unit 1

1. PES Institute of Advanced Management Studies,
Department of Commerce AND mANAGEMENT.
NH-206 Sagar Road, Shimoga, Karnataka.
Topic: Computer- meaning, definition, types, application, Operating system,
Windows, RAM and ROM.
Prepared by :
Ayesha Siddiqua,
Assistant Professor,
PESIAMS.

2. Meaning of computer:
The word compute is derived from the Latin word ‘computare’, which means
"arithmetic, accounting".
The Computer meaning is the digital device that stores information in memory
using input devices and manipulate information to produce output according to given
instructions.
The actual machinery, the physical parts of a computer system refer to as Computer
hardware; the instruction (a program) that tells the computer what to do or how to
do, that is called Computer software (often called just software).
Technically, a computer means to calculate or electronic programmable machine.
Computer is used to perform some sequence of instructions in fast and accurate
manner. Computer receives input in the form of digitalized data, using input devices
like keyboard, mouse, joystick, scanner etc. It process based on a program instructions
to give output.

3. Computer – definition:
A computer is a machine or device that performs processes, calculations and
operations based on instructions provided by a software or hardware program. It is
designed to execute applications and provides a variety of solutions by combining
integrated hardware and software components

4. Basic characteristics about computer are:
1. Speed: - As you know computer can work very fast. It takes only few seconds for
calculations that we take hours to complete. You will be surprised to know that computer can
perform millions (1,000,000) of instructions and even more per second.
Therefore, we determine the speed of computer in terms of microsecond (10-6 part of a second)
or nanosecond (10 to the power -9 part of a second). From this you can imagine how fast your
computer performs work.
2. Accuracy: - The degree of accuracy of computer is very high and every calculation is
performed with the same accuracy.
The accuracy level is
determined on the basis of design of computer. The errors in computer are due to human and
inaccurate data.
3. Diligence: - A computer is free from tiredness, lack of concentration, fatigue, etc. It can work
for hours without creating any error. If millions of calculations are to be performed, a computer
will perform every calculation with the same accuracy. Due to this capability it overpowers
human being in routine type of work.
4. Versatility: - It means the capacity to perform completely different type of work. You may
use your computer to prepare payroll slips. Next moment you may use it for inventory
management or to prepare electric bills

5. 5. Power of Remembering: - Computer has the power of storing any amount
of information or data. Any information can be stored and recalled as long as you require
it, for any numbers of years. It depends entirely upon you how much data you want to
store in a computer and when to lose or retrieve these data.
6. No IQ: - Computer is a dumb machine and it cannot do any work without instruction
from the user. It performs the instructions at tremendous speed and with accuracy. It is
you to decide what you want to do and in what sequence. So a computer cannot take its
own decision as you can.
7. No Feeling: - It does not have feelings or emotion, taste, knowledge and experience.
Thus it does not get tired even after long hours of work. It does not distinguish between
users.
8. Storage: - The Computer has an in-built memory where it can store a large amount of
data. You can also store data in secondary storage devices such as floppies, which can be
kept outside your computer and can be carried to other computers.

11. 1. Computers Are Used for Communication
When it comes to establishing contact with clients, computers are a vital tool; they are
also vital when it comes to maintaining that contact. This is a very
important computer application in business, enabling a business to communicate with
its clients via email, IM, Skype, collaboration software, and via various other
communication solutions that a business might wish to use.
When a business can keep in touch with its clients, it becomes easier for the clients to
make inquiries of the business or to ask for more information about the services and
products the business offers. It also becomes easier for the business to offer customer
support to its clients in a timely, efficient manner. The business will also be able to
keep the clients updated about any new developments concerning the business.
Communication goes beyond a business' clients. A business also needs to
communicate with its employees, and computers play an important role. Rather than
have time-wasting one-on-one meetings with employees, managers can simply email
their employees or they can message them on any other acceptable communication
platform. This saves time, and it also improves the internal communication of the
business.
Application of Computers in Business

