Computer Notes

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1.Q. What is operating system?
Ans: An operating system is the most important software that runs on a
computer. It manages the computer's memory, processes, and all of its
software and hardware.
2.Q. What is CD rom & it uses?
Ans: CD ROM, stands for Compact Disc Read Only Memory. It is a type of
storing data that goes up to 700 MB. It is an optical disk that has the capacity to
store data, music files, video files etc.
3. Compare Dos & Windows.
Ans:
DOS

Windows

DOS (Disk Operating System) are simple
text command based operating systems.

Windows provide the graphic interface to
the user for interacting with hardware and
executing their application programs.

DOS provide the command based
interface to the user.

Windows uses graphics, images and text to
provide the interface to the user to interact
with the machine.

4. What is internal Dos Command?
Ans: In DOS systems, an internal command is any command that resides in
the COMMAND.COM file. This includes the most common DOS commands,
such as COPY and DIR.
5. What is Application software?
Ans: Application software is a set of computer programs designed to permit the
user to perform a group of coordinated functions, tasks, or
activities. Application software cannot run on itself but is dependent on
system software to execute.

6. Difference between primary and secondary memory?
Primary Memory

Secondary Memory

This is volatile.

This is Non-volatile.

Access Time is lower Than
Secondary memories.

Access Time is higher Than
primaryary memories.

This is a Temporary
Memory.

This is a Permanent
Memory.

7. Full form:
RAM = Random Access Memory
ROM= Read only memory
8. Define information.
Ans: Information is the summarization of data. Technically, data are raw facts
and figures that are processed into information.
9. What do you mean by ALU?
Ans: Arithmetic logic unit is the part of a computer that performs all arithmetic
computations, such as addition and multiplication, and all comparison
operations. The ALU is one component of the CPU (central processing unit).
10. What is Flowchart?
Ans: A flowchart is a type of diagram that represents an algorithm, workflow
or process, showing the steps as boxes of various kinds, and their order by
connecting them with arrows.
11. What is booting?
Ans: Booting is the process of powering on a computer and getting into
the operating system. During the boot process, the computer will perform a self-

diagnostic, also known as a POST and load necessary drivers and programs that
help the computer and devices communicate.
12. Define System software.
Ans: System software is computer software designed to operate and control the
computer hardware and to provide a platform for running
application software. System software can be separated into two different
categories, operating systems and utility software.
Ex: Unix, Windows 7 etc.
13. Q. What is Software?
Ans: Computer software is any set of machine-readable instructions that directs
a computer's processor to perform specific operations. Computer software
contrasts with computer hardware, which is the physical component of
computers.
14.Q. What is secondary memory?
Ans: Secondary memory is where programs and data are kept on a long-term
basis. Common secondary storage devices are the hard disk and optical disks.
The hard disk has enormous storage capacity compared to main memory. The
hard disk is usually contained inside the case of a computer.
15.Q. Why Hard disk is needed?
Ans: In a computer system, a hard disk drive (HDD) is the
mechanism that controls the positioning, reading, and writing of
Data, information and also store largest amount of data for the
PC.
16. Short notes on Windows.
Ans:
Microsoft
Windows is
a
popular operating
system software for computers. Windows is made by
the Microsoft company.
Windows
makes
it
easier
to
run programs (applications) than DOS did. It also helps people
keep their files safe and in order. It is a GUI based operating
system that can do multitasking.

17. What is Hardware? Give Example.
Ans: Computer hardware is the collection of physical parts of a
computer system. This includes the computer case, monitor,
keyboard, and mouse. It also includes all the parts inside the
computer case, such as the hard disk drive, motherboard, video
card, and many others. Computer hardware is what one can
physically touch.
18. What is Primary memory?
Ans: Primary storage, also known as main storage or memory,
is the area in a computer in which data is stored for quick
access by the computer's processor. This includes several types
of memory, such as the processor cache and system ROM.
However, in most cases, primary memory refers to
system RAM.
19. Full form:
VDU : Visual Display Unit
20. Difference between Ram & Rom.
Ans:
Random Access Memory

Read-only memory

RAM allows the computer to read
data quickly to run applications. It allows
reading and writing.

