Designing software for a million users
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The document discusses the challenges and complexities involved in designing software for a large user base, specifically a system intended to replace Glow, a digital learning environment for educational stakeholders in Scotland. It highlights the need for stakeholder collaboration, the various types of complexities such as technical, governance, and environmental, and the pitfalls of reductionist assumptions in software engineering. Additionally, it stresses the importance of adaptability, architecture, and the perspectives of educators who require functional systems rather than merely new technologies.
Designing software for a million users
- 1. Designing Software for a Million Users Slide 1 Designing Software for a Million Users A story about a socio-technical system
- 2. Designing Software for a Million Users Slide 2
- 3. Designing Software for a Million Users Slide 3 2007 Collaboration tools Educational content Document management
- 4. Designing Software for a Million Users Slide 4 Why me? “There are a number of contractual stakeholders identified as users of Glow. These are the 32 local authorities, the 7 faculties of education within universities, Learning and Teaching Scotland, the Scottish Qualifications Agency, Her Majesty's Inspectorate of Education and the Scottish Government itself. “
- 5. Designing Software for a Million Users Slide 5 Replacing Glow December 2013
- 6. Designing Software for a Million Users Slide 6 Remit • Deliver a specification for a system to replace Glow – Deadline was end- 2012 – System has to be acceptable to the teaching community • Must be compatible with educational experiments in 1:1 device provision in schools and BYOD. • Budget unspecified but ‘significantly less’ than the current Glow budget of £5 million/year
- 7. Designing Software for a Million Users Slide 7 Digital learning environment
- 8. Designing Software for a Million Users Slide 8 Potential users 658, 000 52, 000 650, 000 10, 000
- 9. Designing Software for a Million Users Slide 9
- 10. Designing Software for a Million Users Slide 10 Software complexity Technical complexity Governance complexity Management complexity Environmental complexity
- 11. Designing Software for a Million Users Slide 11 Technies don’t understand other types of complexity Non-techies don’t understand technical complexity
- 12. Designing Software for a Million Users Slide 12 Governance complexity • Education Scotland – Responsible for managing the Glow service and deciding on the tools to be supported within Glow • Research Machines – Responsible for providing the Glow service, system enhancement, etc. – Service also seen as basis of product to be sold elsewhere • Local authorities – Hardware and network provision. Content filtering. – Often outsourced to IT companies (BT, Fujitsu, etc.) • Schools – Policies for Glow use; Some hardware provision.
- 13. Designing Software for a Million Users Slide 13 Environmental complexity • Heterogeneous hardware platform from 8 year old PCs (honestly) to iPads • Network connectivity from <1Mbit/second to 25 Mbits/second • Wide range of content filtering policies across local authorities • Government structure – Legally, Scottish Govt. can only advice local authorities on policies – they cannot compel them to adopt policies • Education is a newsworthy issue
- 14. Designing Software for a Million Users Slide 14 Software engineering Establish the requirements for the DLE Define an architecture for the system Stakeholder consultation Use-case modelling Prototyping Conflict analysis System modelling, ADLs, UML
- 15. Designing Software for a Million Users Slide 15 What didn’t work!
- 16. Designing Software for a Million Users Slide 16 Requirements engineering!
- 17. Designing Software for a Million Users Slide 17 Viewpoints!
- 18. Designing Software for a Million Users Slide 18 “We don’t need a new system, just the freedom to use what is available”
- 19. Designing Software for a Million Users Slide 19 System modelling and the UML!
- 20. Designing Software for a Million Users Slide 20 Prototyping!
- 21. Designing Software for a Million Users Slide 21 Use-cases!
- 22. Designing Software for a Million Users Slide 22 Software engineering meets reality Prof. Ian Sommerville School of Computer Science University of St Andrews Scotland
- 23. Designing Software for a Million Users Slide 23 Reductionism • Reductionism – “an approach to understanding the nature of complex things by reducing them to the interactions of their parts, or to simpler or more fundamental things”. • Its focus is on the parts of a system, not the relationships between those parts • Reductionism underpins most engineering, including software engineering
- 24. Designing Software for a Million Users Slide 24 Reductionist assumptions Owners of a system control its development Decisions made rationally, driven by technical criteria Definable problem and clear system boundaries No single owner or controller Decisions driven by political motives Wicked problem and constantly renegotiated system boundaries Reductionist assumptions Control Rationality Problem definition Large-scale complex IT systems reality
- 25. Designing Software for a Million Users Slide 25
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- 27. Designing Software for a Million Users Slide 27 Jack is a primary school teacher in Ullapool, teaching P6 pupils. He has decided that a class project should be focused around the fishing industry in the north- west Highlands, looking at the history, development and economic impact of fishing. As part of this, pupils are asked to gather and share reminiscences from relatives, use newspaper archives and collect old photographs related to fishing and fishing communities in the area. Pupils use a Glow+ wiki to gather together fishing stories and SCRAN to access newspaper archives and photographs. However, Jack also needs a photo sharing site as he wants pupils to take and comment on each others' photos and to upload scans of old photographs which they may have in their families.
- 28. Designing Software for a Million Users Slide 28 Jack sends an email to a primary school teachers group which he is a member of to see if anyone can recommend an appropriate system. Two teachers reply and both suggest that he uses KidsTakePics, a photo sharing site that allows teachers to check and moderate content. As KidsTakePics is not integrated with the Glow+ authentication service, he sets up a teacher and a class account. He uses the Glow+ setup service to add KidsTakePics to the services seen by the pupils in his class so that when they login, they can immediately use the system to upload photos from their phones and class computers.
- 29. Designing Software for a Million Users Slide 29 What happened?
- 30. Designing Software for a Million Users Slide 30 Trusted professionals
- 31. Designing Software for a Million Users Slide 31 Architecture for adaptability •
- 32. Designing Software for a Million Users Slide 32 Deliver capability not features
- 33. Designing Software for a Million Users Slide 33
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- 35. Designing Software for a Million Users Slide 35 Implementation experience
- 36. Designing Software for a Million Users Slide 36 Lessons learned
- 37. Designing Software for a Million Users Slide 37 Coolness! “It has to look cool or the kids won’t use it”
- 38. Designing Software for a Million Users Slide 38 Digitising Government Delivering technology to people who don’t really want it and who won’t really see any real benefit from it
- 39. Designing Software for a Million Users Slide 39 Politicians won’t or can’t accept that the problems with complex Government systems are not technical problems
- 40. Designing Software for a Million Users Slide 40 Government (and EU) procurement models are designed for police cars and paper clips, not software
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- 42. Designing Software for a Million Users Slide 42