Chapter 10 : Managing a Database

Databases, Data, and Information

1. Database - Collection of data organised in a manner that allows access, retrieval, and use of that data.
2. Data - Collection of unprocessed items such as Text, Numbers, Images, Audio, Video
3. Information - Processed data, Documents, Audio, Images, Video
4. Database software, often called a database management system (DBMS), allows users to: Create a computerised database. Sort and retrieve data.

-Valuable information should have the following characteristics : 

• Accurate
• Verifiable
• Timely
• Organized
• Useful
• Accessible
• Cost-effective.

The Hierarchy of Data

A character is one byte - Numbers, letters, space, punctuation marks, or other symbols.

A field is a combination of one or more related characters. 

1. Field name 
2.  Field size 
3. Data type.

 Common data types include : 

• Text
• Numeric 
• Date 
• Memo 
• Object
• AutoNumber
• Currency

A record is a group of related fields 

-- primary key uniquely identifies each record

-A data file is a collection of related records.

Maintaining Data

File maintenance refers to the procedures that keep data current :

• Adding records 
• Modifying records  
• Deleting records.

Validation compares data with a set of rules or values to find out if the data is correct.

•Alphabetic/Numeric check

•Range check

•Consistency check

•Completeness check

•Check digit

•Other checks

File Processing Versus Databases
File processing system  

•  used for many years  
• have data redundancy 
• isolate data

Database approach 

•Programs and users share data

•Reduce data redundancy

•Improve data integrity

•Share data

•Allows easier access

•Reduces development time

•Can be more vulnerable

Database Management System

-A data dictionary contains data about each file in the database each field in those files.

-A DBMS provides tools allow users to retrieve and maintain data in the database 

• Query language
• Query by example
• Form
• Report generator.

A query language consists of simple, English-like statements that allow users to specify the data to display, print, or store.

Query by example (QBE) provides a GUI to assist users with retrieving data.

A form is a window on the screen that provides areas for entering or modifying data in a database

A report generator allows users to design a report on the screen, retrieve data into the report design, and then display or print the report.

A DBMS provides a variety of techniques to restore the database to a usable form in case it is damaged or destroyed such as :

• Backup
• Log 
• Recovery utility 
• Continuous backup.

Relational, Object-Oriented, and Multidimensional Databases

A data model consists of rules and standards that define how the database organizes data.

A relational database stores data in tables that consists of rows and columns. 

-Each row has a primary key

-Each column has a unique name.

A relationship is a link within the data.

An object-oriented database (OODB) stores data in objects.

Examples of applications appropriate for an object-oriented database include :

• multimedia database 
• Groupware database
• Hypertext database.

A multidimensional database can store data in more than two dimensions of data

• Sometimes known as a hypercube
• Can consolidate data much faster than a relational database

A data warehouse is a huge database that stores and manages the data required to analyze historical and current transactions.

Web Database

Databases on the Web allow you to: 

1. Check semester grades
2. Search for a job
3. Buy or sell stocks
4. Shop for products or services
5. Make airline reservations
6. Register for college classes.

Database Administration

Database analysts and administrators are responsible for managing and coordinating all database activities

Database Analyst (DA)

-Decides on proper field placement, defines data relationship, and identifies users’ access privileges

Database Administrator (DBA)

-Creates and maintains the data dictionary, manages security, monitors performance, and checks backup and recovery procedures

Chapter 9 : Networks and Communications

Communications

-Communications describes a process in which two or more computers or devices transfer data, instructions, and information. Sending device, Communications channel, Receiving device.

Uses of Computer Communications

-Users can send and receive wireless messages using wireless messaging services. Text messaging allows users to send message thru phone or other mobile devices. Picture messaging allows users to send pictures and sound files. Video messaging allows users to send short video clips.

-Wireless Internet access points allow people to connect wirelessly to the Internet from home, work, school, and in many public locations.

-A cyber cafe is a coffeehouse, restaurant, or other location that provides personal computers with Internet access to its customers.

-A global positioning system (GPS) is a navigation system that consists of one or more earth-based receivers that accept and analyze signals sent by satellites in order to determine the GPS receiver's geographic location.

