Introduction to Computers and Windows: Hardware Components and Data Processing, Lecture notes of Computer Science

Download Introduction to Computers and Windows: Hardware Components and Data Processing and more Lecture notes Computer Science in PDF only on Docsity! COMPUTER MANUAL ©2017 INTRODUCTION TO COMPUTERS AND WINDOWS What is a computer? A computer is an information-processing machine. It may also be defined as a device that works under the control of stored programs automatically accepting, storing and processing data to produce information that is the result of that processing. BASIC COMPUTING TERMS Data-Refers to raw facts describing a situation Information – Refers to data that has been assembled into a more useful form or intelligible form e.g. invoices, vouchers, reports e.t.c Binary- A base-2 number system in which values are expressed as combinations of two digits, 0 and 1. Bytes A unit of data that typically holds a single character, such as a letter, a digit, or a punctuation mark. Some single characters can take up more than one byte. 1 COMPUTERS SYSTEM A Computer System is made up of three main components ♦ Hardware ♦ Software ♦ Liveware Hardware are the physical components of a computer e.g. keyboard, printer, mouse, system unit etc. Hardware categories A computer system is a set of integrated devices that input, output, process, and store data and information. Computer systems are currently built around at least one digital processing device. There are five main hardware components in a computer system: the central processing unit (CPU); primary storage (main memory); secondary storage; and input and output devices. Basic elements of hardware The basic elements that make up a computer system are as follows: a. Input Most computers cannot accept data in forms customary to human communication such as speech or hand-written documents. It is necessary, therefore, to present data to the computer in a way that provides easy conversion into its own electronic pulse-based forms. This is commonly achieved by typing data using the keyboard or using an electronic mouse or any other input device. ✳ Keyboard can be connected to a computer system through a terminal. A terminal is a form of input and output device. A terminal can be connected to a mainframe or other types of computers called a host computer or server. There are four types of terminals namely dumb, intelligent, network and Internet. 1. Direct data entry devices – Direct entry creates machine-readable data that can go directly to the CPU. It reduces human error that may occur during keyboard entry. Direct entry devices include pointing, scanning and voice-input devices. Pen input devices e.g. Lightpen Pen input devices are used to select or input items by touching the screen with the pen. Light pens accomplish this by using a white cell at the tip of the pen. When the light pen is placed against the monitor, it closes a photoelectric circuit. The photoelectric circuit identifies the spot for entering or modifying data. Engineers who design microprocessor chips or airplane parts use light pens. Touch sensitive screen inputs Touch sensitive screens, or touch screens, allow the user to execute programs or select menu items by touching a portion of a special screen. Behind the plastic layer of the touch screen are crisscrossed invisible beams of infrared light. Touching the screen with a finger can activate actions or commands. Touch 2 Monitors – Output device for soft-copy output (temporal screen display of output which lasts as long as the monitor’s power is on). They are the most frequently used output devices. Some are used on the desktop; others are portable. Two important characteristics of the monitor are size and clarity. Voice-output devices 1. Voice-output devices make sounds that resemble human speech. ✳ Voice-output devices use prerecorded vocalized sounds to produce output. ✳ The computer “speaks” synthesized words. ✳ Voice output is not as difficult to create as voice input. ✳ Most widely used voice-output devices are stereo speakers and headphones. ✳ Devices are connected to a sound card in the system unit. ✳ Sound card is used to capture sound as well as play it back. Examples of voice output uses: ✳ Soft-drink machines, the telephone, and in cars. ✳ Voice output can be used as a tool for learning. ✳ Can help students study a foreign language. ✳ Used in supermarkets at the checkout counter to confirm purchases. ✳ Most powerful capability is to assist the physically challenged. Auxiliary/Secondary Storage devices Secondary storage devices store a larger amount of data or instructions than does main memory, on a more permanent basis. On a per megabyte basis, secondary storage is also cheaper than primary storage. Secondary storage is also infinitely extendable, unlike main memory, which is finite. Secondary storage is not volatile. Secondary