ICT Fundamentals Report

8/8/2019 ICT Fundamentals Report

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GROUP 1BSCE 2C


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DIFFERENT NETWORK TOPOLOGIES

Topology in Network Design

Think of a topology as a network's virtual shape orstructure. This shape does not necessarily correspond to theactual physical layout of the devices on the network. Forexample, the computers on a home LAN may be arranged in acircle in a family room, but it would be highly unlikely tofind a ring topology there.

Network topologies are categorized into the followingbasic types:

bus

ring

star

tree mesh

More complex networks can be built as hybrids of two ormore of the above basic topologies.


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Bus Topology

Bus networks (not to be confused with the system bus of a

computer) use a common backbone to connect all devices. A single

cable, the backbone functions as a shared communication medium that

devices attach or tap into with an interface connector. A device

wanting to communicate with another device on the network sends a

broadcast message onto the wire that all other devices see, but

only the intended recipient actually accepts and processes the

message.

Ethernet bus topologies are relatively easy to install and don't

require much cabling compared to the alternatives. 10Base-2

("ThinNet") and 10Base-5 ("ThickNet") both were popular Ethernet

cabling options many years ago for bus topologies. However, bus

networks work best with a limited number of devices. If more than a

few dozen computers are added to a network bus, performance

problems will likely result. In addition, if the backbone cable

fails, the entire network effectively becomes unusable.


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Ring Topology

In a ring network, every device has exactly two neighbors

for communication purposes. All messages travel through a ring

in the same direction (either "clockwise" or

"counterclockwise"). A failure in any cable or device breaks

the loop and can take down the entire network. To implement a

ring network, one typically uses FDDI, SONET, or Token Ring

technology. Ring topologies are found in some office buildings

or school campuses.


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Star Topology

Many home networks use the star topology. A star network

features a central connection point called a "hub" that may be

a hub, switch or router. Devices typically connect to the hub

with Unshielded Twisted Pair (UTP) Ethernet. Compared to the

bus topology, a star network generally requires more cable, but

a failure in any star network cable will only take down one

computer's network access and not the entire LAN. (If the hub

fails, however, the entire network also fails.)


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Tree Topology

Tree topologies integrate multiple star topologies

together onto a bus. In its simplest form, only hub devices

connect directly to the tree bus, and each hub functions as the

"root" of a tree of devices. This bus/star hybrid approach

supports future expandability of the network much better than a

bus (limited in the number of devices due to the broadcast

traffic it generates) or a star (limited by the number of hub

connection points) alone.


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Mesh Topology

Mesh topologies involve the concept of routes. Unlike

each of the previous topologies, messages sent on a mesh

network can take any of several possible paths from source to

destination. (Recall that even in a ring, although two cable

paths exist, messages can only travel in one direction.) Some

WANs, most notably the Internet, employ mesh routing. A mesh

network in which every device connects to every other is called

a full mesh. As shown in the illustration below, partial mesh

networks also exist in which some devices connect only

indirectly to others.


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NETWORKING DEVICES/CABLES

NETWORK DEVICES

Network Card

Often referred to NIC (network interface card), these are

used with PCs, Servers and printers to allow communication on

the network take place. Every single NIC has an address burned

onto a chip that sits on the card. This address is known as a

hardware or MAC address.


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Hub

The most basic piece of networking equipment is a hub. A

hub simply allows several networking devices to speak to each

other. Each device plugs into a port on the hub. The simplest

network you can build will be with some PCs connecting into a

hub. Hubs have no memory or hard drive so they can never

remember which device is plugged into which port. This causes a

lot of unnecessary traffic to pass on the network.


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Router

A router can be considered to be a large directory of

networks. Rather than concerning itself about which PC is

where, a routers job is to find out where different networks

are. It then sends the traffic via the best path, be it the

fastest, most reliable or shortest. If the router does not know

how to get to its intended destination it will either drop the

packet or forward it to another router who should know how to

get there.

It is important to remember that by default, routers do

not forward broadcasts. If they did we would find that most

networks including the internet would be extremely slow because

of all the broadcasts passing across them.


