Computer Fundamentals 2

Computer - Ports

What is a Port?

A port:

• is a physical docking point using which an external device can be connected to the computer.
• can also be programmatic docking point through which information flows from a program to computer or over the internet.

Characteristics

A port has the following characteristics:

• External devices are connected to a computer using cables and ports.
• Ports are slots on the motherboard into which a cable of external device is plugged in.
• Examples of external devices attached via ports are mouse, keyboard, monitor, microphone, speakers etc.

Following are few important types of ports:

Serial Port

• Used for external modems and older computer mouse
• Two versions : 9 pin, 25 pin model
• Data travels at 115 kilobits per second

Parallel Port

• Used for scanners and printers
• Also called printer port
• 25 pin model
• Also known as IEEE 1284-compliant Centronics port

PS/2 Port

• Used for old computer keyboard and mouse
• Also called mouse port
• Most of the old computers provide two PS/2 port, each for mouse and keyboard
• Also known as IEEE 1284-compliant Centronics port

Universal Serial Bus (or USB) Port

• It can connect all kinds of external USB devices such as external hard disk, printer, scanner, mouse, keyboard etc.
• It was introduced in 1997.
• Most of the computers provide two USB ports as minimum.
• Data travels at 12 megabits per seconds
• USB compliant devices can get power from a USB port

VGA Port

• Connects monitor to a computer's video card.
• Has 15 holes.
• Similar to serial port connector but serial port connector has pins, it has holes.

Power Connector

• Three-pronged plug
• Connects to the computer's power cable that plugs into a power bar or wall socket

Firewire Port

• Transfers large amount of data at very fast speed.
• Connects camcorders and video equipments to the computer
• Data travels at 400 to 800 megabits per seconds
• Invented by Apple
• Three variants : 4-Pin FireWire 400 connector, 6-Pin FireWire 400 connector and 9-Pin FireWire 800 connector

Modem Port

• Connects a PC's modem to the telephone network

Ethernet Port

• Connects to a network and high speed Internet.
• Connect network cable to a computer.
• This port resides on an Ethernet Card.
• Data travels at 10 megabits to 1000 megabits per seconds depending upon the network bandwidth.

Game Port

• Connect a joystick to a PC
• Now replaced by USB.

Digital Video Interface, DVI port

• Connects Flat panel LCD monitor to the computer's high end video graphic cards.
• Very popular among video card manufacturers.

Sockets

• Connect microphone, speakers to sound card of the computer

Computer - Hardware

Hardware represents the physical and tangible components of a computer i.e. the components that can be seen and touched.

Examples of Hardware are following:

• Input devices -- keyboard, mouse etc.
• Output devices -- printer, monitor etc.
• Secondary storage devices -- Hard disk, CD, DVD etc.
• Internal components -- CPU, motherboard, RAM etc.

Relationship between Hardware and Software

• Hardware and software are mutually dependent on each other. Both of them must work together to make a computer produce a useful output.
• Software cannot be utilized without supporting hardware.
• Hardware without set of programs to operate upon cannot be utilized and is useless.
• To get a particular job done on the computer, relevant software should be loaded into the hardware
• Hardware is a one-time expense.
• Software development is very expensive and is a continuing expense.
• Different software applications can be loaded on a hardware to run different jobs.
• A software acts as an interface between the user and the hardware.
• If hardware is the 'heart' of a computer system, then software is its 'soul'. Both are complimentary to each other.

Computer - Software

Software is a set of programs, which is designed to perform a well-defined function. A program is a sequence of instructions written to solve a particular problem.

There are two types of software

• System Software
• Application Software

System Software

The system software is collection of programs designed to operate, control, and extend the processing capabilities of the computer itself. System software are generally prepared by computer manufactures. These software products comprise of programs written in low-level languages which interact with the hardware at a very basic level. System software serves as the interface between hardware and the end users.

Some examples of system software are Operating System, Compilers, Interpreter, Assemblers etc.

Features of system software are as follows:

• Close to system
• Fast in speed
• Difficult to design
• Difficult to understand
• Less interactive
• Smaller in size
• Difficult to manipulate
• Generally written in low-level language

Application Software

Application software products are designed to satisfy a particular need of a particular environment. All software applications prepared in the computer lab can come under the category of Application software.

