Application Architecture

1
CHAPTER 9

• Application Architecture

2
Objectives

• List main issues that a SA should consider when
  an application architecture
• Enterprise resource planning
• Initial costs
• TCO
• Scalability
• Web integration
• Legacy requirements
• Security
• Processing options

3
Objectives

• Describe servers, server and client based
  processing
• Explain client/server architecture
• Client/server tiers, cost-benefit issues
• Explain impact of Internet
• Describe online and batch processing
• Define network topology

4
Objectives

• Explain network protocols and licensing issues
• Describe tools for modeling application
  architecture
• Explain system management tools
• Describe system design specifications

5
Application Architecture

• Application requires hardware, software, data,
  procedures, people to accomplish organized set of
  functions
• Effective system combines those elements into an
  architecture design that is flexible,
  cost-effective, technically sound, and able to
  support information needs of the business

6
Application Architecture

• Translates logical design of an information
  system into a physical structure that includes
  hardware, software, network support, and
  processing methods

7
Design Checklist

• Enterprise resource planning
• Initial cost and TCO
• Scalability
• Web Integration
• Legacy interface requirements
• Security
• Processing options

8
Enterprise Resource Planning

• Defines a specific architecture, including
  standards for data, processing, network and user
  interface design
• Describes specific environment (platform) is the
  combination of hardware and systems software used
  for the developed information system
• Ensures hardware connectivity and easy
  integration of future applications, including
  in-house and commercial packages

9
Initial Cost and TCO

• Review options to determine if outcome may be
  affected by new developments.

10
Scalability

• Measure of systems ability to expand, change, or
  downsize easily to meet changing needs.
• Can drastically affect systems life expectancy

11
Web Integration

• Part of e-commerce????
• Intranet based????

12
Legacy

• older systems that typically run on mainframe
  computers (architecture)
• Interface with legacy systems
• How will new system communicate?

13
Security

• Physical and logical security
• Web-based security

14
Processing Options

• High capacity transaction processing system (eg.
  order entry) requires more network , processing
  and data storage resources -- 24/7
• Must consider backup and recovery procedures
• System updates, file maintenance and other batch
  processing done off-peak lower costs and
  resources

15
Planning the Architecture

• Server a computer that supplies data,
  processing services, or other support to one or
  more computers (client)
• Client a computer that is connected to a server
• Mainframe architecture -- server performs all
  the processing

16
Planning the Architecture

• Processing performed on a server
• Processing performed on a client
• Processing divided between server and client
• We must plan (advantages and disadvantages) of
  each design approach

17
Planning the Architecture - Mainframe

• Server-based processing relies on network
  technology
• Centralized design remote user keystrokes
  transmitted to mainframe responds by sending
  screen output back to user terminal
• Advantage various types of terminals can
  communicate with mainframe and mainframe does all
  the work
• Disadvantage character-based terminals no GUI
• All data storage, access, and application
  programs on mainframe

18
Planning the Architecture

• Clients
• Stand-alone computing
• LAN
• WAN

19
(No Transcript)
20
(No Transcript)
21
Client/Server Architecture

• Systems that divide processing between one or
  more networked clients and a central server
• Client handles user interface, data entry, data
  query, and screen presentation
• Server stores data and provides data access and
  management functions

22
Client/Server --- Mainframe
23
Fat Client --- Thin Client
24
Client / Server Architecture

• Client / Server Tiers
• Cost-Benefit Issues
• Performance Issues

25
(No Transcript)
26
Processing Methods

• Online vs. Batch Processing

27
On-line processing

• System in which transactions are processed when
  and where they occur, allows output directly to
  end users
• also called online transaction processing or
  interactive processing

28
On-line processing

• workstation -- either a PC or terminal connected
  to online processing system
• online processing system verifies the transaction
  values and allows end user to interactively enter
  data and correct errors

29
On-line processing

• Online file -- data file with direct or indexed
  organization that allows random access
• sequential files not used for online processing
• IS must be continuously available whenever end
  users require processing of transactions

30
Batch Processing

• IS in which data is collected and, at some later
  time, all the data that has been gathered is
  processed as a group, or batch
• Used extensively in 1950s-60s
• Still used today for many applications

31
Batch Processing

• Any application that requires periodic processing
  of a large number of records is good candidate
  for batch processing
• payroll
• billing/invoicing
• hard copy reports

32
Todays processing trends

• Online and batch processing combined in single IS
• random access files are available for
  transactions that require interaction
• actual files available off-line for large batch
  processing
• copies of online files available for batch
  reports that dont require update

33
Online vs. Batch

• Online Advantages
• data is entered and validated as it occurs
• data is available sooner in more accurate form
• data is up-to-date

34
Online vs. Batch

• Online Disadvantages
• more expensive/difficult to maintain
• creation is more difficult
• more sophisticated hardware
• backup and recovery more difficult
• effects of computer failure more disruptive

35
(No Transcript)
36
NETWORK

• Data communications network
• collection of terminals, computers, and other
  equipment that use communication channels to
  share data, hardware and software

37
Network Topology

• Four patterns
• Hierarchical
• Bus
• Star
• Ring

38
Network Topology --
39
Network Topology --
40
Network Topology --
41
Network Topology --
42
System Architecture

• Network Protocols
• Licensing issues

43
(No Transcript)
44
Performance Management

• Designed to collect information about system
  resources and activity levels.
• System usage
• Capacity
• Trends

45
Fault Management, Backup and Disaster Recovery

• RAID
• Online Disaster Backup and Recovery plans
• Batching processing Backup and Recovery plans

46
System Design Completion

• Software Design Stages
• System Analysis phase functional primitives
  were identified and documented
• System Implementation phase Programmers
  determine exactly how each program will
  accomplish its objectives.

47
System Design

• Final activities
• System Design Specification
• Obtaining user approval
• Delivering presentation to Management

48
System Design Specification

• Management Summary
• System Components Details
• Environmental Requirements
• Implementation Requirements
• Time and Cost Estimates
• Appendices