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Bridge

A data-link bridge is a device that connects two similar

networks or divides one network into two. It takes frames from

one network and puts them on the other, and vice versa. As it

does this, it regenerates the signal strength of the frames,

allowing data to travel further. In this sense, a data-link

bridge incorporates the functionality of a repeater, which also

regenerates frames to extend a LAN. But a bridge does more than

a repeater. A bridge is more intelligent than a repeater. It

can look at each frame and decide on which of the two networks

it belongs. Repeaters simply forward every frame from one

network to the other, without looking at them.

A bridge looks at each frame as it passes, checking the

source and destination addresses. If a frame coming from

Station 1 on LAN A is destined for Station 5 on LAN B, thebridge will pass the frame onto LAN B. If a frame coming from

Station 1 on LAN A is destined for Station 3 on LAN A, the

bridge will not forward it; that is, it will filter it.


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Bridges know which frames belong where by looking at the

source and destination addresses in the Medium Access Control

(MAC) layer information carried in the frame. The MAC layer,

which is part of the second layer of OSI Model, defines howframes get on the network without bumping into each other. It

also contains information about where the frame came from and

where it should go. Because bridges use this level of

information, they have several advantages over other forms of

interconnecting LANs.


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Repeaters

Repeaters connect multiple network segments together. They

amplify the incoming signal received from one segment and send

it on to all other attached segments. This allows the distance

limitations of network cabling to be extended. There are limits

on the number of repeaters which can be used. The repeater

counts as a single node in the maximum node count associated

with the Ethernet standard [30 for thin coax].

Repeaters also allow isolation of segments in the event of

failures or fault conditions. Disconnecting one side of a

repeater effectively isolates the associated segments from the

network. Using repeaters simply allows you to extend your

network distance limitations. It does not give you any more

bandwidth or allow you to transmit data faster.


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Gateway

A node on a network that

serves as an entrance to another

network. In enterprises, the gateway

is the computer that routes the

traffic from a workstation to the

outside network that is serving the

Web pages. In homes, the gateway is

the ISP that connects the user to

the internet. In enterprises, the

gateway node often acts as a proxyserver and a firewall. The gateway

is also associated with both a

router, which use headers and

forwarding tables to determine where

packets are sent, and a switch,

which provides the actual path for

the packet in and out of the

gateway.

A computer system located on

earth that switches data signals and

voice signals between satellites and

terrestrial networks.

An earlier term for router,

though now obsolete in this sense as

router is commonly used.


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Firewall

A system designed to prevent unauthorized access to or

from a private network. Firewalls can be implemented in both

hardware and software, or a combination of both. Firewalls are

frequently used to prevent unauthorized Internet users from

accessing private networks connected to the Internet,

especially intranets. All messages entering or leaving the

Intranet pass through the firewall, which examines each message

and blocks those that do not meet the specified security

criteria.


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NETWORK CABLE

Cable is the medium through which information usually

moves from one network device to another. There are severaltypes of cable which are commonly used with LANs. In somecases, a network will utilize only one type of cable, othernetworks will use a variety of cable types. The type of cablechosen for a network is related to the network's topology,protocol, and size. Understanding the characteristics ofdifferent types of cable and how they relate to other aspectsof a network is necessary for the development of a successfulnetwork.

The following sections discuss the types of cables used innetworks and other related topics.

Unshielded Twisted Pair (UTP) Cable

Shielded Twisted Pair (STP) Cable

Coaxial Cable

Fiber Optic Cable

Wireless LANs

Installing Cable - Some Guidelines


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Unshielded Twisted Pair (UTP) Cable

Twisted pair cabling comes in two varieties: shielded andunshielded. Unshielded twisted pair (UTP) is the most popular

and is generally the best option for school networks (See fig.

1).

Fig. 1 Unshielded Twisted Pair


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The quality of UTP may vary from telephone-grade wire toextremely high-speed cable. The cable has four pairs of wires

inside the jacket. Each pair is twisted with a differentnumber of twists per inch to help eliminate interference from

adjacent pairs and other electrical devices. The EIA/TIA(Electronic Industry Association/Telecommunication Industry

Association) has established standards of UTP and rated five

categories of wire.

Categories of Unshielded Twisted Pair

TYPE USE

CATEGORY 1 Voice Only (Telephone Wire)

CATEGORY 2 Data to 4 Mbps (Local Talk)

CATEGORY 3 Data to 10 Mbps (Ethernet)

CATEGORY 4 Data to 20 Mbps (16 Mbps Token Ring)

CATEGORY 5 Data to 100 Mbps (Fast Ethernet)


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One difference between the different categories of UTP isthe tightness of the twisting of the copper pairs. The tighterthe twisting, the higher the supported transmission rate andthe greater the cost per foot. Buy the best cable you canafford; most schools purchase Category 3 or Category 5.Category 5 cable is highly recommended.

