1. Lecture 16: Processes Intro to IT COSC1078 Introduction to Information Technology Lecture 16 Processes James Harland james.harland@rmit.edu.au

2. Lecture 15: BootingIntro to IT Introduction James Harland Email: james.harland@rmit.edu.au URL: www.cs.rmit.edu.au/~jah Phone: 9925 2045 Office: 14.10.1 Consultation: Mon 4.30-5.30, Thu 11.30-12.30 What colour is my office door? Carpet? Chair?

3. Lecture 16: ProcessesIntro to IT Introduction to IT 1 Introduction 2 Images 3 Audio 4 Video WebLearnTest 1 5 Binary Representation Assignment 1 6 Data Storage 7 Machine Processing 8 Operating Systems WebLearn Test 2 9 Processes Assignment 2 10 Internet 11 Internet Security WebLearn Test 3 12 Future of ITAssignment 3, Peer and Self Assessment

4. Lecture 16: ProcessesIntro to IT Overview  Questions?  Assignment 2  Assignment 3  Processes  Questions?

5. Lecture 16: ProcessesIntro to IT Processes

6. Lecture 16: ProcessesIntro to IT Processes A program is a static set of instructions A processes is the execution of a program, which changes state over time.

7. Lecture 16: ProcessesIntro to IT Processes Executing in Context Program Counter Instruction Register CC ROM RAM ProcessorMemory Disk 00 CC

8. Lecture 16: ProcessesIntro to IT Processes Executing in Context Program Counter Instruction Register DD ROM RAM ProcessorMemory Disk 00 CC DD

9. Lecture 16: ProcessesIntro to IT Processes Switching Ready Waiting Scheduler maintains process table

10. Lecture 16: ProcessesIntro to IT Processes Switching

11. Lecture 16: ProcessesIntro to IT Interrupts  Signals to the CPU  Often generated by timing circuits  CPU reacts by jumping to appropriate memory location  Dispatcher  selects a ready process  resets timing circuit  starts process  CPUs often designed to switch process states efficiently

12. Lecture 16: ProcessesIntro to IT Processes Executing in Context Program Counter Instruction Register BB ROM RAM Processor Memory Disk 00 BB

13. Lecture 16: ProcessesIntro to IT Processes Executing in Context Program Counter Instruction Register 11 ROM RAM Processor Memory Disk 00 BB

14. Lecture 16: ProcessesIntro to IT Processes Executing in Context Program Counter Instruction Register FF ROM RAM Processor Memory Disk 00 FF

15. Lecture 16: ProcessesIntro to IT Processes Executing in Context Program Counter Instruction Register BB ROM RAM Processor Memory Disk 00 BB

16. Lecture 16: ProcessesIntro to IT Processes Executing in Context Program Counter Instruction Register BB ROM RAM Processor Memory Disk 00 BB

17. Lecture 16: ProcessesIntro to IT Processes Executing in Context Program Counter Instruction Register FF ROM RAM Processor Memory Disk 00 FF

18. Lecture 16: ProcessesIntro to IT Processes Executing in Context Program Counter Instruction Register BB ROM RAM Processor Memory Disk 00 BB

19. Lecture 16: ProcessesIntro to IT ``Thomas, you wouldn’t! Naughty!’’ Program Counter Instruction Register BB ROM RAM Processor Memory Disk 00 BB

20. Lecture 16: ProcessesIntro to IT ``Thomas, you wouldn’t! Naughty!’’ Program Counter Instruction Register BB ROM RAM Processor Memory Disk 00 BB

21. Lecture 16: ProcessesIntro to IT ``Thomas, you wouldn’t! Naughty!’’ Program Counter Instruction Register BB ROM RAM Processor Memory Disk 00 BB

22. Lecture 16: ProcessesIntro to IT Software  `Programs should be able to do anything!’ (???)  Programs should be able to do anything reasonable  What is reasonable?  Not changing OS, not deleting other processes from memory, not playing with other people’s things, …

23. Lecture 16: ProcessesIntro to IT Interrupts  Provide mechanism to switch processes  CPU doesn’t have to wait for I/O transfers  Switching leads to faster throughput  `Save document’ means CPU does something else while the save takes place

24. Lecture 16: ProcessesIntro to IT Conclusion  Work on Assignment 2 (and 3?)  Web Quizzes and Web Test 2  Finish reading book!