How does a feedback work in Simulink at the Solver level

Hi, I would like to understand how does the solver work in Simulink when I have a feedback. Let's assume I have a really easy feedback system, like this for example

What does the solver do? I take the input, I go through the two blocks, and then the output should be fed back in the sum block. At the really first instant, when I do not have an output, what does the solver do? Is the feedback considered to be zero for 1 sample time, so that, at the first sample time, the output of the sum block is just the input? Best

Answer 1

[Birdman]

At the first instant, everything is set to be zero. If you look at the scope's beginning, you will see that the output is conditioned as zero at the beginning. Therefore at the first time, the sum output is just the input value. Otherwise, how an error can be formed at the beginning? Or if it was different than zero, how the desired behaviour for the system can be achieved? Think about this questions.