12. 2. Computers Are Used for Marketing
Computers allow a business to perform a variety of tasks. For starters, with the
help of the internet, computers help put a business on the map. With a computer,
a business’s team of IT developers can create a professional website complete
with enticing graphics and content with different forms of media, such as text,
images, and videos. They can do search engine optimization – SEO – for the
website so that it appears prominently in Google’s search results, which then
attracts traffic, which, ultimately, will enable the business to sell those products
to website visitors.
With a computer, a business can create and execute entire marketing campaigns
that span across every social media platform on the internet. The business can
create ads to run on websites and social media platforms, using special software,
and it can also buy marketing services from other businesses – all connected to
the internet. The computer is likely the greatest marketing device ever built!

13. 3. Computers Are Used for Accounting
Accounting is a function in which accuracy is of the utmost importance. When
you perform accounting functions – and you have nothing nothing except pen and
paper - and you're relying solely on brain power, you expose yourself to errors.
Accounting software helps prevent that from happening.
Accounting software enables a business to quickly and accurately obtain large-
and small-scale pictures of the company's financial situation. All the employees
need to do is to input his financial information into the software and – with a few
clicks – the employees understand everything about the financial health of the
business' operations.
Computers are also critical for tasks such as invoicing clients; maintaining data
about debtors and creditors; calculating payroll, calculating and filing tax forms,
as well as for a lot of other functions.
With the computer, accountants can now focus on the higher level picture of a
business’s finances, leaving the lower level stuff to the machines.

14. 4. Computers Are Used for Storage
Businesses have come a long way from the era of filing cabinets thanks to
computers. Although a filing cabinet will occupy a very large space but will store
only a small amount of information, a computer will occupy only a fraction of
that space but it will store thousands of times the amount of information. With
computers and servers, businesses are able to store and sort millions of files, to
enable the business to access at any time.
Computers also enable a business to store its data in different ways. The business
could store the data in a central location, and it could have other computers on the
network access the data whenever the business needs to; when the business has
the permission to; or, when the business could store the data locally on individual
computers.
Not only is digital storage much larger than physical storage in terms of capacity,
but it is also much more efficient because of the level of sorting that takes place,
which is one of the greatest benefits of the computer. Digital storage is also more
secure, as it is more difficult to lose or steal files from a well-protected database.

15. 5. Computers Are Used to Produce Documents
Most businesses will need to produce numerous documents, either in the form of
written documents or spreadsheets. Computers provide word processors and
spreadsheet software to help with this.
With these two types of software, a business can generate virtually everything, from
memos to letters to tutorials to reports to ads for the company’s services and products
or company events.
With spreadsheet applications, a business has the power to manipulate alphanumeric
data and organize it into tables, charts, graphs, and reports. Another kind of software
that businesses make use of is presentation software. With presentation software, a
business can make slides for presentations, either internal ones or external ones meant
for clients. Businesses can also make letters, memos, and reports, using word
processing software, either for disbursement to the client or for internal use.
In general, a computer has plenty of productivity software that a business can use to
make its functions easier; this is software that enables a business to be much faster
and more efficient that it was only 20 or 30 years ago.

16. 6. Computers Are Used for Educational Purposes
Computers can be used to educate employees. A business can use a computer to educate
the employees on such things as the company policy, software use, as well as standard
procedures and safety.
Rather than hire teachers to teach its employees, a business can let employees learn what
the employee needs, by learning at their own pace via webinars and live Q&A sessions.
With the internet, a business' employees will have access to a world of information, and
the business will not need to create all of its own educational content.
Computers also enable employees to learn in a way that they enjoy. Employees can learn
via different media, such as videos, text, and even games, enabling them to better
understand the subject matter.

17. 7. Computers Are Used for Research
Computers allow a business to do a variety of things, including research about the
competition, as well as what its customers want. With modern data-mining
techniques, a business can acquire insightful information about its customers and
competition from all kinds of places, including forums, search engines, industry-
specific websites and even from social networks.

