Basic Info about Computer & Peripheral devices

1. COMPUTER & NETWORK
TECHNOLOGY
By Janaki S Ganesan

2. HISTORY OF COMPUTER’S
• The history of computers starts out about 2000 years ago in Babylonia
(Mesopotamia), at the birth of the abacus, a wooden rack holding two horizontal
wires with beads strung on them.
• Blaise Pascal is usually credited for building the first digital computer in 1642. It
added numbers entered with dials and was made to help his father, a tax collector.
• Charles Babbage, an English mechanical engineer and polymath, originated the
concept of a programmable computer. Considered the "father of the computer“ he
conceptualized and invented the first mechanical computer in the early 19th
century.

3. WHAT IS A COMPUTER?
• A computer is an electronic device, operating under the control of instructions stored
in its own memory, that can accept data, process the data according to specified
rules, produce results, and store the results for future use.

4. DATA & INFORMATION
• Computers process data into information. Data is a collection of unprocessed items,
which can include text, numbers, images, audio, and video.
• Information conveys meaning and is useful to people.
Information Processing cycle
Computers process data (input) into information (output).
Computers carry out processes using instructions, which are the steps that tell the
computer how to perform a particular task

5. WHAT IS OPERATING SYSTEM & TYPES
• An operating system (OS) is the program that, after being initially loaded into the computer by
a boot program, manages all of the other application programs in a computer. The application programs make
use of the operating system by making requests for services.
• There are many type’s of OS;
1. Batch Operating System –
This type of operating system does not interact with the computer directly. There is an operator which takes
similar jobs having same requirement and group them into batches. It is the responsibility of operator to sort the
jobs with similar needs.
2. Time-Sharing Operating Systems –
Each task is given some time to execute, so that all the tasks work smoothly. Each user gets time of CPU as they
use single system. These systems are also known as Multitasking Systems.
3. Distributed Operating System –
These types of operating system is a recent advancement in the world of computer technology and are being
widely accepted all-over the world and, that too, with a great pace.
4. Network Operating System –
These systems run on a server and provide the capability to manage data, users, groups, security, applications,
and other networking functions. These type of operating systems allow shared access of files, printers, etc.

7. BOOTING
• Booting is a startup sequence that starts the operating system of a computer when it is turned on.
A boot sequence is the initial set of operations that the computer performs when it is switched on.
Every computer has a boot sequence. The average computer doesn’t understand the boot sequence
but is important to know for customizing and troubleshooting your computer.
• The boot device is the device from which the operating system is loaded. A modern PC BIOS (Basic
Input/Output System) supports booting from various devices.
• Typically, the BIOS will allow the user to configure a boot order. If the boot order is set to:
1.CD Drive
2.Hard Disk Drive
3.Network

8. BOOTING SEQUENCE

9. PORTS OF CPU
• A port is a physical docking point using which an external device can be connected to the
computer. It can also be programmatic docking point through which information flows
from a program to the computer or over the Internet.
• Important types of port
Serial Port
Parallel Port
PS/2 Port
SCSI Port
USB

11. HARD-DSISK
• A hard disk drive (sometimes abbreviated as hard drive, HD, or HDD) is a non-
volatile memory hardware device that permanently stores and retrieves data on a
computer. A hard drive is a secondary storage device that consists of one or more
platters to which data is written using a magnetic head, all inside of an air-sealed
casing.
• Internal hard disks reside in a drive bay, connect to the motherboard using an ATA,
SCSI, or SATA cable, and are powered by a connection to the PSU (power supply
unit).
• All computers have a hard drive installed in them, which is used to store files for the
operating system, software programs, and a user's personal files

12. HARD-DISK COMPONENTS
• The desktop hard drive consists of the following components: the head actuator,
read/write actuator arm, read/write head, spindle, and platter. On the back of a hard
drive is a circuit board called the disk controller or interface board and is what allows
the hard drive to communicate with the computer.

13. BITS, BYTES, MB, GB, TB…

14. OPTICAL STORAGE DEVICES
• Optical storage refers to recording data using light. Typically, that's done using a
drive that can contain a removable disk and a system based on lasers that can read
or write to the disk.
• Compared to other types of storage such as magnetic hard drives, the disks used in
optical storage can be quite inexpensive and lightweight, making them easy to ship
and transport. They also have the advantage of being removable.
• The most common example of the storage medium is the CD, DVD, and Blu-ray
discs which are made with a shiny surface to reflect the laser back into a sensor.

