3. UNIX design

There are 4 main layers to the UNIX system

1. the kernel
2. the shell
3. applications
4. users

UNIX filesystem layout

3.1. the Kernel

3.2. Virtual memory

3.3. Multi-user

3.4. the Filesystem

3.4.1. The UNIX philosophy: Everything is a file

3.4.2. Hierarchy

3.5. Access-rights

3.5.1. Various example combinations

3.5.2. Special bits