18. Operating System:
An Operating System acts as a communication bridge (interface) between
the user and computer hardware. The purpose of an operating system is to
provide a platform on which a user can execute programs in a convenient
and efficient manner.
An operating system is a piece of software that manages the allocation of
computer hardware. The coordination of the hardware must be appropriate
to ensure the correct working of the computer system and to prevent user
programs from interfering with the proper working of the system.
Definition:
An operating system is a program that acts as an interface between the
user and the computer hardware and controls the execution of all kinds of
programs.

20. Important functions of an operating System:
1.Security –
The operating system uses password protection to protect user data and
similar other techniques. it also prevents unauthorized access to programs
and user data.
2.Control over system performance –
Monitors overall system health to help improve performance. records the
response time between service requests and system response to have a
complete view of the system health. This can help improve performance by
providing important information needed to troubleshoot problems.

21. 3. Job accounting –
Operating system Keeps track of time and resources used by various tasks and
users, this information can be used to track resource usage for a particular user
or group f user.
4. Error detecting aids –
Operating system constantly monitors the system to detect errors and avoid the
malfunctioning of computer system.
5.Coordination between other software and users –
Operating systems also coordinate and assign interpreters, compilers,
assemblers and other software to the various users of the computer systems.

22. 6. Memory Management –
The operating system manages the Primary Memory or Main Memory.
Main memory is made up of a large array of bytes or words where each
byte or word is assigned a certain address. Main memory is a fast storage
and it can be accessed directly by the CPU. For a program to be executed,
it should be first loaded in the main memory. An Operating System
performs the following activities for memory management:It keeps tracks of
primary memory, i.e., which bytes of memory are used by which user
program. The memory addresses that have already been allocated and the
memory addresses of the memory that has not yet been used. In multi
programming, the OS decides the order in which process are granted
access to memory, and for how long. It Allocates the memory to a process
when the process requests it and deallocates the memory when the
process has terminated or is performing an I/O operation.

23. 7. Processor Management –
In a multi programming environment, the OS decides the order in
which processes have access to the processor, and how much
processing time each process has. This function of OS is called
process scheduling. An Operating System performs the following
activities for processor management.Keeps tracks of the status of
processes. The program which perform this task is known as traffic
controller. Allocates the CPU that is processor to a process. De-
allocates processor when a process is no more required.

24. 8.Device Management –
An OS manages device communication via their respective drivers. It
performs the following activities for device management. Keeps tracks of
all devices connected to system. designates a program responsible for
every device known as the Input/Output controller. Decides which process
gets access to a certain device and for how long. Allocates devices in an
effective and efficient way. Deallocates devices when they are no longer
required.

25. 9. File Management –
A file system is organized into directories for efficient or easy navigation
and usage. These directories may contain other directories and other
files. An Operating System carries out the following file management
activities. It keeps track of where information is stored, user access
settings and status of every file and more. These facilities are
collectively known as the file system.

26. Windows OS :
Windows OS, computer operating system (OS) developed
by Microsoft Corporation to run personal computers (PCs).
Featuring the first graphical user interface (GUI) for IBM-
compatible PCs, the Windows OS soon dominated the PC
market. Approximately 90 percent of PCs run some version of
Windows.

27. Features of Windows:
1. Windows Search
We can have numerous files and contents located on our system and
sometimes we may run out of memory about the exact location of our file.
Windows Search is a search function included with Windows that allows the
user to search their entire computer
2. Windows File Transfer
We may have the need to transfer in or transfer out the files and contents from
our machine to other devices such as other computers or mobiles and tablets.
We can do this by using an Easy Transfer Cable, CDs or DVDs, a USB flash
drive, wireless Bluetooth, a network folder, or an external hard disk.
3. Windows Updates
Windows includes an automatic update feature with the intended purpose of
keeping its operating system safe and up-to-date.
4. Windows taskbar
At the bottom most part of your windows, you will see a row which is known as
the taskbar. It has the currently running applications, you can also pin
applications that you frequently use by using an option Pin to Taskbar”. The
taskbar is the main navigation tool for Windows
5.Remote Desktop Connection
This feature of windows allows you to connect to another system and work
remotely on another system.

