1. Topic 12: Systems Specification and Selection
Computer Systems
Topic 12:
Systems Specification and Selection
NCC Education - Title Master

2. Scope and Coverage - 1 This topic will cover: Selection criteria
System integration
Accessibility
Alternative solutions
Identification, selection & justification
Matching client requirements and system requirements with system components
NCC Education - Slide Master 2

3. Scope and Coverage - 2 This topic will cover (cont.): Systems options
Off the shelf, self build, customise
Alternatives
System documentation
Case study – selection & specification
NCC Education - Slide Master 3

4. Learning Outcomes By the end of this topic, students will be able to:
Produce a system design specification to meet a client’s needs
Evaluate the suitability of a system design specification
Build and configure a computer system to meet a design specification

5. The Selection Process - 1
Having determined the requirements, we need to select appropriate solutions. This involves:
Assessing whether computer and human resources are lacking
Do we actually need a new system?
Can we use existing technologies or is a fresh start better?
Is reuse of legacy systems a requirement?

6. The Selection Process - 2
Do we have all the information we need about the requirements?
Is the problem a business model or a technology issue?
Is the information up-to-date?
Or will requirements be outdated by the time design decisions are made?
Are key stakeholders available during the whole project?

7. The Selection Process - 3
What are the service levels required?
Are service level agreements (SLA) in place?
Estimate the costs and resources required
These need to be agreed with management or customer.
Identify any functions, processes and features currently lacking, as well as any new capabilities required by the new system.
Note that this may be an iterative process
It may be necessary to revisit some points as others change.

8. Selection Strategy
There are a number of different approaches to making systems selection, depending on the nature and size of the project.
Selection committee
Should include appropriate stakeholders and technical experts
Can be unwieldy and slow
Individual or small group decision
Often quicker than a full committee
May have biased views or not consider important aspects such as cost

9. Selection Considerations - 1
When selecting a solution, you need to consider:
Needs assessment as discussed earlier
Volume of information to be processed
Customising solutions
Off the shelf products may not be suitable
The design must fully justify each component in the specification
Developing hardware and software specifications
Detailed specification of the necessary hardware and software

10. Selection Considerations - 2
Request for proposals (RFP)
Invitation for tender in cases where different vendors may be required to provide specific components
May be used as a proposal for different computer system specifications
Evaluate proposals
Identify criteria for assessment of solutions based on priorities from requirements analysis stage.

11. Selection Considerations - 3
Selecting additional services
Supporting services, after sales support
Ranking
A table may be used to establish a ranking of the possible solutions
Reporting
A concise document that fully justifies the selection made is a good evaluation tool

12. Selection Considerations - 4
Negotiations
It may be possible or even necessary to reconsider and negotiate certain aspects of the system to get a better fit with the requirements.
Implementation
Issues may arise during implementation that impact the solution.
Review
To resolve any outstanding issues
To inform future projects

13. Selection Criteria - 1
It is important to match the system specification with the requirements.
Acceptable response time
CPU spec, quantity of RAM, hard disk spec, network speed, printer speed
Availability (uptime, reliability)
Some systems are required 24/7/365, whereas others may only be used during office hours.
Some systems are mission critical and must be available when needed, whereas other jobs may be postponed.

14. Selection Criteria - 2
Data capacity
Storage space, network throughput or bandwidth
Scalability
Will the demands on this system grow and can it cope?
Software
Is specific software required and if so, what are its hardware requirements?
Note that several of these performance requirements may be relevant.

15. Selection Criteria Classification
You can classify these selection criteria under three headings:
Time
Cost
Quality
There may be trade-offs between these criteria.
You can save time (i.e. do things quicker) but it costs more to buy faster equipment.