ROM stores the program required to
initially boot the computer. It only
allows reading.

RAM is volatile i.e. its contents are lost when
the device is powered off.

It is non-volatile i.e. its contents are
retained even when the device is
powered off.

21.Q. What is Linux?
Ans: The Linux is an open source operating system, it is freely
distributable, cross-platform operating system based on Unix

that can be installed on PCs, laptops, netbooks, mobile and
tablet devices, video game consoles, servers, supercomputers
and more.

22.Q. Define Data.
Ans: Data can be defined as a representation of facts, concepts or instructions
in a formalized manner which should be suitable for communication,
interpretation, or processing by human or electronic machine.
23.Q. Draw the block diagram of the computer and explain
each component in brief.
Ans: A computer can process data, pictures, sound and
graphics. They can solve highly complicated problems quickly
and accurately. A computer as shown in Fig. performs basically
five major computer operations or functions irrespective of their
size and make. These are
1) It accepts data or instructions by way of input,
2) It stores data,
3) It can process data as required by the user,
4) It gives results in the form of output, and
5) It controls all operations inside a computer.

Input: This is the process of entering data and programs in to the computer
system. You should know that computer is an electronic machine like any other
machine which takes as inputs raw data and performs some processing giving
out processed data. Therefore, the input unit takes data from us to the computer
in an organized manner for processing.

2. Storage: The process of saving data and instructions permanently is known
as storage. Data has to be fed into the system before the actual processing starts.
It is because the processing speed of Central Processing Unit (CPU) is so fast
that the data has to be provided to CPU with the same speed. Therefore the data
is first stored in the storage unit for faster access and processing. This storage
unit or the primary storage of the computer system is designed to do the above
functionality. It provides space for storing data and instructions.

The storage unit performs the following major functions:
• All data and instructions are stored here before and after processing.
• Intermediate results of processing are also stored here.

3. Processing: The task of performing operations like arithmetic and logical
operations is called processing. The Central Processing Unit (CPU) takes data
and instructions from the storage unit and makes all sorts of calculations based
on the instructions given and the type of data provided. It is then sent back to
the storage unit.

4. Output: This is the process of producing results from the data for getting
useful information. Similarly the output produced by the computer after
processing must also be kept somewhere inside the computer before being given
to you in human readable form. Again the output is also stored inside the
computer for further processing.
5. Control: The manner how instructions are executed and the above operations
are performed. Controlling of all operations like input, processing and output
are performed by control unit. It takes care of step by step processing of all
operations inside the computer.
FUNCTIONAL UNITS
In order to carry out the operations mentioned in the previous section the
computer allocates the task between its various functional units. The computer
system is divided into three separate units for its operation. They are
1) arithmetic logical unit
2) control unit.
3) central processing unit.
Arithmetic Logical Unit (ALU) Logical Unit
Logical Unit :After you enter data through the input device it is stored in the
primary storage unit. The actual processing of the data and instruction are
performed by Arithmetic Logical Unit. The major operations performed by the
ALU are addition, subtraction, multiplication, division, logic and comparison.
Data is transferred to ALU from storage unit when required. After processing
the output is returned back to storage unit for further processing or getting
stored.
Control Unit (CU)
The next component of computer is the Control Unit, which acts like the
supervisor seeing that things are done in proper fashion. Control Unit is
responsible for coordinating various operations using time signal. The control
unit determines the sequence in which computer programs and instructions are

executed. Things like processing of programs stored in the main memory,
interpretation of the instructions and issuing of signals for other units of the
computer to execute them. It also acts as a switch board operator when several
users access the computer simultaneously. Thereby it coordinates the activities
of computer’s peripheral equipment as they perform the input and output.
Central Processing Unit (CPU)
The ALU and the CU of a computer system are jointly known as the central
processing unit. You may call CPU as the brain of any computer system. It is just like
brain that takes all major decisions, makes all sorts of calculations and directs
different parts of the computer functions by activating and controlling the
operations.

