Saturday, 4 June 2011
ssc 9thclass notes
Q.# 1. What are the main components of a digital computer?
There are three main components of a digital computer.
(1) Input (2) Out put (3) C.P.U
INPUT: - The devices that are used to enter data and instruction into the computer system are called Input devices.
Example: - Key board, Mouse, Scanner, Camera, etc.
OUTPUT: - The devices that are used to receive processed data from the computer are called Output devices.
Example: - Monitor Printer, Speaker, Microphone, etc.
C.P.U:- It stands for Central Processing Unit. It is the “Brain” of the computer. It is the main part of the computer system. All data passes through it and is processed in it. C.P.U consists of two main parts:
1:- Control Unit.
2:- Arithmetic and Logic Unit.Q.#.2 :- What is C.P.U? What tasks does the C.P.U perform? What are its components?
C.P.U:- It stands for Central Processing Unit. It is the “Brain” of the computer. It is the main part of the computer system. All data passes through it and is processed in it and the result is sent to the out put units.
Task of the C.P.U:- The C.P.U performs many tasks:-
(1) It can perform arithmetic calculations, such as (-, +, ×, %,÷) etc.
(2) It can perform logical decisions.
(3) It helps other devices in data transmission.
(4) It can perform manipulating tasks such as word processing.
Components of the C.P.U:- C.P.U consists of two main parts:
(1) C.U (2) A.L.U
C.U:- It stands for Control Unit. It controls all computer operation and the orders to all of its units.
A.L.U:- It stands for Arithmetic and Logic Unit. It performs all arithmetic and logical operations on the data. They consist of two parts.
Arithmetic section:- Arithmetic section of the ALU performs basic arithmetic operations such as (-, +, ×, %,÷).
Logic section:- Logic section of the ALU performs logical operations, such as greater than, less than, equal to, not equal, etc.Q.#.3:- Write short not on the following:-
Cash Memory:- It is part of the C.P.U. It is in the path between the main memory and the processor. It is in the form of a memory, but is faster than the main memory.
Secondary memory:- The secondary memory is an external memory. It is also called the Auxiliary Storage Device. It can store system files, compilers, assemblers and other programs. It includes devices such as magnetic tape, floppy disk, CDs etc.Q.#.4:- What are the Types of computer: -
Computer can be divided into three types.
1. Analogue computer: - These are special purpose computers and are mostly used in engineering and medical fields etc. Their input and output is in form of wave’s i.e. they accept data and provide results in form of waves.
2. Digital computer: - The computer, which accepts and provides data in digital form i.e. in the form of letters, numbers, and symbols, are called Digital Computers.
3. Hybrid computer: - These are also special purpose computers. But they have the capability for input in digital form and provide output in analogue form or input in analogue form while output in digital form.
What do you mean by input? Name all the input devices.
INPUT: - The devices that are used to enter data and instruction into the computer system are called Input devices.
Example: - Key board, Mouse, Scanner, Camera or web cam, Track ball, Light pen.
1. Key board: - A key board is an input device. Type writer like in appearance, it has from 84 to 108 buttons/keys. These are in groups: Alphabetic and numerical keys, (arranged as on a type writer), Numpad keys, Function keys, etc.
2. Mouse: - A small round hand held input device which is moved about on a desk or table top. It looks like a mouse and so is called a mouse. It is used to select options, to draw and helps in many other functions.
3. Joy stick: - It is and input device. It consists of a head of buttons and is used for computer games. It controls the movement of a certain object on the screen.
4. Track ball: - A track ball operates like a mouse. In the case of the track ball,the ball on the device is rotated.
5. Light pen: - It is a hand held pen like input device used to make structures which could not be done with a mouse.
6. Scanner: - This device is used to transfer the image of a photo, drawing or written text off a flat page into the computer.
7. Web camera: - This input device can be used to input moving images and still picture images into a computer. It can store still picture images and send them to the computer.Q. # :- What do you mean by out put? What devices are used for output? Briefly describe each.
OUTPUT: - The devices that are used to receive processed data from the computer are called Output devices or the results of processed data or called output.
TYPE OF OUTPUT: - There are two main types of output.
1. SOFTCOPY:- This refers to data that is shown as a display on the screen or audio/voice. Such copy can not be held in the hand.
2. HARD COPY: - This refers to printed output in the form of text or graphics.
OUTPUT DEVICES:-
MONITER: - This is a T.V like device that is used to display the result of a computer.
