General IT Concepts

7/31/2019 General IT Concepts

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A system may be defined as a set of socia l, biological,technologica l or material partners co-operating on acommon purpose. System theory is a philosophicaldoctrine of describing systems as abstract organizationsindependent of substance, type, time and space. Systemstheories are connected to both ontological and

epistemological views. The ontological view imply thatthe world consist of systems or integrative levels. Theepistemological view implies a holistic perspectiveemphasizing the interplay between the systems and their

elements in determining their respective functions. It isthus opposed to more atomistic approaches in whichobjects are investigated as individual phenomena


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System theory everything that everything is a system in thesense that the concept system can be applied to everything ina meaningful and practical sense . Every thing is a system thatis composed of sub systems that interact to create that system

The name Information System Theory has previously beenused to describe theoretical computer science, whereby acomputer is a system that processes information, butinformation is far more general that just the contents of computer files or data structures. Every system is composedof information and it also processes information, regardless of

what form that information takes, whether its medium iscomputer files, light rays, particles of matter and so on.Information is simply discernible difference and may thereby manifest in any medium whatsoever.

www.iva.dk/jni/lifeboat_old/Positions/ Systems %20 theory .htm


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System analysis System: An organized relationship among the functioning units orcomponents, which work in sync to achieve a common goal.System Study: A study of operations of a set of connected elements andthe inter connections between these elements. It clearly shows that noone can ignore an element while doing a system study.System Approach: Shows a set of procedure to solve a particularproblem, It applies scientific methods to understand the interrelationship between the elements to solve the problem.System analysis: It is a management exercise, which helps us indesigning a new system or improving the existing system.Characteristics of a System1. Organization: It says the Structure or order of built.

2. Interaction: Procedure in which the components interact.3. Interdependence.4. Integration5. Central Objective


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Elements of System AnalysisThere are 4 basic elements of System analysis, they

are1. Outputs

Inputs : The essential elements of Inputs are

Accuracy of dataTimelinessProper formatEconomy.

3. Files4. Process


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Types of Systems1. Physical or abstract systems

2. Open or closed systems3. Deterministic or probabilistic4. Man made systems

Formal systems Organization

representationInformal systems Employee based systemComputer based information systems

Computer handling business applications.These are collectively known as ComputerBased Information systems (CBIS).


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A system architecture or systems architecture is the conceptualmodel that defines the structure, behavior, and more views of asystem.

Types of systems architecturesSeveral types of systems architectures (underlain by the samefundamental principles have been identified as follows

1. Collaborative Systems Architectures(such as the Internet,intelligent transportation systems, and joint air defense systems)

2. Manufacturing Systems Architectures3. Social Systems4. Software and Information Technology Systems(Architectures)

5. Strategic Systems Architecture[3]

6. Hardware architecture7. Software architecture8. Enterprise architecture


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www.Googlebooks.com
http://www.googlebooks.com/http://www.googlebooks.com/http://www.googlebooks.com/http://www.googlebooks.com/


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TimelinessTimeliness is the degree to which information is up-to-date. It can be seenin an objective fashion, meaning that information represents the current

state of the real world. Timeliness can also be seen as task-dependent,meaning that the information is timely enough to be used for a specific task.

Attributes of Information

Security Security has been identified as another important information quality dimension. If information is not secure, it can be easily intercepted by any intelligent opponent (e.g., terrorists, criminals) and used in a harmfulmanner. For example, if there is a huge fire that needs to draw police,medical and fire responders from surrounding areas, and if a criminalcomes to know this, (s)he can take undue advantage of this information:

Accessibility For information to be utilized in an effective manner, it must be accessible. Accessibility implies the degree to which information is available, easily obtainable or quickly retrievable when needed. But this availability of information to the users is generally within the constraints of policy andconfidentiality


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CompletenessCompleteness is the degree to which information is notmissing. Incomplete information can be hazardous.

However, complete information for one person may beincomplete for another

Accuracy Accuracy is the degree of correctness and precision with which information in an automatedsystem represents states of the real world

CoherenceCoherent information is what gels or blends with

itself consistently. Incoherent information canlead to confusion and panic during a disaster

RelevanceRelevancy is the extent to which information isapplicable and helpful for the task at hand.


