A computer is
a programmable machine designed to sequentially and automatically
carry out a sequence of arithmetic or logical operations. The particular
sequence of operations can be changed readily, allowing the computer to solve
more than one kind of problem. A computer does not need to be electric,
nor even have a processor, RAM, or a hard disk. The minimal definition of
a computer is anything that transforms information in a purposeful
way.
Hardware: The mechanical, magnetic,
electronic, and electrical components making up a computer system. It combines
with the software to carry out the preferred tasks.
Software: Is a general term primarily used
for digitally stored data such as computer programs and other kinds of
information read and written by computers. They are the written programs or
procedures or rules and associated documentation relating to the operation of a
computer system and that are stored in read/write memory.
Network: Is two or more computers
connected so that they can communicate with each other and share information,
software, peripheral devices, and/or processing power. The information sent or
received must be secured, (encrypted) or else it can easily be stolen by
hackers and crackers. To understand the working of a network and thoroughly
interpret communication one must also know about the OSI Model. (Open
Systems Interconnection model)
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OSI Model
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Data unit
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Layer
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Function
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Host
layers
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Data
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7. Application
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Network
process to application
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6. Presentation
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Data
representation, encryption and decryption, convert machine dependent data to
machine independent data
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5. Session
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Interhost
communication
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Segments
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4. Transport
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End-to-end
connections and reliability, flow
control
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Media
layers
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Packet/Datagram
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3. Network
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Path
determination and logical addressing
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Frame
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2. Data Link
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Physical
addressing
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Bit
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1. Physical
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Media,
signal and binary transmission
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Hacking: Hacking is the art of exploiting
and using something beyond the manufacturer’s will.
Hacker: Hacker is a person who is an
expert of computers and knows it very well. (Even the extra tricks and tweaks)
He may gain unauthorized access to another person’s computer. (He is termed as
Black Hat hacker, criminal) Another catches the black hat hacker and thus is
known as white hat hacker. (the cyber police) And the last one doesn’t go about
stealing and even about catching the bad guys; he hacks for himself and is
known as a grey hat hacker!
The
computer comprises of CPU (Central Processing Unit) which is its main part. It
contains all the hardware necessary for the operation of a computer and
contains all other ports with which you can connect other hardware necessary
for its functioning. (eg. Monitor, USB – Universal Serial Bus, etc)
Motherboard: Motherboard is the main part of
the CPU. It has all the ports for the peripheral devices and its inbuilt
circuits. (Peripheral devices are like the add ones to the system. They don’t
form its core but they extend its capabilities) Motherboard is the central printed circuit board (PCB)
Note: The arrangement of the motherboard shown
below changes according to the companies and up gradations and enhancements but
the basic structure remains the same.
A microprocessor carry’s out the functions of a computer's central processing unit (CPU) on a single integrated circuit (IC, or microchip). It is a multipurpose,
programmable, and clock-driven, register based electronic device that accepts
binary data as input, processes it according to instructions stored in its
memory, and provides results as output. It’s speed is measured in GHz
or MHz (1GHz = 1,000,000,000 Hz) and is
referred to as the CLOCK SPEED. (Clock
speed or clock rate is the rate of cycles or tasks per seconds) When the CPU executes tasks,
it does so at a certain speed--think of a worker picking fruit. The faster the
worker picks the fruit, the better. The processor's speed is measured in tasks
per cycle, and a cycle is one second. So a speed of one megahertz--(mega equals
one million) means the CPU executes one million tasks per second. There is
always a fan fitted over the processor to keep it cool.
Multiple Cores
Most modern computers have dual-core processors, and some even have triple- and
quad-core processors. This means that there are two or more distinct processors
that can work in parallel. This is more efficient than one high-performing
processor, but it can also put strain on the rest of the system.
RAM
(random
accessing-memory)
§ Memory, often abbreviated as RAM or Random Access Memory, is just
as important as processor speed. When the computer is working on a task, it can
temporarily store information in the memory to be worked on later. The information stored in the RAM is
removed when the power is disconnected from it. (for instance – Shutdown,
restart) RAM is a form of computer
data storage. There are various types of
RAMs:
§ DRAM (e.g., DDR, SDRAM) {Dynamic RAM)
§ SRAM
(Static RAM)
§ In development
§ T-RAM
§ Z-RAM
§ TTRAM
Note: A
computer may not boot up (start) if the RAM (at least1) is missing or not fit
properly. In that case it makes BEEP-BEEP-BEEP sound and then shuts down
automatically. In such cases check the RAM first.
