INFORMATION TECHNOLOGY
Computers for Individual Users
Most computers are meant to be used by only one person at a time
The six primary types of computers in this category are
>> Desktop computer
>>Workstations
>>Notebook computers
>>Tablet computers
>>Handheld computers
>>Smart phones
These systems are all examples of personal computers (PCs)
A term that refers to any computer system that is designed for use by a single person.
Personal computers are also called microcomputers, because they are among the smallest computers created for people to use.
How important are computers to our society?
People often talk in fantastic terms
about computers and their impact on our lives. You probably have heard or read
expressions such as “computers have changed our world** or “computers have
changed the way we do everything” many times. Such statements may strike you
as exaggerations, and sometimes they are. But if you stop and really think about
the effect computers have had on our daily lives; you still may be astonished.
Because of the cat; people were able to travel farther and cheaper than ever before, and this created huge opportunities for businesses to meet the need of the traveling public.
≫ Because vehicles could be mass-produced, the nature of manufacturing and industry changed and throngs of people began working on assembly lines.
≫ Because of road development, suburbs became a feasible way for people to live dose to a city without actually living in one.
places where there had previously been nothing.
Manage Your Schedule on a Daily or Hourly Basis. Handheld computers are popular for their calendar and schedule-management capabilities, which enable you to set appointments, track projects, and record special events
Why Are Computers So Important?
People can list countless reasons for the importance of computers
For someone with a disability, for example, a computer may offer freedom to communicate, learn, or work without leaving home. For a sales professional, a PC may mean the ability to communicate whenever necessary, to track leads, and to manage an ever changing schedule. For a researcher, a computer may be the workhorse that docs painstaking and time-consuming calculations.
Computers are important because information is so essential to our lives. And information is more than the stuff you see and hear on television. Facts in a textbook or an encyclopedia are information, bur only one kind. Mathematical formulas and their results arc information, too, as arc the plans for a building or the
recipe for a cake. Pictures, songs, addresses, games, menus, shopping lists, resume the list goes on and on. All these things and many others can be thought of as information, and they can all be stored and processed by computers
Industry
Today, enterprises use different kinds of computers in many combinations. A corporate
headquarters may have a standard PC-based network, for example, but its production facilities may use computer controlled robotics to manufacture products. Here are just a few ways computers are applied to industry:
» Design. Nearly any company that designs and makes products can use a
computer-aided design or computer-aided manufacturing system in them
creation (sec Figure 1A.29).
» Shipping. Freight companies need computers to manage the thousands of
ships, planes, trains, and trucks that are moving goods at any given moment.
In addition to tracking vehicle locations and contents, computers can manage
maintenance, driver schedules, invoices and billing, and many other activities.
» Process Control. Modem assembly lines can be massive, complex systems,
and a breakdown at one point can cause chaos throughout a company. So*
phisricatcd process-control systems can oversee output, check the speed at
which a machine runs, manage conveyance systems, and look at parts inventories,
with very little human interaction.
Government
Not only are governments big consumers of technology, but
they help to develop it as well. As you will Iern in “Presenting the Internet," the U.S. government played a key
role in developing the Internet. Similarly, NASA has been in*
evolved in the development of computer technologies of all
sorts. Today, computers play a crucial part in nearly every
government agency:
Population. The U.S. Census Bureau was one of the first organizations to use computer technology, recruiting me chemical computers known as “difference engines" to assist in tallying the American population in the early 20th century.
Taxes. Can you imagine trying to calculate Americans’ tax bills without the help of computers? Neither could the Internal Revenue Service. In fact, the IR Snow encourages taxpayers to file their tax returns online, via the Internet.
military. Some of the world's most sophisticated computer technology has been developed primarily for use by the military. In fact, some of the earliest digital computers were created for such purposes as calculating the trajectory
of missiles. Today, from payroll management to weapons control, the armed
forces use the widest array of computer hardware and software imaginable.