storage is also more portable than primary storage – that is, it is possible to remove it from a computer and use the device and its contents in another. Types of secondary storage devices 1. Magnetic disks – Stores bits as magnetic spots. Magnetic disks are similar to magnetic tapes in that areas are magnetized to represent bits. However the disks’ read/write head can go directly to the desired record, allowing fast data retrieval. Magnetic disks can range from small and portable, such as diskettes with 1.44MB of storage capacity, to large capacity fixed hard disks, which are more expensive and less portable. o Floppy disks (diskettes) F 0 A 75 ¼ floppy disks F 0 A 73 ½ floppy disks – The most common size with a capacity of 1.44 MB. They are not very fast and durable. o Hard disks/Fixed disks – Also called hard drives. Their capacity range from 20 to 120 GB. They are fast and durable though not foolproof. Most are internal, but disks that use removable cartridge are available. Disk compression can be used to increase capacity but slows performance. 5 2. Optical Disks – Store bits as “pits” and “lands” on surface of disk that can be detected (read) by a laser beam. o CD-ROM (Compact-Disk Read Only Memory) – Only read and cannot be erased for rewriting. Has a capacity of 650 MB o CD-R (Compact-Disk Recordable) / WORM (Write Once, Read Many) – Usually blank at first and can be written only once. Has a capacity of 650 MB o CD-RW (Compact Disk ReWritable) – Can written and read more than once. Has a capacity of 650 MB. o DVD-ROM (Digital Video Disks) – They are similar to CDs except that it has high quality sound and high-resolution video. Has a normal capacity of 4.7 GB and up to 17 GB if double-sided with double layering. Uses laser technology. They are a relatively new technology usually used in the entertainment industry. Storage capacity abbreviations 1. KB - kilobyte - 1000 (thousand) 2. MB - megabyte - 1,000,000 (million) 3. GB - gigabyte - 1,000,000,000 (billion) 4. TB - terabyte - 1,000,000,000,000 (trillion) Communication devices 1. Modem - Modems allow computers (digital devices) to communicate via the phone system (based on analog technology). It turns the computers digital data into analog, sends it over the phone line, and then another modem at the other end of the line turns the analog signal back into digital data. 2. Fax/modem - basic digital/analog modem enhanced with fax transmission hardware that enables faxing of information from computer to another fax/modem or a fax machine (NOTE: a separate scanner must be connected to the computer in order to use the fax/modem to transfer external documents) Computer Memory Memory capability is one of the features that distinguish a computer from other electronic devices. Like the CPU, memory is made of silicon chips containing circuits holding data represented by on or off electrical states, or bits. Eight bits together form a byte. Memory is usually measured in megabytes or gigabytes. A kilobyte is roughly 1,000 bytes. Specialized memories, such as cache memories, are typically measured in kilobytes. Often both primary memory and secondary storage capacities today contain megabytes, or millions of bytes, of space. 1. RAM (Random Access Memory) /RWM (Read Write Memory) – Also referred to as main memory, primary storage or internal memory. Its content can be read and can be changed and is the working area for the user. It is 6 used to hold programs and data during processing. RAM chips are volatile, that is, they loose their contents if power is disrupted. Typical sizes of RAM include 32MB, 64MB, 128MB, 256MB and 512MB. a. EDO – Extended Data Out b. DRAM – Dynamic RAM c. SDRAM – Synchronous 1. ROM (Read Only Memory) – Its contents can only be read and cannot be changed. ROM chips is non-volatile, so the contents aren’t lost if the power is disrupted. ROM provides permanent storage for unchanging data & instructions, such as data from the computer maker. It is used to hold instructions for starting the computer called the bootstrap program. ROM: chips, the contents, or combination of electrical circuit states, are set by the manufacturer and cannot be changed. States are permanently manufactured into the chip. NB 1. Computer Virus is a malicious program written with the intention of destroying computer resources. 2. CONTROL PANEL-Provides you with options of customizing your computer with its functionality. 3. Software refers to the programs that facilitate the working of a computer system. There are two types of software namely: ♦ System software e.g. Operating System ♦ Application software Operating System refers to that software responsible for starting the computer. It is necessary for other programs to run and for the user to interact with the hardware. Commonly used Operating systems are:-MS-DOS (Microsoft Disk Operating System). Windows XP, Windows 2007. STARTING UP A COMPUTER NB: Ensure the power cables are correctly placed in the sockets and they are ON • Press the switch button on system unit and the monitor • The system will boot i.e. Load the operating system from the main memory ready to be used. • Log on to the system. DESKTOP The on-screen work area on which windows, icons, menus, and dialog boxes appear. To change your desktop background 1. Open Display in Control Panel. 