1 System System is an aggregate of two or more physical components and a set of disciplines or procedures by means of which they interact. zA set of

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System

System is an aggregate of two or more physical components and a set of disciplines or procedures by means of which they interact.

A set of elements or components that are formed and interact to accomplish goals or objective.

A subsystem is system component that is a system in its own right.

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Basic System Elements

InputOutputProcessFeedback

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System Block Diagram

Input Process Output

Feedback

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Input

Productive resources that can be defined as natural resources.

Input can be inform of raw materials, labor, capital, information, data, or any other phenomenon that carries some form of content.

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Output

The result of the production process.

It is the goal that the system has as

its purpose for existing.

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Process/Transformation

Process is the method by which the goal of the system is achieved.

Steps or operations the system goes through to converts inputs into outputs.

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Feedback

Information returned to an instigator of change that reflects the result of that change, allowing the originator to correct for undesired results.

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System Boundary

A system boundary defines what is inside and what is outside of the system.

The boundary separate the system from its environment.

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Environment of System

The environment is everything outside of a system’s boundaries that is pertinent to the system.

It contains the sources of inputs into the system and the recipients of outputs from the system.

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Boundary and Environment

Customer

Receive Mail

Process Order

Computer

Order

Confirmation

Availability

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Boundary and Environment

System receives inputs from its environment.

System returns output to its environment.

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Connections in a System

The connection in a system transmit the flows of material and information that coordinate the system’s components.

Connections are essential to all systems.

Without connections, the system would be a set of independent components that ignore each other.

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Control Mechanisms

The control mechanisms in a system are the rules and logic that govern the individual subsystems and the interactions among them.

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Example

Supplier

Design ServiceDeliver SellProduce

Customer

OrderPreferences

Servicerequest

Parts

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Systems Classification

Open or Closed

Simple or Complex

Stable or Dynamic

Permanent or Temporary

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Open System

Open system means they receive input from the environment and return output to the environment.

There is a flow of inputs and outputs across the system boundary.

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Closed System

There is no interaction with the environment within a closed system.

A closed system have sealed boundaries and neither receive inputs nor produce outputs

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Simple Systems

A simple system is one in which there are few elements or components and the relationship or interaction between elements is uncomplicated and straightforward.

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Complex System

A complex system is one in which there are many elements that are highly related and interconnected.

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Stable or Dynamic

Stable is one in which changes in the environment result in no change or little change in the system.

Dynamic system is one that undergoes rapid and constant change due to changes in its environment.

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Adaptive or Nonadaptive

An adaptive system is one that responds to a changing environment.

A nonadaptive system is one that does not change with a changing environment.

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Describing and Evaluating Systems

Cost of ownership The cost of implementing, operating,

and maintaining a system.Efficiency

The ratio between outputs and inputs for a particular task.

Delays Time lags between different things that

happen in a system.

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Capacity The amount of work a system can do.

Reliability The extent to which a system can

dependably remain in service.Complexity

How complicated a system is, based on the number of differentiated components, the number of interacting components, and the nature of interactions between components.

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Compatibility The extent to which the standards and

logic of one system is consistent with the standards and logic of another system.

Controllability The user’s ability to immediately

influence or change what a system does.

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Adaptability The user’s ability to modify a system

over time as business conditions or other requirements change.

Likelihood of operator error the likelihood of mistaken or incorrect

action by people who operate equipment or system.

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Types of Tasks

Structured So well understood that is possible to

specify exactly how to perform the task.Semi-structured

less well understood; information requirements and procedures are generally known, but some aspects of the task still rely on the performer’s judgment.

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Types of Tasks

unstructured poorly understood; can not specify

information to be used, the method of using the information, nor the criteria for judging performance of the task; relies heavily on the performer’s judgment.

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Information System (IS)

An information system is combination of work practices, information, people, and information technologies organized to accomplish goals in an organization. An airline reservation system travel

agents use to book flights for their customers.

