[CST-2] Comp. Sys. Modelling

[Alvin]

Well every device must have service demand Dmax, and the total service
demand can't be lowered (as this would give an upperbound potentially less
than the actual worse case).  So we need 3 devices to fill up the total
service demand of 215ms.

It doesn't matter how many devices you have at 100ms - as long as all the
devices have it, and the total service time hasn't been decreased.

I think.

Alvin

> In the answer for this question for the lower bound, they say: "Total
> service demand of 215ms, and hence require 3 devices at 100ms?"  Can
> anyone explain how that follows? Wouldnt you then have 300ms total
> service demand?
> 
> Also, why does it matter how many devices you have at 100ms? Surely
> you always get equally bad performance if any number >= 1 of devices
> are operating at the same bottleneck performance?
> 
> Tim