Computer Organization and Architecture William Stallings 8 th Edition
Systems Analysis and Design 8 th Edition Chapter 10 System Architecture.
-
Upload
kathryn-hunt -
Category
Documents
-
view
213 -
download
0
Transcript of Systems Analysis and Design 8 th Edition Chapter 10 System Architecture.
![Page 1: Systems Analysis and Design 8 th Edition Chapter 10 System Architecture.](https://reader033.fdocuments.in/reader033/viewer/2022042822/56649e4e5503460f94b459ef/html5/thumbnails/1.jpg)
Systems Analysis and Design 8th Edition
Chapter 10System Architecture
![Page 2: Systems Analysis and Design 8 th Edition Chapter 10 System Architecture.](https://reader033.fdocuments.in/reader033/viewer/2022042822/56649e4e5503460f94b459ef/html5/thumbnails/2.jpg)
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
2
![Page 3: Systems Analysis and Design 8 th Edition Chapter 10 System Architecture.](https://reader033.fdocuments.in/reader033/viewer/2022042822/56649e4e5503460f94b459ef/html5/thumbnails/3.jpg)
System Architecture Checklist
• Enterprise Resource Planning (ERP)– The objective of ERP is to establish a company-wide strategy for
using IT resources– Supply chain management (SCM)
• Faster response, better customer service, and lower costs
• 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
3
![Page 4: Systems Analysis and Design 8 th Edition Chapter 10 System Architecture.](https://reader033.fdocuments.in/reader033/viewer/2022042822/56649e4e5503460f94b459ef/html5/thumbnails/4.jpg)
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
4
![Page 5: Systems Analysis and Design 8 th Edition Chapter 10 System Architecture.](https://reader033.fdocuments.in/reader033/viewer/2022042822/56649e4e5503460f94b459ef/html5/thumbnails/5.jpg)
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
5
![Page 6: Systems Analysis and Design 8 th Edition Chapter 10 System Architecture.](https://reader033.fdocuments.in/reader033/viewer/2022042822/56649e4e5503460f94b459ef/html5/thumbnails/6.jpg)
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
6
![Page 7: Systems Analysis and Design 8 th Edition Chapter 10 System Architecture.](https://reader033.fdocuments.in/reader033/viewer/2022042822/56649e4e5503460f94b459ef/html5/thumbnails/7.jpg)
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
7
![Page 8: Systems Analysis and Design 8 th Edition Chapter 10 System Architecture.](https://reader033.fdocuments.in/reader033/viewer/2022042822/56649e4e5503460f94b459ef/html5/thumbnails/8.jpg)
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
8
![Page 9: Systems Analysis and Design 8 th Edition Chapter 10 System Architecture.](https://reader033.fdocuments.in/reader033/viewer/2022042822/56649e4e5503460f94b459ef/html5/thumbnails/9.jpg)
Planning the Architecture
• Servers– Server– Clients– Mainframe architecture– Server-based processing
9
![Page 10: Systems Analysis and Design 8 th Edition Chapter 10 System Architecture.](https://reader033.fdocuments.in/reader033/viewer/2022042822/56649e4e5503460f94b459ef/html5/thumbnails/10.jpg)
Planning the Architecture
• Clients– As PC technology exploded in the mid-1980s and
1990s, 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
10
![Page 11: Systems Analysis and Design 8 th Edition Chapter 10 System Architecture.](https://reader033.fdocuments.in/reader033/viewer/2022042822/56649e4e5503460f94b459ef/html5/thumbnails/11.jpg)
Planning the Architecture
• Clients– Stand-Alone Computing– Local and wide area
networks– Client-based processing
11
![Page 12: Systems Analysis and Design 8 th Edition Chapter 10 System Architecture.](https://reader033.fdocuments.in/reader033/viewer/2022042822/56649e4e5503460f94b459ef/html5/thumbnails/12.jpg)
Client/Server Architecture
• Overview
12
![Page 13: Systems Analysis and Design 8 th Edition Chapter 10 System Architecture.](https://reader033.fdocuments.in/reader033/viewer/2022042822/56649e4e5503460f94b459ef/html5/thumbnails/13.jpg)
Client/Server Architecture
• Client/Server Design Styles
13
![Page 14: Systems Analysis and Design 8 th Edition Chapter 10 System Architecture.](https://reader033.fdocuments.in/reader033/viewer/2022042822/56649e4e5503460f94b459ef/html5/thumbnails/14.jpg)
Client/Server Architecture
• Fat and Thin Clients
14
![Page 15: Systems Analysis and Design 8 th Edition Chapter 10 System Architecture.](https://reader033.fdocuments.in/reader033/viewer/2022042822/56649e4e5503460f94b459ef/html5/thumbnails/15.jpg)
Client/Server Architecture
• Client/Server Tiers (page 458)– Two-tier design– Three-tier design
• Middleware– Enables the tiers to communicate and pass data