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Computer Based IS (CBIS)

CBIS is an information system that uses computer systems, devices, and technology.

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CBIS consists of: hardware software database telecommunication people procedures

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hardware keyboard scanner magnetic ink characters reader central processing unit memory storage printer monitor

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Software programs and instruction given to the

computer

Database organized collection of facts and

information

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Telecommunication link computer systems together into

effective networks.Local-area Network (LANs)Wide-area Network (WANs)

People people who enter, process, and use data

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Procedures strategies policies methods etc

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Benefit of IS

Better serviceLess errorsHigher quality productsLess expensiveLess laborMore control over operations

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Modeling

Model is a copy of a physical structure or a concept that is designed to demonstrate certain characteristics of that physical structure or concept in accordance with the purposes of modeler.

Model is an abstraction or an approximation of reality.

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Types of Model

NarrativeVerbalPhysicalSchematicMathematicalAnalog

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Types of Model

Narrative verbal and written descriptions of reality

Verbal designed to convert thoughts and

concepts into language, to establish relationship and restrictions of real-world systems, and then to organize them.

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Types of Model

Physical a tangible representation of reality. a model designed to resemble a

physical reality, though not to behave in an analogous manner.

Schematic graphical representation of reality

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Types of Model

Mathematical arithmetic representation of reality. a symbolic manipulative representation

of reality designed to describe relationships among certain factor of the reality that it is designed to represent.

uses numerical representation to describe the reality in question.

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Types of Model

Analog a model that behaves in some manner

similar to the reality that it is designed to represent.

These type of model are useful in investigating and understanding physical phenomena. They often produce large amount of information.

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Modeling Process

Gather information.

Based on this information, reach conclusions about the nature, characteristics, and behavior of the reality to be modeled.

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Modeling Process

Determine an appropriate form of model; what elements are important degree of detail required

Build the model

Compare the model with reality to determine the degree to which the model actually approximate the reality.

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Modeling Process

Adjust the model as necessary to achieve the desired “fit”

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Exercise

Using the modeling process outlined develop a model for some real-world phenomenon in which you are interested. Go through the process and document your choices of form, method, and so forth.

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Problem Solving

Process of using information, knowledge, and intuition to solve a problem that has been defined previously.

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Problem Solving Process

Decision making intelligence design choice

ImplementationMonitoring

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Problem Solving Factors

ComplexityCompetitionSocial and political actionsTechnologyTime compressionDecision objectiveInternational aspects

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Characteristics of Data, Information, Knowledge

Distinguishing factorsTypes of dataAccuracy and precisionAge, timeliness, and time horizoncompleteness and level of

summarizationAccessibilitySourceValue and relevance

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Data, Information, Knowledge

Data data are facts, images, or sounds that

may or may not be to pertinent or useful for a particular task.

Information information is useful data whose form

and content are relevant and appropriate for a particular use.

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Data, Information, Knowledge

Knowledge knowledge is a combination of instincts,

ideas, rules, and procedures that guide actions and decisions.

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Relationship between Data, Information, Knowledge

Accumulateknowledge

Data

Format,Filter,

Summarize

Interpret,Decide,

ActResults

knowledge

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Type of Data

FormattedTextImagesAudioVideo

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Type of Data

Formatted Data formatted data include numerical or

alphabetical items arranged in a prespecified format in which the meaning of each item is defined in advance.

Text text is a series of letters, numbers, and other

characters whose combined meaning does not depend on a prespecified format or definition of individual items.

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Type of Data

Images images are data in the form of pictures,

which may be graphs generated from formatted data, photographs, or hand-draw pictures.

Audio audio is data in form of sounds.

Video video data combine pictures and sounds

that are displayed over time to portray action.

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Accuracy and Precision

Accuracy accuracy is the degree to which the

data portray what is supposed to be portrayed.

Precision precision is the fineness of detail in the

portrayal

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Age, Timeliness, and Time Horizon

Age the age of data is the amount of time that

has passed since the data were produced.Timeliness

timeliness is the extent to which the age of the data is appropriate for the task and user.

