Chapter 10 A Menu Design Screen Design Performance

Chapter 10 A Menu Design, Screen Design, Performance Analysis, and Process Modeling

Chapter Objectives • Provide a checklist of issues to consider when selecting a system architecture • Describe servers, server-based processing, clients, and client-based processing • Explain client/server architecture, including tiers, cost-benefit issues, and performance • Compare in-house e-commerce development with packaged solutions 2

Chapter Objectives • Explain the difference between online and batch processing • Define network topology, including hierarchical, bus, ring, and star models 3

Chapter Objectives • Explain network protocols and licensing issues • Describe wireless networking, including wireless standards, topologies, and trends • Describe the system design specification 4

Introduction • An effective system combines elements into an architecture, or design, that is flexible, cost-effective, technically sound, and able to support the information needs of the business • System architecture translates the logical design of an information system into a physical structure that includes hardware, software, network support, and processing methods 5

System Architecture Checklist • Enterprise Resource Planning (ERP) – The objective of ERP is to establish a companywide strategy for using IT resources – Supply chain management (SCM) • Initial Cost and TCO – During the final design stage, you make decisions that will have a major impact on the initial costs and TCO for the new system – You should review all previous cost estimates 6

System Architecture Checklist • Scalability – Scalability, also called extensibility, refers to a system’s ability to expand, change or downsize easily to meet the changing need of a business enterprise – Especially important in implementing systems that are volume-rated, such as transaction processing systems 7

System Architecture Checklist • Web Integration – An information system includes applications – Web-centric architecture – Avoids many of the connectivity and compatibility problems that typically arise – E-marketplaces 8

System Architecture Checklist • Legacy System Interface Requirements – The new system might have to interface with one or more legacy systems – Interfacing a new system with a legacy system involves analysis of data formats and compatibility – The analyst must know if the new application eventually will replace the legacy system 9

System Architecture Checklist • Processing Options – In planning the architecture, designers also must consider how the system will process data - online or in batches – Provision must be made for backup and speedy recovery in the event of system failure 10

System Architecture Checklist • Security Issues – Security threats and defenses are a major concern to a systems analyst – The analyst must consider security issues that relate to system design specifications – Web-based systems introduce additional security concerns 11

Planning the Architecture • Servers – – Server Clients Mainframe architecture Server-based processing 12

Planning the Architecture • Clients – As PC technology exploded in the mid-1980 s and 1990 s, powerful microcomputers quickly appeared on corporate desktops – Users found that they could run their own word processing, spreadsheet, and database applications – Companies linked the stand-alone computers into networks 13

Planning the Architecture • Clients – Stand-Alone Computing – Local and wide area networks – Client-based processing 14

Client/Server Architecture • Overview 15

Client/Server Architecture • Client/Server Design Styles 16

Client/Server Architecture • Client/Server Performance Issues – In contrast to the centralized system, a client/server design separates applications and data – Distributed database management system (DDBMS) – The system is scalable, so new data sites can be added without reworking the system design – The system is less likely to experience catastrophic failure 17

Internet-Based Architecture • Corporate Portals – A corporate portal can provide access for customers, employees, suppliers, and the public • Cloud Computing – Effectively eliminates compatibility issues – Scaling on demand – Requires significantly more bandwidth 18

Processing Methods • Online Processing – Because it is interactive, online processing avoids delays and allows a constant dialog between the user and the system – Online processing also can be used with fileoriented systems 19

Processing Methods • Batch Processing – The IT operations group can run batch programs on a predetermined schedule, without user involvement, during regular business hours, at night, or on weekends – Require significantly fewer network resources than online systems 20

Processing Methods • Combined Online and Batch Processing 21

Network Models • The OSI Reference Model – The OSI model consists of seven layers – Each layer performs a specific function – Offers a set of design standards 22

Network Models • Network Protocols – In all cases, the network must use a protocol – Transmission Control Protocol/Internet Protocol (TCP/IP) – File Transfer Protocol (FTP) 23

Systems Design Completion • System Design Specification – A typical system design specification uses a structure similar to the following: 1. 2. 3. 4. 5. 6. Management summary System components System environment Implementation requirements Time and cost estimates Additional material 24

Systems Design Completion • User Approval – Users must review and approve the interface design, report and menu designs, data entry screens, source documents, and other areas of the system that affect them – Other IT department members also need to review the system design specification – When the system design specification is complete, you distribute the document to a target group of users, IT department personnel, and company management 25

Systems Design Completion • Presentations – The first presentation is to the systems analysts, programmers, and technical support staff members – Your next presentation is to department managers and users from departments affected by the system – The final presentation is for company management – Management might reach one of three decisions: proceed with systems development, perform additional work on the systems design phase, or terminate the project 26

Chapter Summary • An information system combines hardware, software, data, procedures, and people into a system architecture • The analyst must consider enterprise resource planning, initial cost and TCO, scalability, Web integration, legacy interface requirements, processing options, and security issues • An architecture requires servers and clients 27

Chapter Summary • Compared to file server designs, client/server systems are more scalable and flexible • In implementing a design, an analyst should consider e-commerce strategies, the availability of packaged solutions, and corporate portals, which are entrances to a multifunction Web site • The primary processing methods are online and batch processing 28

Chapter Summary • Networks allow the sharing of hardware, software, and data resources in order to reduce expenses and provide more capability to users • The way a network is configured is called the network topology • The system design specification presents the complete systems design for an information system 29