Computer year summary - Essay Example

A computer system consist not only of the device which can perform computations without human Intervention UT also devices which allows data to be made available for processing and devices on which data can be displayed or printed for use by human beings. 1. List the three main components of a computer system. 1. Input 2. Processor 3. Output 2. Describe the functions of the three main components of a computer system. (I) Input – involves accepting data in machine-readable form and sending it to the Central Processing Unit (CPU) for processing. II) Processor – The central processing unit – controls and manipulates data to produce information. A microcomputer’s CPU is contained on a single integrated recruit or microcomputer chip. These chips are called microprocessor. Microprocessor – It carries out the processing task by interpreting and executing the instruction in a program. (iii) Output – The output function involves the presenting of data externally, passing data for further processing, or sending data for storage. 3. List the three components of the central processing unit. A. Arithmetic Logic unit (ALL’) b.

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Control unit c. Memory 4. Briefly describe the functions of the following three components of the central a. Memory – used to store program being run on the computer processing unit: ND data on which the program works. B. Control Unit – takes one program Instruction at a time and acts upon It. The actions results In the flow of data from one part of the computer to another. C. Arithmetic and Logic unit – the area where the computer performs simple arithmetic on the data, or compares one piece of data with another. 5. Explain what is meant by primary memory/storage.

Primary Storage (main memory) – the part of the computer that holds data and programs before and after they have been processed by the CPU. Secondary Storage (auxiliary storage)- a more permanent storage for data and programs than RAM. Secondary storage uses media such as hard disk, floppy disks and CD-ROOM. 7. Differentiate between random access memory (RAM) and read only memory (ROOM). RAM – Primary storage that is volatile. RAM is memory where data and instructions are held temporarily. When a computer is turned off, everything is lost from memory – all the transistor switches are set to ‘off (or ‘O’).

This means when it is turned back on there is nothing in memory. ROOM – Primary storage that is non-volatile. ROOM hold data and instructions which are fixed at the time of production and cannot be changed by the user or the computer. It is also known as the permanent memory of the computer system. The computer reads the instructions and executes them automatically – they cannot be altered. 8. Identify various types of: a. Input devices Direct Entry Direct entry creates machine-readable data that can go directly to the CAP]. Direct entry includes pointing, scanning and voice-input device.

Keyboard Entry In key entry, people type input. The input usually appears on a monitor. – Keyboard – used for typing, commands, messages and instructions and transmitting them to the CPU for interpretation and action. – Mouse – used for minting at items displayed on the screen (selecting) and activating them by clicking the buttons. Trackballs also operate in the similar manner. – Scanner – can read data off other common medium like paper for input into CPU for processing. – Readers – can read data from magnetic tape, floppy and hard disks, and other storage devices for input to the CPU for processing. Touch Screen : a touch screen is a particular kind of monitor screen covered with a plastic layer. Behind this layer are crisis- crossed invisible beams of infrared light. This arrangement enables someone to elect actions or commands by touching the screen with a finger. – Light Pens : a Light pen is a light-sensitive fanlike device. The light pen is placed against the monitor. This close a photo electronic circuit and identifies the spot for entering or modifying data. – Digitized: A digitized is a device that can be used to trace or copy a drawing or photograph. The shape is converted to digital data.

A computer can then represent the data on the screen or print it on paper. Digitizes are often used by designers and architects. – Pen-based computing: a pen-based computer is a small imputer. It lets you write directly on the display screen with a stylus. What is revolutionary is that these devices contain software that can recognize a person’s handwriting. – Scanning Device: Direct-entry scanning device record images of text, drawing or special symbols. The images a converted to digital data that can be processed by a computer or displayed on a monitor. – Image scanner – identifies images on a paper.