Time horizon the time horizon of data is the interval of

time that data cover.

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Completeness and Level of Summarization

Completeness completeness is the extent to which the

available information seems adequate for the task.

Level of summarization Level of summarization is comparison

between the number of individual items upon which data are based and the number of items in the data presented.

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Accessibility, and Source

Accessibility accessibility is the extent to which the

user can obtain the information in time to use it effectively and in a format that makes it useful.

Source source of data is the person or

organization that produced the data.

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Value and Relevance

Relevance relevance is the extent to which data

can be converted into information that helps a person do a job or make decisions.

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What Is a Computer?

Computer is a system.The computer, also called a

processor, is an electronic device that can interpret and execute programmed commands for input, output, computation, and logic operations.

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Computer System Components

Input devicesOutput devicesCPU- Central Processing Unit

Arithmetic Logic Unit (ALU) Control unit Registers

Storage

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Input devices keyboard microphone mouse scanner

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Output devices monitor printer audio speakers

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CPU-the portion of the computer system that controls execution of program instructions and the processing of data items.

Elements of CPU Arithmetic Logic Unit (ALU) Control unit Registers

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Storage-retention of programs or data on media such as: hard disks floppy disks compact disks tapes

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Types of Computers

Microcomputers personal computers workstations

Minicomputers Mainframe computersSupercomputers

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Types of Computers

Microcomputers PC-Personal Computer Laptop/ Notebook -a portable

microcomputer that weighs less than 12 pounds and can be fit into briefcase.

Palmtop- a pocket microcomputer that weighs less than 1 pounds and has limited function.

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Types of Computers

Minicomputers a computer that is smaller in capacity

and price than a mainframe but that delivers full-system capabilities.

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Types of Computers

Mainframe computers a large computer, so named because in

the past the main processing unit of this computer consisted of a series of circuit boards mounted within a frame structure.

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Types of Computers

Supercomputers the most expensive, largest computer;

can process over 1 billion instructions per second.

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Execution of an Instruction

Instruction Phase Fetch instruction Decode instruction

Execution Phase Execute the instruction Store result

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Primary Storage

Random access memory (RAM)Read only memory (ROM)Programmable ROM (PROM)Erasable PROM (EPROM)

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Data Manipulation

Representing and type of data bits and bytes standardized codes

ASCII-American Standard Coded for Information interchange

EBCDIC-Extended Binary Coded Decimal Interchange

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Storage Capacity

Storage capacity is measured in bytes A bit is a binary digit (0 or 1). Byte = 8 bit Word = 2 bytes = 16 bits Double word = 2 words = 4 bytes = 32

bits

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Boost speed

Miniaturization vacuum to transistors to integrated

circuit to microprocessorsReduce instruction set computing

(RISC)Parallel processingOptical processing

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Software

Software consists of computer programs that control the workings of the computer hardware, along with the program documentation used to explain the programs.

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Programs

Program Programs are set of instructions or

statements to the computer.Program documentation

Program documentation is the collection of narrative descriptions designed to assist in the program’s use, implementation, and operation.

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Program

Program code Program code is the set of instructions

that signal the CPU to perform circuit switching operations.

Programming Writing or coding instruction.

Programmer individual doing the writing or coding.

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Programming: a Translation Process

User

Idea of whatthe systemshould do

Writeprograms

Translate

Computer

Rules and limitation of programming language

Instructionthe computercan execute

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Types of Software

Application software tells the computer how to perform tasks

that structure or automate specific work practices.billing systemsinventory systems

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Types of Software

End-user software tells the computer how to perform tasks

that support general work practices such as writing memos and performing calculations.word processorsspreadsheet programsdatabase systems

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Types of Software

System development software helps analysts and programmers build

information system.compilersdatabase management systemCASE system (computer-aided software

engineering)

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Types of Software

System software controls or supports the operation of the

computer system so it can execute application software or end-user software.operating systemutility programs

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Testing Programs

Syntax errors incorrect use of the programming

language .Logical errors

bugs that cause a program to perform incorrect processing.