15. SMPS & UPS
• A SMPS converts different voltages between its input to output but does not provide
any backup ability to connected equipment (“Load”) in the event of a power failure.
• A UPS (Uninterruptible Power Supply/System) is a system designed to maintain an
(effectively) uninterrupted source of power to connected equipment via the use of
battery storage which is used to convert to the desired AC output voltage through
the use of an inverter system.

16. SMPS AND UPS

17. INPUT DEVICES
• In computing, an input device is a piece of computer hardware equipment used to
provide data and control signals to an information processing system such as a computer
or information appliance. Examples of input devices include;
1.Keyboards
2.Mouse
3.Scanners
4.Digital cameras
5.Joysticks
6.Microphones.

18. PRINTERS
• A printer is an external output device that takes data from a computer and generates output in the
form of graphics / text on a paper”.
• There are mainly two categories of Printer’s;
Impact printer and Non-Impact Printer’s
Impact Printer are as follows;
1. Dot-Matrix Printers
2.Daisy-wheel printers
3.Line printers
4.Drum printer
5.Chain printers
6.Band printers
Non-Impact Printers are as follows;
1.Ink-jet printers
2.Laser printers

19. IMPACT PRINTERS
An impact printer makes contact with the paper. It usually forms the print image by pressing an inked ribbon against the paper using a hammer or pins. Following are some
examples of impact printers.
Dot-Matrix Printers
• The dot-matrix printer uses print heads containing from 9 to 24 pins. These pins produce patterns of dots on the paper to form the individual characters. The pins strike
the ribbon individually as the print mechanism moves across the entire print line in both directions, i-e, from left to right, then right to left, and so on. The user can
produce a color output with a dot-matrix printer (the user will change the black ribbon with a ribbon that has color stripes).
Daisy-Wheel Printers
• In order to get the quality of type found on typewriters, a daisy-wheel impact printer can be used. It is called daisy-wheel printer because the print mechanism looks like
a daisy.
Line Printers
• Line printers, or line-at-a-time printers, use special mechanism that can print a whole line at once; they can typically print the range of 1,200 to 6,000 lines per minute.
Drum Printer
• A drum printer consists of a solid, cylindrical drum that has raised characters in bands on its surface. The number of print positions across the drum equals the number
available on the page. This number typically ranges from 80-132 print positions.
Chain Printers
• A chain printer uses a chain of print characters wrapped around two pulleys. Like the drum printer, there is one hammer for each print position. Circuitry inside the
printer detects when the correct character appears at the desired print location on the page.
• Band Printers
A band printer operates similar to chain printer except it uses a band instead of a chain and has fewer hammers. Band printer has a steel band divided into five sections of
48 characters each.

20. PRINTERS

21. NON-IMPACT PRINTERS
Non-impact printers do not use a striking device to produce characters on the paper;
and because these printers do not hammer against the paper they are much quieter.
Ink-Jet Printers
Ink-jet printers work in the same fashion as dot-matrix printers in the form images or
characters with little dots. However, the dots are formed by tiny droplets of ink. Ink-
jet printers form characters on paper by spraying ink from tiny nozzles through an
electrical field that arranges the charged ink particles into characters at the rate of
approximately 250 characters per second.
Laser Printers
A laser printer works like a photocopy machine. Laser printers produce images on
paper by directing a laser beam at a mirror which bounces the beam onto a drum. The
drum has a special coating on it to which toner (an ink powder) sticks. Using patterns
of small dots, a laser beam conveys information from the computer to a positively
charged drum to become neutralized.

22. DISPLAY INTERFACES
• DisplayPort Display Port is a new digital display interface standard designed to
simplify device interconnections while providing the performance scalability
necessary in order to support the next generation of displays, which feature higher
color depths, refresh rates and display resolutions.
• It is a license-free and royalty-free interface designed to connect audio and video
between a computer and display monitor (PC), or a computer and home theatre
system consumer electronics (CE) devices. Put forth by Video Electronics Standards
Association (VESA), the standard was initially approved in May 2006 and updated
to version 1.1 in April 2007

23. MONITOR
• A monitor is an output device that displays video images and text. A monitor is
made up of circuitry, a screen, a power supply, buttons to adjust screen settings, and
casing that holds all of these components.
• Like most early TVs, the first computer monitors were comprised of a CRT (cathode
ray tube) and a fluorescent screen. Today, all monitors are created using flat panel
display technology, usually backlit with LEDs.

