1. Who’s in charge in there?
Operating Systems
Who’s in charge in there?

2. Types of Software Application Software : Does things we want to do
System Software : Does things we need done Low level details

3. Operating System
Operating System : Software that manages the operation of a computer
Not all computational systems have an OS
Early computers
Embedded systems

4. Operating Systems PC Operating Systems Phone OSes Windows *nix iOS
Linux
MacOS X
Phone OSes
iOS
Android

5. Operating Systems
What is Linux?

6. Varieties of OSes
Embeded

7. Varieties of OSes
Batch
Submit list of jobs

8. Varieties of OSes
Real Time / Dedicated

9. What do the do? API : Application Programming Interface
Set of functions software can do
OS provides API to other programs for
Reading files
Using a network
Drawing windows
Getting mouse position

10. What do they do? Manage hardware resources
Provide an abstraction for resources
Allocate scare resources

11. Resource Scarcity Resources scarce in
Time
Processor
IO / Disk
Space
Memory
Disk
OS responsible for allocating scarce resources

12. Resources - Processes OS manages what process(es) are running
Programs take turns on processor
Run until time limit or need to wait
OS handles all hardware events

13. Resources - Memory Main Memory :
Where running programs & data are stored
Computer may have ~4 or 8 billion bytes
Programs can "use" up to 200 trillion bytes (48 bit addresses)

14. Virtual Address Space Program uses virtual addresses OS maps to
Nice, orderly
OS maps to
Main memory
Hard drive (Virtual Memory)

15. Other Resources Hard Disk Abstraction: Allocation:
Programs ask for files ("MyEssay.doc"), OS deals with details
Allocation:
What users/programs get to work with which files

16. Other Resources Monitor: Abstraction Allocation:
How exactly to draw to screen
Allocation:
What program's get to draw in what order

17. Other Resources Monitor: Abstraction Allocation:
How exactly to draw to screen
Allocation:
What program's get to draw in what order