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 181
56. Compare and Swap, and the Atomic Variable 185
57. Mutex Locks and the Spinlock 189
58. Semaphores: Wait and Signal 192
59. Counting and Binary Semaphores, Without Busy Waiting 196
60. The Bounded Buffer Problem 200
61. The Readers and Writers Problem 203
62. The Dining Philosophers Problem 207
63. Deadlock and Starvation from Semaphores Used Wrongly 211

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

1. The Address the Program Uses, and the Address the Hardware Sees 215
2. Binding an Address: Compile, Load and Run Time 218
3. The Memory Management Unit and the Relocation Register 221
4. The Base and Limit Registers 224
5. Dynamic Loading and Dynamic Linking 227
6. Swapping 230
7. What Swapping Costs, and When It Is Worth It 233
8. One Partition, then Fixed Partitions 236
9. Variable Partitions and the List of Holes 239
10. First Fit, Best Fit and Worst Fit 242
11. External and Internal Fragmentation, and Compaction 245
12. Paging: the Page and the Frame 248
13. The Page Table and the Address Split 251
14. Working a Paging Sum 254
15. The Frame Table, and What Paging Costs in Space 257
16. The Translation Look-aside Buffer 260
17. Effective Access Time with a TLB 263
18. Protection Bits, the Valid-Invalid Bit, and Shared Pages 266
19. Hierarchical Page Tables 269
20. Hashed and Inverted Page Tables 272
21. Segmentation 275
22. Segmentation with Paging 278
23. Virtual Memory: What It Is, and What It Buys 281
24. Demand Paging 284
25. The Page Fault, Step by Step 287
26. The Effective Access Time of Demand Paging 290
27. Page Replacement: the Problem and the Reference String 293
28. First In First Out Replacement, and Belady's Anomaly 297
29. Optimal Replacement 301
30. Least Recently Used Replacement 304
31. Approximating LRU: the Reference Bit and Second Chance 307
32. Counting Based Replacement, and Page Buffering 310
33. Every Replacement Algorithm on One Reference String 314
34. Allocation of Frames: How Many Each Process Gets 317
35. Global and Local Replacement 320
36. Thrashing 323
37. The Working Set Model 326
38. Page Fault Frequency, and What to Do About Thrashing 329
39. The System Model: Resources and Instances 332
40. The Four Necessary Conditions 335
41. The Resource Allocation Graph 338
42. The Four Ways to Handle a Deadlock 341
43. Deadlock Prevention, Condition by Condition 344
44. The Safe State 348
45. The Resource Allocation Graph Algorithm 351
46. The Banker's Algorithm 354
47. A Request Tested Against the Banker's Algorithm 357
48. Detecting a Deadlock with a Wait-For Graph 361
49. The Detection Algorithm for Several Instances 364
50. Recovery by Killing Processes 367
51. Recovery by Taking Resources Back 370
52. What a File Is 373
53. The Operations on a File, and the Open File Table 376
54. File Types and the Structure Inside a File 379
55. Sequential Access 382
56. Direct Access 385
57. Indexed Access 388
58. The Single Level and Two Level Directory 391
59. The Tree Directory 394
60. The Acyclic Graph and General Graph Directory 397
61. The Layers of a File System 401
62. The Structures on the Disk Itself 404
63. A Real File System Opened Up 407
64. The Disk the File System Is Written On 410
65. Disk Scheduling 413
66. The Examination Itself 417