-Groupware : helps groups of people work together on projects and share information over a network. Major feature is group scheduling.

-Voice mail : allows someone  to leave a voice message for one or more people. A voice mailbox is a storage location on a hard disk in the voice mail system.

Networks

-A network is a collection of computers and devices connected together via communications devices and transmission media. Advantages of a network include :Sharing hardware and software, Transferring funds, and Sharing data and information.

-A local area network (LAN) is a network that connects computers and devices in a limited geographical area

-A wireless LAN (WLAN) is a LAN that uses no physical wires.

-A wide are network (WAN) is a network that covers a large geographical area.

-A network topology refers to the layout of the computers and devices in a communications network.

-An intranet is an internal network that uses Internet technologies.

-An extranet allows customer or suppliers to access part of its intranet.

Network Communications Standards

-Ethernet is a network standard that specifies no computer controls when data can be transmitted. The token ring standard specifies that computers and devices on the network share or pass a special signal (token). TCIP/IP is a network standard that defines how messages are routed from one end of a network to another.

-Bluetooth defines how two Bluetooth devices use short-range radio waves to transmit data.

-WiMAX (802.16) : Developed by IEEE. Towers can cover a 30-mile radius. Provides wireless broadband Internet access.

-Wireless Application Protocol (WAP) : Specifies how some mobile devices can display the content of Internet services. Uses a client/server network.

Communications Software

Communications software consists programs that : 

1. Help users establish a connection to another computer or network. 

2 .Manage the transmission of data, instructions, and information. 

3. Provide an interface for users to communicate with one another.

Communications Over the Telephone Network

-The public switched telephone network (PSTN) is the worldwide telephone system.

-ADSL connections transmit data downstream at a much faster rate than upstream.

Communications Devices

A communications device is any type of hardware capable of transmitting data, instructions, and information between a sending deice and a receiving device.

-A digital modem sends and receives data and information to and from a digital line such as DSL modem and Cable modem.

-A wireless modem uses the cell phone network to connect to the Internet wirelessly from a notebook computer, a smart phone, or other mobile device. 

-A network card enables a computer or device to access a network.

Home Networks

Home networks provide computers with the following capabilities : 

-Connect to the Internet at the same time

-Play multiplayer games

-Connect game consoles to the Internet.

Types of wired home networks : 

-Ethernet

-Powerline cable 

-Phoneline.

Wireless Transmission Media

Cellular radio is a form of broadcast radio that its used widely for mobile communications

Microwaves are radio waves that provide a high-speed signal transmission

A communications satellite is a space station that receives microwaves signals from an earth-based station, amplifies it, and broadcasts the signal over a wide area.

Chapter 8 type of storage

Storage

Storage holds data, instructions, and information for future use. A storage medium is the physical material on which a computer keeps data, instructions, and information.

-Capacity is the number of  bytes a storage medium can hold.

-A storage device is the computer hardware that records and/or retrieves items to and from storage media. 

-Reading is the process of transferring items from a storage medium into memory. 

-Writing is the process of transferring items from memory to a storage medium.

Hard Disks

A hard disk contains one or more inflexible, circular platters that use magnetic particles to store data, instructions, and information.

Characteristics of hard disk :

•Capacity

•Platters

•Read/Write Heads

•Cylinders

•Sectors and Tracks

•Revolutions per Minute

•Transfer Rate

•Access Time

-Formatting is the process of dividing the disk into tracks and sectors so that the operating system can store and locate data and information on the disk.

-RAID (redundant array of independent disks) is a group of two or more integrated hard disks

-A network attached storage (NAS) device is a server connected to a network with the sole purpose of providing storage

Flash Memory Storage

Flash memory chips are a type of solid state media and contain no moving parts.

- memory card is a removable flash memory device that you insert and remove from a slot in a computer, mobile device, or card reader.

- USB flash drives plug into a USB port on a computer or mobile device.

Cloud Storage

Cloud storage is an Internet service that provides storage to computer users for variety of reasons such as : Access file from any computer, Store large files instantaneously, Allow others to access their files.