It automatically converts them to electronic signals that can be stored in a computer. The process identifies pictures or different typefaces by canning each image with light and breaking it into dots. The dots are then converted into digital codes for storage. – Visual Display Unit (VADUZ) – one of the most common methods of output in which the information or data is displayed for viewing by the user. Also known as monitor, is similar in many ways to an ordinary television screen. The monitor is used to present text and graphics, which are simply any kind of pictures, drawings, charts or plots.

Almost all computer monitors create text and graphics on screen with tiny dots called pixel (short for picture elements). – Printers – There are two types: Impact Printer – printing device which print by some print mechanism striking paper, ribbon and characters together. – Non Impact Printers – Printers which use a specially coated or sensitizes paper that responds to stimuli to cause an image to appear on a form – Plotters are special-purpose output devices for producing bar charts. Maps, architectural drawings and even three-dimensional illustrations.

The images output on the monitor are often referred to as soft copy. Information output on paper – whether by a printer or by a plotter is called hard copy. SOFTWARE – is another name for programs. Programs are the step-by-step instructions that tell the computer how to process data into the form you want. Software performs useful work on general-purpose tasks such as word processing and cost estimating. Packaged software consist of any program that has been overwritten by professional programmers and is typically offered for sale on a diskette.

Egg Word processing, Electronic spreadsheet, Database Management system, graphics programs and communications programs. Custom-made software – are programs written by computer professional to instruct he company computer to perform whatever tasks the organization wants. A program might compute payroll checks, keep track of goods in the warehouse, calculate sales commissions or perform similar business needs. Cost estimating, airline reservation, educational, inventory and payroll. Systems Software – program that helps the computer manage its own internal resources.

It manages the overall operation of the computer system. Egg. Windows XP, Windows 2000, DOS, unit. Microcomputer hardware – the physical equipment – falls into five categories. They are input devices, the system unit, secondary storage, output devices and immunization devices. Communication Device – communications hardware sends data and programs from one computer or secondary storage device to another. Many microcomputers use a modem. This device translates the electronic signals from the computer into electronic signals that can travel over a telephone line Data – is used to describe facts about something.

If data is stored electronically in files, it can be used directly as input for the information system. A file is a collection of characters organized as a single unit. Connectivity is the microcomputer’s ability to communicate with other computers and information sources. Connectivity is the capability of the microcomputer to use information from the world beyond your desk IT. 2 TYPES OF COMPUTERS 1. List and describe the four traditional categories of computers. – supercomputer, mainframe, minicomputer, microcomputer Personal Computers also known as Microcomputers.

It is most widely used and the fast-growing type. There are two categories of microcomputer – desktop and portable. Minicomputers also known as midrange computers and are desk-sized machines. They fall between microcomputer and mainframes in their processing speeds and data storage capabilities. Medium size companies or departments of use them to do research or to monitor a particular manufacturing process. Smaller size companies typically use microcomputers for their general data processing needs, such as accounting. Mainframe Computers are large computers occupying especially wired, air-conditioned rooms.

They are capable of great processing speeds and data storage. They are used by large organizations – businesses, banks, universities and government agencies – to handle millions of transactions. Foe example, insurance companies use mainframes to process information about millions of policy holders. Supercomputers – the most powerful type of computer. These machines are special, high-capacity computers used by very large organizations. For example, NASA uses supercomputers to track and control space explorations. Supercomputers are also used for oil exploration, simulations and worldwide weather forecasting. 2.

List the characteristics of the following in terms of size, speed, cost, abundance, use, users: TYPE COST No of Users at same time Users Examples Supercomputer Many Million Few of many Science & military Cray – 1 Mainframe millions Hundreds large business IBM system 370 Minicomputers SIS’S of OHIO’S Departments of business. DECK Micro – fax IBM ASSES Microcomputer hundreds to thousands Usually one Everyone IBM PC Apple Macintosh Commodore 64 Medium business 3. List the different categories of microcomputers. Portable. Desktop computers are small enough to fit on top or along the side of a desk and yet are too big to carry around.