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Validity

Information should be valid in the sense that it must be trueand verified; it must satisfy the set standards related to other

dimensions such as accuracy, imeliness, completeness andsecurity. The most common form of information validation isauditing. Auditing can uncover mistakes and is a good way tomeasure the quality of information (WhiteHouse, 2006).

Validity is a resultant rather than a causal dimension of information quality. This means that even though someinformation may be classified as being highly valid, it still may fall under poor quality information if other crucial dimensionslike accuracy, timeliness etc. is absent (H. Miller, 1996)...When indicators possess high degree of reliability and

validity, the data and information they generate is more usefulin continuously improving performance. Conversely, indicatorsthat are unreliable and invalid produce confusing, irrelevantand useless data and information while consuming preciousresources... (O'Leary, 2004)

http://www.som.buffalo.edu/isinterface/papers/IA%20_080917-1.pdf
http://www.som.buffalo.edu/isinterface/papers/IA%20_080917-1.pdfhttp://www.som.buffalo.edu/isinterface/papers/IA%20_080917-1.pdfhttp://www.som.buffalo.edu/isinterface/papers/IA%20_080917-1.pdfhttp://www.som.buffalo.edu/isinterface/papers/IA%20_080917-1.pdf


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Usability Delivery

11 Attributes of Information

Relevant Simple Flexible Economical

Timely Accessible Secure

Quality Accurate Verifiable Complete Reliable

James Hall AIS


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Role of Information in Business

Support for the business process andoperations: An 'Information System' helpsmanagers to conduct daily activities andfunctions properly. For example in a bank different activities, which involve but are notlimited to: account creation, the withdrawal of money, statement generation among others,the Information System helps mangers toconduct such activities accurately and in atimely manner


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Support for decision making in terms of employees and managers: An Information System will take data as an input and process itthus generating information. Managers can then use this

information for to better their organisation. As an example, anInformation System can analyse existing historical data aboutcustomers in a bank and generate information such as whichcustomers were 'good', which were 'bad' as well as other attributes,Managers could then use this information while deciding toprovide a loan for new customers, whether it be the restrictionsthereof, the amount the loan is for or even whether a loan can begiven at all support in making decision for competitiveadvantages. IS can give information like which items to launch in

which location by analysing data collected from different sourcessuch that company can have advantage by using these informationover their competitors . IS also can help business houses inconducting their business process differently than theircompetitors.http://wiki.answers.com/Q/What_is_the_strategic_role_of_an_information_system_
http://wiki.answers.com/Q/What_is_the_strategic_role_of_an_information_system_in_businesshttp://wiki.answers.com/Q/What_is_the_strategic_role_of_an_information_system_in_businesshttp://wiki.answers.com/Q/What_is_the_strategic_role_of_an_information_system_in_business


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Human Information Processing Theories

View of humanity Information Processing Theory views humansas information processing systems, with

memory systems (a stimulus) is inputted(sensed) and the brain then performs processessuch as comparing the information to

previously stored information (schemas),transforming information (encoding), or storinginformation in long-term memory.

http://en.wikipedia.org/wiki/Information

_processing_theory
http://en.wikipedia.org/wiki/Information_processing_theoryhttp://en.wikipedia.org/wiki/Information_processing_theoryhttp://en.wikipedia.org/wiki/Information_processing_theoryhttp://en.wikipedia.org/wiki/Information_processing_theory


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Executive Support System ("ESS") -is designed to helpsenior management make strategic decisions. It gathers,analyses and summarises the key internal and externalinformation used in the business . Uses what -if" analysis tohelp strategic decision-making.Management Information Systems- (MIS) is mainly concerned with internal sources of information. MIS usually take data from the transaction processing systems (see below)

and summarise it into a series of management reports.MISreports tend to be used by middle management andoperational supervisors.

