Computer System
A computer system is fundamentally an integrated collection of components that work together to process, store, and communicate information automatically
Operating System
Vertical View: It is an extended machine
- Present user with a virtual machine - this allows developers no need to rewrite programs when switching to different hardware (since different hardware has different ISA)
UNIX Architecture System Calls vs. Function Calls Modes of Execution System Memory (User Space vs. Kernel Space)
Horizontal View: It is a resource managaer
- Manage hardware resources: CPU, memory, I/O devices
- Each program gets time using the resource and space on the resource
- OS makes sure programs have a fair use on the resource
- Act as interface for user to access kernel