PRINTER:- This is used to print the soft copy on to paper. Some print out only text and others both text and graphics. The size of the print is generally that of standard paper sizes. There are two main types of printer.
1. Impact printer 2. Non-impact printer.
CD- WRITER: - This is used to read data from and write data on CDs.
Write a detailed note on printers.
A printer is an output device. A printer receives information and prints it on paper. Printers may be categorized in tow ways. Firstly into 1) Slow speed printers and 2 ) High speed printers:
1) Slow speed printers, e.g. Dot Matrix and Daisy wheel printers.
2) High speed printers, e.g. Laser printer and Drum printer with a speed up to 2000 lines per minute.
Secondly into 1) Non-impact printers and 2) Impact printers.
1) Non-impact printers:- These printers use magnetic, electrostatic, chemical, thermal, optical, inkjet or laser principles to write on paper.
Advantage: - They can not produce a fast single copy and make little noise.
Disadvantages: - They can not produce multiple copies without having to print the same data repeatedly, which is time consuming. They are costly.
Examples: - Thermal printer, Inkjet printer, Drop on demand printer.
2) Impact printers:- These printers print by striking a ribbon again the paper.
Disadvantages: - They are noisy. Have limited graphics. There are two types of impact printers. (1) Character printers (2) Line printers.
1) Character printer: - Which print one character at a time and so is slower, e.g Dot
Matrix printer and Daisy wheel printer.
2) Line printers: - Which print a line of characters essentially at the save time and so are faster, e.g. Drum printer and Chain printer.
Write a short note on the following:
Daisy wheel printer: - These printers are also called letter quality printers. It is called Daisy wheel printer, because of a wheel on which characters are embossed all around. An electronic motor spins the Daisy wheel. This printer does not printer pictures, drawings or graphics.
Plotter: - It is a printing device. It prints only drawings with the help of special pens fixed onto its arm. A plotter can make drawings on big sheets of paper. There are two types.
(1) Drum plotters (2) Flat bed plotters.
Q. # :- What is meant by main memory? What are its types? Explain.
Main memory: - Main memory is a type of computer memory. It is located within the C.P.U. In size, it is much smaller than that of secondary storage devices. The main memory may or may not be permanent. There are two type of main memory.
RAM: - It stands for Random Access Memory. It can also called Temporary or Primary memory. In the RAM, stored data can be read, written, deleted and modified, so it is called Read/Write memory also. When the computer is shut down, all the data stored in the RAM is lost, so it is also called volatile memory. RAM is used to hold those programs and data that are being executed in the processor.
ROM: - It stands of Read Only Memory. It is a permanent storage of memory. It can not be deleted or modified as it only readable. The data still remains in the ROM even it we shut down the computer, so it is also called Non-volatile memory.Q. # :- What is secondary memory? Which secondary storage devices are used in computers these days?
Secondary memory: - Secondary storage devices are useful and add to the functionality of a computer as they can be used for both input and output, so they are also called dual purpose devices. The data of this device is stored in a magnetic form. Such data can be stored for a long time, even if the computer is off.
Secondary memory devices: - Some of the most important devices which are commonly in use now-a –days are:
(1) Floppy Disk:- It is a disk coated with magnetic material. They are commonly available in two sizes (1) 3 ½ inches. (2) 5 ½ inches. The storage capacity such floppy disks is 1.44 MB and 1.2 MB respectively. With the help of a floppy disk, we can transfer up to 1.44 MB data from one computer to another.
(2) Hard disk:- This is another secondary storage device. It is a metallic disk fixed in the computer which can store a large amount of data that can be accessed by the computer. The storage range is from 5 MB up to some Terabytes.
(3) CD: - It stands for compact disk and is sometimes called optical disk. It is a plastic disk recorded on by means of lazer beam rays. We can not store data on CDs, they contain read only data with a capacity of up to 650 MB storage, hence the storage memory is called CD.ROM, (Compact Disk Read Only Memory).
(4) Magnetic Tape: - It is a reel of tape coated with a magnetic substance such as iron oxide. The reel of tape usually enclosed in a plastic box called a cassette, (similar to an audio cassette). As per an audio cassette, it is sequential with one thing recorded after another, hence to access data on it, other data must be passed over first. This takes time as compared to the direct retrieval possible from disks.
Write a short note on:-
SIMM: - It stands for Single Inline Memory. It is an arrangement of memory chips on the single side of a circuit board that forms a package of RAM. As SIMMs are removable, the RAM can be increased or decreased by adding or removing SIMMs. SIMM memory chip capacity is usually 32 bits.