Decision-Support System ("DSS") -are specifically

designed to help management make decisions in situations where there is uncertainty about the possible outcomes of those decisions. DSS comprise tools and techniques to helpgather relevant information and analyse the options andalternatives. DSS often involves use of complex spreadsheetand databases to create "what-if" models

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Knowledge Management Systems ("KMS")- exist to help businessescreate and share information. These are typically used in a business whereemployees create new knowledge and expertise - which can then be shared by other people in the organisation to create further commercialopportunities. Good examples include firms of lawyers, accountants andmanagement consultants. KMS are built around systems which allow efficient categorisation and distribution of knowledge. For example, theknowledge itself might be contained in word processing documents,spreadsheets, PowerPoint presentations. internet pages or whatever. Toshare the knowledge, a KMS would use group collaboration systems such as

an intranet.Transaction Processing Systems - As the name implies, TransactionProcessing Systems ("TPS") are designed to process routine transactionsefficiently and accurately. A business will have several (sometimes many)TPS; for example:

- Billing systems to send invoices to customers- Systems to calculate the weekly and monthly payrol l and tax payments- Production and purchasing systems to calculate raw materialrequirements- Stock control systems to process all movements into, within and out of

the business


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Office Automation Systems - Office AutomationSystems are systems that try to improve the productivity

of employees who need to process data and information.Perhaps the best example is the wide range of softwaresystems that exist to improve the productivity of employees working in an office (e.g. Microsoft Office2010) or systems that allow employees to work fromhome or whilst on the move.


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Hardware and Processors

Mainframes are large computers used forcentralized information systems.

Microcomputers or PCs are computers used by

one person. Processor (CPU) is where data processing is

performed. Processor speed is measured by the number of

cycles that occur per second.


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Processors

MHz stands for millions of cycles per second . Word is the measure of how many bits can be

moved with one cycle of the processor. Word size is how many characters, A, can be

moved in a single cycle of the processor. Power is affected by both word size and processor

speed.

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Table 5.1 Major Computer Components

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2007 by Prentice Hall

ManagementInformation Systems,

10/e Raymond McLeodand George Schell

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Memory and Storage Memory (primary storage or RAM ) is the

storage area on the computers circuit board. Volatile Extremely fast

Fixed storage is permanently installed in thecomputer.

Removable storage media tape, disk, CD,DVD, USB flash drive, etc.


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Microcomputer Circuit Board, also known as a Motherboard


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Personal Computers What is a desktop computer? Designed so the system unit,

input devices, output devices,and any other devices fitentirely on or under a desk or

table

p. 1.20 Fig. 1-23


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Personal Computers

What are some desktopcomputer variations?

Tower model

Tall andnarrow system unitthat can sit

on the floor vertically

p. 1.20 Fig. 1-23


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Personal Computers

What are some desktopcomputer variations? All-in-one computer

Less expensivedesktop thatcombines themonitor andsystem unitinto a singledevice

p. 1.21 Fig. 1-24


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Mid-Range Servers

What is a mid-rangeserver? More powerful and

larger than a

workstation computer Supports up to 4,000

users Often connected via a

personal computer orterminal Once known as a

minicomputerp. 1.25 Fig. 1-32


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Sometimes called dumbterminals

No processing power

Cannot stand alone Must be connected

to a server to operate

Mid-Range Servers What is a terminal?

Device with a monitor and keyboard used toaccess a server


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Mainframes What is a mainframe? Large, expensive,

very powerfulcomputer

Can handlehundreds orthousands of connected userssimultaneously

Stores tremendousamounts of data,

instructions, andinformation


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Company on the Cutting EdgeInternational Business Machines(IBM)

Incorporated in 1911

The first family of computers withinterchangeable software andperipherals

Worlds largest information technologycompany

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Personal Computing Devices Cell phones with interactive messaging and video

Smart cell phones are phones that perform tasksassociated with PCs, i.e., BlackBerry 7270, Treo650.

Global Systems for MobileCommunications (GSM) digital cellularphone protocol

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Home Networks Home computer networks assess the Internet via

cable modems or DSL modems .

Setup usually requires the modem, network card(s), wireless router.

Wireless security uses Wired equivalentprivacy ( WEP ) which encrypts the data

transferred between the computer and wirelessrouter.

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Home Computing Security Updates for OS and application software.

For security and efficiency

Microsoft Update Hackers are people who try to break into

computer systems in order to Gather information;

Deny the owner access to his resources; Delete files; Disrupt the use by the owner.

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Home Computing Security (Contd) Viruses are small computer programs that

replicate by inserting themselves into computerresources such as programs or files.

Worms are self-contained files or programs Does not have to attach to program or file.

Can delete, change files, send e-mails, and causeproblems.

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Home Computing Security (Contd) Denial-of-service attack is when the user is

denied access to the services of the computer because it is overwhelmed with e-mail.

Antivirus software Norton, MacAfee, etc.Keep virus definitions updated.