Police. When it comes to stocking their crime-fighting arsenals, many police
forces consider computers to be just as important as guns and ammunition
Health Care
Pay a visit to your family doctor or the local hospital, and you'll find yourself surrounded
by computerized equipment of all kinds. Computers, in fact, arc making
health care more efficient and accurate while helping providers bring down costs.
Many different health care procedures now involve computers, from ultrasound
and magnetic resonance imaging, to laser eye surgery and fetal monitoring.
Q 3) The parts of a computer system hardware
A complete computer system consists
of four parts.
≫ Hardware
≫ Software
≫ Data
≫ User
Hardware
The mechanical devices that make up the computer are called hardware. Hard*
ware is any part of the computer you can touch. A computer’s hardware consists of interconnected electronic devices that you can use to control the computer’s operation, input, and output.
Software
Software is a set of instructions that makes the computer perform tasks. In other
words, software tells the computer what to do.
Data
Data consist of individual facts or pieces of information that by themselves may
not make much sense to a person. A computer’s primary job is to process these
tiny pieces of data in various ways, converting them into useful information.
Q4 The information processing cycle, the information processing cycle has four parts, and each part involves one or more specific components of the computer:
Using a ll its parts together, a computer converts data into information by performing
various actions on the data. For example, a computer might perform a
mathematical operation on two numbers, then display the result. Or the computer
might perform a logical operation such as comparing two numbers, then display
that result. These operations are part of a process called the information process*
in cycle, which is a set of steps the computer follows to receive data, process the
data according to instructions from a program, display the resulting information
to the user, and store the results
The information processing cycle has four parts, and each part involves one or
more specific components of the computer:
Input. During this part of the cycle, the computer accepts data from some
source, such as the user or a program, for processing.
Processing. During this part of the cycle, the computer’s processing components
perform actions on the data, based on instructions from the user or a program.
Output. Here, the computer may be required to display the results of its processing.
For example, the results may appear as text, numbers, or a graphic on the computer’s screen or as sounds from its speaker. The computer also can send output to a printer or transfer the output to another computer
through a network or the Internet. Output is an optional step in the information
processing cycle but may be ordered by the user or program.
Storage. In this step, the computer permanently stores the results of its processing
on a disk, tape, or some other kind of storage medium. As with output, storage is optional and may not always be required by the user or program.
Q 5) Essential computer hardware
A computer’s hardware devices fall into one of four categories
1. Processor
2. Memory
3. Input and output
4. Storage
While any type of computer system contains these four types of hardware, this
book focuses on them as they relate to the personal computer; or PC.
processor: The processor is like the brain of the computer; it organizes and carries out instructions that come from either the user or the software. In a personal computer.
Memory: In a computer, memory is one or more sets of chips that store data and/or program instructions, cither temporarily or permanently. Memory is a critical processing component in any computer
Input and Output:
A personal computer would be useless if you could not interact with it because the machine could not receive instructions or deliver the results of its work. Input devices accept data and instructions from the user or from another computer system (such as a computer on the Internet).
Output devices return processed data to the user or to another computer system.
The most common input device is the keyboard, which accepts letters, numbers, and commands from the user. Another important type of input device is the mouse, which lets you select options from on-screen menus. You use a mouse by moving it across a flat surface and pressing its buttons.
The most common output devices are the monitor and the printer. The computer sends output to the monitor (the display screen) when the user needs only to see the output. It sends output to the printer when the user requests a paper copy—also called a hard copy—of a document.
Storage: A computer can function with only processing, memory, input, and output devices. To be really useful, however; a computer also needs a place to keep program files and related data when they are not in use. The purpose of storage is to hold data permanently, even when the computer is turned off.
There are many types of computer storage, but the most common types are two.
1 Magnetic Storage.
2 Optical Storage.
Magnetic:
disk. A disk is a round, flat object that spins around its center. (Magnetic disks are almost always housed inside a case of some kind, so you can’t see the disk itself unless you open the case.) Read/write heads, which work in much the same way as the heads of a tape recorder or VCR, are used to read data from the disk or write data onto the disk.
Optical storage: devices that use lasers to read data from or write data to the reflective surface of an optical disc.
