Review and Introduction

In this section we will skip over a bunch of seemingly-unrelated topics pretty fast as you probably know most of it. Pay attention, though, as it is information you need in order to understand later sections.

O/S Review

There are roughly two categories of software:

1. Systems Software (operating systems and their associated tools) and
2. Application software (programs written to solve problems for the user of a system)

The layering of this software looks something like this:

What does an Operating System do?

• Manages H/W resources (CPU, I/O devices, storage, memory, etc)
• Provides a basic, common set of functionality to be used by all applications (device access, communication, security, memory allocation, file access, etc)

Operating systems tend to be very complex (they can be millions of lines of code), yet more than most other software they need to be:

1. efficient (must make efficient use of the system by not wasting resources such as CPU and memory)
2. correct (must contain a minimum of bugs - especially ones that would crash the system)