Application software may consist of a single program, such as a Microsoft's notepad for writing and editing simple text. It may also consist of a collection of programs, often called a software package, which work together to accomplish a task, such as a spreadsheet package.

Examples of Application software are following:

• Payroll Software
• Student Record Software
• Inventory Management Software
• Income Tax Software
• Railways Reservation Software
• Microsoft Office Suite Software
• Microsoft Word
• Microsoft Excel
• Microsoft Powerpoint

Features of application software are as follows:

• Close to user
• Easy to design
• More interactive
• Slow in speed
• Generally written in high-level language
• Easy to understand
• Easy to manipulate and use
• Bigger in size and requires large storage space

Computer - Number System

When we type some letters or words, the computer translates them in numbers as computers can understand only numbers. A computer can understand positional number system where there are only a few symbols called digits and these symbols represent different values depending on the position they occupy in the number.

A value of each digit in a number can be determined using

• The digit
• The position of the digit in the number
• The base of the number system (where base is defined as the total number of digits available in the number system).

Decimal Number System

The number system that we use in our day-to-day life is the decimal number system. Decimal number system has base 10 as it uses 10 digits from 0 to 9. In decimal number system, the successive positions to the left of the decimal point represent units, tens, hundreds, thousands and so on.

Each position represents a specific power of the base (10). For example, the decimal number 1234 consists of the digit 4 in the units position, 3 in the tens position, 2 in the hundreds position, and 1 in the thousands position, and its value can be written as

(1x1000)+ (2x100)+ (3x10)+ (4xl)
(1x103)+ (2x102)+ (3x101)+ (4xl00)
1000 + 200 + 30 + 4
1234

As a computer programmer or an IT professional, you should understand the following number systems which are frequently used in computers.

S.N.	Number System and Description
1	Binary Number System Base 2. Digits used : 0, 1
2	Octal Number System Base 8. Digits used : 0 to 7
3	Hexa Decimal Number System Base 16. Digits used : 0 to 9, Letters used : A- F

Binary Number System

Characteristics of binary number system are as follows:

• Uses two digits, 0 and 1.
• Also called base 2 number system
• Each position in a binary number represents a 0 power of the base (2). Example 2⁰
• Last position in a binary number represents a x power of the base (2). Example 2^xwhere x represents the last position - 1.

Example

Binary Number : 10101₂

Calculating Decimal Equivalent:

Step	Binary Number	Decimal Number
Step 1	101012	((1 x 24) + (0 x 23) + (1 x 22) + (0 x 21) + (1 x 20))10
Step 2	101012	(16 + 0 + 4 + 0 + 1)10
Step 3	101012	2110

Note : 10101₂ is normally written as 10101.

Octal Number System

Characteristics of octal number system are as follows:

• Uses eight digits, 0,1,2,3,4,5,6,7.
• Also called base 8 number system
• Each position in an octal number represents a 0 power of the base (8). Example 8⁰
• Last position in an octal number represents a x power of the base (8). Example 8^xwhere x represents the last position - 1.

Example

Octal Number : 12570₈

Calculating Decimal Equivalent:

Step	Octal Number	Decimal Number
Step 1	125708	((1 x 84) + (2 x 83) + (5 x 82) + (7 x 81) + (0 x 80))10
Step 2	125708	(4096 + 1024 + 320 + 56 + 0)10
Step 3	125708	549610

Note : 12570₈ is normally written as 12570.

Hexadecimal Number System

Characteristics of hexadecimal number system are as follows:

• Uses 10 digits and 6 letters, 0,1,2,3,4,5,6,7,8,9,A,B,C,D,E,F.
• Letters represents numbers starting from 10. A = 10. B = 11, C = 12, D = 13, E = 14, F = 15.
• Also called base 16 number system
• Each position in a hexadecimal number represents a 0 power of the base (16). Example 16⁰
• Last position in a hexadecimal number represents a x power of the base (16). Example 16^x where x represents the last position - 1.