2. On the Desktop tab, do one or more of the following: • Click a picture in the Background list. In Position, click Center, Tile, or Stretch. • Click Browse to search for a background picture in other folders or on other drives. You can use files with the following extensions: .bmp, .gif, .jpg, .dib, .png, .htm. In Position, click Center, Tile, or Stretch. • Select a color from Desktop color. The color fills the space not used by a picture. 7 FEATURES OF MS WORD WINDOW Ms Word has the following features:- ♦ Title bar ♦ Menu Bar ♦ Standard toolbar ♦ Formatting Toolbar ♦ Ruler ♦ Status bar. Create a document The following procedure creates a new, blank document. • On the Standard toolbar, click New Blank Document . From a copy of an existing document 1. On the File menu, click New. 2. In the New Document task pane, under New, click From existing document. 3. Click the document you want to create a new document from. If you want to open a document that was saved in a different folder, locate and open the folder. 4. Click Create New. This document is created in the folder that contains the original document Saving documents To quickly save a document, click Save on the Standard toolbar. 1. On the File menu, click Save As. 2. In the File name box, enter a new name for the file. 3. Click Save Selecting a document view Do any of the following: 4. Click the View menu to select Normal, Web Layout, Print Layout, Outline, Reading Layout, Document Map, or Thumbnails. 5. Click the File menu to select either Web Page Preview or Print Preview view. Change the size of text 1. Select the text you want to change. 2. On the Formatting toolbar, type or click a point size in the Font Size box . For example, type 10.5. Adding page numbers 1. On the Insert menu, click Page Numbers. 2. In the Position box, specify whether to print page numbers in the header at the top of the page or in the footer at the bottom of the page. 10 3. In the Alignment box, specify whether to align page numbers left, center, or right relative to the left and right margins, or inside or outside relative to the inside and outside edges of pages that will be bound. 4. If you don't want a number on the first page, clear the Show number on first page check box. 5. Select any other options you want. Headers and footers • Headers and footers are areas in the top and bottom margins of each page in a document. • You can insert text or graphics in headers and footers— for example, page numbers, the date, a company logo, the document's title or file name, or the author's name — that are printed at the top or bottom of each page in a document. • You can work in the header and footer areas by clicking Header and Footer on the View menu Tables A table is made up of rows and columns of cells that you can fill with text and graphics. Tables are often used to organize and present information. Creating a table 1. Click where you want to create a table. 2. On the Table menu, point to Insert, and then click Table. 3. Under Table size, select the number of columns and rows. 4. Under AutoFit behavior, choose options to adjust table size. 5. To use a built-in table format, click AutoFormat. Select the options you want. Add a cell, row, or column to a table 1. On the Table menu, point to Insert, and then click an option. Note • To quickly add a row at the end of a table, click the last cell of the last row, and then press the TAB or ENTER key. • To add a column to the right of the last column in a table, click in the last column. On the Table menu, point to Insert, and then click Columns to the Right. • You can also use the Draw Table tool to draw the row or column where you want. Word Art You can insert decorative text by using Insert WordArt on the Drawing toolbar. You can create shadowed, skewed, rotated, and stretched text, as well as text that has been fitted to predefined shapes. 11 Because a special text effect is a drawing object, you can also use other buttons on the Drawing toolbar to change the effect— for example, to fill a text effect with a picture. Drawings Use the Drawing toolbar to add any shapes or pictures that you want. Add bullets or numbering Bullet: A dot or other symbol that is placed before text, such as items in a list, to add emphasis.) or numbers to existing lines of text. Add bullets or numbering to existing text 1. Select the items you want to add bullets or numbering to. On the Formatting toolbar, click Bullets or Numbering 12