CS 501: Software EngineeringAdministrationQuiz 2Slide 4Slide 5Slide 6System Architecture and DesignUML: System and Subsystem ModelingUML Notation: Component & NodeSystem Architecture Example: Extensibility in Web BrowsersWeb Interface: BasicUML Notation: Deployment DiagramUML Notation: Application Programming Interface (API)UML Notation: InterfacesWeb User Interface: CGI ScriptUML Notation: CGI Interface DiagramWeb User Interface: JavaScriptUML Notation: PackageExample: Web BrowserWeb User Interface: AppletApplet InterfacesUML Diagrams and SpecificationsComponents and ClassesComponents and ReplaceabilitySystem Design: Data Intensive SystemsBatch Processing Example: Electricity Utility BillingTransaction TypesCriticisms of First AttemptBatch Processing: ValidationUML Deployment Diagram: Batch Processing ValidationBatch Processing: Master File UpdateInterfaces to DataInputBenefits of Batch UpdatingOnline InquiryOnline Inquiry: Use CasesData Intensive Systems Example: A Small-town StockbrokerA Database ArchitectureReal-time TransactionsReal-time Transactions & Batch ProcessingStock Broker: Interface DiagramArchitectural considerations to include in SpecificationData Intensive Systems: Merger of Two BanksMerger of Two Banks: OptionsMerger of Two Banks: Architectural Options1CS 501 Spring 2005CS 501: Software EngineeringLecture 13System Architecture and Design I2CS 501 Spring 2005AdministrationBOOMWednesday, Duffield Atrium 4-63CS 501 Spring 2005Quiz 2Question 1At the end of your CS 501 project, you mount your programs and documentation on GForge. The project team gives the client an unrestricted license to use the project for the client's purposes but not to distribute it to others. A year later, the members of your team decide to go into business, selling a product that is based on your CS 501 system. You start a small company and hire three programmers.4CS 501 Spring 2005Quiz 2(a) You would like to keep the specification of the system secret. For this purpose you remove the system from GForge. Can you claim legal protection of the specification as trade secret? No. The presumption is that by placing it on the GForge for a year, trade secret protection was lost, unless the GForge site is securely protected and, from the very start, everybody who saw the specification was required to keep it secret.5CS 501 Spring 2005Quiz 2(b) Your company extends the system with a new component. Can you protect the specification of the new component as trade secret? If so, what procedure would you follow? Yes, by creating procedures to keep the specification secret, e.g., by restricting access and my ensuring that everybody who has access understands the necessity of keeping it secret. (c) Who owns the copyright in the original system? Who owns the copyright in your new component? You own the copyright to the original system. To be more specific, the members of the project team jointly own the copyright.The company owns the copyright to the new component.6CS 501 Spring 2005Quiz 2(d) Can you charge the CS 501 client money to use your new component? Yes. Unless your license says otherwise. (e) Two of your programmers leave and start their own company. What use can they make of the programs that they wrote while working for your company? Can they write new software based on the specification of your new component? They can make no use of the programs, without permission from the company. They were created as work for hire. They cannot write software based on this specification. The specification is a trade secret of the company. The former employees cannot use it, but they can use ideas from it.7CS 501 Spring 2005System Architecture and DesignThe overall design of a system:• Computers and networks (e.g., monolithic, distributed)• Interfaces and protocols (e.g., http, sql)• Databases (e.g., relational, distributed)• Security (e.g., smart card authentication)• Operations (e.g., backup, archiving, audit trails)• Software environments (e.g., languages, source control tools)8CS 501 Spring 2005UML: System and Subsystem ModelingSubsystem modelA grouping of elements that specifies what a part of a system should do.Component (UML definition)"A distributable piece of implementation of a system, including software code (source, binary, or executable) but also including business documents, etc., in a human system."A component can be thought of as an implementation of a subsystem.9CS 501 Spring 2005UML Notation: Component & Nodeorderform.javaA component is a physical and replaceable part of a system that conforms to and provides the realization of a set of interfaces.ServerA node is a physical element that exists at run time and represents a computational resource.10CS 501 Spring 2005System Architecture Example:Extensibility in Web BrowsersWeb browsers provide a flexible user interface through an extensible architecture.Data types: helper applications, plug-insProtocols:HTTP, WAIS, Gopher, FTP, etc.proxiesExecutable code:CGI scripts at serverJavaScript at clientJava appletsStyle sheets:11CS 501 Spring 2005Web Interface: BasicWeb serverWeb browser• Static pages from server• All interaction requires communication with server12CS 501 Spring 2005UML Notation: Deployment DiagramWebBrowserPersonalCompWebServerDeptServer13CS 501 Spring 2005UML Notation:Application Programming Interface (API)API is an interface that is realized by one or more components.WebServerGet Post14CS 501 Spring 2005UML Notation: InterfacesWebBrowser WebServerHTTPdependencyinterfacerealization15CS 501 Spring 2005Web User Interface: CGI ScriptWeb browser• Scripts can configure pages• Scripts can validate information• All interaction requires communication with serverDataCGIScriptsWeb server16CS 501 Spring 2005UML Notation: CGI Interface DiagramCGIScriptHTTPApacheCGISQLMySQLThese components might be located on a single node.17CS 501 Spring 2005Web User Interface: JavaScriptDataCGIScriptsWeb serverWeb browser• JavaScripts can validate information as typed• Some interactions are local• Server interaction constrained by web protocolsJavaScripthtml18CS 501 Spring 2005UML Notation: PackageA package is a general-purpose mechanism for organizing elements into groups.Note: Some authors draw packages with a different shaped box:JavaScriptJavaScript19CS 501 Spring 2005Example: Web BrowserHTTPJavaScriptHTMLRenderEach package represents a group of
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