1.
What is computer and How it works
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2.
What is a Computer
A computer is a programmable device that
stores, retrieves, and processes data. The
term "computer" was originally given to
humans (human computers) who
performed numerical calculations using
mechanical calculators, such as
the abacus and slide rule. The term was later
given to a mechanical device as they began
replacing the human computers. Today's
computers are electronic devices that accept
data (input), process that data,
produce output, and store (storage) the
results.
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3.
7 Essential/Fundamental Parts of a Desktop Computer
SIMPLE COMPLEX
• Case
• Power Supply
• Mother Board
• Central Processing Unit(CPU)
• Random Access Memory(RAM)
• Hard Drive
• Graphics Card
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4.
Computer Cases
Computer cases are one of the most important
components of a computer, since they have to house the
motherboard, processor, video cards, audio cards and
add-in cards, as well as your hard drives and optical
drives. Most of the computer cases are made of steel or
aluminum. Some parts of a computer case can also be
made of plastic. Computer cases can be divided into
several categories by their sizes and purpose. Mainstream
computer case styles and form factors include ATX Mid
Tower, ATX Full Tower, MicroATX, Mini Tower and Desktop
Cases.
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5.
A power supply unit (PSU)
converts mains AC to low-voltage
regulated DC power for the internal
components of a computer. Modern
personal computers universally
use switched-mode power supplies.
Some power supplies have a manual
switch for selecting input voltage, while
others automatically adapt to the mains
voltage.
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6.
The motherboard is the backbone of
your desktop computer. Choosing the
best motherboard for your PC is a
critical part of the process. The CPU,
GPU, RAM, and other components
are essential, but it's the motherboard
that holds them all together.
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7.
The central processing unit (CPU) or processor, is the unit which performs most of the processing inside a
computer. It processes all instructions received by software running on the PC and by other hardware
components, and acts as a powerful calculator.
The CPU is placed into a specific square-shaped socket found on all motherboards by inserting its metallic
connectors or pins found on the underside. Each socket is built with a specific pin layout to support only a
specific type of processor.
Since modern CPUs produce a lot of heat and are prone to overheating, they must be kept cool with appropriate
fans or ventilation systems, and covered with heat sinks and thermal paste.
To control instructions and data flow to and
from other parts of the computer, the CPU
relies heavily on a chipset, which is a group
of microchips located on the motherboard.
This term is also known as a central
processor, microprocessor or chip.
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8.
Random-access memory (RAM )is a form
of computer memory that can be read and
changed in any order, typically used to store
working data and machine code.
It is a physical hardware inside a computer
that temporarily stores data, serving as the
computer's "working" memory.
Additional RAM allows a computer to work
with more information at the same time,
which usually has a considerable effect on
total system performance.
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9.
A computer hard drive is the place where computer data
is stored. A HDD (Hard Disk Drive) is generally referred
to as the secondary computer storage device, as the RAM
(Random Access Memory) is the primary. A hard drive is a
permanent storage device, so even when the computer is
turned off the information will still be there. The operating
system, program files, and all data files are stored on the
hard drive. A computer can function without a hard drive
but there would be no operating system or programs so it
would be of very little use.
A solid-state drive (SSD) is a new generation of storage
device used in computers. SSDs replace traditional
mechanical hard disks by using flash-based memory,
which is significantly faster. Older hard-disk storage
technologies run slower, which often makes your
computer run slower than it should. SSDs speed up
computers significantly due to their low read-access times
and fast throughputs.
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10.
Powering Up a PC
When you first power up a PC, the machine goes through several internal processes before it's ready for you to
use. This is called the boot process, or booting the PC. Boot is short for bootstrap, a reference to the old
adage, "Pull yourself up by the bootstraps," which means to start something from the very beginning. The boot
process is controlled by the PC's basic input-output system (BIOS).
The BIOS is software stored on a flash memory chip. In a PC, the BIOS is embedded on the motherboard.
Occasionally, a PC manufacturer will release an update for the BIOS, and you can carefully follow instructions
to "flash the BIOS" with the updated software.
Besides controlling the boot process, the BIOS provides a basic configuration interface for the PC's hardware
components. In that interface, you can configure such things as the order to read drives during boot and how
fast the processor should be allowed to run. Check your PC's documentation to find out how to enter its BIOS