DIMM: - Is stands for Dual Inline Memory Module. Dual means double and in DIMMs the memory chips are doubled up on both sides of the circuit board. The effect is to double the capacity of memory chips from 32 to 64 bits.Q. # :- How is memory measured? What are its units? Explain in comparison with the help of a table.
We know that memory or storage occurs in the main memory and also in the secondary memory. In both cases the memory is stored in the form of the digits of either ‘0’ or ‘1’. Some units for the measurement of this type of memory are as follows:-
(1) BIT: - A bit is the smallest unit of memory. It is a binary digit with the values of ‘0’ representing ‘off ‘and ‘1’ representing ‘on’
(2) Nible: - A nible contains 4 bits.
(3) Byte: - A byte contains 8 bits or 2 nibles. It is a higher unit of memory than bit and nible and can represent one alphanumeric character.
(4) Kilobyte: - This unit of memory contains approximately 1000 bytes. Actually 210 bytes = 1024 bytes is one kilobytes, 1KB.
(5) Megabyte: - It contains around one million bytes. Actually 220 bytes = 1048576 bytes is one megabyte, 1MB.
(6) Gigabytes: - It is 240 bytes = 220 × 220 = 1048576 × 1048576 = 1.0995116 × 1012 = 1099511600000 bytes.
(7) Terabytes: - It is the largest unit of memory/ storage. It is equal to the square of the GB. 1TB = 280 bytes.
Memory Unit Square of :- No. of KBs
Kilobyte 25 bytes=32 byte 1KB
Megabyte Kilobyte (KB) 1024 KB
Gigabyte Megabyte 1073741824 KB
Terabytes Gigabyte 1.1805816×10Q. # :- What is the difference between:-
RAM and ROM: - RAM stands for (Random Access Memory) and the ROM stands for (Read Only Memory).
We can directly access the RAM, but we can not access the ROM.
We can easily save, delete and modify the saved data in RAM, but in the ROM we can not.
RAM is washed when the computer is shut down, but ROM is a permanent memory.
SIMM and DIMM: - SIMM is a single sided memory chip, while the DIMM is a double sided memory chip. The capacity of SIMM is usually 32 bits, but the capacity of DIMM is double that of SIMM usually 64 bits.
GIGABYTES and TERABYTES: - Gigabytes, is a smaller unit of memory than Terabytes.1 GB = 240 bytes, while 1 TB = 280 bytes. The TB is the square of the GB.
Hard disk and floppy disk: - Both are secondary memory devices. The floppy disk is a removable unit. While the Hard disk is fixed inside the computer. The Floppy disk storage capacity is up to 1.44 MB. While Hard disk are available in various types with storage ranging form 5 MB. Up to some terra bytes. Data can be easily be transfer from one computer to another by means of a Floppy disk, But this can not be easily done using the Hard disk.
Q. # :- What is data? What are its types? Explain.
Data: - Anything which can be fed to the computer is called data.
Types of data: -
There are three types of data.
1. Alphabetic data: - This type of data consists on only alphabet type characters.
2. Numeric data: - This type of data consists upon Number such as (0…9).
3. Alphanumeric data: - This type of data is combination of alphabets and numeric data.Q. # :- What is numbering system? Discuss it different types.
Numbering system: - Generally a number system is a term used for a set of different symbols or digits, of something.
Digital computers are the machines which responds numbers (1, 2, 3, 4) rather than letters (A, B, C, D).
Types: - Following are the number systems which are used in computers and in our daily life for counting and arithmetic purposes.
1. Decimal Number System ( 10 digits; 0 to 9).
2. Binary Number System (2 digits; 0 to 1)
3. Octal Number System ( 8 digits; 0 to 7 )
4. Hexa Decimal System ( 16 digits; 0 to 9 and then A ,B , C, D, E, F) that is
5. (10, 11, 12, 13, 14, 15).Convert the following decimal numbers to their equivalent binary numbers.
• 43
• 64
• 408
• 4096
1:- 43:-
Hence 43 = (101011)2
2 43
2 21-1
2 10-1
2 5-0
2 2-1
1-0Sol: - (64)
Hence 64 = (1 000000)2
2 64
2 32-0
2 16-0
2 8-0
2 4-0
2 2-0
1-0Convert the following binary number to their equivalent decimal numbers.
