This document provides definitions and explanations of key computer science concepts. It defines a computer as an electronic device that can accept data as input, process that data, and produce information as output under the control of stored software instructions. It distinguishes between hardware, which refers to tangible computer components, and software, which is categorized into operating systems and application software. The document also defines and describes local area networks (LANs), metropolitan area networks (MANs), and wide area networks (WANs). Memory, input/output devices, and calculations of storage capacity are also outlined.

1. MD. TAWHID RAHMAN
ID- 2016103010014
DEPARTMENT OF ENGLISH
BATCH- 6TH
2ND YEARS 2ND SEMESTERS
KHWAJA YUNUS ALI UNIVERSITY

2. WHAT IS COMPUTER?
A computer is an electronic device, operating under the
control of instructions (software) stored in its own
memory unit, that can accept data (input), manipulate data
(process), and produce information (output) from the
processing. Generally, the term is used to describe a
collection of devices that function together as a system.

3. WHAT IS HARDWARE?
Hardware refers to objects that you can actually touch, like
disks, disk drives, display screens, keyboards, printers,
boards, and chips.

4. COMPUTER SOFTWARE
• Computer software is the key to productive use of computers.
Software can be categorized into two types:
• Operating system software
• Application software.

5. OPERATING SYSTEM SOFTWARE
• Operating system software tells the computer how to perform
the functions of loading, storing and executing an application
and how to transfer data.
• Today, many computers use an operating system that has a
graphical user interface (GUI) that provides visual clues such
as icon symbols to help the user. Microsoft Windows 98 is a
widely used graphical operating system. DOS (Disk Operating
System) is an older but still widely used operating system that
is text-based.

6. APPLICATION SOFTWARE
•Application Software consists of programs that tell a
computer how to produce information. Some of the more
commonly used packages are:
•Word processing
•Electronic spreadsheet
•Database
•Presentation graphics

7. LOCAL AREA NETWORK (LAN)
A LOCAL AREA NETWORK (LAN) IS A COMPUTER
NETWORK THAT INTERCONNECTS COMPUTERS
WITHIN A LIMITED AREA SUCH AS A RESIDENCE,
SCHOOL, LABORATORY, CAMPUS OR OFFICE
BUILDING.

8. METROPOLITAN AREA NETWORK (MAN)
A Metropolitan area network (MAN) is a computer network that
interconnects users with computer resources in a geographic
area of region larger than that covered by even a large local area
network (LAN) but smaller than area covered by a wide area
network (WAN)

9. WIDE AREA NETWORK (WAN)
A wide area network (WAN) is a telecommunication
network or computer network that extends over a large
geographical distance. Wide area networks are often
established with leased telecommunication circuits.

10. NETWORK TOPOLOGY
Network topology is the arrangement of the various elements
(links, node, etc.) of a communication network. Network
topology is topological structure of a network and may be
depicted physically or logically.
Other way we can say A network topology is the pattern in
which nodes (i. e.- computers, printers, routers or other
devices) are connected to a local area network (LAN) or other
network.

11. NETWORK SERVERS
Centralized computers
Provides access to network resources
Multiple servers are called server farms
Often simply a powerful desktop
Flexibility to different kinds of tasks
Example : Google.

12. MEMORY
Memory:
• One or more set of chips that stores data or
programmed instructions either temporarily or
permanently.
Classification of memory:
1. Primary memory
2. Secondary memory

13. CALCULATIONS OF STORAGE CAPACITY
01 BYTE (B) 08 bit
01KB 1024 B
01 MB 1024.1024 B
01 GB 1024.1024.1024 B
01 TB 1024.1024.1024.1024 B

14. OUTPUT UNIT
>>Output Unit
Printer
Monitor
plotter
Speaker

15. INPUT UNIT
Keyboard,
Mouse,
Scanner,
OMR,
OCR,
MICR
Barcode reader
Microphone
Joystick
Digital Camera

16. Thank You All…