\section{Introduction}

Our world is getting more and more surrounded by electronical devices. Only a few years ago our surroundings were limited to Radio's and Televisions. Soon after we got our Microwaves and washing machines, not to mention the boom in the mobile phone corner. All these devices require Operating systems and nearly all require real-time operating systems. \\

To define a real-time operating system is beyond the scope of this article, what is not however is that all (real-time) operating systems use some sort of scheduling algorithm. \\

We have done a literature study concerining one of these algorithms, called Fixed Priority Deferred Schedule (FPDS) and looked at various aspects of it. \\

\section{Motivation}

FPPS does many great things. One of which however is not, dealing with caches. Caches are great things if you can use them. Audio/Video almost always work a lot faster with caches, so if you like to use caches in a real-time system, there is a scheduling algorythm that allows exactly this, namly is FPDS. FPDS allows the uses of caches, and still behaves like a real-time system. \\

Resource control can get complex very fast, due to things like Interupt Service Routines (ISR) and buffers to actually access certain resources. With FPPS this is very complex task and introduces a lot of overhead. One of the design goals of FPDS was to simply this and thus also reducing the overhead. \\