interface. This information is often displayed when you first boot the computer, too, with a message such as,
"Press DEL to enter Setup Menu."
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11.
The following is a summary of the boot process in a PC:
1.The power button activates the power supply in the PC, sending power to the motherboard and other
components.
2.The PC performs a power-on self-test (POST). The POST is a small computer program within the BIOS that
checks for hardware failures. A single beep after the POST signals that everything's okay. Other beep sequences
signal a hardware failure, and PC repair specialists compare these sequences with a chart to determine which
component has failed.
3.The PC displays information on the attached monitor showing details about the boot process. These include the
BIOS manufacturer and revision, processor specs, the amount of RAM installed, and the drives detected. Many
PCs have replaced displaying this information with a splash screen showing the manufacturer's logo. You can turn
off the splash screen in the BIOS settings if you'd rather see the text.
4.The BIOS attempts to access the first sector of the drive designated as the boot disk. The first sector is the first
kilobytes of the disk in sequence, if the drive is read sequentially starting with the first available storage address.
The boot disk is typically the same hard disk or solid-state drive that contains your operating system. You can
change the boot disk by configuring the BIOS or interrupting the boot process with a key sequence (often indicated
on the boot screens).
5.The BIOS confirms there's a bootstrap loader, or boot loader, in that first sector of the boot disk, and it loads that
boot loader into memory (RAM). The boot loader is a small program designed to find and launch the PC's
operating system.
6.Once the boot loader is in memory, the BIOS hands over its work to the boot loader, which in turn begins loading
the operating system into memory.
7.When the boot loader finishes its task, it turns control of the PC over to the operating system. Then, the OS is
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12.
PC Operating System
After a PC boots, you can control it through
an operating system, or OS for short. As of this
writing, most non-Apple PCs run a version of
Microsoft Windows or a Linux distribution. These
operating systems are designed to run on various
kinds of PC hardware, while Mac OS X is designed
primarily for Apple hardware.
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13.
An operating system is responsible for several tasks. These tasks fall into the following broad
categories:
•Processor management -- breaks down the processor's work into manageable chunks and prioritizes them
before sending them to the CPU.
•Memory management -- coordinates the flow of data in and out of RAM, and determines when to use virtual
memory on the hard disk to supplement an insufficient amount of RAM.
•Device management -- provides a software-based interface between the computer's internal components and
each device connected to the computer. Examples include interpreting keyboard or mouse input or adjusting
graphics data to the right screen resolution. Network interfaces, including managing your Internet connection,
also fall into the device management bucket.
•Storage management -- directs where data should be stored permanently on hard drives, solid state drives,
USB drives and other forms of storage. For example, storage management tasks assist when creating, reading,
editing, moving, copying and deleting documents.
•Application interface -- provides data exchange between software programs and the PC. An application must
be programmed to work with the application interface for the operating system you're using. Applications are
often designed for specific versions of an OS, too. You'll see this in the application's requirements with phrases
like "Windows Vista or later," or "only works on 64-bit operating systems."
•User interface (UI) - provides a way for you to interact with the computer.
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14.
While we understand Human Language, the computer can understand Machine Language. When a person types
on a computer’s keyboard, the human brain identifies the letters, numbers, and characters combined to create
words and sentences. But the computer does not recognize letters as letters of the alphabet; it sees the letters as a
series of 0’s and 1’s called the binary language.
Computer number system
Number systems are the technique to represent numbers in the computer system architecture, every value that
you are saving or getting into/from computer memory has a defined number system.
Binary number system has only two digits that are 0 and 1. Every number (value) represents with 0 and 1 in
this number system. The base of binary number system is 2, because it has only two digits.
Octal number system has only eight (8) digits from 0 to 7. Every number (value) represents with 0,1,2,3,4,5,6
and 7 in this number system. The base of octal number system is 8, because it has only 8 digits.
Decimal number system has only ten (10) digits from 0 to 9. Every number (value) represents with
0,1,2,3,4,5,6, 7,8 and 9 in this number system. The base of decimal number system is 10, because it has only 10
digits.
Hexadecimal number system has sixteen (16) alphanumeric values from 0 to 9 and A to F. Every number
(value) represents with 0,1,2,3,4,5,6, 7,8,9,A,B,C,D,E and F in this number system. The base of hexadecimal
number system is 16, because it has 16 alphanumeric values. Here A is 10, B is 11, C is 12, D is 13, E is
14 and F is 15.

