Design and Implementation of an OS

Start the design by defining goals and specifications

Affected by choice of hardware, type of system

User goals and System goals

• User goals – operating system should be convenient to use, easy to learn, reliable, safe, and fast

• System goals – operating system should be easy to design, implement, and maintain, as well as flexible, reliable, error-free, and efficient

Policy and Mechanism

Policy - what needs to be done? (print('hello'))

Mechanism - how it is done? (print())

IT A GOOD IDEA TO SEPARATE THE TWO

Implementation

• Early OS's were made in Assembly

• Then in Algol and then PL/1

• When made with higher level languages it is easier to port over to other hardware

What are OS made with:

• Early OS's made in assembly language

• Then system programming languages like Algol, PL/1

• Now C, C++