Optical Discs

An optical disc consists of a flat, round, portable disc made of metal, plastic, and lacquer that is written and read by a laser.

Other types of storage

-Tape is a magnetically coated ribbon of plastic capable of storing large amounts of data and information.

-A tape drive reads and writes data and information on a tape.

-A magnetic stripe card contains a magnetic stripe that stores information.

-A smart card stores data on a  thin microprocessor embedded in the card.

-Microfilm and microfiche store microscopic images of documents on a roll or sheet film.

Chapter 7 understanding output

What is Output

-Output is data that has been processed into a useful form.

-An output device is any type of hardware component that conveys information to one or more people.

Display Devices

-A display device visually conveys text. graphics, and video information 

-A monitor is packaged as a separate peripheral.

Liquid crystal display (LCD) uses a liquid compound to present information on a display device.The quality of an LCD monitor or LCD screen depends primarily on

-Resolution 

-Response time

-Brightness 

-Dot pitch

-Contrast ratio

Resolution is the number of horizontal and vertical pixels in a display device.

Plasma monitors are display devices that use gas plasma technology and offer screen sizes up to 150 inches.

HDTV is the most advanced form of digital television.

A CRT monitor is a desktop monitor that contains a cathode-ray tube.

Printers

A printer produces text and graphic on a physical medium.

-A non-impact printer forms characters and graphics on a piece of paper without actually striking the paper.

-An ink-jet printer forms characters and graphics by spraying tiny drops of liquid ink onto a piece of paper.

-A multi-function peripheral (MFP) is a single device that prints, scans, copies, and in some cases, faxes.

-A thermal printer generates images by pushing electrically heated pins against the heat-sensitive paper.

-A mobile printer is a small, lightweight, battery-powered printer that allows a mobile user to print from a, notebook computer, smart phone, or other mobile device.

-A label printer is a small printer that prints on adhesive-type material

-Plotters used to produce high-quality drawings

-Large-format printers create photo-realistic quality color prints on larger scale

Speakers, Headphones, and Earbuds

An audio output device produces music, speech, or other sounds.

-Headphones are speakers that cover of the ear.

-Earbuds (also called earphones) rest inside the ear canal.

Other Output Devices

An interactive whiteboard is a touch-sensitive device, resembling a dry-erase board, that displays the image on a connected computer screen.

Chapter 6 Understand Input

What is Input?

-Input is any data instructions entered into the memory of a computer.Instructions can be entered into the computer in the form of programs, commands, and user responses.

-Input device is any hardware component that allows users to enter data and instructions into a computer.

The Keyboard

-an input device that contains keys users press to enter data and instructions into a computer.

-Most desktop computer keyboards have between 101 and 105 keys, function keys, CTRL keys, ALT keys, and arrow keys. A numeric keypad on the right side of the keyboard.

-The insertion point is a symbol on the screen that indicates where the next character you type will appear.

-An ergonomic keyboard has a design that reduces the chance of wrist and hand injuries. Ergonomics incorporates comfort, efficiency, and safety into the design of the workplace.

Mouse

-A mouse is a pointing device that fits under your hand comfortably. A mouse can be wired or wireless.

Other Pointing Devices : Trackball ,Touchpad ,Pointing Stick 

Touch Screens and Touch-Sensitive Pads

-A touch screen is a touch-sensitive display device

Pen Input

With pen input, you touch stylus or digital pen on a flat surface to write, draw, or make selections.

Game Controllers

Video games and computer games uses a game controller as the input device that directs movements and actions of on-screen objects such as gamepads, joysticks and wheels, light guns, dance pads, and motion-sensing controllers.

Digital Cameras

A digital camera is a mobile device that allows users to take pictures and store them digitally. There are Studio cameras, Field cameras, and Point-and-shoot cameras.

Two factors affect the quality of digital camera photos : 

-Resolution - is the number of horizontal and vertical pixels in a display device. 

-Number of bits stored in each pixel - each pixel consists of one or more bits of data. The more bits used to represent a pixel, the more colors and shade of gray that can be represented.