25. MODEM
• A modem or broadband modem is a hardware device that connects a computer or
router to a broadband network. For example, a cable Modem and DSL modem are
two examples of these types of Modems.
• The first modem, known as the Dataphone, was released by AT&T in 1960. It later
became more common for home users when Dennis Hayes and Dale Heatherington
released the 80-103A modem in 1977.
• Modem speed is measured in bps and Kbps, which is the speed the modem can send
and receive data. Today, a 56 K (56,000 bps) modem is the fastest solution and is the
only likely speed you will find with a dial-up modem.

27. BACKUP DEVICES
• In computer technologies, a backup storage device is used to make copies of data that is
actively in use. Backup machines provide redundancy of data residing on primary
storage. Should the storage medium, such as a hard disk drive (HDD), fail or become
corrupted, the original data is recovered from copies on the backup hardware. The use of
backup storage is imperative in enterprise environments.
• A backup storage device refers to a type of disk-based hardware appliance bundled with
software for data management and data services. The physical device provides capacity
via the internal storage media, while the backup software schedules policies for moving
data in a tiered storage environment from primary storage to secondary storage (also
known as auxiliary storage or external storage). Backup devices connect to storage using
traditional NFS or iSCSI network protocols.

28. VIRUSES
• A computer virus is malicious code that replicates by copying itself to another
program, computer boot sector or document and changes how a computer works. The
virus requires someone to knowingly or unknowingly spread the infection without
the knowledge or permission of a user or system administrator.
• A virus can be spread by opening an email attachment, clicking on an executable
file, visiting an infected website or viewing an infected website advertisement.
• It can also be spread through infected removable storage devices, such USB drives.
• Types of viruses are as follows;
1.WORM
2.TORJAN HORSE
3.BOMBS

29. LAPTOP
• Laptop computers generally cost more than desktop computers with the same
capabilities because they are more difficult to design and manufacture.
• A laptop can effectively be turned into a desktop computer with a docking station, a
hardware frame that supplies connections for peripheral input/output devices such
as a printer or larger monitor.
• The less capable port replicator allows you to connect a laptop to a number of
peripherals through a single plug.

30. PALMTOP
• A small computer that literally fits in your palm. Compared to full-size computers,
palmtops are severely limited, but they are practical for certain functions such as phone
books and calendars. Palmtops that use a pen rather than a keyboard for input are often
called hand-held computers or PDAs.
• Because of their small size, most palmtop computers do not include disk drives. However,
many contain PCMCIA slots in which you can insert disk drives, modems, memory, and
other devices.
• Palmtops are also called PDAs, hand-held computers and pocket computers.

31. LAPTOP AND PALMTOP

32. INSTALLATION OF OS(WINDOWS 10)
• https://www.wikihow.com/Install-an-Operating-System-on-a-Brand-New-Computer
• https://www.wikihow.com/Install-Linux
• https://www.imore.com/how-install-fresh-copy-os-x-your-mac

33. TROUBLESHOOTING NETWORKS
1. Route
The last of the tools covered in this article is the route utility. This utility is used to display the current status of the routing table on a host. While the
use of the route utility is limited in common situations where the host only has a single IP address with a single gateway, it is vital in other situations
where multiple IP address and multiple gateways are available.
2. Speedtest.net/pingtest.net
A very easy test that can be used to both determine the Internet bandwidth available to a specific host and to determine the quality of an Internet
connection is the use of the tools available at the speedtest.net and pingtest.net websites.
• 3. Netstat
Often, one of the things that are required to be figured out is the current state of the active network connections on a host. This is very important
information to find for a variety of reasons. For example, when verifying the status of a listening port on a host or to check and see what remote hosts
are connected to a local host on a specific port.
4.Ipconfig/ifconfig
• One of the most important things that must be completed when troubleshooting a networking issue is to find out the specific IP configuration of
the variously affected hosts.
• 5. Ping
• The most commonly used network tool is the ping utility. This utility is used to provide a basic connectivity test between the requesting host and a
destination host. This is done by using the Internet Control Message Protocol (ICMP) which has the ability to send an echo packet to a destination
host and a mechanism to listen for a response from this host