• 1101
• 11011
• 111001
1:- 1101:-
Sol: - (1101)2 = 1*23+1*22+0*21+1*20
= 1*8 + 1*4 + 0*2 +1*1
= 8 + 4 + 0 +1
= 13
Hence (1101)2 = 13
Note: - One power less then the whole digits that is 1101/4 = 23,22,21,20Convert the following binary number to their equivalent octal numbers.
• 23
• 932
• 0.55
Sol: - (23)
Hence 23 = (207)8
8 23
8 16-7
2-0Sol: - 1339
Hence 1339 = (24730)8
8 1339
8 167-3
8 20-7
2-4
Q NO2:- What are executable files ? Explain all its types.
Executable files:- When over some task is done by the computer, it is written as a list of instructions in the form of a program file. In order to process the file by the computer, it must be given to the computer in machine language which is also called the language of 0 and 1. This machine language is the natural language of the computer hardware and a computer directely understand this language therfore a file written in machine language can be easily processed or executable by a computer. Thus a file which is written in machine language is called an executable file.
Types of executable files:- There are three main types of executable files.
1. File with .EXE Extension:- Thoses files which are having .EXE as their extention means that they are the executable version of a program. The file is executed whenever the name of such file is entered.
2. File with .COM Extension:- The file with extension .COM have contents which the computer runs when we enter the name of these files.An example of such files is the MS-DOS program which is called COMMAND.COM.This file is us to interpret the user commands internally i.e internal commads of DOS. In other words these external commands must ve separately stored in order to be executed by the COMMAND.CON interpreter.
3. File with .BATExtension:- The file with .BAT extensions are also containing programs. If the names of these files are typed at the command prompt, MS-DOS runs the program that is contained in the file. These file are called batch files. The word ‘batch’ means a collection.Thus in the AUTOEXE.BAT file, there is a batch or collection of commands which will be interpreted or executed by the “COMMAD.CON” before any other activity is started up.
Q NO 3:- What do you mean by command? Describe the types of commands in DOS. Write a detailed note on DIR command.
Command:- The instruction given to the computer to do the work is called command, or command is the name of action or instruction like DIR, COPY etc.
The general syntax of a command is Command Arguments Switches.
Command:- Are the name of action.
Arguments:- Are the requirements, which are required by that command.
Switches:- Are the special characters that amends the working of that command.
There are following two types of DOS command.
1. Internal command:- These commands are in a file COMMAND.COM. DOS loads this file in the RAM, when the computer starts. As these commands are internal part of the COMMAD.COM, so these are called internal commands. When we use these commands, computer reads the instructions for that command from RAM where COMMAND.COM is loaded. DIR, COPY, DEL, etc are few internal commands.
2. External commands:- Extenal commads are stored on separate files. When we use any external command, then the computer loads its file from the disk to the RAM for use. CHKDSK, FORMAT, DISKCOPY, etc are few external commands.
DIR Commands:- This command stands for directory. It is a DOS internal command which is used to view a directory list. A directory list is a file and sub directories which are contained in a directory. In order to show the list of the files we type the command DIR (enter).These can be discussed:-
A. DIR/P:- Here the common “DIR” is used with /p switch. With the help of this command we display all the directory of the disk page wise.
B. DIR/W:- Here the common “DIR” is used with /w swith. With the help of this command we display al the directory wide wise, and the file have no information such as size, date, and time.
C. DIR/W/P:- Here the common “DIR” is used with both switch /p, and /w. With the help of this command we display all files and all directory without information and page wise.
D. DIR/AD:- With the help of this command we display all the subdirectories of the main directory.
Q NO 4:- What is the concept of a subdirectory in DOS? How it is created, entered, and removed.Directory:- It is used to protect the files.The directory is like idraw in which the files are kept. There are two types of directory. ? Root directory:- The starting directory of a drive is called iroot directory. It is normally shown by back slash (\). For example the root directory of drive A is A:\, similarly or C is C:\.
? Subdirectories:- Those directories, which are created under the root directoried, are called subdirectories. Each subdirectory can also have files as well as subdirectories.
How to create a subdirectory:- In DOS and other operating systemes, there are some situations which demand a separate directory or folder such situations may arise whenever we want to have our private files in a separate location. In order to create a new directory, we use MD command. The general syntax of MD command is MD____ directory name (enter).So with the help of this command we make a new subdirectory in DOS program.