15.
How computer Interpret Data
With the different type of number systems, it is important to understand how computers interpret the letters on the
keyboard through series of 1’s and 0’s. this is normally done through the number system conversion(we will not be dealing
with this topic). Depending on the standard used, computer systems convert characters from the keyboard and later display
them on the monitor.

16.
How Computer Communicate with one another
•Bus is a communication channel.
•Characteristic of bus is shared transmission media.
•Limitation of a bus is only one transmission at a time.
•A bus which is used to provide the communication between
the major components of a computer is called as System
bus.
System bus contains 3 categories of lines used to provide
the communication between the CPU, memory and IO
named as:
1. Address lines/bus
2. Data lines/bus
3. Control lines /bus

17.
A data bus is a computer subsystem that allows for the transferring
of data from one component to another on a motherboard or system
board, or between two computers. This can include transferring data
to and from the memory, or from the central processing unit (CPU) to
other components. Each one is designed to handle so many bits of
data at a time. The amount of data a data bus can handle is
called bandwidth.
USB stands for Universal Serial Bus, a type
of data bus.

18.
An address bus is a computer
bus which is used to address the
main system memory. In many
embedded controllers and some
older computers, the processor
address bus is directly wired to the
memory chips. Most desktop and
server motherboards include the
address bus in the memory
bus between the memory
controller chip and the system
memory. The address bus is used
by a processor to indicate the
memory location that it is about to
read data from or write data to.
Some processors may also use it
to indicate an input/output port that
is about to be read or written.
A control bus is what a
computer’s central processing
unit (CPU) uses to communicate
with other devices inside the
machine over a set of physical
connections like cables or printed
circuits. It is a diverse collection of
signals, including read, write, and
interrupt, that allow the CPU to
direct and monitor what the
different parts of the computer are
doing. This is one of three types of
buses that make up the system or
computer bus.

19.
How computers connect to other computers
Computer Network System
A personal area network (PAN) is a computer
network organized around an individual for
personal use only. They typically involve a
computer, phone, printer, tablet, or some other
device like a PDA. The difference between
PANs and other network types like local area
networks, wireless local area networks, wide
area networks, and metropolitan area networks
is that they transmit information between
devices that are nearby instead of sending that
same data through a LAN or WAN before it
reaches something that's already within reach.
You can use these networks to transfer files,
including email, calendar appointments,
photos, and music. If you do the transfers
wirelessly -- for example, using Wi-Fi or
Bluetooth -- it's technically called a WPAN,
which is a wireless personal area network.

20.
LAN stands for local area network. A LAN is a group
of computers and devices that are in a specific
location. The devices connect to the LAN with an
Ethernet cable or through Wi-Fi. Your home may have
a LAN. If your PC, tablet, smart TV, and wireless
printer connect through your Wi-Fi, these connected
devices are part of your LAN. Only devices that you
authorize have access to your LAN.
A LAN differs from other types of computer networks
(like the internet) in that the devices connected to the
LAN are in the same building such as a home, school,
or office. These computers, printers, scanners, and
other devices connect to a router with an Ethernet
cable or through a wireless router and a Wi-Fi access
point. Multiple LANs can be connected over a
telephone line or radio wave(Wireless).

21.
A wide area network spans a large
geographic area such as a city, state, or
country. It can be private to connect
parts of a business, or it can be public to
connect smaller networks.
The easiest way to understand a WAN is
to think of the internet as a whole, which
is the world's largest WAN. The internet
is a WAN because, through the use
of Internet Service Provider, it
connects many smaller local area
networks or metro area networks.

22.
https://www.techopedia.com/definition/2851/central-processing-unit-cpu
https://en.wikipedia.org/wiki/Random-access_memory
https://www.lifewire.com/what-is-random-access-memory-ram-2618159
https://www.computer-hardware-explained.com/computer-hard-drive.html
https://computer.howstuffworks.com/pc.htm
REFERENCES:
Disclaimer: All images are copyright to their respective owners.
Supplementary videos
How Computers Work, Compilation Video of Basics Explained
• https://www.youtube.com/watch?v=Rv73ki6fTuo&t=63s
Computer Boot Process animation
• https://www.youtube.com/watch?v=PSnGuvylWBI
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How Computers Work: Binary & Data
• https://www.youtube.com/watch?v=USCBCmwMCDA
https://www.geeksforgeeks.org/system-bus-design
https://www.easytechjunkie.com