Download Operating System Tutorial (PDF Version) - Tutorials Point

More documents

Recommendations

Info

Schedulers Schedulers are special system software which handles process scheduling in various ways. Their main task is to select the jobs to be submitted into the system and to decide which process to run. Schedulers are of three types Long Term Scheduler Short Term Scheduler Medium Term Scheduler Long Term Scheduler It is also called job scheduler. Long term scheduler determines which programs are admitted to the system for processing. Job scheduler selects processes from the queue and loads them into memory for execution. Process loads into the memory for CPU scheduling. The primary objective of the job scheduler is to provide a balanced mix of jobs, such as I/O bound and processor bound. It also controls the degree of multiprogramming. If the degree of multiprogramming is stable, then the average rate of process creation must be equal to the average departure rate of processes leaving the system. On some systems, the long term scheduler may not be available or minimal. Time-sharing operating systems have no long term scheduler. When process changes the state from new to ready, then there is use of long term scheduler. Short Term Scheduler It is also called CPU scheduler. Main objective is increasing system performance in accordance with the chosen set of criteria. It is the change of ready state to running state of the process. CPU scheduler selects process among the processes that are ready to execute and allocates CPU to one of them. Short term scheduler also known as dispatcher, execute most frequently and makes the fine grained decision of which process to execute next. Short term scheduler is faster than long term scheduler. Medium Term Scheduler Medium term scheduling is part of the swapping. It removes the processes from the memory. It reduces the degree of multiprogramming. The medium term scheduler is in-charge of handling the swapped out-processes. TUTORIALS POINT Simply Easy Learning Page 27
Running process may become suspended if it makes an I/O request. Suspended processes cannot make any progress towards completion. In this condition, to remove the process from memory and make space for other process, the suspended process is moved to the secondary storage. This process is called swapping, and the process is said to be swapped out or rolled out. Swapping may be necessary to improve the process mix. TUTORIALS POINT Simply Easy Learning Page 28
Page 1 and 2: Operating System Tutorial
Page 3 and 4: ABOUT THE TUTORIAL Operating System
Page 5 and 6: Multiprogramming ..................
Page 7 and 8: Clocks ............................
Page 9 and 10: Following are some of important fun
Page 11 and 12: CHAPTER 2 Types of Operating System
Page 13 and 14: Distributed operating System Distri
Page 15 and 16: Real Time operating System Real tim
Page 17 and 18: Program execution Operating system
Page 19 and 20: Error handling Error can occur anyt
Page 21 and 22: Increased performance as a new job
Page 23 and 24: Multiprogramming When two or more p
Page 25 and 26: Spooling Spooling is an acronym for
Page 27 and 28: Program A program by itself is not
Page 29 and 30: Process Control Block, PCB Each pro
Page 31 and 32: CHAPTER 6 Operating System Process
Page 33: Two State Process Model Two state p
Page 37 and 38: Context Switch A context switch is
Page 39 and 40: First Come First Serve (FCFS) Jo
Page 41 and 42: Priority Based Scheduling Each p
Page 43 and 44: Multi Queue Scheduling Multiple
Page 45 and 46: Difference between Process and Thre
Page 47 and 48: Types of Thread Threads are impleme
Page 49 and 50: Multithreading Models Some operatin
Page 51 and 52: Difference between User Level & Ker
Page 53 and 54: Instructions and data to memory add
Page 55 and 56: Logical versus Physical Address Spa
Page 57 and 58: Memory Allocation Main memory usual
Page 59 and 60: Paging External fragmentation is av
Page 61 and 62: Address generated by CPU is divided
Page 63 and 64: Virtual memory is commonly implemen
Page 65 and 66: Step Description Step 1 Check an in
Page 67 and 68: Page Replacement Algorithm Page rep
Page 69 and 70: Least Recently Used (LRU) algorithm
Page 71 and 72: I/O port An I/O port typically cons
Page 73 and 74: I/O devices I/O Devices can be cate
Page 75 and 76: 4 Disk controller sends each byte t
Page 77 and 78: CHAPTER 12 I/O Software This sectio
Page 79 and 80: Clocks Clocks are also called timer
Page 81 and 82: Device driver Device driver is a pr
Page 83 and 84: File Type File type refers to the a
Page 85 and 86:
Space Allocation Files are allocate
Page 87 and 88:
Authentication Authentication refer
Page 89 and 90:
Program Threats Operating system's
Page 91 and 92:
Computer Security Classifications A
Page 93 and 94:
Components of Linux System Linux Op
Page 95 and 96:
Basic Features Following are some o
Page 97:
APPENDIX A About tutorialspoint.com
show all

Download Operating System Tutorial (PDF Version) - Tutorials Point

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?