Example

Hexadecimal Number : 19FDE₁₆

Calculating Decimal Equivalent:

Step	Binary Number	Decimal Number
Step 1	19FDE16	((1 x 164) + (9 x 163) + (F x 162) + (D x 161) + (E x 160))10
Step 2	19FDE16	((1 x 164) + (9 x 163) + (15 x 162) + (13 x 161) + (14 x 160))10
Step 3	19FDE16	(65536+ 36864 + 3840 + 208 + 14)10
Step 4	19FDE16	10646210

Note : 19FDE₁₆ is normally written as 19FDE.

Computer - Number Conversion

There are many methods or techniques which can be used to convert numbers from one base to another. We'll demonstrate here the following:

• Decimal to Other Base System
• Other Base System to Decimal
• Other Base System to Non-Decimal
• Shortcut method - Binary to Octal
• Shortcut method - Octal to Binary
• Shortcut method - Binary to Hexadecimal
• Shortcut method - Hexadecimal to Binary

Decimal to Other Base System

steps

• Step 1 - Divide the decimal number to be converted by the value of the new base.
• Step 2 - Get the remainder from Step 1 as the rightmost digit (least significant digit) of new base number.
• Step 3 - Divide the quotient of the previous divide by the new base.
• Step 4 - Record the remainder from Step 3 as the next digit (to the left) of the new base number.

Repeat Steps 3 and 4, getting remainders from right to left, until the quotient becomes zero in Step 3.

The last remainder thus obtained will be the most significant digit (MSD) of the new base number.

Example

Decimal Number : 29₁₀

Calculating Binary Equivalent:

Step	Operation	Result	Remainder
Step 1	29 / 2	14	1
Step 2	14 / 2	7	0
Step 3	7 / 2	3	1
Step 4	3 / 2	1	1
Step 5	1 / 2	0	1

As mentioned in Steps 2 and 4, the remainders have to be arranged in the reverse order so that the first remainder becomes the least significant digit (LSD) and the last remainder becomes the most significant digit (MSD).

Decimal Number : 29₁₀ = Binary Number : 11101_2.

Other base system to Decimal System

Steps

• Step 1 - Determine the column (positional) value of each digit (this depends on the position of the digit and the base of the number system).
• Step 2 - Multiply the obtained column values (in Step 1) by the digits in the corresponding columns.
• Step 3 - Sum the products calculated in Step 2. The total is the equivalent value in decimal.

Example

Binary Number : 11101₂

Calculating Decimal Equivalent:

Step	Binary Number	Decimal Number
Step 1	111012	((1 x 24) + (1 x 23) + (1 x 22) + (0 x 21) + (1 x 20))10
Step 2	111012	(16 + 8 + 4 + 0 + 1)10
Step 3	111012	2910

Binary Number : 11101₂ = Decimal Number : 29₁₀

Other Base System to Non-Decimal System

Steps

• Step 1 - Convert the original number to a decimal number (base 10).
• Step 2 - Convert the decimal number so obtained to the new base number.

Example

Octal Number : 25₈

Calculating Binary Equivalent:

Step 1 : Convert to Decimal

Step	Octal Number	Decimal Number
Step 1	258	((2 x 81) + (5 x 80))10
Step 2	258	(16 + 5 )10
Step 3	258	2110

Octal Number : 25₈ = Decimal Number : 21₁₀

Step 2 : Convert Decimal to Binary

Step	Operation	Result	Remainder
Step 1	21 / 2	10	1
Step 2	10 / 2	5	0
Step 3	5 / 2	2	1
Step 4	2 / 2	1	0
Step 5	1 / 2	0	1

Decimal Number : 21₁₀ = Binary Number : 10101₂

Octal Number : 25₈ = Binary Number : 10101₂

Shortcut method - Binary to Octal

Steps

• Step 1 - Divide the binary digits into groups of three (starting from the right).
• Step 2 - Convert each group of three binary digits to one octal digit.

Example

Binary Number : 10101₂

Calculating Octal Equivalent:

Step	Binary Number	Octal Number
Step 1	101012	010 101
Step 2	101012	28 58
Step 3	101012	258

Binary Number : 10101₂ = Octal Number : 25₈

Shortcut method - Octal to Binary

Steps

• Step 1 - Convert each octal digit to a 3 digit binary number (the octal digits may be treated as decimal for this conversion).
• Step 2 - Combine all the resulting binary groups (of 3 digits each) into a single binary number.

