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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
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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 Option Components • End product of Stage contains following documents: • Technical Environment Description (TED) • System Description • Impact Analysis • Outline Development Plan • Cost/Benefit Analysis
Technical Environment DescriptionHardware • 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 Environment DescriptionSystem • Textual descriptions which may cover • standards • communications • environment • installation • upgrade arrangements • reliability • serviceability • availability • maintainability • software
Technical Environment DescriptionSoftware • 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
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)
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
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
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
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
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
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
External Constraints • Imposed from outside the project • Typical constraints include • delivery dates • total costs • hardware and/or software preferences
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
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
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