Spyware Microsoft Defender, Lavasoft Ad- Aware, etc. Free from Microsoft.

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Software System software (OS ) performs certain tasks

that all computers require. Hardware interfaces, device drivers Manage computers processes OS Windows XP, Unix, Mac OS X, Linux

Application software processes the users

data. Prewritten application software is

produced by suppliers and sold to users.

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Application Software Custom application software is when

programmers for the business write thesoftware.

User-written software in End-User Computing is created by the user, such asExcel Macros, Access Wizards.

User-friendly software is computer softwarethat is simple and intuitive to use.

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Communications Protocol is the specification for formatting data

to be transferred between communicationsequipment.

Public connections Telephone modems

Integrated Services Digital Network (ISDN) Digital Subscriber Line (DSL)

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Table 5.4 Connecting to the Internet

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Communications (Contd) Packet is a piece of the total data to be

communicated, includes sender and receiveraddresses.

Cable modems connect to the Internet viacoaxial cable.

Asynchronous transfer mode (ATM) Improve data transmission rates Provides increased speed

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Private Line Circuit is a connection that is always connected. Private line is a circuit that is always open to your communication traffic. T-1 line over 1.5 Mbps; T-3 at 43 Mbps Multiplexed is when the line is broken into

separate lanes of communication.

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Virtual Private Networks Virtual Private Networks (VPNs) allow you

to use the security and speed of a private line but

still use the low-cost Internet. Tunneling software establishes the set of intermediary locations of the telephoneequipment that will host a given data

communications transfer. Privacy is attained because the tunnel is notestablished unless the sending and receivingcomputers authenticate one another.

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Communications-Networks Open Systems Interconnection (OSI)-

standard architecture for network connections

established by the ISO. Terminal is a device that has no storage orprocessor; it allows for entering and displayingdata for the computer.

Systems Network Architecture (SNA) is aprotocol for large computers; it polls othercomputers connected by the network fortransfers.

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Table 5.5 OSI Reference Model

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Networks (Contd) Token ring is a peer-to-peer protocol that

allows each computer to act as its own

controller. Ethernet is an open protocol for peer-to-peercommunications. IEEE endorses

Data transmission crash is when two peercomputers try to send data at the same time.

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Figure 5.11 Token Ring ProtocolExample

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Networks (Contd) Data packet is a piece of the total data to be

communicated, combined with the address of

the destination computer, the sending computer,and other control information. Transmission Control Protocol/Internet

Protocol (TCP/IP )

TCP conducts communication over the network. IP handles the packets so they can be routed.

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Networks (Contd) IP address is a four-part set of numbers (each

from 0 to 255), separated by periods.

Network interface card (NIC) is used toattach a device to the communications medium. Local Area Networks (LANs) is a group of

computers and other devices that are connected

together by a communications medium.

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Table 5.6 Communications NetworkHardware

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Networks (Contd) Medium used by LANs can be copper wire, wireless, fiber-optics, or other media.

LANs join computers that are physically locatedtogether. Same room or building Total distance is less than mile. 60 ft. between devices

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Networks (Contd) Metropolitan area network (MAN) is a

network that has a physical distance limit of

roughly 30 miles. Wide area networks (WANs) are used toconnect computers and other devices when thedistance exceeds the constraints of LANs and

MANs. Uses common carrier, public telephone system WANs have been replaced by the Internet.

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Internet, Intranet and Extranet Internet is just a collection of networks that

can be joined together; Public.

Intranet uses the same network protocols asthe Internet but limits accessibility to computerresources to a select group of persons in theorganization.

Extranet is when the intranet is expanded toinclude users beyond the firm; Trustedcustomers and business partners.

San


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San MiguelBrewing

PlantManilaPlastic

Company

Maltsupplier San

MiguelBottling

Plant

SanMiguel

Purefoods

Customer


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NokiaHeadquarter

(Finland)Nokia

Philippines

SunMicroSyste

m Smart

Communications

Customer

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The Convergence of Computing andCommunications Computing devices and communications devices

are now incorporating features of the other intothemselves.

Voice over Internet Protocol ( VoIP ) is therouting of voice communications over theInternet as if they were digital communications. WWW.SKYPE.COM free software
http://www.skype.com/http://www.skype.com/


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Network Topologies


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General IT Concepts

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