Chapter 9 Systems Objectives Implementation systems implementation phase
Chapter 9 : Systems Objectives Implementation ��������������������� (systems implementation phase( p ��������������������� p ����������� �(quality assurance) ����������� (software engineering) ����� p software BC 423 Systems Analysis and Design 2
Objectives ����� top-down ��� modular design p ����� cohesion ��� coupling, ������ structure chart ������������ program flowcharts ��� pseudo code �������� p ����������������������� unit testing, integration testing, ��� system testing p Systems ������������ BC 423 Analysis and Design 3 p
Software Quality Assurance Quality assurance ������������ IT function p ������������ (quality assurance) ������������������������ p Quality assurance ������� -: p n n n Inaccurate requirements : ����������� Design or coding errors : ������������� Faulty documentation : ������� BC 423 Systems Analysis and Design 6
Software Quality Assurance p Software engineering n ������������� software Solid design p Effective structure p Accurate documentation p Careful testing p Software Engineering Institute (SEI) p ������������ software-based systems p ����� Capability Maturity Model (CMM) ������������������������� BC 423 Systems Analysis and Design 7 n
Software Quality Assurance Capability Maturity Model (CMM, CMMI) BC 423 Systems Analysis and Design 8
Software Quality Assurance p International Organization for Standardization (ISO) n n Seeks to offer global consensus of what constitutes good management practices ISO 9000 -3 provides a quality assurance framework for developing and maintaining software BC 423 Systems Analysis and Design 11
Overview of Application Development p Planning the overall design strategy n p Develop programs and modules : ������ n p Use top-down (modular) approach and partition the system into subsystems and modules Design, code, test, and document Test the system : ����� n n n Link test System test Complete all documentation BC 423 Systems Analysis and Design The main steps in application development. 12
Overview of Application Development p Documentation review : ������ n Program designs are based on System design specification : �������� p DFDs p Process descriptions p Object models p Class diagrams p ERDs p Screen layouts p Report layouts p Source documents p Data dictionary entries p BC 423 Systems Analysis and Design 13
Structured Application Development p programmer ����� modules ������������ n p module �������������������������� top-down ��������� BC 423 Systems Analysis and Design 14
Structured Application Development p Structure charts n ������������ modules ����� p p n Control module Subordinate modules Chart symbols represent Module : �������������� �� p Data couple: �������� module p Control couple: �������������� ��� BC 423 Systems Analysis and Design p Condition : ���� p 15
Structured Application Development BC 423 Systems Analysis and Design 16
Structured Application Development p Cohesion and coupling n Cohesion : ����� (����� ( ������������ module ������������� p n module ����� function ��������������� Coupling : ������������������ modules Modules ������������� loosely coupled p If one module refers to internal logic contained in another module, those modules are tightly coupled p BC 423 Systems Analysis and Design 17
Structured Application Development BC 423 Systems Analysis and Design 18
Structured Application Development p Structure chart examples Initial design for a structure chart based on the sales promotion policy that was described in structured English A structure chart based on the Grading System DFD BC 423 Systems Analysis and Design 19
Structured Application Development p ��������� structure chart ����� DFDs ��� object models n ����� modules ������� (relationships( n ����� couples, loops, ��� conditions n ����� structure chart ��� data dictionary n BC 423 Systems Analysis and Design 20
DFDs for a sample Order System. The top DFD is Diagram 0; under it is Diagram 1. BC 423 Systems Analysis and Design A structure chart based the Order System DFDs 21
Other Structured Development Tools p Program flowcharts n ������������������ module ����� BC 423 Systems Analysis and Design 22
Other Application Development Tools p Pseudo code : ����� n n p �������������������������� ������������ Program Specification n n ������������������� BC 423 Systems Analysis and Design 23
Coding p p ����������� ���������������������� Many programming languages exist n n n Visual C++ Visual Basic SQL HTML Java BC 423 Systems Analysis and Design 24
Testing the Application p p p ������������������� ���������������� (syntax errors) ������������� (compile( �������������� (logic errors( n Techniques include desk checking, structured walkthrough, and code review The first step in testing is unit testing, followed by integration testing, and then system testing. BC 423 Systems Analysis and Design p ������� ��� 25
Documentation p ������������ p �������� n n Program Documentation : ������������� System Documentation : ������������� Operations Documentation : ������������� operator User Documentation : ������������� BC 423 Systems Analysis and Design 29
Documentation p Program Documentation n n ������������� (systems analysis) ������������� (systems implementation( ����������� (process descriptions) ��� report layouts Programmers �������������������������� ����� program documentation BC 423 Systems Analysis and Design 30
Documentation p System Documentation n System Documentation ������������� system documentation ������������� ��� (systems analysis) ������������ (systems design( ������ -: Data dictionary entries p Data flow diagrams p Object models p Screen layouts p Source documents p Systems request p BC 423 Systems Analysis and Design 31
Documentation p Operations Documentation n ������������� minicomputer ���� mainframe ���������� (centralized processing) ���������� batch ������������� ��� operator ������� run programs �������� program run sheet ������������� output ���� e-mail ������������� BC 423 Systems Analysis and Design 32
Documentation p User Documentation n Online Documentation ������������������������ ��IT p p Context-sensitive Help Interactive tutorials Hints and tips Hypertext ����������������������� ��(user manual( n ������������������������ http: //www. readyplanet. com/product_ready_website/ ����������� http//: www. software. worldmedic. com/smartdrugstore/posexpress/sm_drg_posexpress. html BC 423 ����������� Systems Analysis and Design n 34
Operational and Test Environments p Test environment : ���������� n p Programmer ���������������������� (test environment( The test environment versus the operational environment. ����������� Notice that access to the test environment is limited to IT staff, while the operational environment is restricted to users. ���� (test environment) ��������� n n Programs Procedures BC 423 Systems Analysis and Design 40
Operational and Test Environments p Operational environment : ������������ production environment n n ������������� IT ������������� ������� (live data) ������������������ BC 423 Systems Analysis and Design 41
Operational and Test Environments p Preparation of the operational environment : ������������ n ������������� -: Hardware and software configurations p Operating system programs and utilities p Telecommunication resources p n n �������� (feature) ���������������� BC 423 Systems Analysis and Design 42
Training p Outside Training Resources : ������������ n n �������������������������� ������ -: Consultants p Universities p Industry associations p Information management organizations p BC 423 Systems Analysis and Design 45
Training BC 423 Systems Analysis and Design 48
Data Conversion p p �������� (Data conversion) ���������������������������� (operational environment( ������������� -: n n n Automated conversion techniques : ���������������� Methods of exporting data to the new system: ���������������� Programs designed to extract and convert data : ���������������� Controls required to protect vulnerable data: ���������������� Verification of results by users: ���������������� BC 423 Systems Analysis and Design 50
System Changeover p p System changeover : ���������������������� ����� -: n n Direct Cutover Parallel Operation Pilot Operation Phased Changeover ��������������������� The four system changeover methods. ����������� BC 423 Systems Analysis and Design ������� p 51
System Changeover Relative risk and cost characteristics of the four changeover methods. BC 423 Systems Analysis and Design 52
Post-Implementation Tasks p ������������ -: n Post-Implementation Evaluation : n ������������ Report : ������������ BC 423 Systems Analysis and Design 57
Post-Implementation Evaluation Sample user evaluation form. The numerical scale allows easy tabulation of results. Following this section, the form provides space for open-ended comments and suggestions. BC 423 Systems Analysis and Design 61
Post-Implementation Evaluation p ������������������������ ����������� n n ������ IT �������� (internal auditor) ���������� (external auditor( BC 423 Systems Analysis and Design 64
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