Jakob Engblom

Integration and Testing the Integration

The US National Highway Traffic Safety Administration (NHTSA) recently released a deep report into last year's issue with "unintended acceleration" on certain Toyota cars. They actually employed a team from NASA who analyzed the throttle control software using a wide range of cutting-edge tools. Reading their report gives a good idea for how embedded control software is developed, and the challenges inherent in validating it.

Being Helpful or simply Correct?

The other day, I spent some time getting a new operating system up on one of our Simics virtual platforms. The platform is stable, the hardware is shipping and it is being used with the very software I was setting up. However, as the operating system was booting, I got quite a lot of warnings from Simics about incorrect hardware settings. The operating system still worked, however, so why did we see all these warnings? Actually, when is it prudent to issue warnings to a user about suspicious uses of hardware? When building Simics models, we want them to be helpful and offer warnings as much as possible - especially for cases where some uses might be considered technically "correct" but are actually somewhat suspicious.

Physical or Virtual

When you explain what a virtual platform or full-system simulation solution like Wind River Simics is, a key part is that it runs the same software as a physical board or physical system. This does capture the core of the idea - but it does not mean that the virtual platform is only "just like the real thing".

Comparing virtual and physical systems is like comparing apples and apples, not apples and oranges: while apples are mostly interchangeable, they is certainly variation between them. Some apples are best for eating, some are better for making sauce, some are pie material, and some are best for fermenting cider. The type you select depends on what you want to cook. The difference between physical and virtual hardware is similar: they can be used as replacements for each other to some extent, but the connoisseur can make much better use of both by looking at the differences.

This post goes through some of the important fundamental ways that virtual hardware is different from physical hardware. 

Virtual Trace

I spent most of last week at the S4D conference in Southampton, the UK. A small gathering of people interested in debug, it seems to be a good indicator of trends in debug. The dominant trends this year were clearly tracing and instrumentation. From the perspective of a virtual platform, tracing is a natural task, and it can be done with much less pain than on a physical platform.

Transporting Bugs with Checkpoints

I have a paper about "Transporting Bugs with Checkpoints" to be presented at the S4D (System, Software, SoC and Silicon Debug) conference in Southampton, UK, on September 15 and 16, 2010. The core concept presented is to leverage Wind River Simics checkpointing to capture and move a bug from the bug reporter to the responsible developer. It is a fairly simple idea, but getting it to work efficiently does require that some things are done right.

True Concurrency is Truly Different (Again)

A recent article at Ars Technica describes yet another security flaw in Windows. Nothing much new in that respect, but this is indeed an interesting attack in that it is enabled by using multicore hardware. It is not practical on a single processor, demonstrating once again how multicore is fundamentally different from multitasking on a single processor.