Voice Input

-Voice input is the process of entering input by speaking into a microphone.

-Voice recognition is the computer's capability of distinguishing spoken words.

-Audio input is the process of entering any sound into the computer like : Speech, Music, Sound Effects.

Video Input

-Video Input is the process of capturing full-motion images and storing them on a computer's storage medium.

-A Web cam is a type of digital video camera that enables user to : Capture video and still images, Make video telephone calls, and add live images to instant messages.

-A video conference is a meeting between two or more geographically separated people.

Scanner and reading devices 

-Optical character recognition (OCR) involves reading characters from ordinary documents.

-A turnaround document is a document you return to the company that creates and sends it.

-A bar code reader, also called a bar code scanner users laser beams to read bar codes.

- Magnetic stripe card readers read the magnetic stripe on the back of cards such as : Credit cards, Entertainment cards, Bank cards, Other similar cards.

Biometric input 

-Biometrics authenticates a person’s identity by verifying a personal characteristic

-Fingerprint reader

-Face recognition system

-Hand geometry system

-Voice verification system

-Signature verification system

-Iris recognition system

-Retinal scanners

Chapter 5 type of utility programs nad operating systems

Chapter 5 : Type of utility Programs and operating systems 

System Software

System Software consists of 2 programs that control or maintain the operations of the computer and its devices.

1. Operating Systems - is a set of programs containing instructions that work together to coordinates all the activities among computer hardware resources.

Utility program - type of system software that allows a user to perform maintenance-type tasks

Operating System Functions

• The process of starting or restarting a computer is called booting.Cold boot is turning on a computer that has been powered off completely.
• Warm boot is using the operating system to restart a computer.

A boot drive is the drive from which your computer starts.You can boot from a boot disk.A recovery disk contains a few system files that will start the computer.

• Sleep mode saves any open documents and programs to RAM, turns off all unneeded functions, 

and then places the computer in a low-power state

• Hibernate saves any open documents and programs to a hard disk before removing power from 

the computer 

User interface controls how you enter data and instructions and how information is 

displayed on the screen .A command-line interface, a user uses the keyboard to enter data 

and instructions. 

How an operating system handles programs directly affects your productivity .

-single user and multiuser 

- single tasking and multi tasking 

- fore background and background 

-Preemptive multitasking 

-Multi processing 

Memory management optimises the use of RAM.Virtual memory is a portion of a storage 

medium functioning as a additional RAM.

A driver is a small program that tells the operating system how to communicate with a 

specific device. Plug and Play automatically configures new devices as you install them.

Operating systems typically provide a means to establish Internet connections

A performance monitor is a program that assesses and reports information about various 

computer resources and devices.

Operating systems often provide users with the capability of : 

-managing files 

-uninstalling programs

-searching for files 

-cleaning up disks 

-backing up files and disks

-viewing images

-defragmenting disks

-setting up screen savers 

-securing a computer 

-diagnosing problems

Automatic update - automatically provides updates to the program

Server operating system - organises and coordinates how multiple users access and share 

resources on a network.

Type of Operating system 

-Stand-alone 

-Server

-embedded 

Stand-alone Operating system 

A stand-alone operating system is a complete operating system that works on a desktop 

computer, notebook computer, or mobile computing device . 

Windows 7 is a Microsoft's fastest, most efficient operating system to date and is available 

in multiple editions: 

-Windows 7 Starter 

-Windows 7 Home Premium

-Windows 7 Ultimate 

-Windows 7 Professional

Macintosh operating system has set the standard for operating system ease of use. 

Latest version is Mac OS X.

UNIX is a multitasking operating system developed in the early 1970s.

Linux is an open-source popular, multitasking UNIX-type operating system.

Server Operating systems

-Windows server 2008 

-UNIX

-Linux

-Solaris 

-Netware

Windows Server 2008 is an upgraded Windows Server of 2003

Embedded Operating system

Embedded operating system -resides on a ROM chip on a mobile device or consumer 

electronic device.