CMOS Backup
Battery
CMOS Backup Battery is used to
retain the system’s configuration (e.g. BIOS settings) and its clock circuit
(time) Rechargeable or primary Lithium
batteries (Non-Rechargeable) are used. Primary batteries need to be regularly
checked and replaced while the rechargeable batteries need no care.
BIOS
BIOS - Basic input/output system, also known as the System
BIOS or ROM BIOS. BIOS is the first code which runs on the PC when
powered on and is responsible for the starting of the operating system. When the PC starts up, the first job for the BIOS is to
initialize and identify system devices such as the video
display card, keyboard and mouse (Pointing Device), hard
disk, CD/DVD drive and other hardware. The BIOS then locates software held on a
peripheral device (labeled as a 'boot device'), such as a hard disk or a CD,
and loads and executes that software, giving it control of the PC This
process is known as booting, or booting up, which is short for bootstrapping.
HDD (Hard Disk Drive)
Hard disk drive is a type of computer data
storage. In olden times the HDDs were quit small, only about 3-4 GBs (Giga-Byte)
but now the capacities have become considerably large, almost up to 2TBs
(Tera-Byte) However yet the capacity of whole world’s hard disks and storage
hasn’t reached up to one YB. It has been reported that by 2006 it had reached
to almost 160 ZBs. Modern HDDs are attached via, serial ATA (SATA) or serial attached SCSI (SAS)
cables. Earlier it used to IDE.
Data Units:
1 Bit (the smallest part)
1 Nibble – 4 Bits
1 Byte or an Octet– 8 Bits
1 KB (Kilo-Byte) - 1024 Bytes
1 MB (Mega-Byte) – 1024 KBs
1 GB (Giga-Byte) – 1024 MBs
1 TB (Tera-Byte) – 1024 GBs
1 PB (Peta-Byte) – 1024 TBs
1 EB (Exa-Byte) – 1024 PBs
1 ZB (Zetta-Byte) – 1024 EBs
1 YB (Yotta-Byte) – 1024 ZBs
You may also come across terms like Kbs, Mbs, Gbs in
that case it becomes Kilo-Bits, Mega-Bits, Giga-Bits and so on. To convert it
to KB, MB or GB and so just divide the value by 8. This nuisance is used widely
on the internet to attract users to their Downloading sites. Therein they
ensure their user that they give 2000Kb/s downloading speeds or more which is
merely 250KB/s! Many users get easily trapped! And of course the speed also
depends on your internet connection speed! (Capitalization is in case
sensitive)
Think
Quest: Why 1024 and not 1000?
Answer:
Because, the
primary language of computer is Binary language. (Binary – Two) Therefore 1 bit
becomes two, then 4, then 8, and so on. Thus reaching up to 1024 and not 1000
(Thousand can’t be reached in this sort of doubling) Binary language has two
codes – 1 and 0. 0 – for a circuit means off and 1 means on. Whatever we give
as the commands the computer first converts the command to its binary form
that’s the combination of 0s and 1s up to 8 characters to form a byte. (Of
information) There are many programming languages which are known as Higher-Level
Languages. (E.g. C, C++ etc.) The programs are written in these languages, but
still the computer has to convert these languages also to the binary codes. Since
this process would be tiring hexadecimal numeral system was invented. Hex means
with the base of 16. It uses 16 symbols: 0–9 to represent values zero to nine, and A, B, C, D, E, F (or alternatively a–f)
to represent values ten to fifteen. It represents four bits. (a nibble) For
example: 2AF3 is equal, in decimal, to (2 × 163) + (10 × 162)
+ (15 × 161) + (3 × 160) , or 10,995.
Digital
Storage Disks
CD: Compact
Disk
Capacity: 700MB (generally)
DVD: Digital
Video Disk
Capacity:
4.7 GB (Single Layer), 8.5GB (Dual Layer
HD DVD: High
Definition Digital Video Disk
Capacity:
15 GB (Single Layer, 30 GB (Dual Layer)
BD: Blu-ray Disk
Capacity:
25 GB (Single Layer), 50 GB (Dual Layer)
Video and Resolution
Many a times you may have come across the Term Resolution. The display resolution of a digital
television or display device is the number of distinct pixels
that can be displayed. In digital imaging, a pixel, or pel, (picture element) is a single point in a raster
image, or the smallest addressable screen element in a display device. Raster
image or bitmap is a data structure representing a generally rectangular grid
of pixels, or points of color,
viewable via a monitor. Data structure is a
particular way of storing and organizing data in a computer so
that it can be used efficiently. In computers any color is represented by three – four
basic colors namely, red, green, and blue, or cyan, magenta, yellow, and black.
