Recent computers are multi-core and can do multiple things at the same time. When we write concurrent programs to exploit them there is a whole new set of defects that we can introduce. Since these defects are often "Heisenbugs", i.e. only show up rarely and unpredictably, they can be very hard and costly to find. Stress testing is often used in these scenarios, but it takes time and is not guaranteed to find any problems.

A new tool have been released that can automatically find defects in multithreaded/concurrent programs. It currently supports normal windows (Win32) binaries, but a DotNet version will be released shortly. The tool systematically explores the behaviors of executable concurrent programs. The user needs to specify interesting scenarios that should be explored. This is done by writing executable unit tests.

The tool has found several unknown concurrency bugs in heavily stress tested systems.


SWELL is a National Innovation Driver for Software V&V funded by Vinnova and a number of Swedish universities and companies.


Reviews and inspections are ways to find problems and increase quality of software and development artefacts. In fact, they are among the most effective methods known. Many practitioners use them. However, many do not, do them partly (without preparation) or do not use them continuously. With shorter release cycles these methods are often avoided altogether.

IBM Haifa labs introduced selective, homeworkless reviews three years ago at different IBM departments. Instead of developers spending 20-30% of their time doing inspections, they now have one hour booked weekly where a part of the code is selected for a focused review. Participants need not prepare but use checklists and other techniques to guide the review. The advantages are:

* Less time spent in review, only critical code or documents are reviewed
* No preparation needed, also cuts the time
* Efficient, finds 2-3 defects per person-hour, like formal inspections
* Normal review advantages like increased developer awareness => better programs with fewer bugs in future

So not much to loose and much to gain. Maybe you can adopt (more) lightweight review methods in your development team?


SWELL is a National Innovation Driver for Software V&V funded by Vinnova and a number of Swedish universities and companies.


Welcome to V&V News - the blog from the Swedish research school in Verification and Validation (V&V) of Software!

We will use this blog to bridge the gap between software development companies and academia within V&V. Lots of good research is happening in academia and lots of good ideas on how to improve V&V is tested and refined in companies but there is too little exchange between the two. By increasing the exchange of information we hope to bridge the gap and create more and better V&V innovation together!

We will try to keep blog posts brief and to the point, summarizing new results, pointing to upcoming conferences and events and in general giving useful ideas for anyone interested in software testing and VaV. We will not flood you with information but try to keep ourselves to weekly or bi-weekly updates. The goal is to poke your interest and give you new ideas without taking much of your time.

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SWELL is a National Innovation Driver for Software VaV funded by Vinnova and a number of Swedish universities and companies.