Utility Programs 

-is a type of system software that allows a user to perform maintenance-type tasks

File manager - is a utility that performs functions related to file management 

For example:

-Displaying a list of files

-Organising files in folder

-Copying, renaming, deleting, moving, and sorting files and folders 

-Creating shortcuts 

A search utility is a program that attempts to locate a file on your computer based on 

criteria you specify.

An image viewer allows users to display, copy, and print the contents of a graphic file.

An uninstaller removes a program, as well as any associated entries in the system files.

A disk cleanup utility searches for and removes unnecessary files.

A disk defragmenter reorganizes the files and unused space on a computer's hard disk so 

that the operating system accesses data more quickly and programs run faster.

A backup utility allows users to copy files to another storage.

A restore utility reverses the process and returns backed up files to their original form.

Screen saver causes a display of a moving image if no activity occurs for a specified time.

Personal firewall detects and protects a personal computer from unauthorized intruders.

A virus damage the computer program and affects the computer potentially. 

A worm copies itself repeatedly in memory or over a network. 

A Trojan horse hides within or looks like legitimate program. 

An antivirus program protects a computer against viruses.

Spyware is a program placed on a computer without the user's knowledge that secretly 

collects information about the user.

Spyware remover detects and delete spyware and other similar programs.

Adware displays an online advertisement in a banner or pop-up window. 

An adware remover is a program that detects and deletes adware.

Chapter 4

Chapter 4 : System Unit Components 

System unit is a case that contains electronic components of the computer used to process data .

Inside system unit have :

1. Drive bay
2. Power supply 
3. Sound card 
4. Video card 
5. Processor 
6. Memory 

Motherboard - Main circuit board of the system unit

Processor 

Processor also known as Central Processing Unit (CPU), interprets and carries out the basic instructions that operate a computer and contain a control unit and an arithmetic logic unit(ALU)

Have 3 different processor : Multicore processor , Dual-core processor ,  Quad-core Processor 

Control units - is a components of the processor that directs and coordinates most of the operations in the computer

Arithmetic logic unit (ALU) - Performs arithmetic , comparison , and  other  operations

Systems clock - Controls the timing of all computer operations . The pace of the systems clock is called the clock speed , and is measured in gigahertz

A processor chips generates heat that could cause the chips burn up so require a cooling systems to cool it down like Heat sinks and Liquid cooling technology .

Data representation 

Analog - signals are continuous and vary in strength and quality

Digital -  signals are in one of two states : on or off

The Binary system uses two unique digits (0 and 1)

ASCII(American standard Code For Information Interchange) is the most widely used coding scheme to represent data

How a letter is converted to binary  form and back 

• Step 1 : Press 'T' (Shift + T keys ) on the keyboard which in turn creates a special code , called scan code .
• Step 2 : The scan code for the capital letter T is sent to the system units
• Step 3 : The system unit converts the scan code for the capital letter T to its ASCII Binary code  and stores its in its memory for processing.
• Step 4 : After processing , the binary code for the capital letter T is converted to an image and display on the output 

Memory

Memory consists of electronic components that stores instructions waiting to be executed by processor ,data needed by those instructions . 

Memory size is measured in kilobytes(K) , megabytes (MB) , gigabytes (GB) , terabytes (TB)

The system unit contains two types of memory 

Volatile memory - contains will lose when power off 

Non-volatile memory - contains will not lose when power off

Three basics type of RAM

1. Dynamic RAM(DRAM)
2. Static RAM (SRAM)
3. Magnetoresistive RAM(MRAM)

RAM chips is locate on a memory module and inserted into memory slots .The amount of RAM is important and its depends on types of software you using 

Memory cache - speeds the processes of the computer because it stores frequently used instructions and data 

Flash memory - can be erased and rewritten 

Expansion slots and Adapter cards

Expansion slots is a sockets on the mother board that can hold an adapter card 

Adapter card enhances functions of a component or provides connections to peripherals like sounds card and Video card

Removable flash memory - Memory cards , USB Flash drives , and PC Cards 

Port and Connectors 

Port - peripheral attaches to or communicates with a system unit