A resolution may be represented like this: 102x64, 240x64, 320x200, 1280x720,
1920x1080, and 4096x2304 up to 28000x9334. (All of these have a specific name.
For example 1280x720 is called 720p HD and 1920x1080 is called 1080p or i HD
where p stands for progressive scan and i stand for interlaced) HD DVDs and BDs
are made for recording 1080p HD Video content in it. The higher the resolution
the bigger the picture gets. General TVs have a resolution of 1080p or 720p.
1080p is also known as full HD. As the picture size increases, at the same time
the file size also increases. For example a full HD video of say 1 minute may
be of 80MB, but at the same time the same video encoded in 28K (28000x9334) may
be of a 10GBs! A video size is compared by the number of pixels it contains. A
full HD has 1920x1080 pixels (2073600 pixels) while 28K video has 28000x9334
pixels (261352000 pixels) which is almost 126 times greater than full HD. (thus 126 times larger pixel count)
Full HD has a bit rate of merely around 10MB/s while 28K has the Bitrate of
around 225MB/s or 500MB/s! More the Bitrate, the better the quality.
Hardware and Software go hand and glove. (For one to
function, other must be there) So when your hardware is ready you must have the
corresponding software to make use of the materials. In olden times computers
used to run on DOS-Mode. (Denial of Service) Today it is referred to as Command Prompt. Earlier people used to
work in that mode only, wherein they had to type the commands to accomplish
their tasks. After a few years the concept of operating system came in. It is
known as GUI – Graphic User Interface. Operating systems had a goal to
accomplish. Instead of working in a black environment with white fonts
continuously typing, it gave users the option to handle information with
graphics and writing both. An operating
system (OS) is software, consisting of programs and data,
which runs on computers, manages computer
hardware resources, and provides common services for execution of various application
software. Even
in modern systems command prompt forms the core of the operating systems but
now generally it is not preferred due to its hardships. But it is also a fact
that Command Prompt is still today that efficient, sometimes better than
operating systems! There various companies creating their own operating
systems, example Microsoft Windows, Linux, Google Chrome OS, Macintosh etc.
with a basic idea to give their users comfortable and flawless usage. Almost
90% of the computer users prefer Microsoft Windows, but at the same time it is
also a fact that Mac is a Leading OS all over the World. It is way more costly
than any other Oss but it is a satisfactory result. Apple is the creator of
Mac. (Macintosh) Apple is also the number one creator of laptops. All Apple
products are costly but they are better than any other products.
Microsoft has created its operating systems through
1993. Its first OS was Windows 95 followed by 98. Today in latest we have
Microsoft Windows 7. It had many versions:
Starter, Home Basic, Home Premium, Enterprise, Professional and Ultimate
in both 64 Bit (x64) and 32 Bit (x86). Windows 7 Ultimate is the best Edition
of windows 7 having all the features.
Besides building operating systems, Microsoft has
also contributed in building up office. Its first office to be released was
Microsoft Office 95 and its latest office right now is Microsoft Office 2010. It also has many versions: (office 2010) Office
Starter, Office Standard, Office Professional Academic, Office Home and
Student, Office Home and Business, Office Professional, Office Professional
Plus and Office Mobile. Out of them Office Professional Plus is the best
edition having all the features of all office suites, excluding office mobile
because that’s a different thing altogether.
Office
Professional Plus 2010:
Word: Short Cut to run it, Press the start button
along with the ‘R’ key. A Dialogue box will appear. (Run) Type in ‘winword’ and
hit enter.
Excel: Short Cut to run it, Open the run dialogue
box and type in ‘excel’ and press enter.
PowerPoint: Short Cut to run it, Open the run
dialogue box and type in ‘powerpnt’ and press enter.
Note that these commands are common for all
Microsoft offices and thus will be accepted even in office 97 and even office
2010.
All
Programs:
1.