24.Q. Briefly discuss the generation of Computers.
Ans: First generation (1946 – 1956) – Includes those computers, which were
based on the use of the vacuum tubes. Such computers were very big in size
with limited values for memory and processing. The vacuum tubes were used
for storage and processing of the data but these tubes generated a lot of heat and
also used a great amount of power. These type of computers were used for
scientific and engineering purposes, involving programming, firstly in the
machine language and then in the assembly language. The main drawback of
such a computer was that it had a very short life span – which further resulted in
low MTBF (Mean Time Between Failure) of the order of an hour. For e.g. the
ENIAC – had only 20 registers for storage and could only support 5,000
additions per second.
2. Second Generation (1957 – 1963) – During this time period, such computers
came to the stage that used transistors, instead of the vacuum tubes for the
storing and processing of the data. These transistors were made of the
germanium semi conductors’ material making them more compact in size and
also more reliable in nature. Unlike the vacuum tubes, these transistors
consumed less power and as a result of this MTBF became longer. These second
generation computers were more accurate and faster and also cheaper than the
first generation computers. Such a computer could have up to 32 KB of RAM,
supported by a speed of up to 2 lakh to 3 lakh instructions per second.

Computers of this generation were used only in the works involved in inventory,
pay roll, marketing, accounting etc.
It was during this generation only, that the world observed the upcoming of the
various high level languages like ALGOL, COBOL, FORTRAN and SNOBOL.
3. Third generation (1964 – 1979) – This generation saw the development of a
new technology to be used in the computers called the integrated circuits or the
integrated chips. In the computers of this generation, in place of the transistors
silicon chips were used, which were known as the integrated circuits or chips.
These circuits improved the working of the computer to a great deal increasing
speed, reliability by a factor of 10 and power dissipation was reduced by a
factor of 10.
The integrated circuits were made of the transistors, resistors, capacitors
brought together on a single silicon chip. These circuits were made by printing
hundreds and then thousands of silicon chips, called as the semiconductors.
In this generation, memory of the computers went up to 2 MBs of RAM with
the speed of the CPU going up to 5 Million Instructions per Second (MIPS). As
a result of this, computers now were able to find work for themselves in the
field of business, airlines reservation systems etc.
The computer of this generation had very good CPU capabilities leading to the
development of Integrated Data Base Management Systems.
4. Fourth generation (1980 onwards) – The computers being used by us today
belong to this generation. In the fourth generation computers, VLSIC’s (very
large scale integrated circuits) are used which consist of 2,00,000 to over
3,00,000 circuits per chip. Memory of the computer has now gone up to over 2
Giga Bytes in large computers with the speed of processing going up to 200
MIPS.
5. Fifth generation – This type of computers involve more of expectations than
the reality. Such computers are expected to follow parallel processing
procedures, with artificial intelligence and intricate mathematical models.

25.Q. What are the five basic operations performed by any computer
system?
Ans: All computer systems perform the following five basic operations, for
converting raw input data into information, which is useful to their users:


Inputting: The process of entering data and instructions into the
computer system



Storing : Saving data and instructions to make them readily available for
initial or additional processing, as and when required.

Processing : Performing arithmetic operations or logical operations on
data to convert them into useful information.


Outputting : The process of producing usefull information or results for
the user, such as a printed report or visual display.

Controlling : Directing the manner and sequence in which all of the
above operations are performed.
26.Q. Write down about different types of printers.
Ans: Printers are Output devices used to prepare permanent Output devices on
paper. Printers can be divided into two main categories:
Impact Printers: In this hammers or pins strike against a ribbon and paper to
print the text. This mechanism is known as electro-mechanical mechanism.
They are of two types.
(i) Character Printer
(ii) Line Printer
Non-Impact Printers : There printers use non-Impact technology such as inkjet or laser technology. There printers provide better quality of O/P at higher
speed.

