Disclaimer:

This is a set of notes, that summarizes the class coverage of material. By no means is this comprehensive or is a substitute for class notes and attendance. Also, updating of this page is not guaranteed to be frequent.

Class 1: Jan 19th

• Discussion on TV class logistics, homeworks, exams, projects, cheating
• What is an operating system - various definitions
• Design goals of operating systems
• "convenience" and "efficiency"
• Government and Resource Management
• Old computers - how they worked
• Resident monitor and automation
• Spooling and Buffering

Class 2: Jan 24th - pretaped

• Spooling and buffering continued
• Multiprogrammed systems - batch and interactive
• Parallel, Distributed and Real time systems
• PC systems
• Structure of Operating Systems
• Process management, Memory management, File Systems, I/O management and how things fit together.
• Security and Protection
• Interrupt handling

Class 3: Jan 26th - pretaped

• How System calls are implemented (and why)
• The need for protection
• How protection is implemented via memory bounds and Interrupt handling

Class 4: Jan 31st

• Operating System Structures - layering and modularity
• Assigned reading Chapter 1-3
• The process concept (processes and Programs)
• States of a process
• Scheduling Queues

Class 5: Feb 2nd

• Scheduling continued
• CPU and I/O burst of a process
• How a process executes
• Context Switching - how contexts are saved and restored
• Policy and Mechanisms
• Scheduling Policies: FIFO and SJF
• Good and bad features of SJF
• Priority Scheduling

Class 6: Feb 7th - pretaped

• Overlapping of I/O and CPU as a method for getting effiiency
• SJF revisited - optimality of SJF
• Pre-emptive policies
• Round robin - what it is and how it works
• Response time
• Pros and cons of round robin

Class 7: Feb 9th - pretaped

• How to make round robin better
• Multi level queues
• Starvation revisited
• Multi level feedback queues (adaptive, dynamic scheduling)
• Scheduling in Unix
• Fine tuning of schedulers
• Evaluation of Schedulers: Deterministic, Queuing Models and 2 kinds of simulations
• Implementing real schedulers - issues

Class 8: Feb 14

• Concurrent Processes, Shared Memory, and Threads
• Why are threads or shared memory processes important in the OS context
• What is the problem with shared memory:
    - race conditions
    - need for critical sections
• Properties of a critical section
• Towards a software solution (2 process)

Class 9: Feb 16

• Peterson's Algorithm for 2-process software solution
• Lamport's Bakery Algorithm for N process critical section

Class 11: Feb 21

• Lamport's Bakery Algorithm for N process critical section (revisited)
• Overflow problem with Lamport
• Software solution without overflow
• Hardware solution techniques
• Test and Set ... mutex OK but Bounded Waiting not OK.
• A Test and Set solution that provides Bounded Waiting

Class 12: Feb 23

• Types of Critical Sections (associated with variables)
• Programming with critical sections
• Introduction to Semaphores
• Dijkstra's definition
• Usage of semaphores for Critical sections and Synchronization
• The Bounded waiting problem with Dijkstra Semaphores
• The Busy Waiting problem with Dijkstra Semaphores 
• Bounded Buffer problem (producer consumer and solution)

Class 13: Feb 28

• The Readers and Writers Problem
• Using Dijkstra Semaphores lead to starvation
• Simple solution to RW problem
• Book solution to RW problem
• Even FIFO semaphores can starve in RW solution

Class 14: March 1

• Implementation of Dijkstra Semaphores
• Atomicity needed for semaphore implementation
• Methods of obtaining atomicity: Interrupt Masking,  Test-Set instruction
• Implementation of Blocking Semaphores
• Properties of Blocking semaphores (FIFO Behavior)

Class 15: March 6th

• Review of material
• The Readers and Writers problem - correct solution (click here)

Class 16: March 8th

• Mid Term Exam. Open Book, Open Notes. Material covered till Class 14, March 1.

    Spring Break  March 13-17

Class 17: March 20th

• Project details - how to write semaphore programs on Unix
• Project details - sample programs and software (project info)
• Introduction to the Dining Philosophers Problem

Class 18: March 22

• Solutions to the Mid Term Exam
• The Dining Philosophers - review
• Avoiding deadlock - all or nothing resource allocation (pick both chopsticks on nothing)
• Starvation in Dining Philosophers

Class 19: March 27th

• The conditional critical region (CCR)
• How to use CCRs - bounded buffer, readers and writes and dining philosophers

Class 20: March 29th

• CCRs and Dining Philosophers
• Proving the equivalence of CCRs and Semaphores
• Introduction to Monitors (and semantics of wait/signal)

Class 21: April 3rd

• Usage of Monitors - Bounded buffer, Readers and Writers, Dining Philosophers
• Introduction to Memory Management - Binding, relocating, protection, DLL, swapping

Class 22: April 5th

• Memory management - process address space layout
• Allocating memory using contiguous allocation (fixed and variable partitions)
• Problems of fragmentation, sharing, dynamic allocation
• Paging (address translation and sharing)

Class 23 April 10th

• Paging continued - description of how pagingis done
• Page tables
• Protection
• Sharing
• MMU function
• Paging cache (TLB)

Class 24 April 12th

• Multilevel paging (VAX memory architecture)
• Shortcomings of paging
• How segmentation works
• Shortcoming of segmentation
• Fixing segmentation, and making it really work
• Why segmented paging is similar to 2-level paging

Class 25 April 17th

• Virtual Memory concepts
• Locality property of programs
• Demand paging - valid bit
• Demand paging mechanisms (page faults, etc)
• Page replacement, FIFO, Belady's anomaly

Class 26 April 19th

• Page replacement: OPT, LRU
• LRU Approximations
• Paging problems, thrashing
• Program structure

Class 27 April 24

• Deadlocks
• necessary conditions for deadlocks
• modeling deadlocks, RAG, WFG
• Deadlock Preventaion (4 algorithms)
• Intro to deadlock Avoidance

Class 28 April 26

• Bankers Algorithm (complete version)
• Deadlock detection
• Recovery from deadlock

Class 29 May 1

• Plan Secondary storage mgmt

Class 30 May 3 No class - reading day

Final Exam: May 10th