Software Engineering 1 Some Definitions Lesson 2

Software Engineering 2 Some Definitions Definition of Software: (from the IEEE Glossary of Software Engineering) software is a set of items or objects that form a “System” that includes programs, functions, rules, documents and data. Notice: Software is also documents!!! 4.000/5.000 pages only for Analysis

Software Engineering 3 Some Definitions Definition of Software Engineering: Software engineering is an engineering discipline which is concerned with all aspects of software production (development, maintainess, replacement …) Notice: Software Engineering is also replacing of software!!!

Software Engineering 4 Some Definitions Definition of Software Engineering: Software engineers should adopt a systematic and organised approach to their work and use appropriate tools and techniques depending on the problem to be solved, the development constraints and the resources available coherently with the estimated time and costs Notice: We have to find a precise cost for each Software Development Process

Software Engineering 5 Software Engineering’s dimensions Lesson 2

Software Engineering 6 Sw Engineering’s dimensions 1. Technological Dimension: Languages, networks, architectures, … This is trivial for you!!! But it isn’t enough…

Software Engineering 7 Sw Engineering’s dimensions 2. Economic Dimension: make or buy? software costs more to maintain than it does to develop

Software Engineering 8 Sw Engineering’s dimensions Approaches to developing software depend on the application Example: MS Windows is enough to write a document MS Windows isn’t recommended to control a plane

Software Engineering 9 Sw Engineering’s dimensions Costs of software are higher than hardware cost Relation between Software and Hardware cost

Software Engineering 10 Sw Engineering’s dimensions Measure of costs: lines day How many lines does a programmer write in a day? 10 lines!!! In the remaining time he makes Software Engineering!!!

Software Engineering 11 Sw Engineering’s dimensions 3. Social Dimension: Trouble issues: Introduce new software Substitute software Digital Divide Open Source

Software Engineering 12 Software Engineering Basic Concepts Lesson 2

Software Engineering 13 Basic Concepts ProcessProduct Set of activities whose goal is the development or evolution of software (Software Life Cycle) Software

Software Engineering 14 Basic Concepts This course is about the Process!!! Notice: Cost of production of software is zero. Costs are considered only for their conception (for process).

Software Engineering 15 Software Engineering Process and Product Qualities Lesson 2

Software Engineering 16 Software isn’t only the code but also documentation, comments, reports of the test analysis, … every derivable of each phase of Software Development Process Process and Product Qualities

Software Engineering 17 Tons of problems during Software Development Process: -during Requirements Analysis -during Software Implementation -during Maintenance Process and Product Qualities

Software Engineering 18 Complexity of some kind of problems during Software Development Process: Technological problems Economical problems Social problems Process and Product Qualities

Software Engineering 19 For any kind of software we could have many products and many Software Development Processes. Products are classified through their quality Processes are different sequences of the same set of phases Process and Product Qualities

Software Engineering 20 Process and Product Qualities External Qualities (Black Box) What are the users’ needs (Users can see it) Example: low diesel oil consumption

Software Engineering 21 Process and Product Qualities Internal Qualities (White Box) Structural Properties (Users cannot see it) Example: high thermal insulation

Software Engineering 22 Process and Product Qualities External Qualities (Black Box) Requested from users Example: high portability

Software Engineering 23 Process and Product Qualities Internal Qualities (White Box) Requested from developers Example: software in Java

Software Engineering 24 Process and Product Qualities About 50% of the Process fails because they don't meet the needs of users and developers

Software Engineering 25 Software Engineering Software Qualities Lesson 2

Software Engineering 26 Software Qualities Correct Dependable Robustness Secure & Safe Usable Portable Maintainable Reusable Modular Understandable Interoperable