Personal computers are one type of desktop. They are used by a wide range of individuals, from clerical people to managers. Workstations are another type of desktop computer. Portable computers are microcomputers that are small enough and light enough to move easily from one place to another. There are four categories of portable computers: laptops, notebooks, subcutaneous, and personal digital assistants. Laptops, which weigh between 10 to 16 pounds, may be either AC powered or battery powered or both. The user off laptop might be an accountant or financial person who needs to work on a computer away from desk.

Notebooks are a small version off laptop. They weigh between 5 to 10 pounds and can fit into most briefcases. The user off notebook PC might be a student, salesperson or Journalist, who uses the computer for note-taking. It is especially valuable in locations where electrical connections are not available. Notebook computers are the most popular portable computers today. Subcutaneous – are for frequent flyers and life-on-the road types. Subcutaneous users give up a full size display screen and keyboard in exchange for less weight. Weighing between 2 to 6 pounds, these computers fit easily into a briefcase.

Personal Digital Assistant (PDA) – are much smaller than even the subcutaneous. The typical PDA combines pen input, writing recognition, personal organizational tool and communication capabilities in a very small package. A PDA user might be a worker at a warehouse who records changes in inventory or a busy executive handling daily 5. Explain what an IBM compatible computer means. Of the desktop micros, the most common ones in Fiji today are the IBM Compatible Computers. There are more IBM Compatible Computers around mainly because they are cheaper than the pure IBM kind.

These computers have similar internal structures and can run the same programs. 6. Identify the different brands of IBM compatible computer currently found in Fiji. Some of those brands in Fiji are: Digital, Amsterdam, IDLE, Computed, Compact, Alter, Olivetti, etc 7. Identify the specifications of the different models of PC’s available. Another type of computer is called Apple Macintosh. It is relatively expensive and it has a different internal structure from the MOM. Another type of computer is the Commodore 64 which was the first computer in our school. These three types of computers are incompatible I. Their operating systems are different and they will not run the same program. Unit 1. 3 OPERATING SYSTEM 1. Explain what an operating system is. An Operating System is a software that manages the overall operation of the computer system. An operating system is a collection of programs used to control a computer system. It is a set of programs that instructs and controls the hardware features of a computer. The operating system manages resources. The main resource they manage is the computer hardware I. E. Processors, storage, input/ output devices and communication device. 2. Explain what DOS stands for.

Disk Operating System 3. List six broad categories of DOS programs. – bootstrap loader, diagnostic tests, operating system executive, BIOS, utility programs, file maintenance 4. Explain the functions of each of the following disgorges of the operating system programs: Bootstrap Loader – used to read the main portion of the operating system from secondary memory when the computer is turned on. The program is kept in ROOM. Diagnostic Tests – used to test the operation of the system’s components egg. Condition of the disk drive and RAM. Some of it is kept in ROOM and some are loaded from secondary memory when needed.

Operating System Executive – controls the activities of the system including executing programs and assigning tasks to various hardware devices. It is read into RAM when the computer is first started. Some sophisticated operating system executive allows for multitasking and multi-user systems. BIOS – stands for Basic Input/output System. Controls basic functions of hardware. egg. Reading a character from the keyboard writing a character to the display writing a character to the printer determining whether the printer is busy or not reading a sector from the disk in a particular disk drive.

Programs are kept in ROOM. They are thus, permanently available to programmers to create, write, read and erase data. egg. Formatting a disk displaying the content of a disk copying the content of a disk determining the space left in the disk making the backup copy of the disk restoring the contents of a hard disk from a backup copy. File Maintenance Programs – provide service routines to maintain files in different hardware devices. Allows programs to create, read and write files. They are not stand alone utility programs but are designed to be called from within user programs. . Name the three part of the DOS that are usually in ROOM. BIOS, Bootstrap Loader, Diagnostic test 7. Explain what is meant by booting the operating system. Turning on the computer and having the operating system loaded. 8. Recognize he DOS prompt. Is the symbol on the screen which indicates that the computer is ready for input. 9. Explain the terms resident and transient as applied to programs of the operating system. Resident – is one that resides in ROOM while the Transient is one that has to be loaded from the secondary storage in order to be used . 10.

