Computer Science Notes (KWASU) PDF

Peripheral storage devices are those devices used to store or back up useful information. Such devices can also be used to save work for future use. E.g. diskettes ,flash drive and memory cards. **PRINTER** This peripheral output device attached to the central processing unit (CPU)to print out pro...

Peripheral storage devices are those devices used to store or back up useful information. Such devices can also be used to save work for future use. E.g. diskettes ,flash drive and memory cards. **PRINTER** This peripheral output device attached to the central processing unit (CPU)to print out processed information. TYPES OF PRINTERS - Dot Matrix Printers(DMP) - Daisywheel Printer(DP) - Laser jet Printer (LP). **Dot Matrix Printers (DMP):** These are the most popular and cheapest printer. They form each by a combination of dots usually in a pattern of 8rows by 11 columns. While 7rows by 9 columns are used for the characters, the remaining 1 row and 2 columns are used for spacing between characters. They are fast, versatile, economical and multi-purpose printers e.g. EPSON FX 1050. They can print graphics, spreadsheet charts and different types of fonts or characters that are not necessarily as sharp as those of electronic typewriters. **Daisywheel Printer (DP):** These adopt a thimble shaped printing element called Daisywheel to generate Letter Quality (LQ) **Laser jet Printer (LP**): These are high revolution printers that produce typeset quality texts and graphics.They are essentially based on the same technology as photocopy machines. They are high quality printers and give high density to produce per inch. E.g. 300 0r 600 per inch. However, the most recently designed printers are the inkjet and heat sensitive printers **TAPEUNIT** This is also a peripheral storage device designed to provide cheap and reliable back up for vital information. This is because hard disk a prone to corruption or damage particularly by power surges. Hence it provides a very convenient remedy to backup large volumes of information e.g. diskettes. **KEYBOARD** This is one of the unit devices used to send data into the system. There are two types of keyboard. They are: 1. Standard keyboard 2. Enhanced keyboard **1. 4 Introduction to Computer Software** **Introduction** Unlike hardware which refers to the physical parts of the computer that can be touched, software is the set of intangible instructions that tell the computer what to do. This unit discusses the two major categories of computer software, namely application and system software, as well as the types of software in each category. **Categories of Computer Software** Software is broadly divided into two categories: **System Software:** These are the software that interact with the computer at a very basic level. They help the computer to carry out its basic operating functions such as managing files, interacting with input/output devices, and removing viruses from the computer. Examples of system software are operating systems, utilities and language translators. **Application Software:** These are the software that help users to do real work such as creating documents, editing photos or tracking finances. Application software do not interact with the computer directly. Rather, they do so through system software such as operating systems and utilities. **Comparison Application Software and System Software** +-----------------------+-----------------------+-----------------------+ | | System Software | Application Software | +=======================+=======================+=======================+ | | Computer software, or | Application software, | | | just software is a | also known as an | | | general term | application or an | | | primarily used for | \"app\", is computer | | | digitally stored data | software designed to | | | such as computer | help the user to | | | programs and other | perform specific | | | kinds of information | tasks. | | | read and written by | | | | computers. App comes | | | | under computer | | | | software though it | | | | has a wide scope now. | | +-----------------------+-----------------------+-----------------------+ | Example: | 1\) Microsoft | 1\) Opera (Web | | | Windows | Browser) | | | | | | | 2\) Linux | 2\) Microsoft Word | | | | (Word Processing) | | | 3\) Unix | | | | | 3\) Microsoft Excel | | | 4\) Mac OSX | (Spreadsheet | | | | software) | | | 5\) DOS | | | | | 4\) MySQL (Database | | | | Software) | | | | | | | | 5)MicrosoftPowerPoint | | | | (Presentation | | | | Software) | | | | | | | | 6\) Adobe Photoshop | | | | (Graphics Software) | +-----------------------+-----------------------+-----------------------+ | Interaction: | Generally, users do | Users always interact | | | not interact with | with application | | | system software as it | software while doing | | | works in the | different activities. | | | background. | | +-----------------------+-----------------------+-----------------------+ | Dependency: | System software can | Application software | | | run independently of | cannot run without | | | the application | the presence of the | | | software. | system software. | +-----------------------+-----------------------+-----------------------+ Figure 1.0, provides an overview of application software and system software, as well as the types of software in each category. Figure 1 Overview of types of software **1.5 Operating Systems** Operating systems are the most important programs that run on a computer, because they control all activities that take place in a computer. Operating systems perform basic tasks such as keeping Strack of files, management of memory allocated to programs and data, and controlling input/output devices such as keyboard and printer. Examples of operating systems for general-purpose computers are Microsoft Windows, Mac OS, UNIX and Linux. Handheld devices use operating systems such as Windows Mobile OS, iOS and Android OS. **Utilities** A utility is a program designed to perform tasks such as optimizing a computer's performance, protecting data and facilitating communication. Examples of utility programs are: i. **Antivirus software** for protecting the computer from computer virus. ii. **Backup software** that help store copies of files, which can be restored in case the files get lost