Operating System Notes | B.Sc. (Information Technology) Semester 3 | Mumbai University | munotes

Contents

Module I Operating System Overview: Basics of operating systems: Generations, Types, Structure, Services, System Calls, System Boot, System Programs, Protection and Security

1. What an Operating System Is 1
2. The Two Jobs: Handing Out the Machine, and Hiding It 5
3. Interrupts, Traps and the Two Modes 8
4. The Timer, and Getting the Processor Back 12
5. The First Generation: a Machine with No Operating System 15
6. The Second Generation: the Batch and the Resident Monitor 18
7. The Third Generation: Multiprogramming and Spooling 21
8. The Fourth Generation: Time Sharing and the Personal Computer 24
9. Batch, Multiprogrammed and Time Sharing Systems 27
10. Multiprocessor Systems 30
11. Distributed and Clustered Systems 33
12. Real Time Systems, Hard and Soft 36
13. Embedded and Handheld Systems 39
14. The Simple Structure and the Monolithic Kernel 42
15. The Layered Approach 45
16. The Microkernel 48
17. Modules, Hybrid Kernels and the Virtual Machine 51
18. The Services an Operating System Offers 55
19. The User Interface: Command Line, Batch and Graphical 58
20. What a System Call Is, and the Trap that Makes One 61
21. How a System Call Carries Its Arguments 64
22. The Six Kinds of System Call 67
23. System Boot: from Power On to the First Process 70
24. System Programs 74
25. Protection 77
26. Security 81
27. Protection and Security on a Machine You Can Log In To 85
28. What a Process Is 89
29. The Memory a Process Occupies 92
30. Operations on Processes: Creation and Termination 95
31. The Five Process States 99
32. The Queues a Process Waits In 102
33. The Process Control Block 105
34. The Context Switch, and What It Costs 108
35. The Five Scheduling Criteria 112
36. First Come First Served 115
37. Shortest Job First 118
38. Shortest Remaining Time First 121
39. Priority Scheduling and Starvation 124
40. Round Robin and the Quantum 128
41. Multilevel Queue Scheduling 132
42. Multilevel Feedback Queue Scheduling 135
43. Every Algorithm on One Problem 139
44. Evaluating a Scheduling Algorithm: Deterministic Modelling 143
45. Queueing Models, Simulation and Implementation 146
46. What a Thread Is 150
47. User Threads, Kernel Threads and the Three Models 153
48. Threading Issues 156
49. Two Processes, One Variable, and an Answer that Changes 160
50. A Race Condition Made to Happen 163
51. The Critical Section Problem 167
52. Two Attempts that Fail, and Why 171
53. Peterson's Solution 174
54. Why Peterson's Solution Works, and Where It Still Breaks 178
55. Synchronization Hardware: Test and Set 182
56. Compare and Swap, and the Atomic Variable 186
57. Mutex Locks and the Spinlock 190
58. Semaphores: Wait and Signal 193
59. Counting and Binary Semaphores, Without Busy Waiting 197
60. The Bounded Buffer Problem 201
61. The Readers and Writers Problem 204
62. The Dining Philosophers Problem 208
63. Deadlock and Starvation from Semaphores Used Wrongly 212

Module II Memory Management: Main Memory, Swapping, Contiguous Memory 15 Hrs

1. The Address the Program Uses, and the Address the Hardware Sees 216
2. Binding an Address: Compile, Load and Run Time 219
3. The Memory Management Unit and the Relocation Register 222
4. The Base and Limit Registers 225
5. Dynamic Loading and Dynamic Linking 228
6. Swapping 231
7. What Swapping Costs, and When It Is Worth It 234
8. One Partition, then Fixed Partitions 237
9. Variable Partitions and the List of Holes 240
10. First Fit, Best Fit and Worst Fit 243
11. External and Internal Fragmentation, and Compaction 246
12. Paging: the Page and the Frame 249
13. The Page Table and the Address Split 252
14. Working a Paging Sum 255
15. The Frame Table, and What Paging Costs in Space 258
16. The Translation Look-aside Buffer 261
17. Effective Access Time with a TLB 264
18. Protection Bits, the Valid-Invalid Bit, and Shared Pages 267
19. Hierarchical Page Tables 270
20. Hashed and Inverted Page Tables 273
21. Segmentation 276
22. Segmentation with Paging 279
23. Virtual Memory: What It Is, and What It Buys 282
24. Demand Paging 285
25. The Page Fault, Step by Step 288
26. The Effective Access Time of Demand Paging 291
27. Page Replacement: the Problem and the Reference String 294
28. First In First Out Replacement, and Belady's Anomaly 298
29. Optimal Replacement 302
30. Least Recently Used Replacement 305
31. Approximating LRU: the Reference Bit and Second Chance 308
32. Counting Based Replacement, and Page Buffering 311
33. Every Replacement Algorithm on One Reference String 315
34. Allocation of Frames: How Many Each Process Gets 318
35. Global and Local Replacement 321
36. Thrashing 324
37. The Working Set Model 327
38. Page Fault Frequency, and What to Do About Thrashing 330
39. The System Model: Resources and Instances 333
40. The Four Necessary Conditions 336
41. The Resource Allocation Graph 339
42. The Four Ways to Handle a Deadlock 342
43. Deadlock Prevention, Condition by Condition 345
44. The Safe State 349
45. The Resource Allocation Graph Algorithm 352
46. The Banker's Algorithm 355
47. A Request Tested Against the Banker's Algorithm 358
48. Detecting a Deadlock with a Wait-For Graph 362
49. The Detection Algorithm for Several Instances 365
50. Recovery by Killing Processes 368
51. Recovery by Taking Resources Back 371
52. What a File Is 374
53. The Operations on a File, and the Open File Table 377
54. File Types and the Structure Inside a File 380
55. Sequential Access 383
56. Direct Access 386
57. Indexed Access 389
58. The Single Level and Two Level Directory 392
59. The Tree Directory 395
60. The Acyclic Graph and General Graph Directory 398
61. The Layers of a File System 402
62. The Structures on the Disk Itself 405
63. A Real File System Opened Up 408
64. The Disk the File System Is Written On 411
65. Disk Scheduling 414
66. The Examination Itself 418