Confused by Simulink

The most common modelling tool in the automotive domain is Simulink. It started as a Matlab-based tool to graphically model and simulate differential equations needed in control design. Now it has expanded way beyond that to enable generation of production code for embedded controllers.

For someone like me, with a background in software and systems engineering and only the mandatory control engineering course, Simulink is confusing. Not the model elements as such, since it basically is an executable time-discrete data flow model. But the terminology used in the Simulink community is really confusing since they are using terms very common in software development, but with different meanings. I am not even sure the explanations below are valid...

Some examples:

• A layer in Simulink is not what what one usually calls a layer in software. What is called a layer in Simulink I would personally call a view since it adresss a specific concern, see some defintion of the J-MAAB layers here. But I have also seen a layer as something found at a certain level in a functional hierarchy (boxes in boxes...). Maybe these two even are the same in the Simulink world?
  A software layer would rather be called a subsystem in Simulink, but that is a generous interpretation from my side. (See Pattern-Oriented Software Architecture by Buschmann et al. for a definiton of software layer).
• There are classes and objects in Simulink. Data objects are used to "specify values, data types, tunability, value ranges, and other key attributes of block outputs and parameters", where blocks are the basic entities that one build the simulink model from.
  The Simulink software uses objects called data classes to define the properties of specific types of data objects." So in a sense the class is a template for the objects. On the other hand the data object does not specify a behaviour or input-output relationship. But classes seem also to be a special type of objects in thelast quote above. Ouch!
  Contrast this to common OO design where the class is the template for the object, which is the main item encapsulating both a behaviour and associated data. A block in Simulink most closely resembles a function in a procedural language such as C or Pascal.

The importance of the team

I am reviewing and grading documentation in a student project. Or rather 12 student projects, all trying to develop similar software. The context is this: The students work in teams of 6. Each student has a separate role; project manager, architect, designer, quality/testing responsible, GUI designer and communications expert (it is an peer-to-peer application based on TCP). Alla students have to write code, and in addition to this they are supposed to turn in documentation related to their role.

What strikes me is that in the teams with good documentation all documents are good, regardless of author. How come? There could be several explanations:

• Good students want to work with each other (they could choose their teammates, they weren't assigned by us teachers).
• In good teams they cooperate on everything, inlcuding reviewing each others documents. In not-so-good teams they instead might try to split the tasks and work as independently as possible.
• In the good teams there is an exceptional student that functions as a mentor to the others.
• Excellent documementation from one role supports the others in their roles, e.g. an excellent architeture description supports testing etc.
• The good teams had not only a notion about what to deliver when they started, they also had a good notion on how to do it early on, e.g. they discussed so they had a common understanding of coding responsibility (everybody had to write code) and they choose an interative process or SCRUM already the first week.
• The good teams started with coding as quickly as possible. This is counterintuitive, but I think they felt more comfortable spending time on documentation if they already had some prototype running.
• It seems that analysis paralysis actually produces worse documentation. I think this is due to an inability to focus on the vital concerns and stop when they are sufficiently covered.
• It is hard to excel if your teammates drag you down. This could explain why there are no groups where just one role shines above the rest.

I'm sure there could be other explanations that I didn't think of...

IT talents in Sweden

For my Swedish readers:

Skill har skickat ut enkäten till studenter vid samtliga svenska lärosäten som har IT-utbildningar. 1140 IT-talanger har besvarat enkäten och det är deras svar som ligger till grund för denna rapport. Av de som har svarat är 20% kvinnor och 80% män. IT-talangerna är 27 år i snitt och åldersspridningen är mellan 19 och 54 år.

Improving quality with well-written requirements

I discussed with a colleague about how to improve specifications and we agreed that one of the actions that would yield quality improvements with very little investment was to educate people in our organisation on how to write good requirements.
Unfortunately such a course is not available internally at Volvo Cars (don't ask me why). But a search found some useful pages that could serve as an introduction:

• The Story of the Paperclip: Writing Good Functional Requirements from StartupCTO
• Writing Good Requirements – The Big Ten Rules from Tyner Blain
• Writing good requirements is a lot like writing good code by Jim Heumann, IBM
• Writing Good Requirements (A Requirements Working Group Information Report)
• SMART Requirements by Mike Mannion and Barry Keepence

Is software engineering immature?

Is software engineering an "immature" engineering discipline? I have often heard this both in presentations and in reading, for example SEMAT states on the homepage:

"Software engineering is gravely hampered today by immature practices."

If I draw parallels between software engineering and civil engineering (arguably the most mature engineering discipline) my spontaneous conclusion was: Yes, software engineering seems to be more like how cathedrals were built in medieval times. The construction of them were based on rules of thumb and the practical skills and experience of architects and stone masons instead of the type of engineering practices taught at universities today. Interestingly enough, one can still see the "successful" cathedrals still standing several centuries later. But it would have been impossible for the architect of  Lund Cathedral to build something like the nearby Turning Torso. So the engineering in civil engineering has certainly "matured".
But where is software engineering failing? Everyone has heard of software projects running over time, over budget or have not been used as intended (or not used at all). But wait a minute! Exactly the same thing is common within civil engineering as well. There are many examples from a single contractor renovating a small house up to world known buildings such as the Sydney Opera House:

"The original cost estimate in 1957 was £3,500,000 ($7 million). The original completion date set by the government was 26 January 1963 (Australia Day).[16] Thus, the project was completed ten years late and over-budget by more than fourteen times."

So in this respect software engineering is as immature as other engineering disciplines.
So what is the fuss about? I agree that there is no consensus in the software community on how to do the equivalence of structural mechanics calculations or stress tests. Are we more hampered by this lack of consensus on how to do engineering tasks than by the difficulty to run large projects, which seem to be common to other engineering disciplines?

Available infotainment platforms

I have previously written about various platforms for infotainment systems. I also had a slide about it in my presentation on Lindholmen Software Development day, where my point was to say that it is possible to use either a commercial platform, such as Windows Embedded Automotive or an open source such as Meego. It is a business decisions which way an OEM wants to go, not a technical.

I have probaly missed some, but here is a list of infotainment platforms available today for an OEM to build an in-vehicle infotainment system on:

• Windows Embedded Automotive, used for example in Ford's Sync.
• QNX Aviage
• Mecel Betula Suite - Automotive Bluetooth Platform
• Meego
• GENIVI, but there is little informaiton about the techical solition on the webiste. They will most likely utilise the Meego platform.
• Harman has an infotainment platform. They recenlty acquired AHA Mobile which probably will be integrated.
• There are alot of notices on using Android for in-vehicle infotainment if one searches the web, but I have not been able to find any open source software based on Android for in-vehicle use.
• Continental's Autolinq seems to be Android-based, but is not open source in the same sense as e.g. Meego, and apps must be approved (by Continental?) to be downloaded.
• Luxoft offers LUXnet, which is also Android-based, but I cannot find any information besides a press release on their homepage.