? How to enter in the directory or change the directory:- The directories are changed in order to work in different directories.For example if we are in the directory in which only C programs are stored and we want to work in such a directory in which the FORTRAN programs are stored, we must change that directory by another directory in which our requirements can be fulfilled. The common use of this change is CD command and synatx of this command is
CD____directory name (enter).
? How to remove or delete a directory:- If we need to create a new directory,or sometimes we need to remove an existing directory.This may be caused due to low space available on the secondary storage device for example a floppy, hard disk. If you want to delete a empty directory we use RD command. The general syntax of the RD command is RD_____directory name (enter).
Q no 5:- Write down the purpose and the syntax of the following commands. Also give at least one example of each.
? Copy command:- This command is used to copy one or more files from one directory to another directory or from one drive to another drive. If yor want to copy one file from one directory to another then use this command.
Syntax:- copy___ \source directory name\file name__\terget directory name (enter).
Example:- To copy all files name 123 from the root directoty of the drive B: to subdirectory LOTUS of drive C: then the command will be.
C:\> copy___B:\123.*___C:\LOTUS (enter).
? Format command:- This command is used to make a new disk usable.
Syntax:- FORMAT____A: (enter).
FORMAT____B: (enter).
Example:- If we want to make a disk as a DOS or SYSTEM DISK, Then the /S is added at the end of the FORMAT command.
Syntax:- FORMAT_____A: or B: ADD /S (enter).
? Deltree command:- This command is used to delete all files and all subdirectories of the current directory.The general syntax of this command is
Deltree___directory name (enter).
? Diskcopy:- This command is used to make duplicate of a disk. The general syntax is Diskcopy____A:B: (enter).
Example:- Some times we need to make a duplicate of the A: drive then we use this command. Syntax:- Diskcopy____A: A: (enter) then insert source disk (enter) Then insert target disk (enter).
? Path command:- This command is used to set a search path for different directories.The general syntax of this command is
Path=[directory _name] ; [directory _name].......
Example:- When we type the name of any executable file press enter to run some
program. The DOS, first searches this file in the current directory and if it does not find it, then it searches in all sub-directories given in the PATH command. For example,
PATH=C:\;C:\DOS;C:\WINDOW;C:\DATA\PERSONAL (enter).
Q NO 4:- Differentiate the following as internal and external commands?
? INTERNAL COMMANDS:- The following are internal commands:
DIR CLS TYPE DATE RD VER.
? EXTERNAL COMMANDS:- The fllowing are external commands:
PRINT XCOPY CHKDSK EDIT.
Q NO 5:- Write the commands to do the following tasks;
1) Display all those files having extension exe in all the directories and subdirectories.
2) Copy all those files having the extension com from a subdirectory source to another subdirectory destination on the root directory.
3) Delete all those files, in a directory abc inside directory xyz, starting with ab.
4) Format a disk in drive a: such that all system files are also copaied.
5) To get help about a command xcopy only.
Q NO 8:- Fill in the blanks:-
1) There are two types of software, namely system software and ---------------------
Software.
2) The syntax of print command is -----------------------------------------------
3) Diskcopy A:B: comman is used to -------------------------------------------
4) Executable file have extension ----------------------------------------------.
5) The extension bat stand for ------------------------------------------------.
6) To check the version of the dos we use ---------------------------------.
7) Erease command performed similar function as ----------------command.
8) To display the contents of the text file we use -------------------command.
9) Subdirectories in dos are called ------------------------ windows.
10) Dos stands for -------------------------------------------.
Q NO 9:- Mark True or False for each of the following.
1) Device drivers are a kind of application software..................
2) Renaming a file named lodfile to newfile canbe done by the command COPYODFILE NEWFILE...................
3) Deleting a file named EXTRAFILE.EXE can be done by the command DELEXTRAFILE.EXE.....................
4) The scandisk command checks your computer for viruses..................
5) MSWORD is an application software ............................
6) A computer command is an instruction to the user to do spacific job------------
7) In dos ? and* are called wild card -------------.
8) Diskcopy command is an internal dos command----------------.
9) Msdos.sys is a dos kernel file--------------------.
10) Print command is used to take soft copy of a text file on a line printer---------.
Q NO 1:- What is an operating system? What tasks are performed by the operating system?
Before starting windows it is better to define an operating system. An operating system is the software, wich makes your computer functional.Without an operating system it is not possible for a computer to work. It is the bridge between the computer and user. It makes the hardware of the computer and other’s software functional. In other words for the hardware and software of the computer to work, there must be an operating system for the computer.