back and forth– Provides a transparent interface– Can integrate legacy systems and Web-based
applications
15
![Page 16: Systems Analysis and Design 8 th Edition Chapter 10 System Architecture.](https://reader033.fdocuments.in/reader033/viewer/2022042822/56649e4e5503460f94b459ef/html5/thumbnails/16.jpg)
Client/Server Architecture
• Cost-Benefit Issues– Client/server systems enable the firm to scale the
system in a rapidly changing environment– Client/server computing also allows companies to
transfer applications from expensive mainframes to less expensive client platforms
– Client/server systems reduce network load and improve response times
16
![Page 17: Systems Analysis and Design 8 th Edition Chapter 10 System Architecture.](https://reader033.fdocuments.in/reader033/viewer/2022042822/56649e4e5503460f94b459ef/html5/thumbnails/17.jpg)
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
![Page 18: Systems Analysis and Design 8 th Edition Chapter 10 System Architecture.](https://reader033.fdocuments.in/reader033/viewer/2022042822/56649e4e5503460f94b459ef/html5/thumbnails/18.jpg)
Internet-Based Architecture
• Developing E-Commerce Solutions In-House
18
![Page 19: Systems Analysis and Design 8 th Edition Chapter 10 System Architecture.](https://reader033.fdocuments.in/reader033/viewer/2022042822/56649e4e5503460f94b459ef/html5/thumbnails/19.jpg)
Internet-Based Architecture
• Packaged Solutions and E-commerce Service Providers– Many vendors offer turnkey systems for
companies – Another alternative is to use an application service
provider (ASP)– Another option is managed hosting– Consider the experience of other companies in the
same industry
19
![Page 20: Systems Analysis and Design 8 th Edition Chapter 10 System Architecture.](https://reader033.fdocuments.in/reader033/viewer/2022042822/56649e4e5503460f94b459ef/html5/thumbnails/20.jpg)
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– Availability– Security
20
![Page 21: Systems Analysis and Design 8 th Edition Chapter 10 System Architecture.](https://reader033.fdocuments.in/reader033/viewer/2022042822/56649e4e5503460f94b459ef/html5/thumbnails/21.jpg)
Internet-Based Architecture
• Web 2.0– Envisions a second
generation of the web that will enable people to collaborate, interact, and share information more dynamically
– Wiki – Collective knowledge
– Internet operating system, sharing resources
21
![Page 22: Systems Analysis and Design 8 th Edition Chapter 10 System Architecture.](https://reader033.fdocuments.in/reader033/viewer/2022042822/56649e4e5503460f94b459ef/html5/thumbnails/22.jpg)
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 file-oriented systems
22
![Page 23: Systems Analysis and Design 8 th Edition Chapter 10 System Architecture.](https://reader033.fdocuments.in/reader033/viewer/2022042822/56649e4e5503460f94b459ef/html5/thumbnails/23.jpg)
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
23
![Page 24: Systems Analysis and Design 8 th Edition Chapter 10 System Architecture.](https://reader033.fdocuments.in/reader033/viewer/2022042822/56649e4e5503460f94b459ef/html5/thumbnails/24.jpg)
Processing Methods
• Combined Online and Batch Processing
24
![Page 25: Systems Analysis and Design 8 th Edition Chapter 10 System Architecture.](https://reader033.fdocuments.in/reader033/viewer/2022042822/56649e4e5503460f94b459ef/html5/thumbnails/25.jpg)
Network Models
• The OSI Reference Model (page 471)– The OSI model consists of seven conceptual layers– Each layer performs a specific function– Offers a set of design standards
• Network Modeling Tools– As you translate the OSI logical model into a
physical model of the networked system, you can use software tools, such as Microsoft Visio
25
![Page 26: Systems Analysis and Design 8 th Edition Chapter 10 System Architecture.](https://reader033.fdocuments.in/reader033/viewer/2022042822/56649e4e5503460f94b459ef/html5/thumbnails/26.jpg)
Network Models
• Network Topology– Hierarchical network
• it mirrors the actual operational flow in the organization
• One disadvantage of a hierarchical network is that if a business adds additional processing levels, the network becomes more complex and expensive to operate and maintain
26
![Page 27: Systems Analysis and Design 8 th Edition Chapter 10 System Architecture.](https://reader033.fdocuments.in/reader033/viewer/2022042822/56649e4e5503460f94b459ef/html5/thumbnails/27.jpg)
Network Models
• Network Topology– Bus network
• Devices can be attached or detached from the network at any point without disturbing the rest of the network
