CO531 Software Engineering

Standalone - Systems that are made, marketed and sold to any customer who wishes to buy them

Customised - Systems that are made, marketed and sold to a specific customer to meet the customer's needs.

Computer programs and associated documentation.

• Should deliver the required functionality
• Should deliver the required performance
• Should be maintainable
• Should be usable

Software engineering is an engineering discipline that is concerned with all aspects of software production.

• Software Specification
• Software Development
• Software Validation
• Software Evolution

Computer Science focuses on theory and fundamentals

Software Engineering focuses on the practicalities of developing and delivering useful software.

• Increased diversity
• Demands for reduced delivery times
• Developing trustworthy software

• 60% development costs
• 40% testing costs

(In custom hardware, sometimes evolution costs can exceed development costs)

• Maintainability
• Dependability (Security)
• Efficiency
• Acceptability

• Software should be written in such a way so that it can evolve to meet the changing needs of customers.
• Software change is inevitable because the business environment it lies within will forever be changing.

• Reliability
• Security
• Safety

Software should not make wasteful use of system resources such as memory or processor cycles.

• Software must be acceptable to the type of users for which it is designed. 
• Understandable
• Usable
• Compatible

Where customers and engineers define the software that is to be produced and the constraints on its operation.

Where the software is designed and programmed.

Where the software is checked to ensure that it is what the customer wanted.

Where the software is modified to reflect changing customer and market requirements.

Where systems are required to operate as distributed systems across networks that include different types of computer and mobile devices.

• Business and society are changing incredibly quickly
• They both need to be able to change their existing software and to rapidly develop new software.
• Competition with other developing economies.

As software is intertwined with all aspects of our lives, it is essential that we can trust that software.

• Systems should be developed using a managed and understood development process.
• Dependability and performance are important for all types of system.
• Understanding and managing the software specification and requirements are important.
• Where appropriate, you should reuse software that has already been developed rather than write new software.

• Organisations are increasingly developing web-based systems rather than local systems.
• Cloud computing is an approach where applications run remotely on the 'cloud'.

Software Process Descriptions include the individual processes needed to create a system with optional accompanying information such as which team member will be assigned to these tasks and the outcomes of each activity. 

• Examples:
• Specifying a data model
• Designing a user interface

Plan-driven processes are processes that have all of the process activities planned in advance and progress is measured against this plan.

Planning is incremental and it is easier to change the process to reflect changing customer requirements.

• Plan-driven model.
• Separation of specification and development.

• Specification, development and validation are interleaved.
• May be plan-driven or agile.

• The system is assembled from existing components.
• May be plan-driven or agile.

• It is difficult to respond to changing customer requirements.
• It is harder to get user feedback on the product during development

• The cost of accommodating changing customer requirements is reduced.
• It is easier to get customer feedback during the development stages.
• More rapid delivery and deployment of useful software to customers is possible.

• The process is not visible. (There is not a lot of documentation involved due to the rapid nature of the development).
• Regular change tends to corrupt its structure. Future changes to the software quickly become difficult and costly.

• Feasibility study: Is the project technically or financially feasible?
• Requirements elicitation: What do the stakeholders want from the system?
• Requirements specification: Defining the requirements in detail
• Requirements validation: Checking the validity of the requirements

Testing of the system as a whole. Testing of emergent properties is particularly important.

Individual components are tested independantly.

Testing with customer data to check that the system meets the customer's needs

Where parts of the system are delivered to the customer in incremental parts, rather than the final system being delivered as a whole.

• Fairly and lawfully processed
• Processed for limited purposes
• Adequate, relevant and not excessive
• Accurate and up to date
• Not kept for longer than is necessary
• Processed in line with your rights
• Secure
• Not transferred to other countries without adequate protection

• Access
• Correction
• Preventing processing if distressing/damaging
• Preventing unsolicited marketing
• Preventing automated decision making
• Compensation
• Complaining

• 1. Unauthorised access to computer material 
• 2. [1]... with intent to commit or facilitate commission of further offences
• 3. Unauthorised acts with intent to impair operation of computer
• 4. Making, supplying or obtaining articles for [1] or [3]

An agreement between an individual and the state to prevent anyone from making, using, selling or importing the individuals invention for up to 20 years

A trade mark is a symbol or sign used by a trader to distinguish his or her product or service from those of other traders.

Unauthorises reproduction, display, distribution.

An act that says you are not allowed to discriminate against the disabled.

An act which gives administrators the power to investigate personal information under the following circumstances:

• - To establish compliance with UK legislation
• - To investigate or detect unauthorised use of the organisation's facilities.
• - To secure effective system operation 
• - To prevent or detect crime
• - In the interests of national security

It can allow government to intercept an individual's communications without the individual being told.