Example

Octal Number : 25₈

Calculating Binary Equivalent:

Step	Octal Number	Binary Number
Step 1	258	210 510
Step 2	258	0102 1012
Step 3	258	0101012

Octal Number : 25₈ = Binary Number : 10101₂

Shortcut method - Binary to Hexadecimal

Steps

• Step 1 - Divide the binary digits into groups of four (starting from the right).
• Step 2 - Convert each group of four binary digits to one hexadecimal symbol.

Example

Binary Number : 10101₂

Calculating hexadecimal Equivalent:

Step	Binary Number	Hexadecimal Number
Step 1	101012	0001 0101
Step 2	101012	110 510
Step 3	101012	1516

Binary Number : 10101₂ = Hexadecimal Number : 15₁₆

Shortcut method - Hexadecimal to Binary

steps

• Step 1 - Convert each hexadecimal digit to a 4 digit binary number (the hexadecimal digits may be treated as decimal for this conversion).
• Step 2 - Combine all the resulting binary groups (of 4 digits each) into a single binary number.

Example

Hexadecimal Number : 15₁₆

Calculating Binary Equivalent:

Step	Hexadecimal Number	Binary Number
Step 1	1516	110 510
Step 2	1516	00012 01012
Step 3	1516	000101012

Hexadecimal Number : 15₁₆ = Binary Number : 10101₂

Computer - Data and Information

What is data?

Data can be defined as a representation of facts, concepts or instructions in a formalized manner which should be suitable for communication, interpretation, or processing by human or electronic machine.

Data is represented with the help of characters like alphabets (A-Z,a-z), digits (0-9) or special characters(+,-,/,*,<,>,= etc.).

What is Information?

Information is organised or classified data which has some meaningful values for the receiver.

Information is the processed data on which decisions and actions are based.

For the decision to be meaningful, the processed data must qualify for the following characteristics:

• Timely - Information should be available when required.
• Accuracy - Information should be accurate.
• Completeness - Information should be complete.

Data Processing Cycle

Data processing is the re-structuring or re-ordering of data by people or machine to increase their usefulness and add values for particular purpose. Data processing consists of basic steps input, processing and output. These three steps constitute the data processing cycle.

• Input - In this step the input data is prepared in some convenient form for processing. The form will depend on the processing machine. For example, when electronic computers are used, the input data could be recorded on any one of several types of input medium, such as magnetic disks, tapes and so on.
• Processing - In this step input data is changed to produce data in a more useful form. For example, pay-checks may be calculated from the time cards, or a summary of sales for the month may be calculated from the sales orders.
• Output - Here the result of the proceeding processing step are collected. The particular form of the output data depends on the use of the data. For example, output data may be pay-checks for employees.

Computer - Networking

What is a Computer Network?

A computer network is a system in which multiple computers are connected to each other to share information and resources.

Characteristics of a computer network

• Share Resources from one computer to another
• Create files and store them in one computer, access those files from the other computer(s) connected over the network
• Connect a printer, scanner, or a fax machine to one computer within the network and let other computers of the network use the machines available over network.

Following is the list of hardware's required to setup a computer network.

• Network Cables
• Distributors
• Routers
• Internal Network Cards
• External Network Cards

Network Cables

Network cables are used to connect computers. The most commonly used cable is Category 5 cable RJ-45.

Distributors

A computer can be connected to another one via a serial port but if we need to connect many computers to produce a network, this serial connection will not work. The solution is to use a central body to which other computers, printers, scanners etc. can be connected and then this body will manage or distribute network traffic.

Router

A router is a type of device which acts as the central point among computers and other devices that are part of a network. A router is equipped with holes called ports and computers and other devices are connected to a router using network cables. Now-a-days router comes in wireless modes using which computers can be connected without any physical cable.

Network Card

Network card is a necessary component of a computer without which a computer cannot be connected over a network. It is also known as network adapter or Network Interface Card (NIC). Most branded computers have network card pre-installed. Network cards are of two types : Internal and External Network Cards.