Q 6) System software operating system, network operating system and utility application software word processing, spreadsheets, database management software etc.
System Software
System software is any program (hat controls the computer’s hardware or that can be used to maintain the computer in some way so that it runs more efficiently.
There are three basic types of system software.
An operating system tells the computer how to use its own components.Examples of operating systems include Windows, the Macintosh Operating System, and Linux operating system is as an interpreter between the hardware, application programs, and the user.
A network operating system allows computers to communicate and share data across a network while controlling network operations and overseeing the network’s security.
A utility is a program that makes the computer system easier to use or performs highly specialized functions.
Application Software
Application software tells the computer how to accomplish specific tasks, such as word processing or drawing, for the user.
Word processing software for creating text-based documents such as newsletters or brochures.
Spreadsheets
for creating numeric-based documents such as budgets or balance sheets.
Database management software for building and manipulating large sets of data, such as the names, addresses, and phone numbers in a telephone directory.
Presentation programs for creating and presenting electronic slide shows.
Q 7) Computer users the user's role, user less" computer.
Personal computers, , arc designed to work with a human user. In fact, the user is a critical part of a complete computer system, especially when a personal computer is involved.
The User's Role
When working with a personal computer; the user can take on several roles, depending on what he or she wants to accomplish:
≫ Setting up the System. Have you ever bought a new PC? When you got it home, you probably had to unpack it, set it up, and make sure it worked as expected. If you want to change something about the
system (a process called configuration), your will likely do it yourself, whether you want to add a new hardware device, change the way programs look on your screen, or customize the way a program functions.
≫ Installing Software. Although your new computer probably came with an operating system and some applications installed, you need to install any other programs you want to use. This may involve loading software from a disk or downloading it from a Web site. Either way, it is usually the user’s responsibility to install programs, unless the computer is used at a school or business. In that case, a system administrator or technician may be available to do the job.
≫ Running Programs. Whenever your computer is on, there are several programs running in the background, such as the software that runs your mouse and printer. Such programs do not need any user input; in fact, you may not even be aware of them. But for the most part, if you want to use your computer to perform a task, you need to launch and run the software that is designed for the task.
≫ Managing Files. As you have already learned, a computer saves data in files. If you write a letter to a friend, you can save it as a file, making it available to open and use again later. Pictures, songs, and other kinds of data are stored as files. But it is the user's job to manage these files, and this means setting up a logical system for storing them on the computer It also means knowing
when to delete or move files, or copy them to a disk for safekeeping.
≫ Maintaining the System. System maintenance does not necessarily mean opening the PC and fixing broken parts, as you would repair a car's engine. But it could! In that case, you might call a qualified technician to do the job, or roll up your sleeves and tackle it yourself. PC maintenance, however, generally means running utilities that keep the disks free of clutter and ensure that the computer is making the best use of its resources.
"User less" Computers Of course, there are many kinds of computers that require no human interaction, once they have been programmed, installed, and started up. For example, if you own a car that was built within the last decade, it almost certainly has an on-board computer that controls and monitors engine functions.
User less computers are typically controlled by their operating systems. In these devices, the operating system may be installed on special memory chips rather than a disk. The operating system is programmed to perform a specific set of tasks, such as monitoring a function or checking for a failure, and little else.
Q 8) The keyboard, the standard keyboard layout, the alphanumeric keys, the modifier keys, the numeric keypad, the function keys.
The Keyboard
The keyboard was one of the first peripherals to be used with computers, and it is still the primary input device for entering text and numbers. A standard keyboard includes about 100 keys; each key sends a different signal to the CPU. The skill of typing, or keyboarding, is the ability to enter text and numbers with skill and accuracy. Certainly, you can use a computer without having good typing skills. Some people claim that when computers can interpret handwriting and speech with 100 percent accuracy, typing will become unnecessary.
The Standard Keyboard Layout
Keyboards come in many styles. The various models differ in size, shape, and feel; except for a few special-purpose keys, most keyboards arc laid out almost identically. Among IBM-compatible computers, the most common keyboard layout is
the IBM Enhanced Keyboard. It has about 100 keys arranged in five groups (The term IBM-compatible computer refers to any PC based on the first personal computers, which were made by IBM.