Character Printer : It prints only one character at a time. It has relatively
slower speed. Eg. Of them are Dot matrix printers.
Dot Matrix Printer : It prints characters as combination of dots. Dot matrix
printers are the most popular among serial printers. These have a matrix of pins
on the print head of the printer which form the character.
Laser Printer is a type of printer that utilizes a laser beam to produce an image
on a drum. The light of the laser alters the electrical charge on the drum
wherever it hits. The drum is then rolled through a reservoir of toner, which is
picked up by the charged portions of the drum. Finally, the toner is transferred
to the paper through a combination of heat and pressure.
Ink-Jet Printer : It prints characters by spraying patterns of ink on the paper
from a nozzle or jet. It prints from nozzles having very fine holes, from which a
specially made ink is pumped out to create various letters and shapes.
27.Q. Write the Evolution of Internet.
Ans: The vast, global internet of today had rather humble origins when it
initiated. In 1969, the Department of Defense Advanced Research Projects
Agency (ARPA) developed an experimental network called ARPAnet to link
together four supercomputing centres for military research. This network had
the many and difficult design requirements that it had to be fast, reliable, and
capable of withstanding a nuclear bomb destroying any one computer center on
the network. From those original four computers, this network evolved into the
sprawling network of millions of computers we know today as the internet.
The internet itself is really a massive "network of networks." There is no central
"Internet, Inc," to which you can connect. Essentially, it is a collection of
Internet service providers (ISPs) who each operate their own networks, with
their own clients, and agree to interconnect with each other and exchange
packets. Many of the large ISPs sell connections to their network to smaller
ISPs, some of whom again sell connections to other ISPs.
Ultimately, these ISPs at all levels sell connections to individuals and
corporations, who then merge their networks (or individual computers) into this
larger network called the internet.
While there is no exact governance of the Internet, communication standards
and coordination of ISP actions are overseen by a nonprofit organization called
the Internet Society.

An affiliated organization, the Internet Engineering Task Force (IETF)
coordinates the work of numerous committees that define Internet
communication standards and research methods of explaining and improving
Internet communication. The actual communication standards are referred to as
RFCs (Requests for Comments) and are voluntarily adhered to by all ISPs.
Internet uses can be simply categorized as publishing and getting information
on various subjects like marketing, management, science, new technologies,
training materials, jobs, higher education, mathematics, music, games, software,
etc. and E-Commerce and the kind of information available in the internet can
also be listed as text documents, graphic files, sound and video files,
downloadable games and software, demo games and software, etc.
At the speed the internet has been evolving, many predictions can be made
about the internet in the future, like main communication method coming with
functions of being translated automatically into the language preferred by the
receiver, finding a tune through humming into the microphone, virtual tours of a
house, car, etc. could become common thing.
This is what the Internet has become today, starting from its modest birth in
1969, to become an indispensable service for the human race at present and will
remain the same in the future.
Q. ADVANTAGES OF COMPUTERS IN A BUSINESS:
1. Data Storage: Many small businesses keep and store important business
documents on their computers. Since these computers have big storage harddrives, they can be in position to store millions of files and the discovery or
retrieval of these files is very easy. Data can be stored in specific folders to
make it easy to access, and some data can be made private by use of password
protected folders. For medium size growing companies, they invest in a
centralized powerful computers which store all business data, this data can be
accessed via an internal or external network with in the company. This all
process creates efficiency within a business and it also helps in the transfer of
data and information from one department to another.
2. Education: Many companies use computers as a training tool at work. Due
the increased advancement in technology and business trends, it is very
important for a business to train their employees new skills. So for a business to
save money in this process of training employees, computers can be used to
educate and update their employees. However, to save time, business owners or