If you are designing a 10 Mbps Ethernet network and areconsidering the cost savings of buying Category 3 wire insteadof Category 5, remember that the Category 5 cable will providemore "room to grow" as transmission technologies increase. Bothcategory 3 and category 5 UTP have a maximum segment length of

100 meters. In Florida, Category 5 cable is required forretrofit grants. 10BaseT refers to the specifications forunshielded twisted pair cable (category 3, 4, or 5) carryingEthernet signals.


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Unshielded Twisted Pair Connector

The standard connector for unshielded twisted pair cabling

is an RJ-45 connector. This is a plastic connector that looks

like a large telephone-style connector (See fig. 2). A slot

allows the RJ-45 to be inserted only one way. RJ stands for

Registered Jack, implying that the connector follows a standard

borrowed from the telephone industry. This standard designates

which wire goes with each pin inside the connector.

Fig. 2 RJ-45 connector

Unshielded Twisted Pair cable used

in Category 5 looks like:


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Category 5 cable uses 8 wires. The length of exposed wires is very

critical; the standard limits this to less than 1/2" an inch. The

various jack connectors look like:

The patch cord which connects the workstation to the wall jack looks like:

In 10BaseT, each PC is wired back to a central hub using its own cable.

There are limits imposed on the length of drop cable from the PC network

card to the jack, the length of the horizontal wiring, and from the jack

to the wiring closet.

This is obviously a physical STAR configuration, in that

each PC is wired back to a central point (the Hub).


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Ethernet 10Base-T wiring specifies an 8 position

jack, but uses only two pairs.

TWISTED PAIR ETHERNET HORIZONTAL WIRING (Solid 24Awg)

PIN COLOR SIGNAL

1 White/orange Tx data +

2 Orange/white Tx data -

3 White/green Rx data +

4 Blue/white --

5 White/Blue --

6 Green/white Rx data -

7 White/brown --

8 Brown/white --


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Shielded Twisted Pair (STP) Cable

A disadvantage of UTP is that it may be susceptible to

radio and electrical frequency interference. Shielded twisted

pair (STP) is suitable for environments with electricalinterference; however, the extra shielding can make the cables

quite bulky. Shielded twisted pair is often used on networks

using Token Ring topology.

Coaxial Cable

Coaxial cabling has a single copper conductor at its

center. A plastic layer provides insulation between the center

conductor and a braided metal shield (See fig. 3). The metal

shield helps to block any outside interference from fluorescent

lights, motors, and other computers.

Fig.3. Coaxial cable


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Although coaxial cabling is difficult to install, it ishighly resistant to signal interference. In addition, it cansupport greater cable lengths between network devices thantwisted pair cable. The two types of coaxial cabling are: thickcoaxial and thin coaxial.

Thin coaxial cable is also referred to as thinnet. 10Base2refers to the specifications for thin coaxial cable carryingEthernet signals. The 2 refers to the approximate maximumsegment length being 200 meters. In actual fact the maximumsegment length is 185 meters. Thin coaxial cable is popular inschool networks, especially linear bus networks.

Thick coaxial cable is also referred to as thicknet.10Base5 refers to the specifications for thick coaxial cablecarrying Ethernet signals. The 5 refers to the maximum segmentlength being 500 meters. Thick coaxial cable has an extraprotective plastic cover that helps keep moisture away from thecenter conductor. This makes thick coaxial a great choice whenrunning longer lengths in a linear bus network. One

disadvantage of thick coaxial is that it does not bend easilyand is difficult to install.


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Coaxial Cable Connectors

The most common type of connector used with coaxial cables

is the Bayone-Neill-Concelman (BNC) connector (See fig. 4).

Different types of adapters are available for BNC connectors,

including a T-connector, barrel connector, and terminator.

Connectors on the cable are the weakest points in any network.

To help avoid problems with your network, always use the BNC

connectors that crimp, rather than screw, onto the cable.

Fig.4. BNC

connector


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Fiber Optic Cable

Fiber optic cabling consists of a center glass core

surrounded by several layers of protective materials (See fig.