The Alphanumeric Keys
The alphanumeric key the area of the keyboard that looks like a typewriter's
Key are arranged the same way on almost every keyboard. Sometimes this common
arrangement is called the QWERTY (pronounced KWER-tee) layout because
the first six keys on the top row of letters are Q, W, E, R, T, and Y.
Along with the keys that produce letters and numbers, the alphanumeric key
group includes four keys having specific functions. The tab, CAPS LOCK, Back Space and enter.
The Modifier Keys
The SHIFT, ALT (Alternate), and CTRL (Control) keys are called modifier keys because they modify the input of other keys. In other words, if you hold down a modifier key while pressing another key, then you are changing the second key's. input in some way. For example, if you press the J key, you input a small letter (j) But if you hold down the shift key while pressing the J key, you input a capital (J).
The Numeric Keypad
The numeric keypad looks like a calculator's keypad, with its 10 digits and mathematical operators (+, -, *, and /). The numeric keypad also features a NUM LOCK key, which forces the numeric keys to input numbers. When NUM LOCK is deactivated, the numeric keypad's keys perform cursor movement control and other functions.
The Function Keys
The function keys, which are labeled F 1, f 2, and so on are usually arranged in a row along the top of the keyboard. They allow you to input commands without typing long strings of characters or navigating menus or dialog boxes. Each function key's purpose depends on the program you are using.
9)The cursor-movement keys, special-purpose keys.
The Cursor-Movement Keys
Most standard keyboards also include a set of cursor-movement keys, which let you move around the screen without using a mouse. In many programs and operating systems, a mark on the screen indicates where the characters you type will be entered. This mark, called the cursor or insertion point, appears on the screen as a blinking vertical line, a small box, or some other symbol to show your place in a document or command line.
Special-Purpose Keys
In addition to the five groups of keys described earlier, all IBM compatible keyboards feature six special-purpose keys, each of which performs a unique function. Since 1996, nearly all IBM-compatible keyboards have included two additional special-purpose key’s designed to work with the Windows operating systems.
10) How the computer accepts input from the keyboard, keyboard controller, keyboard buffer.
the process of accepting input from the keyboard is more complex When you press a key, a tiny chip called the keyboard controller notes that a key has been
pressed.
The keyboard controller places a code into part of its memory, called the keyboard buffer, to
indicate which key was pressed. (A buffer is a temporary storage area that holds data until it can be processed.) The keyboard controller then sends a signal to the computer's system software, notifying it that something has happened at the keyboard .
11) Ergonomics, repetitive stress injuries, carpal tunnel syndrome and avoid risk while working with your keyboard and mouse.
Ergonomics
Any office worker will tell you tell working at a desk all day can be extremely uncomfortable.
Not only does the user's body.
ache from being in a chair too long, but hand and wrist injuries can result from using a keyboard and mouse for long periods. Eyes can become strained from staring at a monitor for hours. Such injuries can be extreme, threatening the user’s general health and ability to work.
Repetitive Stress Injuries
The field of ergonomics did not receive much attention until a certain class of injuries began appearing among clerical workers who spend most of their time entering data on computer keyboards. These ailments are called repetitive stress injuries (RSIs) or repetitive strain injuries and result from continuously using the body in ways it was not designed to work. One type of RSI that is especially well documented among computer users is carpal tunnel syndrome, a wrist or hand injury caused by using a keyboard for long periods of time.
In carpal tunnel syndrome, tendons in the tunnel become inflamed because the victim has held his or her wrists stiffly for long periods, as people tend to do at a keyboard. When the tendons become inflamed, they press against the nerves, causing tingling, numbness, pain, or the inability to use the hands. Carpal tunnel syndrome is the best-known repetitive stress injury. It can become so debilitating that victims can miss weeks or months of work. In extreme cases,
surgery is required.
