08:30-10:00 – Real Time System lecture

We went through how processes are changing using semaphores and how to calculate the response time for processes when scheduling of processes is done is done.

Not sure I am using the correct terminology here, since we are having this and most courses, in Swedish.

We were looking at two different types. Static and Dynamic (according RMSA). You use a formula like this:

Using this formula until you get the same result (and using the result as input for next R3 within the formula continuously) twice, which means you have reached convergence and thereby have found your periodic schedule.

Then there are blocking factors to include if there are any.


Didn’t have any lecture and therefore went to a computer room and started with a lab where we are going to write a main program and a number of processes and functions and use semaphores to control a door.

Then we had lunch at L’s Kitchen at Lindholmen Science Park.

13:15-15:15 – Linear Systems lecture

We started with some repetition from yesterday looking at sampling periods, that the sampling frequency need to be at least two times as high as the frequency which is called the Sampling Theorem.

By sampling more than twice the frequency, you will at some point sample the same frequency as earlier and thereby you have a period which is repeated.

Then we went through Difference Equations and some terminology such as Linear, Time invariant, Causal, Transverse and Recursive.

Also step answer and some other… (but then I had to run out because of my stomach and then went home).