This note mainly covers writing multi-threaded programs and implementing synchronization primitives with low-level hardware.

These topics are covered in the first half of the course.

Lecture 1

Role of OS

OS is a software layer between application programs and the hardware:

• virtual machine interface
• physical machine interface

OS allows:

• an easier process to write applications without the need to worry about hardware details
• managing multiple applications with memories and isolation requirements

OS provides abstractions:

• CPU to threads
• Memory to address spaces
• Disk to file system
• Network cards to sockets

In reality, OS is the main program that calls applications as subroutines. Applications run until it returns control back to the OS.

History of OS

Single operator at console

It is interactive but utilizes hardware very poorly.

Batch processing