INTERNAL NETWORK CARDS

Motherboard has a slot for internal network card where it is to be inserted. Internal network cards are of two types in which first type uses Peripheral Component Interconnect (PCI) connection while the second type uses Industry Standard Architecture (ISA). Network cables are required to provide network access.

EXTERNAL NETWORK CARDS

External network cards come in two flavours : Wireless and USB based. Wireless network card need to be inserted into the motherboard but no network cable is required to connect to network

Universal Serial Bus (USB)

USB card are easy to use and connect via USB port. Computers automatically detect USB card and can install the drivers required to support the USB network card automatically.

Computer - Operating System

It is a program with following features:

• An operating system is a program that acts as an interface between the software and the computer hardware.
• It is an integrated set of specialised programs that are used to manage overall resources and operations of the computer.
• It is specialised software that controls and monitors the execution of all other programs that reside in the computer, including application programs and other system software.

Objectives of Operating System

• To make a computer system convenient to use in an efficient manner
• To hide the details of the hardware resources from the users
• To provide users a convenient interface to use the computer system
• To act as an intermediary between the hardware and its users and making it easier for the users to access and use other resources
• To manage the resources of a computer system
• To keep track of who is using which resource, granting resource requests, according for resource using and mediating conflicting requests from different programs and users
• To provide efficient and fair sharing of resources among users and programs

Characteristics of Operating System

• Memory Management -- keeps tracks of primary memory i.e. what part of it is in use by whom, what part is not in use etc. and allocates the memory when a process or program requests it.
• Processor Management -- allocates the processor(CPU) to a process and deallocates processor when it is no longer required.
• Device Management -- keeps track of all devices. This is also called I/O controller that decides which process gets the device, when, and for how much time.
• File Management -- allocates and de-allocates the resources and decides who gets the resources.
• Security -- prevents unauthorized access to programs and data by means of passwords and similar other techniques.
• Job accounting -- keeps track of time and resources used by various jobs and/or users.
• Control over system performance -- records delays between request for a service and from the system.
• Interaction with the operators -- The interaction may take place via the console of the computer in the form of instructions. Operating System acknowledges the same, does the corresponding action and informs the operation by a display screen.
• Error-detecting aids -- Production of dumps, traces, error messages and other debugging and error-detecting methods.
• Coordination between other software and users -- Coordination and assignment of compilers, interpreters, assemblers and other software to the various users of the computer systems.

Computer - Internet and Intranet

Internet

It is a worldwide system which has the following characteristics:

• Internet is a world-wide / global system of interconnected computer networks.
• Internet uses the standard Internet Protocol (TCP/IP)
• Every computer in internet is identified by a unique IP address.
• IP Address is a unique set of numbers (such as 110.22.33.114) which identifies a computer’s location.
• A special computer DNS (Domain Name Server) is used to give name to the IP Address so that user can locate a computer by a name.
• For example, a DNS server will resolve a name http://www.tutorialspoint.com to a particular IP address to uniquely identify the computer on which this website is hosted.
• Internet is accessible to every user all over the world.

Intranet

• Intranet is system in which multiple PCs are connected to each other.
• PCs in intranet are not available to the world outside the intranet.
• Usually each company or organization has their own Intranet network and members/employees of that company can access the computers in their intranet.
• Each computer in Intranet is also identified by an IP Address which is unique among the computers in that Intranet.

Similarities in Internet and Intranet

• Intranet uses the internet protocols such as TCP/IP and FTP.
• Intranet sites are accessible via web browser in similar way as websites in internet. But only members of Intranet network can access intranet hosted sites.
• In Intranet, own instant messengers can be used as similar to yahoo messenger/ gtalk over the internet.

Differences in Internet and Intranet

• Internet is general to PCs all over the world whereas Intranet is specific to few PCs.
• Internet has wider access and provides a better access to websites to large population whereas Intranet is restricted.
• Internet is not as safe as Intranet as Intranet can be safely privatized as per the need.

Computer - How to Buy?

This chapter gives the following information:

• In this guide, we'll help you to buy a desktop on component by component basis.
• As desktops are highly customizable, so it is better to learn about main parts and then go to manufacturer or retailer shop or site instead of looking at some specific model directly.
• Popular desktop brands are Dell, Lenovo, HP and Apple.
• Compare the desktops based on their specifications and base price.