Access
2.
Excel
3.
InfoPath
4.
OneNote
5.
Outlook
6.
PowerPoint
7.
Publisher
8.
SharePoint
Workspace
9.
Visio
Viewer
10.
Word
Internet:
The Internet is a
global system of interconnected computer networks that use the standard Internet
Protocol Suite (TCP/IP) to serve billions of users worldwide. Computer network or
network is nothing but the interconnection of two or more computers to share
digital information through various channels or ways. (Paths) The Internet
Protocol Suite is the set of communications protocols used
for the Internet and other similar networks It is generally referred to as the
TCP/IP Protocol. It is named by the two main protocols in it The Transmission Control Protocol (TCP) and The Internet Protocol. (IP) Protocol is a set of rules to perform any task. Protocol for
a computer is the precise (exact) information to be used as an when communicating
with another computer. Protocol defines how the computers communicate and how
they exchange information. (Transmit – to send off and receive and process that
information) Internet is provided to you by your ISP which is Internet Service Provider. The ISP’s
have complete control on your internet connection and can control what you
browse, what you download and even how much you use the connection! The basic
software needed to use the internet is a browser. There are many browser like
the Internet Explorer, Mozilla FireFox, Safari etc. The basic hardware needed
is a Modem and a LAN (Local Area Network) cable or Wi-Fi and its dongle. Wi-Fi
is a wireless network, through which internet can be accessed without any
cables. The LAN cable is can be plugged into the Ethernet port on the Mother
Board, while Wi-Fi works on signaling. The first internet connections were of
28.4 KBPS and now Google has launched a test of 1 GBPS internet connections. But
generally people have a connections in MBPS, but in India we generally we have
KBPS connections. Through internet one can browse through lots and lots of
digital content, (including texts, audio, video, flash items, online T.V. and
much more that you may have not ever even thought of!) Internet is becoming
very popular among the new generation due to its services. Some of the most
widely used internet service used worldwide is E-Mail, (electronic mail)
Internet T.V., file sharing and downloading websites (Rapidshare, Megaupload etc.)
The most growing community is the Peer-To-Peer system or p2p. It is the fastest
way for one to share content and download/upload it. It may be their own free
content or much illegal content. But mostly these servers have illegal content
hosted onto them and the greatest benefit is that it is available to each and
every user with the internet connection and desktop client. (Like BitTorrent,
UTorrent etc, or some online clients like the BitLet.org. These software or
online services help the user to download the content hosted on to the server.
Usually one gets the direct file. Like .exe or mp4 etc. but in this case, we
get a .torrent file or a magnet link which can be opened through the sources
mentioned and can be downloaded onto the computer)
Note: Any file in computer end in a dot and some name, like .iso,
.torrent, .ppt, .dmg etc. There are millions of such. These are called file
extension. A file name always ends with any of the existing extensions. The
extension of a file is the identification to it. (For example .ppt refers to
PowerPoint Presentation, .doc refers to a Word Document, .exe refers to an
executable file etc.) So an extension is notation of the program to be used
while opening the file. It thus provides valuable information. Interesting Fact: Almost all the file
extensions can be created by using Notepad
in Microsoft Windows until one knows the code or the language to create
that sort of file.
Torrenting is a
good way for getting pirated materials and enjoy, however this is illegal, but
out of a lakh only 100 people wouldn’t be torrenting. (Including me) And let me
tell you something very bluntly, this is free; so all sorts of people upload
their content. It depends on them what they do. Some might be hungry crackers,
sighting for a prey. You may become their victim but that is not the end. If
you get into the fuss you’re gone and anything can happen to you. And there is
a great threat from Pornographic, explicit and erotic content on the web.
Almost 80% of the torrents are such in type, while books are around 1%! One
needs to know about this thing and need to understand. Even on their website to
attract users there are many adult websites linked. So one needs to be aware
and careful. Besides this, there are
many adds stating get an iPhone for a just a dollar and other fake things. This
is for attraction and even it may contain some hacking or cracking tools. Stay
away from such freaking advertisements. Everything has its own strengths and
weaknesses.
E-mail: Service
is the service to send and receive free messages, chat with people. (Via text
messages, audio calling or even video calling all for free but only computer to
computer) You can add up contacts in you address book. There are many E-mail
services like Gmail, Yahoo!Mail, Hotmail, Rediffmail etc.