16. Application Software Choice - 1
In most cases, you should specify the software first as software may dictate the hardware selection.
Software directly affects user perception.
Aim to improve user experience.
Speed or response time
Ease of use
Improved interface
Additional functionality
Manuals, user guides and training

17. Application Software Choice - 2
In many cases, there is little choice
Compatibility with previous or legacy systems
Market dominance
Product availability

18. Operating System Choice
Often, there is no choice. Particular software may only run on a given operating system. The current options include:
Microsoft Windows
Apple Mac OS X
Linux
Android for mobile devices

19. Hardware Guidance - 1 Often dictated by software requirements
Do not rely on “minimum hardware requirements” from software manufacturers
They really are an absolute minimum to get the software running.
They will seriously affect the performance of the system.

20. Hardware Guidance - 2 Some uniformity is helpful.
Select the same base machine, or at least the same manufacturer
Upgrade where necessary with extra memory, faster graphics card or bigger hard disk.
This may result in a better negotiated price for the hardware.
Gives some redundancy across the entire hardware platform
Saves spares costs

21. Hardware Specification - 1
Hardware selection should be driven by software choice and operating system choice.
When specifying hardware, you need to cover:
Computer architecture
This is the overall technology you are buying into
E.g. Intel/Windows or Apple Mac
Processor
Once the architecture is decided, which actual CPUs are you going to buy?
Intel in particular have a wide range of compatible processors with different performance characteristics.

22. Hardware Specification - 2
Memory
How much RAM do you need for your software to perform properly?
Secondary storage
How much hard disk space is required?
What performance is required?
Some disks are designed for high transfer rates for use in video editing for example

23. Hardware Specification - 3
Graphics capability
Most motherboards (and some CPUs) have some graphics capability built in.
On board graphics systems are often slow and may be limited resolution.
Do you need a high speed or high resolution graphics system?
Do you need multiple screens?
Connectivity
What do you need to connect to this system?
USB, Firewire, Ethernet, Wi-Fi, Bluetooth?

24. System Integration
System integration means making sure that all your systems work together.
Including all the new components, both hardware and software
Includes any legacy systems still in use
Includes any other equipment that needs to connect to these systems
E.g. point of sale or telephone equipment
Includes any data being transferred from old to new systems
Includes any manual parts of the business system

25. Accessibility
When putting in new computer systems, you should consider whether they are suitable for people with disabilities. This is a legal requirement in some countries.
Visual impairment
Larger screens, ability to change colours and fonts, text to speech facilities
Mobility issues
Different keyboard designs, voice input

26. Alternative Solutions
In most cases, you should specify alternative solutions, make recommendations and justify them.
Offer a minimum specification and a higher specification alternative.
Presumably at higher cost
Explain what extra benefits the higher spec will bring
If there are none, why are you suggesting it?

27. Alternative Approaches - 1
When specifying new PCs, it is possible to buy off the shelf systems or build your own.
Buying off the shelf
May be cheaper
Will save time if you are putting in a large number of PCs
Will give better manufacturer support and guarantees

28. Alternative Approaches - 2
Building your own PCs
Allows you to get exactly the components you want
Is better for a small number of systems
Is better for specialist requirements
Some manufacturers have base models that you can then customise when you order.

29. Matching Requirements
Your specification should be directly matched to the requirements.
In your specification report, explicitly match the specified components to the requirements.
Where alternatives are suggested, make it clear how each alternative satisfies the requirements.
Make it clear how your recommendations are a better fit for the requirements.

30. System Documentation - 1
It is important to document the new system.
You may not remember everything.
You may not be there to answer questions in the future.
Other people may have to maintain or add to the system.

31. System Documentation - 2
Include all the requirements analysis documentation as well as the systems specifications.
Include all the documentation that came with the hardware and software.
Keep documentation up-to-date when changes or upgrades are done.

32. Sources
You will need to search manufacturers and suppliers websites for technical information on the systems or components you are specifying. There are some global companies, but you can also search for local suppliers in your area.

33. Topic 12 – Systems Specification and Selection
Any Questions?
NCC Education - End Slide Master