Technical System Options
• Specify technical environment
• Confirm functionality of new system
• Analyse impact on organisation
• Provide cost/benefit analyses
• Provide a stop/go point
e.g. Like Feasibility and Business System Options
• Often the basis for procurement
• Enables detailed physical design
Technical System Options 1
Technical System Option Components
• End product of Stage contains following documents:
– Technical Environment Description (TED)
– System Description
– Impact Analysis
– Outline Development Plan
– Cost/Benefit Analysis
Technical System Options 2
Technical Environment Description
Hardware
• Hardware TED is generic rather than specific
• System Diagram showing layout
– number of terminals or PCs
– printers
– communication lines
– processors
– other devices
• Hardware also subject to System TED
Technical System Options 3
Technical Environment Description
System
• Textual descriptions which may cover
– standards
– communications
– environment
– installation
– upgrade arrangements
– reliability
– serviceability
– availability
– maintainability
– software
Technical System Options 4
Technical Environment Description
Software
• May cover following aspects:
– data management software
– system recovery and dumping facilities
– operating system
– application packages
– construction software
e.g. Programming languages, testing tools
– development environment
– access rights and security
– system sizing
– space requirements
– processing performance
– first-cut physical design
Technical System Options 5
System Description
• Shows how option satisfies Requirements Specification
• Supports major decisions taken in Business System Options
• Includes alternative systems with trade-offs
• Shows degree to which system requirements met
NB. It is also important to show which functions/facilities will not be
provided
• Includes
– Required System Logical Data Model
– Function Definitions
– Requirements Catalogue (showing solutions based on the option)
Technical System Options 6
Impact Analysis
• Explains effects on user environment
• Should cover
– organisation and staffing
– changes in user operating procedures
– implementation considerations such as conversion
– savings
– comparative advantages and disadvantages of alternative TSOs
• Includes issues documented in following products:
– Training Requirements Description
– User Manuals Requirements Description
– Testing Outline
– Take-on Requirements Description
Technical System Options 7
Outline Development Plan
• Enables development costs to be estimated
• Shows next module in detail
• Shows outline of subsequent plans
• Should contain time, resource and cost estimates for
– physical design
– program design and programming
– procurement
– system testing
– implementation
Technical System Options 8
Cost/Benefit Analysis
• Most objective way to compare merits of options
• Cost/Benefit Analysis should cover:
– development costs
– operating costs
– tangible benefits and displaced costs
i.e. Current system costs eliminated by new system
– cost containment
• Intangible benefits
– improved product quality
– improved service to customers
– greater job satisfaction for employees
– improved management information
Technical System Options 9
Considerations for TSOs
• Staff involved
• External and internal constraints
• Development of outline Technical System Options
• Refining Technical System Options
• Making the selection
• Documenting the selection
Technical System Options 10
Staff Involved in Technical System Options
• Project board
– often assesses TSOs and makes selection
– may terminate project if no suitable option found
• Project Manager or Module Manager
– finalises TSOs
– finalises and presents TSOs
• Analysts
– research and document requirements
– formulate TSOs for presentation
Technical System Options 11
The Decision Makers
• Usually project board
• Special review group including users and IT specialists
• Standard QA review group
• Consensus approach
– selection made by project board based on user views
Technical System Options 12
External Constraints
• Imposed from outside the project
• Typical constraints include
– delivery dates
– total costs
– hardware and/or software preferences
Technical System Options 13
Internal Constraints
• Set within the project by the user
• Typical constraints include
– mandatory facilities
e.g. On-line access, word processing
– minimum service levels
e.g. Mean time between failures, maximum time to restore system,
availability, reliability
– data storage space requirements
– critical timing criteria
– information objectives
– operating environment conditions
– security requirements
– interfaces to other Information Systems
Technical System Options 14
Making the Selection
• Present TSOs
NB. Presentations frequently made to users as well as Project Board
• Prepare carefully for presentation
– provide amplification and answer queries
– record significant comments
• Often selection chosen is hybrid of options
– document the selection
– record reasons for selection
• Update selected Technical System Option
• Update associated Technical Environment Description
Technical System Options 15
Further Activities
• Develop Application Style Guide from Installation Style Guide
• Service Level Requirements become the basis for Service Level
Agreements
• Physical design will be based on the Technical Environment
Description
Technical System Options 16