5). It transmits light rather than electronic signals,

eliminating the problem of electrical interference. This makes

it ideal for certain environments that contain a large amount

of electrical interference. It has also made it the standard

for connecting networks between buildings, due to its immunity

to the effects of moisture and lighting.

Fiber optic cable has the ability to transmit signals

over much longer distances than coaxial and twisted pair. It

also has the capability to carry information at vastly greater

speeds. This capacity broadens communication possibilities to

include services such as video conferencing and interactive

services. The cost of fiber optic cabling is comparable tocopper cabling; however, it is more difficult to install and

modify. 10BaseF refers to the specifications for fiber optic

cable carrying Ethernet signals.

Fig.5. Fiber optic cable


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Facts about fiber optic cables:

Outer insulating jacket is made of Teflon or PVC.

Kevlar fiber helps to strengthen the cable and prevent

breakage.

A plastic coating is used to cushion the fiber center.

Center (core) is made of glass or plastic fibers.

Fiber Optic Connector

Fiber Optic Connector

The most common connector used with fiber optic cable is

an ST connector. It is barrel shaped, similar to a BNC

connector. A newer connector, the SC, is becoming more

popular. It has a squared face and is easier to connect in a

confined space.

Ethernet Cable Summary

Specification Cable Type Maximum length

10BaseT Unshielded Twisted

Pair

100 meters

10Base2 Thin Coaxial 185 meters

10Base5 Thick Coaxial 500 meters

10BaseF Fiber Optic 2000 Meters


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Installing Cable - Some Guidelines

When running cable, it is best to follow a few simplerules:

Always use more cable than you need. Leave plenty ofslack.

Test every part of a network as you install it. Even ifit is brand new, it may have problems that will bedifficult to isolate later.

Stay at least 3 feet away from fluorescent light boxesand other sources of electrical interference. If it is necessary to run cable across the floor, overthe cable with cable protectors.

Label both ends of each cable.

Use cable ties (not tape) to keep cables in the samelocation together


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NETWORK CONNECTIONS

Wired Network

The most common type of network connection is a wired

connection. This is the jack in the wall that you plug your

computer into for network access. Usually these jacks are

labelled with a room number followed by a sequence number and

are near the telephone jack. The network jack is similar in

shape to the phone jack in your home only bigger. Phone jacks

at Missouri State University are also the larger size and they

are usually white or beige in color. Network jacks, however,

are usually orange (for older wiring) or yellow.


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Wireless Network

Wireless data networks exist in such number and variety as to

be difficult to categorize and compare.

Some wireless data networks run over wireless voice networks,such as mobile telephone networks. CPDP, HSCSD, PDC-P, and GPRS are

examples. Other wireless networks run on their own physical layer

networks, utilizing anything from antennas built into handlheld

devices to large antennas mounted on towers. 802.11, LMDS, and MMDS

are examples. A few wireless networks are intended only to connect

small devices over short distances. Bluetooth is an example.

Wireless networks which run over other wireless networks oftenutilize the lower layer networks to provide security and

encryption. Stand-alone wireless networks either provide their own

security and encryption features or rely upon VPN's (Virtual

Private Networks) to provide those features. In many cases,

multiple layers of security and encryption may be desirable.

Some wireless networks are fixed, meaning that antennas do not

move frequently. Other wireless networks are mobile, meaning thatthe antenna can move constantly. This is sometimes a feature of the

specific implementation and antenna design, instead of an inherent

limitation of the wireless network specification.

Wireless networks may operate on licensed or unlicensed

portions of the frequency spectrum.


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Some Types of Wireless Network:

Bluetooth

Bluetooth technology is named after Harald Bluetooth, a Danish

king who managed to consolidate Denmark and a part of Norway in the

1900s. The choice for the name of this technology is a

manifestation of how influential and central the companies from

this region are to the telecommunications industry.

Bluetooth is a networking technology that does not rely on

user control or large amounts of power. By keeping the transmission

power to an extremely low setting (1 milliwatt), Bluetooth is ideal

for mobile battery operated devices. Moreover, Bluetooth does not

rely on the user since it can automatically detect and communicate

with other Bluetooth devices without any user input.

