KPK G12 Statistics Cha 7 Introduction To Computer

Introduction to Computer

Q.3) Do you think computers are becoming easier to use? Why or why not?

Answer:
Yes, it is now very easy to use computer due to following reasons:

Firstly , due to development of application soft wares of every field day by day. They are easily avaliable in the market for a common user. They are ready made programs and there is no need to write instruction and remember commands. You can easily operate a computer and get your result by just cliking a few icons.
Secondly , the computer prices become very low and it can be affordabale for a common person.

Q.4) Why computers use the binary number system? Why do they use codes like ASCII?

Answer:
Computer use binary number system instead of any other number system, due to the following three reasons:

All the electronic devices/components, by their nature, operate in a binary mode. Te electronic ciecuits/wires can only operates on two states or conditions ON (1) or OFF (0). All the information is represented within the computer by the presence or absence of these various signals. And binary number system has only two digits (0 or 1), so it is most suitable.
The second reason is that the computer circuits only have to handle two binary digits rather than the decimal digits. And these results in simplification of internal circuits as well as the less expensive and more reliable circuits for computers can be development.
Thirdly, the binary system is used because everything that can be done with a base of 10 can also be done in binary.

We use various codes like ASCII or EBCDIC, because computes u se binary number for their internal operations, but we enter the data in the form of decimal numbers, alphabets and other special characters. To represent all these characters we use different codes.

Q.5) What are the four types of computers. Explain the main characteristics of each type of computer.

Answer:
The different types of computes by size are:
MICROCOMPUTER:
Microcomputer are typically known as personal computer (PC). It is the microcomputer that has brought computing into school, small business and home. These are the single user computers. Microcomputers system can be purchase for under Rs.10,000/- only. They are available in the form of Desktop or Laptop.
MINICOMPUTER:
Minicomputers are typically larger and more powerful than microcomputers, but smaller and less powerful than mainframe computers. It is used by several persons at a time through their separate terminal (i.e input and output devices). Minicomputers ae typically less costly and operate easily than mainframe computers.
MAINFRAME COMPUTER:
Mainframe computers are larger and more powerful than minicomputers. These computers have faster processing speed and larger storage capacities. It can be used by thousands of user at a time. They are expensive that is why, they can usually be afforded by Govt., larger business corporations, public utilities such as water, gas and electricity.
SUPERCOMPUTER:
A supercomputer is the most powerful but very expensive. These computers are specially designed for high-speed computations. Users of supercomputers are large Govt. research agencies, military defense, weather forecasting agencies etc.

Q. 6) What are the ASCII codes for each letter of your name?

Answer:
The ASCII codes for the capital letters are starting from 01000001 (65 in decimal) to 01011010 (90 indecimal)

Q.7) How are computer hardware systems classified?

Answer:
The hardware components can be categorized as:
1) Processor
2) Memory
3) Input/Output devices
4) Storage devices
Processor:
It is the brain of computer. In Microcomputers, the processor is a single chip, called a microprocessor. This part of computer carries out the processing.
Memory:
This is the ‘warehouse section’ of computer. It retains the information, which has been entered through the input unit so that information may be made available for processing when it is needed. There are usually two types of primary memory, RAM & ROM.
Input/Output Devices:
The data or instruction can be entered into a computer through input devices like keyboard, Mouse etc., and the results can be obtained or can be seen through output devices (like Monitor, Printer etc.)
Storage Devices:
The data or result or any sort of information can be stored safely on storage devices like Floppy disks, Hard disks, CDs etc. The stored data can be retrieved at any time for further use.

Q.8) Define the following terms and give an example of an object or device that is associated with each of them:

a. Processing
b. Input
c. Output
d. Storage

Answer:
Processing:
An operation or action performed on data to get some result, is called processing. In computer CPU (Central Processing Unit) does processing.
Input:
Any data or information, which we give to the computer, is called input. The input devices are: Keyboard, Mouse, Joystick etc.
Output:
The result, which we obtain after processing, is called Output. The output devices are Printer, Monitor, Plotter etc.
Storage:
The input or output result can be stored in the computer for further use on a medium, called as Storage (Memory). The internal storage is RAM & ROM, while external storage devices are Magnetic tape, Floppy disks, CDs etc.

Q.9) Describe the difference between an operating system and application software.

