Textbook: Operating Systems: Three Easy Pieces by Remzi H. Arpaci-Dusseau and Andrea C. Arpaci-Dusseau. Free online, you can also order a paper copy for a nominal fee.
Week	Lectures/Readings	Examples
1	External content OPTIONAL CONTENT! An excellent (and Free) Computer Architecture course for those who are interested IDE Setup Install Ubuntu Linux using Virtual Box(Running a Mac with a M 1/2/3 chip? Use UTM instead of Virtual Box. Its virtual machines are compatible with the Mn architecture). Be sure to give the linux VM as much memory and CPUs as you can Install g++ on Linux Install Eclipse CDT on Linux Quick Reference C++ reference Card Eclipse Shortcut Keys I use Linux and Git tutorials Linux tutorial Another Linux tutorial Git - the simple guide Git and Linux demo notes Lectures Course Intro Computer Architecture Please read Chapter 2 : Introduction to Operating Systems
2	External content Operating System Interrupts Interrupt types, CPU Execution mode (Supervisor or User), Interrupt process flow Lectures Tangent: The PC boot process Operating System Overview Intro Paging example Please read Chapter 4 : Processes Chapter 5 : Process API - fork(), wait(), exec() in unix plus a bit of linux command line Chapter 6 : Direct Execution
3	External content Optional: Introduction To Unix Signals Programming Difference between fork() and exec() Lectures Interrupts Process Description and Control Please read Chapter 7: CPU Scheduling and Chapter 8: The Multi-Level Feedback Queue and Chapter 9: Scheduling: Proportional Share
4	External content Process Scheduling Overview Very good! Lectures Process Scheduling Please read Chapter 13: The Abstraction: Address Space Please see, Chapter 14, Interlude: Memory API, just this 1/2 page "Aside: Why No Memory is Leaked Once Your Process Exits" and Chapter 15: Mechanism: Address Translation and Chapter 16: Segmentation
5	Lectures Virtual Memory Please read: Chapter 18: Paging Introduction Chapter 19: Paging: Faster Translations (TLBs) Chapter 20: Paging: Smaller Tables
6,7,8	Lectures Paging Simple page table examples Translation Lookaside Buffer (TLB) Reducing the size of page tables Examples: Multilevel Page tables How to drastically reduce the size of page tables ( essential especially for 64 bit systems) Test,3/12/26. Includes everything above and project 2. The test will be given to you on paper. You may bring 1 sheet of paper with notes on both sides if you like. No other resources are allowed. Please read Chapter 21: Beyond Physical Memory: Mechanisms and Chapter 22: Beyond Physical Memory: Policies
9,10	External content Please read Chapter 26: Concurrency: An Introduction (Advanced) C++11 threads, affinity and hyperthreadingExcellent! relates C++ threads to processor hardware Atomics Useful BUT can only synchronize 1 C++ operation at a time. Lectures Threads, an Introduction Threads, Race conditions, critical sections, atomicsA multithreaded introduction Takeaways: Threaded applications can be proven incorrect, but not correct since you cant control the scheduler. Therefore testing is not as helpful. Your only defense is to write perfect code, to do this there are some rules to follow; If you start a thread (thread t1(fun)) you must wait for it to finish (t1.join())! Never, ever rely on knowledge of system behavior to predict thread run order! You cant tell! (see Thread_Race_Condition) Learn to identify minimal critical sections. You want them to be as small as possible since only 1 thread can be in the critical section at a time, the others block and wait. To identify critical sections, start by finding all variables that multiple threads can access. This includes all globals, heap based variables that multiple threads are aware of, and all non-threadsafe API's used (like cout) Are these globals accessed by more than 1 thread? You probably have critical sections that need protection (synchronization). the exception to this rule is a shared variable that is only read, never written. BUT the very first time it's written it needs protection (synchronization) on every read and write Atomic classes are great, IFF you have a single line critical section. For multiple lines, you need a mutex (coming next)	Single thread demo Use disassembly view to see that each c++ statement is equivelent to multiple assembly instructions. An interrupt can be serviced after any assembly instruction, which may be in the middle of a C++ instruction Problems that threads can cause Running several threads, each reading and writing a global will cause unpredictable results. Demo using an atomic variable for a simple (but not generalizable to blocks of code>1 line) solution Thread Race Condition