• Overall performance declines as more users and devices are added
• Today, the bus design is much less popular
27
![Page 28: Systems Analysis and Design 8 th Edition Chapter 10 System Architecture.](https://reader033.fdocuments.in/reader033/viewer/2022042822/56649e4e5503460f94b459ef/html5/thumbnails/28.jpg)
Network Models
• Network Topology– Ring network
• One disadvantage of a ring network is that if a network device fails (such as a PC or a server), the devices downstream from the failed device cannot communicate with the network
• Multistation Access Unit (MAU)– Manages data flow
between connected devicesw
28
![Page 29: Systems Analysis and Design 8 th Edition Chapter 10 System Architecture.](https://reader033.fdocuments.in/reader033/viewer/2022042822/56649e4e5503460f94b459ef/html5/thumbnails/29.jpg)
Network Models
• Network Topology– Star network
• Disadvantage of the star design is that the entire network is dependent on the switch
• However, in most large star networks, backup switches are available immediately in case of hardware failure
29
![Page 30: Systems Analysis and Design 8 th Edition Chapter 10 System Architecture.](https://reader033.fdocuments.in/reader033/viewer/2022042822/56649e4e5503460f94b459ef/html5/thumbnails/30.jpg)
Network Models
• Routers– Routers differ from
switches in that they work at OSI level 3 (IP packets)
– Can connect to a larger, dissimilar network, such as the Internet (Gateway)
– Proxy server• Connects internal LAN
clients to Internet
30
![Page 31: Systems Analysis and Design 8 th Edition Chapter 10 System Architecture.](https://reader033.fdocuments.in/reader033/viewer/2022042822/56649e4e5503460f94b459ef/html5/thumbnails/31.jpg)
Network Models
• Network Protocols– The network must use a protocol– A popular network protocol is Transmission
Control Protocol/Internet Protocol (TCP/IP)– A familiar example of a TCP/IP protocol is the file
transfer protocol (FTP)• Network Licensing Issues– When considering a network design, it is
important to take into account software licensing restrictions
31
![Page 32: Systems Analysis and Design 8 th Edition Chapter 10 System Architecture.](https://reader033.fdocuments.in/reader033/viewer/2022042822/56649e4e5503460f94b459ef/html5/thumbnails/32.jpg)
Wireless Networks
• A wireless local area network, or WLAN• Wireless Network Standards– 802.11– Institute of Electrical and Electronics Engineers
(IEEE)– Versions or amendments to improve bandwidth,
range and security – Mbps (megabits per second)
32
![Page 33: Systems Analysis and Design 8 th Edition Chapter 10 System Architecture.](https://reader033.fdocuments.in/reader033/viewer/2022042822/56649e4e5503460f94b459ef/html5/thumbnails/33.jpg)
Wireless Networks
• Wireless Network Standards
33
![Page 34: Systems Analysis and Design 8 th Edition Chapter 10 System Architecture.](https://reader033.fdocuments.in/reader033/viewer/2022042822/56649e4e5503460f94b459ef/html5/thumbnails/34.jpg)
Wireless Networks
• Wireless Network Topologies (pgs. 477-478)– Basic Service Set (BSS) – infrastructure mode– Access point– Extended Service Set (ESS)– Roaming– Independence Service Set (ISS) – peer-to-peer
mode
34
![Page 35: Systems Analysis and Design 8 th Edition Chapter 10 System Architecture.](https://reader033.fdocuments.in/reader033/viewer/2022042822/56649e4e5503460f94b459ef/html5/thumbnails/35.jpg)
Wireless Networks
• Wireless Trends– Wi-Fi Alliance– Wi-Fi (wireless fidelity)– BlueTooth (close acces, low power)– On addition to 802.11 protocols for LANs, IEEE is
working on 802.16 standards (30 mile range) called:
– MANs (metropolitan area networks)– WirelessMAN™ - WiMAX
35
![Page 36: Systems Analysis and Design 8 th Edition Chapter 10 System Architecture.](https://reader033.fdocuments.in/reader033/viewer/2022042822/56649e4e5503460f94b459ef/html5/thumbnails/36.jpg)
Systems Design Completion
• System Design Specification– A typical system design specification uses a
structure similar to the following:• Executive summary• System components• System environment• Implementation requirements• Time and cost estimates• Appendices
36
![Page 37: Systems Analysis and Design 8 th Edition Chapter 10 System Architecture.](https://reader033.fdocuments.in/reader033/viewer/2022042822/56649e4e5503460f94b459ef/html5/thumbnails/37.jpg)
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
37
![Page 38: Systems Analysis and Design 8 th Edition Chapter 10 System Architecture.](https://reader033.fdocuments.in/reader033/viewer/2022042822/56649e4e5503460f94b459ef/html5/thumbnails/38.jpg)
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
38