Einführung in die Softwaretechnik at TU München

• Functionality vs. Usability (Is a system with 100 functions usable?)
• Cost vs. Robustness (a low cost design does not check for errors when user enters wrong data; 8.51€ vs. 8,51€)
• Efficiency vs. Portability
• Rapid development vs. Functionality
• Cost vs. Reusability (additional coding and testing costs for many-many multiplicity) ->design patterns help
• Backward compatibility vs. Readability (e.g. diff hardware) ->design patterns help

1) Number of simultaneous users supported 

2) Amount of information handled 

3) Number of transactions processed within certain time periods (average and peak workload)

-> Divides an interactive application into 3 components:

1) Model: 

-> contains the core functionality and data 

2) View:

-> displays information to the user 

3) Controller: 

-> handles user input 

-> Views and controllers together comprise the user interface

• standord for modeling sw systems

• reduces complexity by focusing on abstractions
• high level "programming language" (as basis for source code)
• mean for communication

1. Compliance to standards: report format, audit tracing)
2. Implementation: tools, programming language -->dev tech should not be constrained by the client
3. Operations: administration & mgmt of system; Ex.: Remote updates for Teslas
4. Legal: licensing, regulation, certificates
5. Packaging: actual delivery (e.g. on floppy disks)
6. Interface: imposed by external systems
7. Legal: must comply with federal law (e.g. GDPR)

1) Model subsystem: 

-> store application domain knowledge 

2) View subsystem: 

-> display information to the user 

3) Controller subsystem: 

-> interact with the user and notify views about changes in the model

2) It is about dealing with complexity

3) It is about dealing with change

1) Entity objects 

-> Represent the persistent information tracked by the system (application domain objects, also called “business objects”) 

2) Boundary objects 

-> Represent the interaction between the user and the system 

3) Control objects 

-> Represent the control tasks to be performed by the system

Design focuses on solution domain

• The solution domain is changing very rapidly 

  • Halftime knowledge in software engineering: about 3-5 years 

  • Cost of hardware rapidly sinking

• Design knowledge is a moving target
  
  
  

1. Functional model (functionality system)
2. Object model (structure of system)
3. Dynamic model (behaviour of system)