10,11,12	External content Please read Chapter 28: Locks Please read Chapter 32, Common Concurrency Problems - pay attention to Deadlock and the section entitled 'Conditions for Deadlock' (see below) Four conditions need to hold for a deadlock to occur: Mutual exclusion: Threads claim exclusive control of resources that they require (e.g., a thread grabs a lock). Hold-and-wait: Threads hold resources allocated to them (e.g., locks that they have already acquired) while waiting for additional resources (e.g., locks that they wish to acquire). No preemption: Resources (e.g., locks) cannot be forcibly removed from threads that are holding them. Circular wait: There exists a circular chain of threads such that each thread holds one or more resources (e.g., locks) that are being requested by the next thread in the chain. Lectures Mutexes Mutexes are almost certainly going to be global variables (they will NOT be local variables) Mutexes function as a traffic cop, they allow 1 thread in a critical section at a time(others threads are blocked) Prefer a lock_guard over a raw mutex since it automatically unlocks when it goes out of scope To use: Identify minimal critical sections, then wrap critical section with an auto unlocking lock_guard Mutex Lecture notes. Thread Ticket Agent Slides Goes with project to the right Deadlock Rule of thumb: If you are using 2 or more synchronization objects, then you should always aquire them in the same order. If you break this rule and some threads aquire in different order then your code is prone to deadlock. Deadlock Lecture notes. Test 2, 4/16/26. Includes everything from previous test thru week 13 and project 3. The test will be given to you on paper. You may bring 1 sheet of paper with notes on both sides. No other resources are allowed. You should know; how to identify and protect critical sections in a multi threaded program how to maximize concurrency in a multithreaded program. For example, given 2 unrelated critical sections, you can protect each with a different mutex, and thus have 2 different threads executing in each critical section at the same time. how to recognize and prevent deadlock how to use mutexes in an exception prone environment (use a lock_guard that automatically unlocks)	Fix this non threadsafe code, here is the Solution Stopping a thread Cleanly A spinlock DEMO Do not use! Works but spikes CPU usage for all threads waiting for the lock! Mutexes to synchronize threads Using a mutex to synchronize critical sections (as in multiple lines of code). mutex_lock_guard_sleep_for_yield Using a lock_guard to autounlock a mutex once the guard goes out of scope. Also how to yield a threads timeslice or sleep the amount of time defined by std::chrono.. Simple Deadlock examples Very simple examples of how deadlock can occur A slightly more complex deadlock example Thread ticket agent - in class lab Recursive_mutex A locking object that can be recursively locked (as long as you have 1 unlock() for every lock()). This added functionality typically makes it harder to keep track of locked regions when designing your application.
13	External content Please read Chapter 30, Condition Variables What if you want thread 1 to wait until thread 2 says go? You cannot do this with just a mutex unless you use an ineffecient busy wait. Condition Variables solve this problem. Condition Variables, definition and sample code article Recursive Locks portion only This guy writes excellent C++ tutorials Lectures Condition Variables Demonstration slides Producer Consumer, A common programming task Outline and solution flow.	Simple Condition VariablesOrdering thread operations. Signaling between threads using a mutex a condition variable and a unique_lock Simple Condition Variables>What happens when you do not put cv.wait(...) in a while loop. (BTW you must always put cv.wait(...) in a while loop!) Making all threads start at the same time using Condition Variables All threads wait but there is still a problem with synchronizing the cout and i Simple producer consumer problem. Producer signals consumer.Single Producer, Single Consumer: Producer produces as fast as it can and notifies consumer, consumer consumes as fast as it can. Demoes effecient 1 way thread communication. Consumer will exit when global variable bDone is true and global count, gCount, of produced objects is 0. Can have multiple consumers. Producer consumer problem using mutex and condition variables Single Producer, Multiple Consumers Complex producer consumer problem, Producer signals consumer and vice versaProducer produces one then notifies consumer, consumer consumes one then notifies producer. Demoes effecient 2 way thread communications. Consumer will exit when global variable bDone is true and global count, gCount, of produced objects is 0.