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Special interfaces

Special interfaces. Chapter 5. Reports. Reports on screen and paper are a form of one way communication between product and user Hard to specify Many types of reports are necessary and it is important to specify these correctly. Reports. Reports.

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Special interfaces

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  1. Special interfaces Chapter 5

  2. Reports • Reports on screen and paper are a form of one way communication between product and user • Hard to specify • Many types of reports are necessary and it is important to specify these correctly

  3. Reports

  4. Reports • Some reports must specify external format requirements • “The product shall produce pay slips with the layout shown in Figure xx. The pay slips should be available on paper as well as comma separated files” • Some reports relate to well-defined tasks

  5. Reports • Beware of existing reports with vague purposes • COTS systems may have built in reports that could be used and this will save costs • Reports on demand; is there a report generator and how easy it is to use

  6. Platform requirements • Platform is a combination of HW and SW on which the system will run’ • HW, OS, network, DB (mostly COTS) • We already have a platform • We plan to buy a new platform • We want the platform as part of the product • Can be strategic or obvious

  7. Platform requirements

  8. We already have a platform • Typical for small projects • Pentium with xx Mhz and xx RAM, etc • “Since the customer’s IT staff have expertise in Oracle, which is used for other applications, the product shall use the same DB platform” • Specify platform products and release numbers

  9. We want a new platform • Typical when major changes in IT strategy are involved • Platform requirements are closely related to speed and capacity • Response time requirements dependent on platform speed and memory requirements

  10. We want SW and HW • Typical for dedicated systems for one specific purpose • Could be a multipurpose system where the supplier takes care of maintenance and support • “the supplier shall deliver the necessary HW and SW, and shall upgrade if necessary as load increases” • ISP

  11. We want SW, maybe HW • Customer may not have made up his mind • Combined HW/SW or not? • In this case, specify HW as an option and decide later • “the client part of the product shall run on Pentiums. As an option, the total delivery may include PCs..”

  12. Product integration • What if the customer has little IT skills? • External products – your system has to communicate with these other systems • Integration of two or more products leads to complexity • What should be said about the other system?

  13. Who integrates? • Who is responsible for the adjustments and settings for the whole system? • Customer responsible for the integration • Avoid if possible • Endless problems for non-specialists

  14. Who integrates? • Customer’s IT department • Fine if they have the technical expertise • Customer should regard the IT department as his main contractor and supplier • External supplier • Usually best choice • Supplier may have a product and used to integrating it • Some SW houses and good at “glue code”

  15. Who can integrate?

  16. Integration requirements, domain level

  17. Integrating with a commercial product • “The customer us using WonderAccount xx for his financial accounting. The hotel system must ensure that today’s invoice transactions are transferred automatically to WonderAccount with the next day. Each transaction must be transferred once and only once”

  18. Integrating with a new commercial product • What if the customer wants several new products at once and he wants to integrate them? • “The hotel system supplier shall list the accounting systems with which his system can integrate….”

  19. Consortium model; delivering an integrated product • Suppliers may form a consortium that together deliver the integrated product • Consortium might reduce to a single supplier • Best for large systems where many products have to be integrated

  20. Integration requirements – product level

  21. Product integration – main contractor • Main contractor may be hired to help a customer integrate some products in an ad hoc manner, or he may develop a new product of his own that builds on other products • Product developers use integration with third parties more and more because they offer increasingly complex and intelligent services

  22. Product integration – main contractor • Main contractor will have the responsibility for the integration • Writes requirements for each subcontractor • Specify technical interfaces between the products • Main contractor ultimately responsible for customer requirements

  23. Main contractor

  24. Technical interfaces • Technical interfaces between a product and an external product is always one or more communication channels • Physical channel; how is data communicated/ • Data transmission • Inter-object calls • Snail mail

  25. Technical interfaces • Messages; how is the message identity or the event communicated? • Which formats are involved? • Protocols • What are the possible message sequences, error recovery, etc? • Semantics • What do they communicate about?

  26. Technical interfaces

  27. Examples of channels • File transfer • Hotel accounting system • Object calls • 3D graphics package • Network communication • Remote process control

  28. Channel descriptions • Physical channel • TCP/IP • Messages • Data expressions, data dictionary • Protocol • SDL (telecom) • Semantics • DFD, use cases, etc

  29. “Hard” requirements • Hard requirements in a technical interface • message formats • Protocols • Physical channel • Crucial when two independent organizations develop separate parts of the whole

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