Alternatives

1
Alternatives
2
Issues

• Scope Creepas a project goes on it tends to grow
  larger and less defined
• The project team needs to determine which
  requests are critical
• A common approach is to list requests as
  mandatory, important, desirable

3
Task

• Identify all the functions of the system
• Prioritize the functions in terms of how critical
  they are to success
• Identify the level of automation for each function

4
Level of Automation

• There are usually three levels (different
  functions in a system can have different levels
  of automation)
• Lowcomputers are used for record keeping, word
  processing, etc
• Middleusually a combination from low and high
  range options
• Highthe system takes over as much as possible
  the processing of a function

5
Selecting Alternatives

• Things to consider
• Strategic plan
• Economic Feasibility
• Schedule and resource feasibility
• Technological feasibility
• Operational and organizational feasibility

6
Possible System Architectures

• Centralized Systems
• Distributed Computing
• Internet, Intranet, Extranet

7
Centralized Systems

• Single ComputerMainframe, terminals
• ClusteredSeveral servers that behave as a single
  machine
• Multicomputermultiple computers, but not as
  homogeneous as clustered

8
Distributed Computing

• This means distributing computing functions
  across several computers and or locationsi.e. a
  network
• Local Area networkdistances are local, same
  building
• Wide Area networkdistributed across locations
  city, state, nation

9
Client /Server Architecture

• A server manages one or more resources and makes
  it available to the network
• A client uses a service offered by a server
• (a particular machine can be both a server and a
  client)

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Basic Client Server
Service
Client
Server
11
Three Tier Network
Processed Request
Request
response
Formatted response
Client
Business Layer
Server
12
N-Tier Network
Clients
Business layers
Servers
13
Internet/Intranet/Extranet

• TCP/IP, FTP, SMTP, Telnet, HTML
• Advantages
• Accessibility
• Low cost communication
• Widely implemented protocols
• Disadvantages
• Security
• Reliability
• Volatile standards
• Throughput (band width)

14
Important Components

• Language environments and expertise
• Existing case tools and methodologies
• Required interface to other systems
• Operating system environment
• Database management system

15
Purchased Solutions

• Packaged Softwarebuying off the shelf
• Turnkeya pre-built system solution usually for
  specialized situations
• Enterprise Resource Planningenterprise level
  systems built from existing components to a
  systems requirements

16
Custom Built Software

• AdvantagesTailored to the particular business
  needs of the company
• Disadvantagescost, time, in house expertise

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Selecting the Alternatives

• Identify Criteria
• General requirements
• Technical requirements
• Functional requirements
• Identify Risks

18
General Questions

• Performance record of provider
• Level of technical support for provider
• Availability of experienced staff
• Development costs
• Expected value of benefits
• Length of time until deployment
• Impact on internal resources
• Costs of data conversion
• Warranties and support services (from outside
  vendors)

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Technical Issues

• Robustness (doesnt crash)
• Programming errors (does software calculate
  properly
• Quality of code (maintainability)
• Documentation
• Ease of installation
• Flexibility (can adapt to new environments,
  business changes)
• User friendliness
• Performance
• Scalability
• Compatibility with operating environment

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Weighted Matrix