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Computer-based IS
IS that uses computer and communication technology to perform tasks
Basic component: Hardware Software Database Telecommunication Procedures People
Hardware
Physical component of computer system
System unit and motherboard are used to support and tie other components together
Consists of: Input device▪ Capture and translate data into a form that
can be processed and used by other parts of computer▪ Eg: keyboard, pointing device, bar code
scanner
Computer is composed of the CPU and internal memory▪ CPU is the chip that performs the instructions
received from software▪ Internal memory/Random Access Memory is a
temporary memory that hold software instruction and information for CPU▪ To permanently store info and recall them,
information need to be store in secondary storage device/external memory
Output device▪ Provide copies of data and information on
paper, video screen, etc. Modems▪ Input or output device that allow a computer
to transfer data between each other.
Software
Set of instructions Eg: computer code that hardware
devices carry out to process info Software is fundamental to computer Database software is a software that
allows you to arrange, modify and extract data from a database to create info
Telecommunication & Network
Telecommunication is a vital computer based tool to help communicate information to people in other location
Computer network through the use of communication technology can share resources such as storage database and processing power
Can send and receive information through network
People
Integral part of Information System Includes management and end user Manager use information to make
decisions End user supply data to Information
System and receive info from Information System
Procedure
A series of steps undertaken in a prescribed manner to accomplish a certain job
Human activities requiring people to interact with other components of IS
Can be written in form of manual or documentation such as diagram
When procedures are embodied in computer program, they are considered part of Information Technology component
Developing Information System
System development lifecycle is a series of recommended steps or phases designed as guideline as to what you should do and when you should do it
Actual number of phases and the name given to each phase differs from one organisation to another
It is simplified by combining some of the phases
The phases have a defined product or deliverable
Deliverables can be used to monitor productivity and quality of activities performed
Phases may have more than one deliverable
Phases of System Development Life Cycle
SDLC use to organize activities needed to build a system
Assist management by providing reports on project status and keeping track of resource need
Consist of:1. System planning
i. Prior to developing Information System, long term and short term planning must be done to prevent poor analysis and design of new system
ii. Preliminary investigation is a brief study of the problem.
iii. Output of this step is the project goal, scope and boundary and the terms of reference of the project
iv. May include any restrictions such as part of existing system which cannot be changed, etc
v. Also include rough idea of resource requirement of next phases
vi. The objective of IS project mgt is to deliver a system that is acceptable to users and develop within time and budget
vii. IS project mgt is the process of planning, scheduling and controlling the activities during the SDL
2. System analysisi. Is the detail understanding of
important features of system under investigation
ii. Include finding out how the existing system works, problems and the user requirement of the new system
iii. Determining accurate user information needs and system requirements is important because the design of new system will be based on these determined requirement
3. System designi. Information need and system requirement in
system analysis are studied in more detailii. Can be divided into general and detail
system design▪ At the end of general system design, we will know
what we need to develop and may include what software to use
▪ Detail system design/physical system design is the ext of general design.
▪ During this design, input, output, interface, database, network, programme and control are defined and documented
4. System construction and implementationi. During system construction, the individual
system components are builtii. New programs and changes to existing
program are written and testediii. During implementation, the component built
during construction are put into operational use
iv. After the new system is completed and working, post implementation review is performed to evaluate the new system and suggest minor changes to be made
5. System maintenancei. To eliminate errors in the systemii. Implies that there is continuous
improvement of the new system implemented
Structured Dev Vs Object Oriented Dev
Structured Development Employs a variety of diagrams and
documentations for describing the requirement of IS
Eg: DFD, ERD and structured diagram Involve users in developing the IS User need to participate in the analysis and
design process as they are the people who use the system
Emphasis on logical system design Major critics: takes too long and require too much
documentations
Object-Oriented Development System developer first define the object
needed in the new or revised IS If object already exist, they are reused. If
not they will select an existing object that is closed to the one needed and then modify the existing object as necessary
Unified Modeling Language (UML) is an object oriented programming language use to describe IS
IS Project Team
End user People who directly interact with IS Supply data to IS and receive info from IS
Business analyst Analyses the business aspects and issues
surrounding the IS identifying how they will provide business value in creating, developing and designing new procedure and policies together with the system analyst
Will have business exp and some type of professional training
System analyst Focuses in IS issue surrounding the system by
identifying how IT can improve business processes, design the IS and the new business processes and ensure compliance with std
Responsible for planning, undertaking and coordinating overall dev activities
Likely to have significant training in analysis and design, programming and even areas of business
Infrastructure analyst Identify and implement infrastructure
changes on technical issues involve in how the system will interact with the org’s infrastructure – Eg: hardware, software, database, network
Likely has significant training and exp in database administration, networking and etc
Change management analyst Focuses on people and mgt issues surrounding
the IS installation The roles include ensuring that adequate
documentation and support is available to user, provide user training on the new system and developing strategies to overcome resistance to change
Likely have significant training and exp in organizational behavior in general and change mgt in particular