Answer:
OPERATING SYSTEM:
An operating system is an integrated set of specialized programs, that is used to control and manage the resources and overall operations of a computer, like input/output control, storage management etc.
APPLICATION SOFTWARE:
Application software are computer programs, which are developed for user-related tasks and to serve specific needs. For example, the programs for payroll processing, video games, word processor or engineering design belong to this category.

Q.10) What are the four main functions of an operating system. Which of the major OS are true graphical OSs?

Answer:
The OS has four fundamental jobs:

It manages the hardware devices on the computer.
It supports other software to run on computer.
Through OS, a user communicates with computer.
It also manages the disk file system.

Now-a-days, Windows OS are commonly used which provides a user interface.

Q.11) Write three reasons why computer use the binary number system, rather then the decimal system.

Answer:
Computer use Binary number system instead of any other number system, due to the following three reasons:

All the electronic devices/components, by their nature, operate in a binary mode. The electronic circuits/wires can only operate on two states or conditions ON (1) or OFF (0). All the information is represented within the computer by the presence or absence of these various signals. And Binary number system has only two digits (0 or 1), so it is most suitable.
The second reason is that computer circuits only have to handle two binary digits rather than ten decimal digits. And these results in simplification of internal circuits as well as the less expensive and more reliable circuits for computers can be developed.
Thirdly, the binary system is used because everything that can be done with a base of 10 can also be done in Binary.

Q.12) Why will DOS continue to be used into the twenty-first century?

Answer:
Although DOS is not user friendly (not based on Graphical User Interface) and requires to remember some commands, but still it is popular and used. The reasons are: IBM compatibility, availability of software and intel-based microcomputers. Still there are some video games, which run in DOS mode.

Q.13) What are the two main components of a CPU, and explain what each one does.

Answer:
The CPU contains two basic parts, the CU (Control Unit) and ALU (Arithmetic Logic Unit).
All the components/actions of a computer are controlled from the control unit. Control Unit schedules the input/output operations. When computer runs a program, CU executes the instructions in order.
On the other hand, ALU performs arithmetic and logical operations (decision-making) according to the instruction.

Q.14) What are the two types of computer memory, and how they differ from each other.

Answer:
There are two types of primary/internal memory of computer:
1.RAM
RAM stands for “Random Access Memory”. It holds programs and data until it is saved on storage devices.lt is volatile memory i.e when we turn off the computer, the information in RAM is lost. It is temporary memory which can be changed or erased or written.
2. ROM:
ROM stands for “ Read Only Memory”. It is non-volatile memory. Information can only be read from ROM, not written or changed. ROM might, store small routines (sets of instructions) to check the internal operations or computer hardware when it is powered on.

Q.15) What are the two most common input devices used with personal computers?

Answer:
The two most commonly used input devices are: (1) Keyboard (2) Mouse
KEYBOARD:
A computer keyboard is just like a Piano keyboard. It is attached with the computer through a coiled cable. Whenever a key on the keyboard is pressed, a character appears on the screen or some function is executed on the screen.
MOUSE:
Mouse is another input device, which is commonly used to give an instruction to computer through clicking the written command. It can also be used to draw pictures, lines on the screen very easily.

Q.16) What are the three most common types of magnetic storage devices.

Answer:
The three most common types of magnetic storage devices are:
FLOPPY DISKS:
Data can be stored, retrieved and can be changed on a floppy disk. The most common floppy disks are 3.5-inch floppy disks. It can store 1.44 MB data.
HARD DISKS:
Hard disk has much more capacity of storage as compared to floppy disks. The floppy disks are easily removable and can be taken anywhere, while hard disks can not be easily removable. Now-a-days, hard disks are available in market in the range of 6 GB to 80 GB.
COMPACT DISKS:
Compact Disks (CDs) are also commonly used as a storage devices. Some years ago, CDs are used as permanent storage devices,i.e Data, once recorded can not be erased or changed. But now, rewritable CDs are available in market.

Q.18) What are advantages and disadvantages of floppy disks compared to hard disk.

Answer:
ADVANTAGES;

Floppy is easily removable and can be taken everywhere very easily as compare to Hard disk.
To transfer small amount of data from one computer to another, floppy is best suited.
It is less expensive as compared to hard disk.
It is easily available in market, even you can buy it from a Bookseller. While Hard disk can only be purchased by a computer vendor.

DISADVANTAGES:

Floppy is very sensitive, in the sense if its inner plastic coating is touched carelessly, it becomes useless.
Floppy has less capacity than Hard disk.
Hard disk is fixed inside the computer.

