputers have extremely large storage capacity and computing speeds which are many times faster than other computers. A supercomputer is measured in terms of tens of millions Instructions per second (mips), an operation is made up of numerous instructions. The supercomputer is mainly used for large scale numerical problems in scientific and engineering disciplines such as Weather analysis.
Examples: - IBM Deep Blue
Since the advent of the first computer different types and sizes of computers are offering different services. Computers can be as big as occupying a large building and as small as a laptop or a microcontroller in mobile & embedded systems.
The four basic types of computers are as under:
1. Supercomputer2. Mainframe Computer3. Minicomputer4. Microcomputer
SupercomputerThe most powerful computers in terms of performance and data processing are the Supercomputers. These are specialized and task specific computers used by large organizations. These computers are used for research and exploration purposes, like NASA uses supercomputers for launching space shuttles, controlling them and for space exploration purpose.
The supercomputers are very expensive and very large in size. It can be accommodated in large air-conditioned rooms; some super computers can span an entire building.
See Also: Top ten Supercomputers with HD pictures
Seymour Cray designed the first Supercomputer "CDC 6600" in 1964. CDC 6600 is known as the first ever Supercomputer.
Exascale SupercomputerOn 29th July, 2015, President of the United States, Barack Obama, approved the development of an Exascale Super Computer. The Exascale Super computer will be 30 times faster and more powerful than today’s fastest Super Computers. The need to develop such a high performance Supercomputer comes after China’s surge in high performance computing. However, the US still tops the list of Supercomputers with 233 high performance machines. China has 37 Supercomputers but they lead the list of the most powerful and high performance supercomputers since June 2013.
Presently, China’s "Tianhe – 2" is the world’s faster Supercomputer.
The Tianhe – 2 can perform 100 Petaflops, i.e quadrillions of floating point operations per second.
The following table shows list of top five most powerful Supercomputers in the world. you can also view complete list of Top 500 Supercomputers in the world.
Top five Supercomputers
RANK SITE SYSTEM CORESRMAX
(TFLOPS/S)
RPEAK
(TFLOPS/S)
POWER
(KW)
1National Super computer in Guanzhou, China
Tianhe - 2 (MilkyWay - 2)
3,120,000 33,862.7 54,902.4 17,808
2DOE/SC/Oak Ridge National Laboratory, United States
Titan - Cray XK7, Cray Inc.
560,640 17,590.0 27,112.5 8,209
3DOE/NNSA/LLNL, United States
Sequoia - BlueGene/Q, IBM
1,572,864 17,173.2 20,132.7 7,890
4 RIKEN Advanced Institute for Computational Science
K Computer, Tofu Interconnect
705,024 10,510.0 11,280.4 12,660
Top five Supercomputers
RANK SITE SYSTEM CORESRMAX
(TFLOPS/S)
RPEAK
(TFLOPS/S)
POWER
(KW)(AICS) Japan Fujitsu.
5DOE/SC/Argonne National Laboratory, United States
Mira - BlueGene/Q, Custom IBM
786,432 8,586.6 10,066.3 3,945
Uses of SupercomputersIn Pakistan Supercomputers are used by Educational Institutes like NUST for research purposes. Pakistan Atomic Energy commission & Heavy Industry Taxila uses supercomputers for Research purposes.
Space Exploration
Supercomputers are used to study the origin of the universe, the dark-matters. For these studies scientist use IBM’s powerful supercomputer “Roadrunner” at National Laboratory Los Alamos.
Earthquake studies
Supercomputers are used to study the Earthquakes phenomenon. Besides that supercomputers are used for natural resources exploration, like natural gas, petroleum, coal, etc.
Weather Forecasting
Supercomputers are used for weather forecasting, and to study the nature and extent of Hurricanes, Rainfalls, windstorms, etc.
Nuclear weapons testing
Supercomputers are used to run weapon simulation that can test the Range, accuracy & impact of Nuclear weapons.
Popular Supercomputers
IBM’s Sequoia, in United States
Fujitsu’s K Computer in Japan IBM’s Mira in United States IBM’s SuperMUC in Germany NUDT Tianhe-1A in China
Mainframe computerAlthough Mainframes are not as powerful as supercomputers, but certainly they are quite expensive nonetheless, and many large firms & government organizations uses Mainframes to run their business operations. The Mainframe computers can be accommodated in large air-conditioned rooms because of its size. Super-computers are the fastest computers with large data storage capacity, Mainframes can also process & store large amount of data. Banks educational institutions & insurance companies use mainframe computers to store data about their customers, students & insurance policy holders.
Popular Mainframe computers
Fujitsu’s ICL VME Hitachi’s Z800
MinicomputerMinicomputers are used by small businesses & firms. Minicomputers are also called as “Midrange Computers”. These are small machines and can be accommodated on a disk with not as processing and data storage capabilities as super-computers & Mainframes. These computers are not designed for a single user. Individual departments of a large company or organizations use Mini-computers for specific purposes. For example, a production department can use Mini-computers for monitoring certain production process.
Popular Minicomputers
K-202 Texas Instrument TI-990 SDS-92 IBM Midrange computers
MicrocomputerDesktop computers, laptops, personal digital assistant (PDA), tablets & smartphones are all types of microcomputers. The micro-computers are widely used & the fastest growing computers. These computers are the cheapest among the other three types of computers. The Micro-computers are specially designed for general usage like entertainment, education and work purposes. Well known manufacturers of Micro-computer are Dell, Apple, Samsung, Sony & Toshiba.
Desktop computers, Gaming consoles, Sound & Navigation system of a car, Netbooks, Notebooks, PDA’s, Tablet PC’s, Smartphones, Calculators are all type of Microcomputers.You might also like:
The Five Generations of Computers Advantages & disadvantages of computers Who invented the first Computer?
UNIT 8: COMPUTER APPLICATIONS
A computer application is here defined as a program that is used to perform a user tasks with the computer. You have come across the definition of software in the early sections of this module. You also learnt how this software is classified in which case you learnt that one category or class of software is called the applications software. In this course you will learn mainly three computer applications which are Word processing, Spreadsheet and Power Point. The applications are covered in your practical sessions in the computer laboratory. To help you in the laboratory work, we developed a practical manual that shall be used together with this module.