What tasks are perfored by an operating system:-
? It makes the computer functional.
? It manages the hardware and software of the computer.
? It manages the hard disk, floppy drive, and other drives attached to the computer.
? It gives you a backup and restore facility.
Q NO 2:- Write the steps to perform the following?
Hide the file named hide.exe. Selects those files which have the extension EXE, then press file menu___properties___hide__apply__ok.
Create a folder on a desktop:- Press the right button of the mouse___selects new__folder___type folder name.
Restore files from the recyclebin:- Open recyclebin__selects files__selects restore or undo delete.
Explore the directories:- Open any drive___view__selects explore__selects any one option.
Rename a file; rename.exe stored in My Document folder:- Open my document__selects the file__click file menu___selects rename__type new file name and extension.
Q NO 3:- Explain the complete environment of Windows.
If window 9x is installed on your computer, and you turn on your computer, you will see the following start up screen on your computer.
START BUTTON:- At the bottom of the screen, there is a start button.It is called the start button, because it is the starting point of windows.When you click on it the following menu will appear, called the start menu.
START MENU:- It shows all the commands/tolls available inWindows 98.This is the only menu from where you can selects the command you want to run.
TASK BAR:- It is the bar usually at the bottom on the screen having the start button on it.
DESKTOP:- It is all the area, which you see on the screen. It is the area where you can move icons, open your programs, create icons for the programs, and delete icons.
ICON:- These are small figures having the name under them. These represent the programs, folders, and Windows icons.
WINDOWS:- This is frame used by Windows operating system to open a program. A typical Windows has the following parts:-
BORDER:- These are the borders, which shows the area taken by the program.
TITLE BAR:- This is the bar at the top of a Window, which shows the name of the program running in it.
STATUS BAR:- It shows items like data, number of objects in the windows, etc.
VERTICAL SCROLL BAR:- Appears when the program or text exceeds the vertical area provided by the window.
HORIZONTAL SCROLL BAR:- Appears where the program or text exceeds the horizoantal area provided by the window.
Clip control:- These maximize, restore and close buttons at the top of the window.
Maximize Button:- When you click on this button, the respective window will take its largest possible size and will take up the whole desktop area.
Minimize Button:- When you click on this button, the respective window will take its smallest possible size and appers on the taskbar.
Close button:- When you ckick on it, the respective window will be closed.
Restore button:- When you click on it, it brings the window to its previous position.
Control Menu:- It is used to manage the size and postion of a window. It appears when you click on the right icon at the title bar.It has the following options:-
? Restore
? Maximize
? Minimize
? Move
? Size
Move:- Used to move the windows from one position to another on the desktop.
Size:- Used to set the size of the window.
My computer:- This icon comes with window 9x operating system. It shows all the devices that a computer has, like floppy drive A, hard disk C, and D, CD- drive F or E, printers, Deal Up networking, Control panel, Scheduled tasks like anti virus program, and web folders.
Recyclebin:- When you delete some object from your computer, it comes in the recyclebin. It has two options:-
? Restore:- When you click on it, the selected item will be undeleted or restored back to its original location in the computer.
? Empty recyclebin:- It is used to delete all the items from the recyclebin.Once the items are deleted from the recyclebin, there is no way to restore them back.
Control panel:- As its name indicates, it is the panel consisting of a program used to control the computer and peripherals.
Display:- It is used to set the following properties:-
? Backgrouind:- It sets the background of the windows environment like a wallpaper, pattern that appears on the dektop.
? Appearance:- It is used to sets the colour and size of different parts of a windows.
? Screen saver:- It is used to sets the screen saver of the computer.
Mouse:- It is used to sets the different function of the pointer:-
? Double click speed:- It is used to increase or decrease the double click speed used to run the programs.
? Right handed and left handed mouse:- It is used toset the mouse for right hand or left hand use.
? Motions:- It is used to set the mouse movement
? speed.
Keyboard:- It is used to set the function of the keyboard eg. repeat rate, delay after first repeat, etc.
Modem:- It is used to set the modem used in the computer.
Network:- It is used to set the network option.
Printer:- It is used to add / install the printer.
Add /Remove programs:- It is used to add or remove the program from the hard disk of the computer.
Fonts:- It is used to add / remove fonts.
Shuting down windows 9x:- If you want to close or shut down the windows 9x.
M:- Start___shut down___selects shut down___ok.