28. Advantages of Windows:
•Desktop as well as tablet-friendly OS
•Switch between applications is very easy
•Not much technical knowledge is required to operate windows
•Windows OS is the dominant OS and enjoys more than 90% of
Market share
•MS OS have a great support community and it also has the
largest number of applications
•Microsoft provides a powerful set of Enterprise focused Operating
System, Applications and the services making it the most dominant
player in the OS market.
•More gaming

29. Disadvantages of Windows:
•There are privacy and security concerns and incidents and
they are widespread. Linux OS is by far most secure OS ever
built.
•Cost for upgrade
•Windows OS attracts a large number of virus programs due to
its largest market share and easy to breach paradigm
•Windows OS is not that much of touch-friendly

30. Computer memory
Computer memory is any physical device capable of storing
information temporarily, like RAM (random access memory), or
permanently, like ROM (read-only memory). Memory devices
utilize integrated circuits and are used by operating
systems, software, and hardware.

31. Primary memory is a computer system's volatile storage mechanism. It may
be random access memory (RAM), cache memory or data buses, but is
primarily associated with RAM.
As soon as a computer starts, primary memory loads all running
applications, including the base operating system (OS), user interface and
any user-installed and running software utility. A program/application that is
opened in primary memory interacts with the system processor to perform
all application-specific tasks.
Primary memory
Primary memory is computer memory that a processor or computer accesses
first or directly. It allows a processor to access running execution applications
and services that are temporarily stored in a specific memory location.
Primary memory is also known as primary storage or main memory.

32. Secondary memory:
Secondary memory is computer memory that is non-volatile and persistent
in nature and is not directly accessed by a computer/processor. It allows a
user to store data that may be instantly and easily retrieved, transported
and used by applications and services.
Secondary memory is also known as secondary storage.
Secondary memory consists of all permanent or persistent storage devices,
such as read-only memory (ROM), flash drives, hard disk drives (HDD),
magnetic tapes and other types of internal/external storage media. In
computing operations, secondary memory is accessed only by the primary or
main memory and later transported to the processor.
Secondary memory is slower than primary memory but can store and retain
data, even if the computer is not connected to electrical power. It also has
substantial storage capacities, ranging from megabytes to several terabytes
of storage space within single memory.

34. Random access memory (RAM)
Random access memory (RAM) is a type of data storage used in computers
that is generally located on the motherboard. This type of memory is volatile
and all information that was stored in RAM is lost when the computer is turned
off. Volatile memory is temporary memory while ROM (read-only memory) is
non-volatile and holds data permanently when the power is turned off.
The RAM chip may be individually mounted on the motherboard or in sets of
several chips on a small board connected to the motherboard. Older memory
types were in the form of chips called dual in-line package (DIP). Although
DIP chips are still used today, the majority of memory is in the form of a
module, a narrow printed circuit board attached to a connector on the
motherboard. The three main memory circuit boards types containing chips
are: RIMMs (Rambus in-line memory modules), DIMMs (dual in-line memory
modules) and SIMMs (single in-line memory modules). Most motherboards
today use DIMMs.

