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Rocket clouds

1. Monitor Point of view

1.1. Monitor controls the events

1.2. Resident monitor is software always in memory

1.3. Job returns control to monitor

2. Processor Point of view

2.1. Processor executes instruction from thr memory containing the monitor

2.2. Control is passed to a job

2.3. Control is returned to the monitor

3. Main Objective

3.1. Convenience

3.2. Efficiency

3.3. Ability to evolve

4. Role of OS

4.1. A computer is a set of resources for the movement,storage and processing of data

4.2. OS responsible for managing

5. Serial Processing

5.1. Earliest Computer

5.1.1. No Operating Systems Computers ran from a display light,taggle switch some form of input device and printers

5.2. Problem

5.2.1. Scheduling Set up time

6. Simple Batch System Overhead

6.1. Processor time between execution of user programs and execution of monitor

6.2. Despite overhead the simple batch system improves utilization of the computer

7. Simple Batch System

7.1. Early computers were very expensive

8. Multi programmed Batch Systems

8.1. Processor is often idle

8.2. Several jobs are kept in main memory at the same time

9. Time Sharing Systems

9.1. Can be used to handle multiple interactive jobs

9.2. Processor time is shared among multiple users

10. Batch Multi programmed and Time Sharing

10.1. Batch Multoprogrammed

10.1.1. Maximize Processor use

10.2. Time Sharing

10.2.1. Minimize Response Time

11. Parallel System

11.1. Advantages

11.1.1. Increased Througput

11.1.2. Economical

11.1.3. Increased Reliability

12. Symmetric Multiprocessing

12.1. Several processor can run in parallel

12.2. Multiple processor are transparent to user

13. Asymmetric Multiprocessing

13.1. Each processor is assigned a specific task

13.2. More common in extremely large systems

14. Hard Real Time Task

14.1. One that must meet its deadline

14.2. Other wise will cause damage

15. Soft Real Time Task

15.1. Has an associated deadline

15.2. Still make sense to complete task even has passed deadline

16. Characteristic of Real Time Systems

16.1. Determinism

16.2. Reliability

16.3. User control

16.4. Fail-soft operation

17. Distributed Systems

17.1. Loosely coupled systems

17.1.1. Each processor has its own local memory processor comminicated with one another through various communication lines Advantages of Distributed Systems Resources Sharing Reliability Computation Speed-up