Monitor

• Size - It is the diagonal size of the LCD screen. Larger the area, bigger the picture screen. A bigger picture is preferable for movie watching and gaming. It will increase productivity as well.
• Resolution - This is the number of pixels on the screen. For example, 24-inch display is 1920x1200 (width by length) and 22-inch display which is 1680x1050. High resolution provides better picture quality and a nice gaming experience.
• Inputs - Now-a-days monitors can accept inputs from cable as well apart from computer. They also can have USB ports.
• Stand - Some monitors come with adjustable stands while some may not.
• Recommended - 24 Inch LCD.

Operating System

• Operating System is the main software of the computer as everything will run on it in one form or other.
• There are primarily three choices : Windows, Linux, Apple OS X.
• Linux is free but people generally do not use it for home purpose.
• Apple OS X works only on Apple Desktops.
• Windows 7 is very popular among desktop users.
• Most of the computers come pre-equipped with Windows 7 Starter edition.
• Windows 8 is recently introduced and is available in market.
• Windows 7 and Windows 8 come in multiple versions from starter, home basic, home premium, professional, ultimate and enterprise editions.
• As edition version increases, their features list and price increases.
• Recommended - Windows 7 Home Premium.

Optical Drive (CD / DVD / Blu-ray)

• Optical drive is the drive on a computer which is responsible for using CD, DVD and Blu-ray discs.
• Now-a-days, DVD burners are industry standards.
• DVD Burner can burn CD, DVD and play them.
• DVD Burner is cheaper than Blu-ray drives.
• Blu-ray drives can play HD movies but are costlier component.
• Recommended - DVD Burner.

Memory

• RAM is considered as Computer Memory as performance of a computer is directly proportional to its memory and processor.
• Today's software and operating system require high memory.
• Today commonly used RAM is DDR3 which operates at 1066Mhz
• As per Windows 7, 1 GB is the minimum RAM required to function properly.
• Recommended - 4 GB.

Hard Drive

• Hard disk is used for storage purpose. Higher the capacity, more data you can save in it.
• Now-a-days computers are equipped with 500GB hard drive which can be extended to 2TB.
• Most hard drives in desktop operate at the standard performance speed of 7200RPM.
• Recommended - 500GB.

CPU

• Frequency (GHz) - This determines speed of the processor. More the speed, better the CPU.
• Cores - Now-a-days CPUs come with more than one core, which is like having more than one CPU in the computer. Programs which can take advantage of multi-core environment will run faster on such machines.
• Brand - Intel or AMD. Both are equivalent. Intel is in lead.
• Cache - Higher the L1, L2 cache, better the CPU performance
• Recommended - Intel Core i3 i3-3225 3.30 GHz Processor.

Computer - Available Courses

Now–a-days, various types of educational courses are provided by educational institutions.

Course	Name	Duration (years)	Minimum Qualification
B.C.A	Bachelor of Computer Applications	3	10+2
P.G.D.C.A	Post Graduate Diploma in Computer Applications	1	Graduation
M.C.A	Master of Computer Applications	3	Graduation
B.Sc.(CS)	Bachelor of Science (Computer Science)	3	10+2
M.Sc.(CS)	Master of Science (Computer Science)	2	Graduation
B.Tech.(CSE)	Bachelor of Technology (Computer Science and Engineering)	4	10+2
B.Tech.(IT)	Bachelor of Technology (Information Technology)	4	10+2
M.Tech.(CSE)	Master of Technology (Computer Science and Engineering)	2	B.Tech / B.E.
M.Tech.(IT)	Master of Technology (Information Technology)	2	B.Tech / B.E
B.E.(CSE)	Bachelor of Engineering (Computer Science and Engineering)	4	10+2
B.E.(IT)	Bachelor of Engineering (Information Technology)	4	10+2

Diploma Courses

Apart from regular degree courses, now computer centers also provide short term courses (from 3 months to 1 year).

Online courses are also getting popularity.

• Computer Basics
• Programming Language Trainings
• Hardware Trainings
• Network Certifications