Bluetooth technology relies on two things, a radio frequency

technology and the protocol software enabling it to transmit data

to other devices. Bluetooth-capable devices can transmit data to

other devices not within the line of sight of the user. It also

enables different devices to communicate using certain rules suchas the amount of data that will be sent, the type of communication

between the devices and the radio frequency or frequencies this

communication will take place. These protocols ensure that

Bluetooth devices experience the least amount of interference from

other Bluetooth capable objects while communicating with each

other.


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Wi-fi

Wi-Fi is a trademark of the Wi-Fi Alliance for certified

products based on the IEEE 802.11 standards. This certification

warrants interoperability between different wireless devices.In some countries the term Wi-Fi is often used by the

public as a synonym for IEEE 802.11-wireless LAN (WLAN).

Not every IEEE 802.11 compliant device is certified by the

Wi-Fi Alliance, which may be because of certification costs

that must be paid for each certified device type. The lack of

the Wi-Fi logo does not imply that a device is incompatible to

certified Wi-Fi-devices.

Wi-Fi is used by most personal computer operating systems,

many video game consoles, laptops, smartphones, printers, and

other peripherals.


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Infrared

IR data transmission is also employed in short-range communication

among computer peripherals and personal digital assistants. These

devices usually conform to standards published by IrDA, the InfraredData Association. Remote controls and IrDA devices use infrared light-

emitting diodes (LEDs) to emit infrared radiation which is focused by a

plastic lens into a narrow beam. The beam is modulated, i.e. switched on

and off, to encode the data. The receiver uses a silicon photodiode to

convert the infrared radiation to an electric current. It responds only

to the rapidly pulsing signal created by the transmitter, and filters

out slowly changing infrared radiation from ambient light. Infrared

communications are useful for indoor use in areas of high populationdensity. IR does not penetrate walls and so does not interfere with

other devices in adjoining rooms. Infrared is the most common way for

remote controls to command appliances.

Free space optical communication using infrared lasers can be a

relatively inexpensive way to install a communications link in an urban

area operating at up to 4 gigabit/s, compared to the cost of burying

fiber optic cable.

Infrared lasers are used to provide the light for optical fiber

communications systems. Infrared light with a wavelength around 1,330 nm

(least dispersion) or 1,550 nm (best transmission) are the best choices

for standard silica fibers.

IR data transmission of encoded audio versions of printed signs is

being researched as an aid for visually impaired people through the RIAS

(Remote Infrared Audible Signage) project.


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Microwave

Microwave communication is the transmission of signals via

radio using a series of microwave towers. Microwave

communication is known as a form of line of sightcommunication, because there must be nothing obstructing the

transmission of data between these towers for signals to be

properly sent and received.

Microwave communication takes place both analog and

digital formats. While digital is the most advanced form of

microwave communication, both analog and digital methods pose

certain benefits for users.


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DATABASE SYSTEM

A Database Management System (DBMS) is a set of computer

programs that controls the creation, maintenance, and the use

of the database of an organization and its end users. It allows

organizations to place control of organization-wide database

development in the hands of database administrators (DBAs) and

other specialists. DBMSs may use any of a variety of database

models, such as the network model or relational model. In largesystems, a DBMS allows users and other software to store and

retrieve data in a structured way. It helps to specify the

logical organization for a database and access and use the

information within a database. It provides facilities for

controlling data access, enforcing data integrity, managing

concurrency controlled, restoring database.


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DBMS Building Blocks

A DBMS includes four main parts: modeling language, data

structure, database query language, and transaction mechanisms:

Components of DBMS

DBMS Engine accepts logical request from the various other DBMS

subsystems, converts them into physical equivalent, and actually

accesses the database and data dictionary as they exist on a storage

device.

Data Definition Subsystem helps user to create and maintain the data

dictionary and define the structure of the files in a database.

Data Manipulation Subsystem helps user to add, change, and delete

information in a database and query it for valuable information.

Software tools within the data manipulation subsystem are most often

the primary interface between user and the information contained in

a database. It allows user to specify its logical information

requirements.

Application Generation Subsystem contains facilities to help usersto develop transactions-intensive applications. It usually requires

that user perform a detailed series of tasks to process a

transaction. It facilities easy-to-use data entry screens,

programming languages, and interfaces.

Data Administration Subsystem helps users to manage the overall

database environment by providing facilities for backup and

recovery, security management, query optimization, concurrency

control, and change management.