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Generation of programming languages

First Machine language

Second Assembly language

Third High-level language

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Generation of programming languages

Fourth Query and database languages

Fifth Object oriented language

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Operating System

Operating systems are complex programs that control the execution of other programs and use of computer system resources.

Operating system runs or control the computer hardware and acts as an interface with application programs.

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Operating Systems

Allocating resources and running jobs

Controlling jobs in progressControlling access to dataInterfacing with the user

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Criteria for Selecting Software

Fit to the business situationEase of useCompatibilityConversion requirementLong term direction

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SignalsPeriod (T)Frequency (f)Bandwidth (BW)Spectrum

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Periodic signal

A signal is periodic if and only if

s(t + T) = s(t) for all values of t

T is the period of the signal.

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Analog signal

An analog signal is a continuously varying electromagnetic wave that may be propagated over a variety of media, depending on spectrum.

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Digital signal

A digital signal is a sequence of voltage pulses that may be transmitted over a wire medium.

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Characteristics of a periodic signalAmplitude

instantaneous value of a signal at any time.

Frequency the inverse of the period (1/T), or the

number of repetition of the period per second; it is expressed in cycles per second, or hertz (Hz).

Phase measure of the relative position in time

within a single period of a signal.

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Spectrum and bandwidth

Spectrum of a signal is the range of frequencies that it contains.

Bandwidth of a signal is the width of the spectrum in which most of the energy in the signal is contained.

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Transmission

Data transmission occurs between transmitter and receiver over some transmission medium.

Transmission media may be classified as guided or unguided.

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Guided media

With guided media, the wave are guided along a physical path; example of guided media are:

twisted paircoaxial cableoptical fiber

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Unguided media

Unguided media provide a means for transmitting electromagnetic waves but do not guide them; examples are propagation through:

airvacuumseawater

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Direct link

The term direct link is used to refer to the transmission path between two devices in which signals propagate directly from transmitter to receiver with no intermediate devices, other than amplifier or repeaters used to increase signal strength.

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Point-to-Point

A guided transmission medium is point-to-point if it provides a direct link between two devices and those are the only two devices sharing the medium.

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Point-to-Point

Transmitter/receiver Medium

Amplifieror repeater

Medium Transmitter/

receiver

0 ormore

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Multipoint

In a multipoint guided configuration, more than two devices share the same medium.

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Multipoint

Transmitter/receiver

Medium Amplifieror repeater




Medium

0 or more

….

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Simplex transmission

In simplex transmission, signals are transmitted in only one direction; one station is transmitter and the other is receiver.

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Half-duplex transmission

In half-duplex transmission, both station may transmit, but only one at a time.

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Full-duplex transmission

In full-duplex transmission, both station may transmit simultaneously. In this case the medium is carrying signals in both direction.

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Telecommunication Devices

ModemsFax modemsSpecial purpose modemsMultiplexers

TDM FDM

Communication processors

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Telecommunication Carriers & Services

Common carriers AT&T MCI Sprint

Value added carriers Telnet SprintNet

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Switched Lines

Switched line is a standard telephone line that uses switching equipment to allow one transmission device to be connected to other transmission devices.

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Dedicated Line

Dedicated line is a line that provides a constant connection between two points.

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Private Branch Exchange

PBX is a communications system that can manage both voice and data transfer within a building and to outside lines.

PBX can store callsPBX can transfer callsPBX can serve as a connection

between different office devices

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Wide Area Telecommunication Service

WATs is a billing method for heavy users of voice band media.

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Integrated Services Digital Network

ISDN is a technology that uses existing common carrier lines to simultaneously transmit voice, video, and image data in digital form.