Avoiding Keyboard-Related Injuries
If you use a computer frequently, you can avoid RSIs by adopting a few good work habits, and by making sure that your hardware and workspace are set up in an ergonomically friendly way.
12 Os types of operating systems, real-time operating systems, single-user/single-tasking, operating systems, single-user/multitasking operating systems, multiuser/multitasking operating systems.
Real-Time Operating Systems
A real-time operating system is a very fast, relatively small OS. Real-time OS are often also embedded OS.
Real-time applications arc needed to run medical diagnostics equipment, life-support systems, machinery, scientific instruments, and industrial systems.
Single-User/Single-Tasking Operating Systems
An operating system that allows a single user to perform just one task at a time is a single-user/single tasking operating system.
MS-DOS is one example of a single-tasking OS, and the Palm O
Single-User/Multitasking Operating System
A single-user/multitasking operating system is one that allows a single user to perform two or more functions at once.
Multi-User/Multitasking Operating Systems
A multi-user/multitasking operating system is an operating system that allows multiple users to use programs that are simultaneously running on a single network server; called a terminal server.
13) Database, three of the most important terms to know about databases are, field, records, tables and MySQL.
Database
There are a lot of thing people can’t manage due to that he manages some kind of list. We are talking about storing of something for permanent or temporary basis.
UCAR wana hire a person with salary 3 Lacs who brings business employee data who travel by plane
Airport staff manages it manually
Such data being related for passenger as a base. Like foji base. Where only army staff being there.
A company have a 1000 employee, hire an accountant, can he/she remember whole staff’s salary with their names, emails, ranks and designation
Then how can he manage it.
Small tile company hire a person to manage sale. So he takes out receipt book and write product name and price. Then count per day sale.
Three of the most important terms to know about databases are
» Fields.
For example, each entry has a field for Name, as well as fields for Address, City, State, ZIP code, and Phone. Each unique type of data is stored in its own field. (The term column is sometimes used instead of field. IBM uses column fairly consistently, and Microsoft now uses it increasingly.)
» Records. One full set of fields—that is, all the related data about one person or object—is called a record. Therefore, all the information for the first person is record 1, all the information for the second person is record 2, and so on. (The term row is sometimes used instead of record by IBM and Microsoft.)
» Tables. A complete collection of records makes a table
SQL is a standard language for storing, manipulating and retrieving data in databases.
Some of The Most Important SQL Commands
SELECT - extracts data from a database
UPDATE - updates data in a database
DELETE - deletes data from a database
INSERT INTO - inserts new data into a database
CREATE DATABASE - creates a new database
ALTER DATABASE - modifies a database
CREATE TABLE - creates a new table
ALTER TABLE - modifies a table
DROP TABLE - deletes a table
SELECT * FROM Business passenger;
14) Video display devices, and how crt works.
VIDEO DISPLAY DEVICES
The primary output device in a graphics system is a video monitor. The operation of most video monitors is based on the standard cathode-ray-tube (CRT) design, but several other technologies exist and solid-state monitors may eventually predominate.
Refresh Cathode-Ray Tubes
Following figures illustrate the basic operation of a CRT. A beam of electrons (cathode rays), emitted by an electron gun, passes through focusing and deflection systems that direct the beam toward specified positions on the phosphor-coated screen. The phosphor then emits a small spot of light at each position contacted by the electron beam.
Phosphor is available in different kinds. One variety is available in color but a major issue is their persistence.
Lower persistence phosphors require higher refresh rates to maintain a picture on the Screen without flicker.
A phosphor with low persistence is useful for displaying highly complex, static pictures.
Monitors normally come with persistence in the range from 10 to 60 microseconds.
The maximum number of points (that can be uniquely identified) on a CRT is referred to as the resolution.
A pixel (short for picture element) represents the shortest possible unique position/ element that can be displayed on the monitor without overlapping.
15) Transmission media with guided and unguided media.
