上降充通大学 SHANGHAI JIAO TONG UNIVERSITY 3.Hardware Software Mapping Software Engineering
Software Engineering 3. Hardware Software Mapping
上游充通大￥ Hardware Software Mapping SHANGHAI JIAO TONG UNIVERSITY This activity addresses two questions: How shall we realize the subsystems:Hardware or Software? How is the object model mapped on the chosen hardware software? Mapping Objects onto Reality:Processor, Memory,Input/Output Mapping Associations onto Reality:Connectivity Much of the difficulty of designing a system comes from meeting externally-imposed hardware and software constraints. Certain tasks have to be at specific locations Software Engineering
Software Engineering Hardware Software Mapping This activity addresses two questions: • How shall we realize the subsystems: Hardware or Software? • How is the object model mapped on the chosen hardware & software? • Mapping Objects onto Reality: Processor, Memory, Input/Output • Mapping Associations onto Reality: Connectivity Much of the difficulty of designing a system comes from meeting externally-imposed hardware and software constraints. • Certain tasks have to be at specific locations
上游充通大￥ SHANGHAI JIAO TONG UNIVERSITY Mapping the Objects Processor issues: Is the computation rate too demanding for a single processor? Can we get a speedup by distributing tasks across several processors? How many processors are required to maintain steady state load? Memory issues: Is there enough memory to buffer bursts of requests? ④l/O issues: Do you need an extra piece of hardware to handle the data generation rate? Does the response time exceed the available communication bandwidth between subsystems or a task and a piece of hardware? Software Engineering
Software Engineering Mapping the Objects Processor issues: • Is the computation rate too demanding for a single processor? • Can we get a speedup by distributing tasks across several processors? • How many processors are required to maintain steady state load? Memory issues: • Is there enough memory to buffer bursts of requests? I/O issues: • Do you need an extra piece of hardware to handle the data generation rate? • Does the response time exceed the available communication bandwidth between subsystems or a task and a piece of hardware?
上游充通大￥ Mapping the Subsystems Associations: SHANGHAI JIAO TONG UNIVERSITY Connectivity Describe the physical connectivity of the hardware Often the physical layer in ISO's OSI Reference Model Which associations in the object model are mapped to physical connections? Which of the client-supplier relationships in the analysis/ design model correspond to physical connections? Describe the logical connectivity (subsystem associations) Identify associations that do not directly map into physical connections: How should these associations be implemented? Software Engineering
Software Engineering Mapping the Subsystems Associations: Connectivity Describe the physical connectivity of the hardware • Often the physical layer in ISO’s OSI Reference Model • Which associations in the object model are mapped to physical connections? • Which of the client-supplier relationships in the analysis/ design model correspond to physical connections? Describe the logical connectivity (subsystem associations) • Identify associations that do not directly map into physical connections: • How should these associations be implemented?
上溶充通大粤 Typical Informal Example of a Connectivity Drawing SHANGHAI JIAO TONG UNIVERSITY Application Application Application Physical Client Client Client Connectivity TCP/IP Ethernet Logical LAN Connectivity Communication 口 Agent for Application Clients LAN Global Data Server Communication Communication Backbone Network Agent for Data Agent for OODBMS Application Clients Server Communication Global Agent for Data Data Server Server LAN RDBMS Local Data Global Data Server Server Software Engineering
Software Engineering Typical Informal Example of a Connectivity Drawing DistributedDatabaseArchitecture Tue, Oct 13, 1992 12:53 AM Application Client Application Client Application Client Communication Agent for Application Clients Communication Agent for Application Clients Communication Agent for Data Server Communication Agent for Data Server Local Data Server Global Data Server Global Data Server Global Data Server OODBMS RDBMS Backbone Network LAN LAN LAN TCP/IP Ethernet Physical Connectivity Logical Connectivity