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Network Topology

RingBusStarHybridHierarchical

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Type of Networks

LANWAN

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Communication Protocol

Open System Interconnection (OSI)Transmission Control

Protocol/Internet Protocol (TCP/IP)System Network Architecture (SNA)EthernetX.400X.500

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SOI

Physical layer transmits the data from one node to

another.Data link layer

format the data into a record called a frame and performs error detection.

Network layer causes the physical layer to transfer the

frames from node to node.

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OSI

Transport layer enable the user and host nodes to

communicate with each other.Session layer

initiate, maintains, and end each session.Presentation layer

formats the data so that it can be presented to the user or the host.

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OSI

Application layer controls user input from the terminal

and executes the user’s application program in the host computer.

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Data Transfer Modes

Packet switchingFrame relayVoice over frame relayAsynchronous transfer mode (ATM)

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Internet

The internet is the world’s largest computer network.

It is a collection of interconnected networks, all freely exchanging information.

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Internet Protocol

The set of conventions used to pass packets from one host to another is known as the internet protocol (IP)

TCP (transport control protocol is widely used.

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Ways to connect to internet

LANSLIP ( serial line internet protocol) or

PPP (point to point protocol)On-line service

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World Wide Web (www)

WWW is a collection of over 30,000 independently owned computer that together as one in an internet service.

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Web Browser

Web browser creates a unique, hypermedia based menu on your computer screen that provide a graphical interface to the the Web.

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Hypermedia

Connects the data on pages, allowing users to access topics in whatever order they wish.

Allows you to bring up pictures, graphs and other displays with sound and motion.

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Web Search Engine

Web search engines take the place of the card catalog.

They are software programs that allow you to search for information on the Web.

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Intranet

An intranet is an internal corporate network built using internet and Web standards.

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Cryptography

Cryptography is the process of converting a message into a secret code and changing the encoded message back to regular text. (digital signature)

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Firewalls

The most popular method of preventing unauthorized access to corporate computer data to construct is known as a firewall.

Firewalls can be a set of filtering rules or specially configured hardware.

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Zone

edu = educational sitesmil = militarygov = governmentnet = networking organizationsnom = individualsorg = organizationcom = commercial

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Telnet and FTP

Logon to another computer and access its public files.

Copy a file from another computer to your computer.

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E-mail (store and forward)

To send text, binary files, sound, and images to others.

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Amplitude Shift Keying (ASK)

To encode binary data by varying the amplitude of signal.

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Frequency Shift Keying (FSK)

To encode binary data by varying the frequency of signal.

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Phase Shift Keying (PSK)

To encode binary data by transition or shift from one phase to another.

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Bit Synchronization

Coordination of signal measurement timing is called bit synchronization.

There are two methods of bit synchronization: Asynchronous Synchronous

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Asynchronous Bit Synchronization

Massages begin with a start bit so that the receiving device can synchronize its internal clock with the timing of the massage.

Asynchronous transmissions are normally short, and the end of message is signaled by a stop bit.

Media is idle and the sender’s and receiver’s clocks are not synchronized when no data is being transmitted.

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Synchronous Bit Synchronization

Clocks of the sender and receiver are synchronized by one of the following methods: guaranteed state change separate clock signal oversampling

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Baseband & Broadband Transmissions

Baseband: these transmission use the entire media bandwidth for a single channel. Most LAN use baseband signaling.

Broadband: these transmission provide the ability to divide the entire media bandwidth into multiple channels.

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Selecting NIC

Type of network Token Ring, Ethernet, ATM,…etc

Type of media coaxial cable, STP, UTP, fiber,…etc

Type of bus ISA, EISA, VESA,…etc

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Bus Architectures

ISA (Industry Standard Architecture) 8 bit and 16 bit bus (10MHz)

PCI (Peripheral Computer Interconnect) 32 bit or 64 bit bus

EISA (Extended Industry Standard Architecture) 32 bit bus built on the ISA architecture (33

MHz)

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Bus Architectures

MCA (Micro Channel Architecture) 32 bit bus. MCA can work in 16 or 32 bit

mode. (66MHz)

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Memory Requirement

Minimum RAM recommended for Windows NT Server is 16 MB.