35. There are two main types of RAM:
1. DRAM (Dynamic Random Access Memory) – The term dynamic indicates
that the memory must be constantly refreshed or it will lose its
contents. DRAM is typically used for the main memory in computing
devices. If a PC or smartphone is advertised as having 4-GB RAM or 16-GB
RAM, those numbers refer to the DRAM, or main memory, in the device.
More specifically, most of the DRAM used in modern systems is synchronous
DRAM, or SDRAM. Manufacturers also sometimes use the acronym DDR (or
DDR2, DDR3, DDR4, etc.) to describe the type of DRAM used by a PC or server.
DDR stands for double data rate, and it refers to how much data the memory can
transfer in one clock cycle.
In general, the more RAM a device has, the faster it will perform. The RAM in
most personal computers (PC’s) is Dynamic RAM. All dynamic RAM chips on
DIMMs, SIMMs or RIMMs have to refresh every few milliseconds by rewriting
the data to the module.

36. 2. SRAM (Static Random Access Memory) – While DRAM is typically used
for main memory, today SRAM is more often used for system cache. SRAM
is said to be static because it doesn't need to be refreshed, unlike dynamic
RAM, which needs to be refreshed thousands of times per second. As a
result, SRAM is faster than DRAM. However, both types of RAM
are volatile, meaning that they lose their contents when the power is turned
off. Static RAM (SRAM) is volatile memory and is often used in cache
memory and registers because it is a lot faster and does not require refreshing
like Dynamic RAM. SRAM retains information and is able to operate at
higher speeds than DRAM.

37. Read-only memory (ROM)
Read-only memory (ROM) is a type of storage medium that permanently
stores data on personal computers (PCs) and other electronic devices. It
contains the programming needed to start a PC, which is essential for boot-
up; it performs major input/output tasks and holds programs or software
instructions.
Because ROM is read-only, it cannot be changed; it is permanent and non-
volatile, meaning it also holds its memory even when power is removed.
By contrast, random access memory (RAM) is volatile; it is lost when
power is removed.
There are numerous ROM chips located on the motherboard and a few on
expansion boards. The chips are essential for the basic input/output system
(BIOS), boot up, reading and writing to peripheral devices, basic data
management and the software for basic processes for certain utilities.

38. Other types of non-volatile memory include:
•Programmable Read-Only Memory (PROM)
•Electrically Programmable Read-Only Memory (EPROM)
•Electrically Erasable Programmable Read-Only Memory (EEPROM;
also called Flash ROM)
•Electrically Alterable Read-Only Memory (EAROM)
However, these types of non-volatile memory can be altered and are
often referred to as programmable ROM. One of the original forms of
non-volatile memory was mask-programmed ROM. It was designed for
specific data such as bootstrap, which contains the startup code. Mask-
programmed ROM can never be changed.

39. Because ROM cannot be changed and is read-only, it is mainly used
for firmware. Firmware is software programs or sets of instructions
that are embedded into a hardware device. It supplies the needed
instructions on how a device communicates with various hardware
components. Firmware is referred to as semi-permanent because it
does not change unless it is updated. Firmware includes BIOS,
erasable programmable ROM (EPROM) and the ROM
configurations for software.
ROM may also be referred to as maskROM (MROM). MaskROM is
a read-only memory that is static ROM and is programmed into an
integrated circuit by the manufacturer. An example of MROM is the
bootloader or solid-state ROM, the oldest type of ROM.

40. Some ROM is non-volatile but can be reprogrammed, this includes:
Erasable Programmable Read-Only Memory (EPROM): This is programmed
with the use of very high voltages and exposure to approximately 20 minutes
of intense ultraviolet (UV) light.
Electrically-Erasable Programmable Read-Only Memory (EEPROM): This is
used in many older computer BIOS chips, is non-volatile storage that can be
erased and programmed several times and allows only one location at a time to
be written or erased. An updated version of EEPROM is flash memory; this
allows numerous memory locations to be altered simultaneously.
Ultraviolet-Erasable Programmable Read-Only Memory (UV-EPROM): This
is read-only memory that can be erased by the use of ultraviolet light and then
reprogrammed.
ROM is also often used in optical storage media such as various types of
compact discs, including read-only memory (CD-ROM), compact disc
recordable (CD-R) and compact disc rewritable (CD-RW).