Q.19) Describe the system software and application software. What is the main difference between these software?

Answer:
System software include a group of programs that are used to supervise and control the operation of hardware, and provide commonly needed services to the several computer users. One of type of system software is Operating System.
On the other hand, the application software are those software which are developed for user to complete specific task, such as Payroll processing software, word processor, spreadsheets etc.

Q.20) Explain and differentiate between

a) ROM and RAM
b) Input and Output devices.

Answer:
RAM:
RAM stands for “Random Access Memory”. It holds programs and data until it is saved on storage devices. It is volatile memory i.e when we turn off the computer, the information in RAM is lost. It is temporary memory which can be changed or erased or written.
ROM;
ROM stands for “ Read Only Memory”. It is non-volatile memory. Information can only be read from ROM, not written or changed. ROM might, store small routines (sets of instructions) to check the internal operations or computer hardware when it is powered on.
INPUT:
Any data or information, which we give to the computer, is called input. The input devices are: Keyboard, Mouse, Joystick etc.
Output:
The result, which we obtain after processing, is called Output. The output devices are Printer, Monitor, Plotter etc.

Q.21) Explain the main features of different programming languages.

Answer:
Some of the more widely used languages are:
FORTRAN:
FORTRAN stands for Formula Translation. It is a high level language, and is widely used for mathematical and scientific problems.
BASIC:
BASIC stands for Beginners All Purpose Symbolic Instructions Code. It is similar to FORTRAN and is popular language widely used on the minicomputer and microcomputer system.
COBOL:
COBOL stands for Common Business Oriented Language). COBOL is most commonly used language for application in business processing.
PASCAL:
Pascal is also a high level language developed in the mid 1970. It is the structured programming language.
C & C++:
These are increasingly popular programming language for system software programming and development of packages.

Q.22) Define and explain the functions of the following DOS commands.

a) VER
b) CHKDISK
c) RMDIR
d) DEL

Answer:
VER:
This commands displays MS-DOS version number (model number). When you enter the VER command, MS-DOS displays the following message:
MS-DOS version 6.22
CHKDSK:
It checks the status of a selected disk and displays several important informations about a particular disk. For example, the command
CHKDSK D:
Will check the drive D and will displays the following information:
· The total disk space
· The total disk space occupied and the number of files
· The total disk space either lost or considered unusable by the system.
· The amount of disk space available for use.
· Total amount of memory available in your computer etc.
RMDIR:
The RMDIR (or RD) command is used to remove a subdirectory. First you must delete all files within a subdirectory before it can be deleted, e.g, to remove an empty directory having name “WP”, go to the directory one level above and type the command
RD WP
and press enter.
DEL:
It deletes all the files or some specific files within a certain directory or drive. For example, to delete a file name “ABC.DOC”, type the command
DEL ABC.DOC
and press enter.
To delete all the files in a directory or drive, use the DEL command with two asterisks with a period between them. For example,
DEL A:*.*
Will delete all files of A drive (floppy disk).

Q.23) Explain and differentiate the following with the help of examples.

a) DIR and DIR/W
b) COPY and DISKCOPY
c) DIR A *.* and DIR *.E*

Answer:
DIR & DIR/W:
These commands are used to display a list of all files and subdirectories of a * current directory/ drive. For example, if you are currently in C drive; then giving the command.
DIR: In front of “C :\>” prompt, it will give you list of all files and subdirectories of C drive.
Similarly, DIR W can also be used to view the list of files and directories width wise.
The difference between these two commands is that, by DIR command computer will give you file name, extension, time and date (on which this file was created) and size of file. But DIR/W will give you only file/directory names and extension. Moreover, by DIR, each filename will be on separate line, while by DIR/W we will get the list of files directories with extension only: This is useful when the list is very large.
COPY & DISK COPY:
The copy command is used to copy duplicate a list of files or a specific file to another location. For example, the following command:
COPY A: ABC. DOC C:
Will copy the file “ABC.DOC” from drive A to drive C.
While on the other hand, DISKCOPY command copies the entire contents of one disk/drive to another disk/drive. For example:
DISKCOPY A: B: *
Will copy all the files and directories from drive A-to another disk in drive B.
DIR A*.* & DIR *.E*:
The DIR command is used to view the list of files or directories in a specified drive location. The command.
DIR a*.*
Will display all the files whose names start with “A” and having any extension in the current directory.
While the command (DIR *.E*)
Will display all the files whose extension starts with “E” and having any name within the current directory.