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Modeling Language

A data modeling language to define the schema of each

database hosted in the DBMS, according to the DBMS database

model. The four most common types of models are the: hierarchical model,

network model,

relational model, and

object model.

Inverted lists and other methods are also used. A given

database management system may provide one or more of the four

models. The optimal structure depends on the natural

organization of the application's data, and on the

application's requirements (which include transaction rate

(speed), reliability, maintainability, scalability, and cost).

The dominant model in use today is the ad hoc one embedded

in SQL, despite the objections of purists who believe this

model is a corruption of the relational model, since it

violates several of its fundamental principles for the sake of

practicality and performance. Many DBMSs also support the Open

Database Connectivity API that supports a standard way for

programmers to access the DBMS.


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Before the database management approach, organizations relied on

file processing systems to organize, store, and process data files. End

users became aggravated with file processing because data is stored in

many different files and each organized in a different way. Each file

was specialized to be used with a specific application. Needless to say,

file processing was bulky, costly and nonflexible when it came to

supplying needed data accurately and promptly. Data redundancy is an

issue with the file processing system because the independent data files

produce duplicate data so when updates were needed each separate file

would need to be updated. Another issue is the lack of data integration.

The data is dependent on other data to organize and store it. Lastly,

there was not any consistency or standardization of the data in a file

processing system which makes maintenance difficult. For all these

reasons, the database management approach was produced. Database

management systems (DBMS) are designed to use one of five database

structures to provide simplistic access to information stored in

databases. The five database structures are hierarchical, network,

relational, multidimensional and object-oriented models.

The hierarchical structure was used in early mainframe DBMS.Records relationships form a treelike model. This structure is simple

but nonflexible because the relationship is confined to a one-to-many

relationship. IBMs IMS system and the RDM Mobile are examples of a

hierarchical database system with multiple hierarchies over the same

data, RDM Mobile is a newly designed embedded database for a mobile

computer system. The hierarchical structure is used primary today for

storing geographic information and file systems.


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Data Structure

Data structures (fields, records, files and objects)

optimized to deal with very large amounts of data stored on a

permanent data storage device (which implies relatively slowaccess compared to volatile main memory).

Database Querry Language

A database query language and report writer allows users

to interactively interrogate the database, analyze its data and

update it according to the users privileges on data. It also

controls the security of the database. Data security preventsunauthorized users from viewing or updating the database. Using

passwords, users are allowed access to the entire database or

subsets of it called subschemas. For example, an employee

database can contain all the data about an individual employee,

but one group of users may be authorized to view only payroll

data, while others are allowed access to only work history and

medical data.

If the DBMS provides a way to interactively enter and

update the database, as well as interrogate it, this capability

allows for managing personal databases. However, it may not

leave an audit trail of actions or provide the kinds of

controls necessary in a multi-user organization. These controls

are only available when a set of application programs are

customized for each data entry and updating function.


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Transaction Mechanism

A database transaction mechanism ideally guarantees ACID

properties in order to ensure data integrity despite concurrent

user accesses (concurrency control), and faults (faulttolerance). It also maintains the integrity of the data in the

database. The DBMS can maintain the integrity of the database

by not allowing more than one user to update the same record at

the same time. The DBMS can help prevent duplicate records via

unique index constraints; for example, no two customers with

the same customer numbers (key fields) can be entered into the

database. See ACID properties for more information (Redundancyavoidance).


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SOFTWARE DEVELOPMENT

The largely growing body of software development organizations

implement process methodologies. Many of them are in the defense

industry, which in the U.S. requires a rating based on 'process models'

to obtain contracts.

The international standard for describing the method of selecting,

implementing and monitoring the life cycle for software is ISO 12207.

A decades-long goal has been to find repeatable, predictable

processes that improve productivity and quality. Some try to systematize

or formalize the seemingly unruly task of writing software. Others apply

project management techniques to writing software. Without project

management, software projects can easily be delivered late or over

budget. With large numbers of software projects not meeting their

expectations in terms of functionality, cost, or delivery schedule,effective project management appears to be lacking.

Organizations may create a Software Engineering Process Group

(SEPG), which is the focal point for process improvement. Composed of

line practitioners who have varied skills, the group is at the center of

the collaborative effort of everyone in the organization who is involved

with software engineering process improvement.