Operating system:- Operating system is the first software that first loads into the system memory (RAM) when the computer starts. Operating system is an interface between the user and the computer hardware.
Concept of booting:- The system BIOS (Basic Input Output System) plays a key roll in searching the operating system. The Bios is a burnt in program stored on a chip during the manufacturing process of the computer motherboard.
Q NO 4:- Write the complete process of Windows installation.
A. Insert bootable disk in floppy disk.
B. Insert the Windows 98 cd into your CD- ROM drive.
C. Then selects start computer with CD-ROM
D. A: prompt appears on the screen.
E. Then enter this into the CD-ROM drive.
F. Then enter this into win98 directory.
G. Then type setup.
H. Window 98 setup start by performing scandisk of any possible errors on the hard disk, exit after completion of scan.
I. Setup screen appears, press continue to go ahead.
J. Selects the directory where you want an operating system to be installed and click next.
K. Setup makes the directory and determins available disk space required to install windows.
L. Selects the type of installation you want to perform.
M. Selects the Typical.
N. Type your computer name and workgroup name and click next.
O. Setup will ask if you want to create a startup disk. Click of for the startup disk (insert disk) or cancel if you do not want to create the disk.
P. Windows setup will copy files to the hard disk.This may take 30-60 minutes depending on your computer.
Q. Finally it will restart your computer.
R. Give the user information when setup allows.
S. Give the serial no(CD-KEY) given on the back of the CD cover you purchased.
T. Setup will again start and finalizes the settings.
U. Set the time zone when the time zone screen appears. Set it to Islamabad, Karachi, Tashkant.
V. Once you have done the settings the computer will restart.
W. Once restarted the computer will install the drivers, for example Sound, VGA, etc.
Q NO 5:- What is a computer virus? Describe in detail its different types.
VIRUS:- Virus is a parasitic program that is found in the programs or in the boot sector of the disk. Boot sector of the disk is the logical part of the disk, which contains the operating systems commands necessary to boot up the computer.The boot sector is the first area read by the computer when it is turned on. Viruses are very dagerous and destroys the programs, data files, information on the screen, and even wash the computer hard disk.Viruses is spread when floppy diskes or CDs are used to transfer the data from one compuer to another.
ANTIVIRUS:- Antivirus is a program, which detects the virus in the boot sector and memory of the computer. It also detects the virus in the data files and other files in the disk. It is used to detect the virus and try to remove it.
TYPES OF VIRUS:- The different types of viruses are:-
• Macro Virus
• Devolving Virus
• Boot Sector Virus
• TSR File Virus
• Non TSR Virus
• Companion Virus
• Overwriting Virus
• Multipartite Virus
Macro Virus:- Macro virus is the first virus to infect data files rather than executable files. Today many applications have macro languages, so the problem is a growing one. Macro viruses spread through people who send infected document files to each other, eitheron a floppy disk, or via the interal LAN or via an internet.
Boot Sector Virus:- One of the most common types of viruses are boot sector viruses, for example, Form and stoned. These viruses infect floppy disks in either of the following parts:
? Master Boot Record (MBR).
? Partition Sector of the DOS Boot Record(DBR).
? DOS Boot Sector of the disks.
TSR File Virus:- A less popular kind of virus is the Terminate and Stay Resident (TSR) file virus. As the name suggests these infect files, usually COM and EXE files. Although over 99 percent of executable programs have the extenstion COM and EXE, some do not.
For a TSR virus to spread, someone has to run an infected program. The virus goes memory-resident, typically looking at each proguam run thereafer and infects.Some viruses are called fast infectors and they infect if you just open the file.Dark Avenger was the first fast infector.
Non TSR virus:- There are less than one percent of reported outbreaks of Non-TSR viruses. With such a virus, running an infected program runs the virus, which at that time looks for another file to infect and infects it. Vienna is the most common Non-TSR virus seen very rarely these days.
Companion Virus:- If you have a COM file and EXE file with the same file name and you type that name, DOS runs the COM file in preference to the EXE file. Companion viruses use this fact- each file that you have acquires a companion COM file with the same name.Then, when you try to run you exe program, the COM program is actually run and that is the virus.
Over writing virus:- An overwriting virus simply overwrites each file it infects with itself. Once overwritten the program will not function, it will become so obviously apparent that something is wrong that either you will get rid of it or copy it again. This is the main reason that overwriting viruses were/are never successful in spreading.