Transmission media:
o Transmission media is a communication channel that carries the information from the sender to the receiver. Data is transmitted through the electromagnetic signals. o The main functionality of the transmission media is to carry the information in the form of bits through LAN(Local Area Network). o It is a physical path between transmitter and receiver in data communication. o In a copper-based network, the bits in the form of electrical signals. o In a fibre based network, the bits in the form of light pulses.
o In OSI(Open System Interconnection) phase, transmission media supports the Layer 1. Therefore, it is considered to be as a Layer 1 component. o The electrical signals can be sent through the copper wire, fibre optics, atmosphere, water, and vacuum. o The characteristics and quality of data transmission are determined by the characteristics of medium and signal. o Transmission media is of two types are wired media and wireless media. In wired media, medium characteristics are more important whereas, in wireless media, signal characteristics are more important. o Different transmission media have different properties such as bandwidth, delay, cost and ease of installation and maintenance.
Two Types of transmission media
Bound Transmission Media/ guided media
Unbound Media/ unguided media
Guided media
In guided media, transmitted data travels through cabling system that has a fixed path.
For example,
Twisted pair
Coaxial Cable Optical fibers Twisted pair A cable consisting of two wires twisted round each other, used especially for telephone or computer applications.
Coaxial Cable
is used as a transmission line for radio frequency signals. Its applications include feedlines connecting radio transmitters and receivers with their antennas, computer network (Internet) connections, digital audio (S/PDIF), and distributing cable television signals.
Optical fibers
A technology that uses glass (or plastic) threads (fibers) to transmit data. A fiber optic cable consists of a bundle of glass threads, each of which is capable of transmitting messages modulated onto light waves. ... This means that they can carry more data.
unguided media
In unguided media, transmitted data travels through free space in form of electromagnetic signal it is wireless. For example, Infrared, Radio Frequency, Microwave
Infrared
Low frequency infrared waves are used for very short distance communication like TV remote, wireless speakers, automatic doors, hand held devices etc. Infrared signals can propagate within a room but cannot penetrate walls. However, due to such short range, it is considered to be one of the most secure transmission modes.
Radio Frequency
Transmission of data using radio frequencies is called radio-wave transmission. We all are familiar with radio channels that broadcast entertainment programs. Radio stations transmit radio waves using transmitters, which are received by the receiver installed in our devices.
Both transmitters and receivers use antennas to radiate or capture radio signals. These radio frequencies can also be used for direct voice communication within the allocated range. This range is usually 10 miles. Microwave
Microwaves
travel in straight lines, and so the transmitter and receiver stations should be accurately aligned to each other. Microwave propagation is line – of – sight propagation. So, towers hoisting the stations should be placed so that the curvature of the earth or any other obstacle does not interfere with the communication.
Since it is unidirectional, it allows multiple receivers in a row to receive the signals without interference.
Microwaves do not pass through buildings. So, indoor receivers cannot be used effectively. Microwaves are often refracted by the atmospheric layers. The refracted rays take longer time to reach the destination than the direct rays. This causes out of phase transmission, called multipath fading. Microwaves need unidirectional antennas to send out signals.
Two types of antennas are needed Applications o Long distance telephone communication o Cellular phones o Television networks o Satellites o Wireless LANs.
16)Switch and router, dvd, blue-ray disk.
Switches
Switches are most often used in large networks, such as those found in business and school environments. They connect many computers together within a single local area network, or LAN. A large network may include multiple switches, which connect different groups of computer systems together. These switches are typically connected to a router that allows connected devices to access the Internet.
Router
A router is a device that analyzes the contents of data packets transmitted within a network or to another network. Routers determine whether the source and destination are on the same network or whether data must be transferred from one network type to another, which requires encapsulating the data packet with routing protocol header information for the new network type. DVD A type of compact disc able to store large amounts of data, especially high-resolution audiovisual material.
Blue-ray disk
A Blu-ray disk (BD) is a high-capacity optical disk medium developed for recording, rewriting and playing back high definition video. It can store large amounts of data and was designed to supersede the DVD. Blu-ray was jointly developed by a group of personal computer and consumer electronics companies called the Blu-ray Disc Association. Blu-ray disks support higher resolutions and more advanced video and audio formats compared to DVDs.