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Software Development Activities:

1. Planning

The important task in creating a software product is

extracting the requirements or requirements analysis. Customerstypically have an abstract idea of what they want as an end

result, but not what software should do. Incomplete, ambiguous,

or even contradictory requirements are recognized by skilled and

experienced software engineers at this point. Frequently

demonstrating live code may help reduce the risk that the

requirements are incorrect.

Once the general requirements are gleaned from the client,

an analysis of the scope of the development should be determined

and clearly stated. This is often called a scope document.

Certain functionality may be out of scope of the project

as a function of cost or as a result of unclear requirements at

the start of development. If the development is done externally,

this document can be considered a legal document so that if there

are ever disputes, any ambiguity of what was promised to the

client can be clarified.


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2. Design

Domain Analysis is often the first step in attempting to design a

new piece of software, whether it be an addition to an existing software, a

new application, a new subsystem or a whole new system. Assuming that thedevelopers (including the analysts) are not sufficiently knowledgeable in

the subject area of the new software, the first task is to investigate the

so-called "domain" of the software. The more knowledgeable they are about

the domain already, the less work required. Another objective of this work

is to make the analysts, who will later try to elicit and gather the

requirements from the area experts, speak with them in the domain's own

terminology, facilitating a better understanding of what is being said by

these experts. If the analyst does not use the proper terminology it islikely that they will not be taken seriously, thus this phase is an

important prelude to extracting and gathering the requirements.

Specification - Specification is the task of precisely describing the

software to be written, possibly in a rigorous way. In practice, most successful

specifications are written to understand and fine-tune applications that were already

well-developed, although safety-critical software systems are often carefully specified

prior to application development. Specifications are m ost important for exter nal

interfaces that must remain stable. A good way to determine whether the specifications

are sufficiently precise is to have a third party review the documents making sure that

the requirements and Use Cases are logically sound.

Architecture - The architecture of a software system or software architecture

refers to an abstract representation of that system. Architecture is concerned with

making sure the software system will meet the requirements of the product, as well as

ensuring that future requirements can be addressed. The architecture step also

addresses interfaces between the software system and other software products, as well

as the underlying hardware or the host operating system.


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3. Implementation, testing and documenting

Implementation is the part of the process where software

engineers actually program the code for the project.

Software testing is an integral and important part of the

software development process. This part of the process ensures

that bugs are recognized as early as possible.

Documenting the internal design of software for the

purpose of future maintenance and enhancement is done throughout

development. This may also include the authoring of an API, be itexternal or internal.


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4. Deployment andMaintenance

Deployment starts after the code is appropriately tested, is approved

for release and sold or otherwise distributed into a production environment.

Software Training and Support is important because a large percentage of

software projects fail because the developers fail to realize that it doesn't

matter how much time and planning a development team puts into creating software

if nobody in an organization ends up using it. People are often resistant to

change and avoid venturing into an unfamiliar area, so as a part of the

deployment phase, it is very important to have training classes for new clients

of your software.

Maintenance and enhancing software to cope with newly discoveredproblems or new requirements can take far more time than the initial development

of the software. It may be necessary to add code that does not fit the original

design to correct an unforeseen problem or it may be that a customer is

requesting more functionality and code can be added to accommodate their

requests. It is during this phase that customer calls come in and you see whether

your testing was extensive enough to uncover the problems before customers do. If

the labor cost of the maintenance phase exceeds 25% of the prior-phases' labor

cost, then it is likely that the overall quality, of at least one prior phase, ispoor. In that case, management should consider the option of rebuilding the

system (or portions) before maintenance cost is out of control.

Bug Tracking Systemtools are often deployed at this stage of the

process to allow development teams to interface with customer/field teams testing

the software to identify any real or perceived issues. These software tools, both

open source and commercially licensed, provide a customizable process to acquire,

review, acknowledge, and respond to reported issues.


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GROUP 1

MEMBERS

JAIME ARDEN E. OLBES

ALGIE G. ALBURO

JOSE LEO D. DICHOSO

ARVIE PHILLIP A. LUDOVICE

TRISHIA MAE A. GROSPE

KEVIN E. ESPINEDA

ALBERT D. ESPINAS

ARNULFO M. VIRTUCIO

ERNUEL RIGIE Q. REMPILLO

RONNEL C. LORENZO


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Thats All

Folks!

ICT Fundamentals Report

Documents

Transcript of ICT Fundamentals Report