or damaged. iii. **Compression utilities (or zip software)** that shrink files so that they require less storage space. Compression utilities can also return files to their original form when required. iv. **Email software** for managing the flow of data to/from an electronic post office box. v. **Language Translators** Computers understand only machine language, in which instructions are written as strings of zeros and ones. However, programming in machine language is tedious and error-prone for humans. As a result, programs are usually written in high level languages which contain English commands and mathematical symbols that humans are familiar with. Language translators are system software that convert high level language programs to machine language programs which the computer understands. Examples of language translators are: i. **Compilers** which translate all instructions in a high level language program to machine language before executing any instruction. ii. **Interpreters** which translate and execute an instruction in a high level language program before moving to the next instruction. **Word Processors** A word processor is a program for producing documents such as letters, memos, reports and manuscripts. Word-processing software allow you to create, edit, format and spell-check documents on the screen before orienting on paper. Examples of word processors are Microsoft Word and Open Office Writer. **Spreadsheets** A spreadsheet is an arrangement of rows and columns containing values that can be manipulated. An electronic spreadsheet is a program for working with spreadsheets. Because electronic spreadsheets allow users to simple or complex formula, they can be used for performing tasks such as budgeting, tracking finances, calculating loan payments, computing student grades and estimating project costs. Electronic spreadsheets allow users to display varieties of colorful graphs. They often support *what-if-analysis*, for analyzing different scenarios such as "What if I score B's in all my courses this semester? But what if I score only C's?" examples of electronic spreadsheets are Microsoft Excel and Open Office Calc. **Database Management Systems** A database is a collection of data stored on one or more computers. A database can contain data such as details of books in a library, university student records, or bank customer details. A database management system (DBMS) is a program for storing, modifying, finding and reporting data contained in a database. DBMS allow users to *query the database*, that is, to extract information that meets certain criteria. For example, a query could request the DBMS to list all students who scored at least a B grade in COS 101, arranged according to their matriculation numbers. Examples of popular DBMS are Microsoft Access, Oracle and My SQL. **Presentation Software** Presentation software enable users to combine text, graphs, photos, sound clips and animation into series of electronic slides. For one-on-one presentations, the slides can viewed on the monitor. However, group presentations are commonly viewed using a computer projector. Presentation slides can also be posted on the Internet. Electronic slides can be used by instructors and students to deliver lecturers and oral presentations. They are also useful for presenting ideas in meetings and conferences. Examples of common presentation software are Microsoft PowerPoint and Open Office Impress and Google Presentations. **Graphics Software** Graphics software allow users to create, edit and manipulate graphics. These graphics could be pictures, images, drawings, icons or photographs. There are different types of graphics software: i. **Paint software help you paint images by providing pens, brushes and paints. They represent images using bitmap** graphics formats such as BMP, PNG, TIF and JPEG. Examples of paint software are Microsoft Paint and Corel Painter. ii. **Drawing software** are designed to for combining lines, shapes and colors into diagrams. They represent diagrams using vector graphics files such as WMF and EPS. Examples of drawing software are Adobe Illustrator and Corel DESIGNER. iii. **Photo editing software** allow you to enhance poor-quality photos by adjusting brightness and contrast, cropping out unwanted portions, and so on. A popular example of photo editing software is Adobe Photoshop. **MODULE 3** **APPLICATION OF COMPUTERS** Computers have proliferated into various areas of our lives. For a user, computer is a tool that provides the desired information, whenever needed. You may use computer to get information about the reservation of tickets (railways, airplanes and cinema halls), books in a library, medical history of a person, a place in a map, or the dictionary meaning of a word. The information may be presented to you in the form of text, images, video clips, etc. Some of the application areas of the computer are listed below--- PRACTICE QUESTIONS 1. What did first generation of computers use for circuitry? 2. What is the main technology used in third generation computers 3. Which of the following device was not invented by Babbage? a: Pascaline b: Difference Engine c: Analytical Engine 4. Which part of the computer is used for calculating and comparing? 5. The hard drive is a:Volatile b:Non --volatile c:Both d:None 6. The hardware that is responsible for processing information and processing instructions given to is a:The motherboard b:The CPU c:The hard drive d:The compact disk 7. All the following are widely used input devices except the a:Keyboard and mouse b:Microphone and scanner c:Digital camera and PC camera d:Printer and monitors 8. Which of the following is/are functions that a mouse CANNOT do? a:Scrolling b:Drag and drop c:Clicking d:Make a copy of a document 9. A joy stick is primary used to/for 10. The software can best be described as a:The team of people who used the computer b:Programmed instruction for the computer perform tasks c:Computer generated printed output d:The physical parts of a computer that cannot be seen 11. Abacus is otherwise known as 12. Who invented Mechanical calculator and which year was it 13. Who is referred to as the father of computing 14. The term GIGO is related to.......................... 15. Microsoft Word is an example of.................................. Software