Software Reliability 2017/2018
MEng 4 and MSc selected specialisms, Department of Computing
Imperial College London


26 September 2017

Software Reliability 2017/2018 web site goes live.

Software Reliability (440)

Open to MEng 4 students and MSc in Computing (Advanced Computing, Software Engineering and Secure Software Systems specialisms) students, this course provides an overview of exciting recent research into techniques and tools that aim to help developers improve the reliability of their software.

The importance of software reliability
Society is becoming ever more reliant on software and software-controlled systems. Some of this software is safety-critical, e.g., the software used to control cars, aeroplanes and other high-speed transport. Defects in safety-critical software can lead to serious injury or death. A much larger volume of software is business-critical, e.g., software that runs in mobile phones, powers web servers and manages data centers. Defects in this type of software can lead to significant financial losses. Underpinning all of these areas is systems software: the low-level operating systems, compilers, device drivers and networking software on which complex systems are built. This foundational role means that the reliability of systems software is of primary importance.
Traditional methods for improving software reliability

Three of the main techniques used in industrial and open source projects to improve software reliability are:

  • Manual testing: Manually crafting a suite of tests to exercise a software system to a reasonably high degree, e.g., covering a high percentage of program statements.
  • Code reviews: Requiring that source code additions or modifications (patches) are reviewed by experienced developers before being committed to the code base.
  • Coding standards: Requiring that all developers adhere to a set of rules when writing or maintaining code. Coding standards can improve source code readability, making it easier to spot defects, and may ban the use of programming idioms that are arguably dangerous.

Rigorous manual testing, code reviews and adherence to standards are essential to the success of large software projects, but they all suffer from two common problems:

  • They depend fundamentally on human reasoning and judgement. Humans are clever, but software can be devilishly complex. It is easy for subtle defects to creep into a project despite adherence to coding standards, and to evade manual testing and code review.
  • They do not provide guarantees. A test suite can demonstrate that certain executions of a software system do not exhibit defects, but provides no further guarantee. For safety- (and often business-) critical systems this may not be enough: it is highly desirable to have a guarantee of defect freedom; ideally an absolute guarantee, but at least a guarantee that system executions have been systematically checked up to some well-defined bound.

This course
The focus of this course is on automatic techniques for improving software reliability which go beyond manual testing. The course will cover:

  • SAT and SMT solving
  • Sanitizers
  • Undefined behaviour
  • Compiler testing and unstable code
  • Safe C compilers
  • Program analysis for security
  • Randomized testing
  • Static verification
  • Dynamic symbolic execution
  • Bounded model checking
  • Invariant generation