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Memory Allocation

Operating system.Services.Processes.Programs.CPU functions.

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Estimating Memory Requirement

Minimum amount needed for Server operating system (16 MB) plus

Number of people who will be accessing the system at the same time plus

Average software requests per user.

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Hard Disk Capacity

Operating system files.Software files.Data and database files.User files.General public files.Utility files.Server management files.

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Fault Tolerance

Fault -tolerance options disk mirroring disk duplexing redundant array of inexpensive disks

(RAID)there are eight levels of RAID.

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Disk Mirroring

server

Controller

Secondarydrive

Primarydrive

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Disk Duplexing

server

Controller

Secondarydrive

Primarydrive

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Project

Set up a NIC in windows NT Server, once the NIC operating system are installed. Click Start button select Settings select Control Panel double click Network icon click Adapters tab click Add button

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Project

Notice the list of adapters that can be install

click Cancel click Cancel close the control Panel

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Windows NT networking Models

Workgroup.Client-server.Domain.

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Workgroup model is a decentralized networking model. All account administration is local to

each machine. Each machine maintains its own

account database

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Client-server model is a centralized networking model. All administration is centralized at

server. Clients can log on to a server via the

server’s account database and access resources associated with that server.

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NT domain model Allows administrators to group users. All administration is centralized to an NT

Server that has been designated as he primary domain controller (PDC).

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In NT domain model the account database that resides on the PDC is called Security Account Manager (SAM)

SAM database is copied to server that has been designated as Backup Domain Controllers (BDC)

Each domain need al least one server

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PDC contains the master copy of SAM for the entire domain and is the only server that can make changes to the database.

If there is more than one server in a domain, selected servers can be designated to keep a backup copy of the SAM.

PDC’s SAM database is read-write.

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Domain models: single domain single master domain multiple master domain complete trust domain

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Criteria for choosing Domain models: # of accounts (windows NT can support

up to 40,000 account). The geographic scope of your domain. How users ant resources will be defined

within the domain.

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Domain Trust Relationship

In situation where there are two or more domains, users can access domains other than their own through trust relationships set up by the network administrator.

Each trust relationship has two parties: trusted domain

granted access to resources

trusting domaingranting the access

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Example

A n organization has a main office and ten branches, each with its own file server and domain. Main office domain needs access to all branches, which is granted. Main office is trusted domain, and branches are the trusting domains

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Trust Relationships

One-way trust the trust relationship is not reciprocated.

One domain is trusted party, and the other is trusting

Two-way trust the trust relationship is reciprocated.

Universal trust two-way trust are set up among more than

two domain.

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Single Domain

Consists of a single domain.Easy to manage.Centralized administration.Good for small networks.Slow when supporting large # of

accounts.

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Single Domain

PDC BDC

User

User

User

Accounts and resources

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Single Master Domain

Several domain are controlled by master domain.

All account are in the master domain.

Other domains containing only resources, such as servers.

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All resources are located at resource domains and can be available to all users.

Resources are decentralized.Administrators in the resource domain

have control over their resources. All user account are centralized in a

master domain.

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Resourcedomain

Resourcedomain

Resourcedomain


Master domain

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Multiple Master Domain

Consists of multiple single master domain connected through two-way trust relationships.

Administration can be centralized or decentralized.

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Number of trusts (n) can be determined as follow:

n=M(M-1)+(R+M)M=# of master or accounts domainsR=# of resource domains

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Masterdomain

Masterdomain

Resourcedomain

Resourcedomain

Resourcedomain


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Complete Trust Domain

Accounts and resources are located in each domain.

Allows decentralized account management.

Each account can implement policies specific to their domain.

N(N-1)=n where N represents # of domain

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Complete Trust Domain

Accountresources

Accountresources

Accountresources

Accountresources

Documents

1 System System is an aggregate of two or more physical components and a set of disciplines or procedures by means of which they interact. zA set of