human resource managers can use virtual technologies to communicate and
train their staff.
3. Research: A computer can be used to make business research on the
internet, the power of the internet is immeasurable, because search engines
like GOOGLE will give you insights in each and every market and company.
Online analytical companies like Compete.com will help you measure your
competitors’ strength online and this will help you make wise business decision
basing on facts and figures.
4. Accounting: Since accounts deals with facts and figures, it is very essential
to use a computer during the accounting process, this reduces on human errors
and it also helps business owners keep track of their businesses without any
need of learning accounting basics. Computers make accounting look too
simple, so any one can use programs like QuickBooks to balance and track
inventory. Mobile computers like tablets and notebooks can be used to access
accounting data remotely. Online QuickBooks software from companies
like intuit.com can automate the invoicing process, billing and reporting which
creates efficiency in a business.
5. Marketing: A business can use a computer to create a business website.
Today, it is very easy to create a website. To create a beautiful company
website, go toThemeforest.com and buy a business Word Press theme for only
$45 then install that theme on your default Word Press site, then start editing the
theme to fit your company goals, the all process is simple and cheap. You can
use your website to market your services and products, reach more customers
by integrating your website content with social media sites like Facebook and
twitter.
6. Creating and Editing of Business documents: One of the most popular
business applications you can use to create and edit documents is ”Microsoft
Word” with this word processing application, you can create any type of
business document, Microsoft Word can check spelling errors , correct grammar
mistakes, include graphics in the document. You can also use Microsoft Excel
spread sheet to organize data inform of figures. Spread sheets can help business
owners manipulate decision variables and determine their impacts on outcomes
like profits and sales. Using a spread sheet, a business owner can have an
accurate answer to a given question in minutes and can often glance at the
whole financial image of the company on a single page. You can also use spread
sheets to set a price for a proposed product.
7. Transfer of information: Computers can be used to transfer information
with in an organization / business. In this lesson we have already seen that a
computer can be used to store data, so this data can be moved across the

company using a computer. Information can easily move from one level to
another using an internal network or external network. An internal network
ensures that information is only shared within the company, so an infrastructure
to move this data is created so that employees and business managers share data
using their computers. Yet for an external network, users will be in position to
access data stored on company database using the internet, in most cases,
companies set up websites which require users to login to access this data.
DISADVANTAGES OF COMPUTERS IN A BUSINESS:
1. Requires Training: In most cases, small business owners don’t know how to
use a computer for business purposes, so they have to hire experts to teach them
and their employees on how to use computers to accomplish specific business
tasks. To some extent, this process is costly and it takes time. For example, if a
small business owner wants to use Quickbooks to manage their accounts , they
have to take off time and learn how Quickbooks works, or they will have to pay
an extra fee to hire a Quickbooks expert to teach them. Even though the end
result is good, time and money will be spent during this process.
2. Computer Crime: Computers are used to provide efficient ways for
employees to share information, but at the same time employees with malicious
intentions can use this opportunity to hack into the system to access private
business information for their personal gains. In most cases this information can
be sold to business rivals, which is harmful to a business. Computer crime is on
the rise and many small businesses have been victims of data loss. Some times
employees or outsiders can modify computer programs to create false
information or illegal transactions or install viruses to corrupt stored
information.
3. Require Additional Infrastructure: Integrating computers in a business can
be costly, you don’t stop at buying a computer, you need to invest money in
different types of business software, this software is used to accomplish specific
business tasks like accounting, tracking inventory, sales, data security and so
much more. You also have to invest money in computer maintenance contracts
with Geek experts who will service your computers every month to ensure that
they operate efficiently. This all process can be costly and some small
businesses can’t afford them.
4. Replaces Human Labor: If a business decides to use computers to complete
most difficult tasks, humans will not be much needed and this will cause job
loss and unemployment. Lets take a simple example in a Bakery business,
electronic temperature sensors can be used to control and report room
temperature in the baking room, in this case, the bakery will need only one

person to monitor results on the computer from the baking room, if the
temperature drops or rises, notifications will be sent to the computer and the
controller will respond immediately. This is a good technology for a business,
because it will guarantee efficiency and quality, but it will also cut off so many
people.

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