Multipartite virus:- Some viruses infect multiple objects, when you run an EXE infected with a multipartite virus, Tequila, puts itself on the MBR,. When you boot up, the computer, Tequila runs from the MBR and goes to memory-resident, while Tequila is in the memory-resident, it infects EXE file thereby infecting multiple objects. Other viruses like, Anticad infects EXE and MBRs interchangeably.Some viruses infected COM, EXE, MBRs, and device drivers.Multipartite viruses are the third most common kind of virus.
Devolving virus:- Some viruses are badly written and ‘lose’ there own macros. The original virus may consist of the set {Auto, File Save, and File Save As}.However, if the user invokes file{Save As, the virus will fail to copy the File Save macro}. The resulting virus set { Auto, File Save, and File Save As}is known as a Devolved Macro and the original virus is devolving.
Q NO 6:- What precautionary measures can be taken to avoid virus attack? Explain.
The following precautionary measures can be taken to avoid viurs attack.
? Use standalone PCS:- As we know that virus need a mediun for its propagation, where disks and especially network- which are quite exposed to infection provides this opportunity and the virus goes on spreading form system to system. Therefore the avoidance of modens will make it difficult for viruses to computer system.
? Avoid the use of Modem:- As virus can pass very easily through electronic mail, bulletin boards, and other communication software and also through software downloads. Therefore the avoidance of modens will make it difficult for viruses to infect computer system.
? Ensure that you are the only user of your computer and software:- This is often a very hard condition to meet and the term’you’ will invariable mean you and your secreatary /partner / clerk etc. However,try to minimize the number of people using a particular computer.The use of Passwords can make it more difficult for unauthorized persons to access your computer.
? Never use Pirated software:- Many viruses are carried on pirated versions of well-known products and so user should always ensure that they are using genuine copy of all the packages on the computer.
? Only use public domain or shareware software from recognized source:- As public domain software is so easily copaied and sent from user to user it provides a good vehicle for transportation of viruses. The sgare ware market has grown a lot over the past few years offering a wide range of good quality utilities and software packages at very low prices, and many cataloguesa and clubs providing this service declare that their software are tested and are virus free. However, it is still recommended to re-test all software before installing on your computer.? Avoid using non-certified anti-virus software:- As we know that there are hundreds of anti-virus program and some of these are not as reputble as the might be, containing lethal viruses themselves.
? Write protect critical or sensitive files:- The simplest form of virus protection on floppy disks is to place a write protect tab on the disk so that any attempt by a virus to write to the disk would be foiled.
? Use of anti-virus software:- Anti-virus software is the solution to many problems created by viruses. There are many kind of anti-virus.actully it is a vest idea to install anti-virus to tell the computer to virus check everything each time when it is loaded.
? Uses of Scanners:- A scanners is a program that knows how to find a particular collection o viruses.Virus Guard(DOS) and Win Grard(Windows) are on-access scanners and work continuously. As soon as any disk is accessed, it is checked for boot sector viruse,and as soon any file is used, it is check for viruses.
? Uses of checksummers:- A checksummers is a change detector. Executabl files should not chage, except for a good reason like updating of the software. A checksummer aims to detect changees. The advantage of checksummers is that
they do not detect a collection of viruses, so do not need updating.
FILL IN THE BLANKS:-
1. GUI stands for Graphical user interface.
2. The software, which is loaded first in to the memory when a computer is started, is called Operating system.
3. BIOS stands for Basic input output system.
4. FDISK command is used to Partitions of hard disk.
5. During installation portable option is chosen for Lop top machines.
6. Anti-virus is used to Remove the virus.
7. Scanners are used to Find a particullor colleution of virus.
8. Chechsummers are used To change the detecter.
9. Boot sector viruses infect Floppy disk.
10. TSR stands for Terminate-and-stay-resident.
MARK TRUE OR FALSE FOR EACH OF THE FOLLOWING.
1. Windows 98 is a complete operating system. (True).
2. Windows 98 is multitasking operating system.
3. Windows 98 is multi user operating system. (True).
4. Windows 98 can support 8 monintors at a time (True).
5. Windows 98 is a command based operating system (True).
6. Start button is used to open My computer folder (False).
7. The three basic parts of windows 9x are my computer, control panel, and recyclebine (False).
8. Close button is used to shut down windows (False).
9. Control menu is used to control the size, the position of a windows (True).
10. Recycle bin contains all the deleted items until they are restored or permanently deleted (True).
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