Explain why all operating system programs cannot be kept in ROOM. Because of the limited space. The same is for RAM when the computer is running. 1 1 . Define the following: a. File – is a collection of text, data or instructions that is treated as a single unit by the computer. . Filename – can be from one to eight characters in length. C. File extension – consist of a period flowed by one, two or three character. 12. Give examples of the following a. Valid filename – 1-8 characters b. Invalid filenames – putting symbols in the filename c. Valid filename extension – . Doc (1-3 characters) d. Invalid filename extension – more then 3 characters 13. Identify where the information on the content of the disk is kept. The information on the content of a disk is kept in the disk directory. Define the following terms a. Read/write – a file that can be read from and written to . Hidden – are not listed in the directory 14. C. Read only – cannot be written to or changed but can be read from. 15. Identify what the operating system does when an application program is run. When a command is given for an application program to be loaded, the operating system finds the program and transfers it to RAM.

It then releases control to the applications program and awaits further instructions. 16. Describe the purpose of the Autocue. Bat file. Autocue. Bat file contains a series of instructions and names of programs that the user wants to run each time the computer boots up. 17. Describe the purpose of the Confining. Sys file. Congo. Sys file contains instructions to load device drivers 18. Describe what A multitasking operating system can allow more than one program to be run at one time. Egg Unix Multiuse Operating Systems – supports a several user at one time.

A:, B:, C:, D: – Name of floppy disk drives or hard disks PORN – stands for printer CON – stands for console/keyboard SCORN – stands for screen COM – stands for communication port Some basic tasks achieved by operating systems are: 1. Provides file sharing, data locking and file security. Disk formatting 2. Provide a range of communication . Database management 4. Peripherals access 5. 6. Input/output management directories – managing locations of information on disk 7. Controls program flows 8. Provides network with programs 9. 10.

Checking that error do not occur when reading to and writing from the disk. UNIT IT. 4 APPLICATION SOFTWARE 1. Define the term application software Application software is a program that are written for specific and general tasks, which are not, related to the computer system itself. 2. Identify the two broad categories of application software – special-purpose programs and general-purpose programs 3. Explain the difference between special-purpose programs and general-purpose programs. Special-purpose programs are dedicated to performing specific tasks egg.

Inventory, payroll, accounting, statistical analysis, education General-purpose programs can be used in a variety of tasks egg. Word processing, spreadsheet, database, graphics. 4. Explain what a word processor is, what it is used for and name example that can be used on a PC. A word processor is a program, which will enable one to write using a computer. It will enable one to enter text, edit it, save it and print it. Examples are Word Perfect, Word Star, Multimate, and Microsoft Word. . Explain what a spreadsheet is what it is used for and name example that can be used on a PC.

A spreadsheet is a program, which works like and electronic worksheet. It enables one to manipulate figures and text in columns and rows and perform calculations on them using formulas. Examples of spreadsheet programs are Lotus 123, Symphony, Equator, and Microsoft Excel. 6. Explain what a database is what it which is used for computerized record keeping. It provides a place to store information and a way to organism data so that it can be accessed in an organization and timely manner. Database can be used to store inventory records, mailing lists, personnel records etc.

Examples of a database programs include: debase ‘V, Reflex, R:Base for DOS, Paradox 7. Explain what is meant by integrated software and give examples. Integrated software is a program, which combines two or more application programs egg. Microsoft Works is an integrated program, which combines a word processor, a spreadsheet and a database. An integrated package usually shares a common user interface and you can switch from one application to another and cut or copy data from one to another. 8. List some areas in business where special- repose programs software is currently used.