Course Schedule¶

Course Setup¶

Technical Experts Duties¶

• Review technical content for the assigned module with Professor Kapfhammer
• Create a technical question that is the focal point for the assigned module
• Create a technical diagram that "sketches" all content for that module
• Assist with creating and proof-reading technical content for that module
• Present the technical diagram and answer any questions about the presented content

Professional Question¶

• What technical content about operating systems will we cover this semester, how will we assess our mastery of this technical material, and how will we structure all aspects of this advanced course in operating systems?

Next Steps¶

• Review and participate in all the discussions in the OS Sketch Issue Tracker for more details
• Review the course timeline for more details about reading assignments

Systems Introduction¶

Technical Questions¶

• How does the operating system use the principle of virtualization to manage the resources of a computer such as the process, memory, and file system? How does virtualization influence the way in which I write programs and use an operating system?

Next Steps¶

• Read the chapters called Introduction (Chapter 2) and Processes (Chapter 4) in OSTEP
• Study the course slides for a detailed investigation of these chapters
• Review the important terms for definitions of the key terms associated with the assigned chapters
• Check out the operating system sketch associated with this module

Process Execution¶

Technical Questions¶

• How does the operating system manage the execution of processes and enable processes to access memory? How does this behavior of the operating system influence the ways in which I program and use software tools?

Next Steps¶

• Read the chapters called Process API (Chapter 5), Direct Execution (Chapter 6), and Memory API (Chapter 14) in OSTEP
• Study the course slides for a detailed investigation of these chapters!
• Review the important terms for definitions of the key terms associated with the assigned chapters
• Check out the operating system sketch associated with this module

CPU Scheduling¶

Technical Questions¶

• How does the operating system separate policy from mechanism and make decisions for which process to execute? How does this behavior of the operating system influence the ways in which I program and use software?

Next Steps¶

• Read the chapters called CPU Scheduling (Chapter 7) and Lottery Scheduling (Chapter 9) in OSTEP
• Check out the course slides for a detailed investigation of these chapters!
• Review the important terms for definitions of the terms associated with the assigned chapters
• Check out the operating system sketch associated with this module

Address Spaces¶

Technical Questions¶

• What are the policies and mechanisms that the operating system uses to facilitate memory access for processes? How does this behavior of the operating system influence the ways in which we program and use software?

Next Steps¶

• Read the chapters called Address Spaces (Chapter 13) and Address Mechanisms (Chapter 15) in OSTEP
• Check out the course slides for a detailed investigation of these chapters!
• Review the important terms for definitions of the terms associated with the assigned chapters
• Check out the operating system sketch associated with this module

Segmentation and Paging¶

Technical Questions¶

• What are the general-purpose policies and mechanisms that the operating system uses to facilitate memory access for processes? How does this behavior influence the ways in which I program and use software?

Next Steps¶

• Read the chapters called Segmentation (Chapter 16) and Paging (Chapter 18) chapters in OSTEP
• Check out the course slides for a detailed investigation of these chapters!
• Review the important terms for definitions of the terms associated with the assigned chapters

Memory Swapping¶

Technical Questions¶

• What are the general-purpose policies and mechanisms that the operating system uses to move memory units from physical memory to the disk? How does this behavior influence the ways in which I program and use software?

Next Steps¶

• Read the chapters called Swapping Mechanisms (Chapter 21) and Swapping Policies (Chapter 22) in OSTEP
• Check out the course slides for a detailed investigation of these chapters!
• Review the important terms to find definitions of the terms associated with the assigned chapters

Introducing Concurrency¶

Technical Questions¶

• What are the trade-offs associated with implementing support for concurrency in the operating system and programming languages? How does the use of concurrency primitives influence the ways in which I program and test software?

Next Steps¶

• Read the chapters called Concurrency: An Introduction and Thread API (Chapter 27) in OSTEP
• Check out the course slides for a detailed investigation of these chapters!
• Review the important terms to find definitions of the terms associated with the assigned chapters

Locking Mechanisms¶

Technical Questions¶

• How can the use of locks support mutual exclusion and reliable concurrency in the operating system and programming languages? How does concurrency influence the behavior of a program? How does the use of concurrency primitives influence the ways in which I create software?

Next Steps¶

• Read the chapters called Locks (Chapter 28) and Condition Variables (Chapter 30) in OSTEP
• Check out the course slides for a detailed investigation of these chapters!
• Review the important terms to find definitions of the terms associated with the assigned chapters

Using Semaphores¶

Technical Questions¶

• How can the use of semaphores support mutual exclusion and reliable concurrency in the operating system and programming languages? How are semaphores similar to and different from locks? How does the use of concurrency primitives influence the ways in which I create software?

Expert Added Content¶

• Read the chapter called Semaphores (Chapter 31) in OSTEP
• Check out the course slides for a detailed investigation of these chapters!
• Review the important terms to find definitions of the terms associated with the assigned chapters

I/O Devices¶

Technical Questions¶

How can does the operating system use the principle of virtualization to manage the input/output devices connected to a computer? How do virtualization policies and mechanisms for I/O devices influence the way in which I implement programs and use an operating system?

Expert Added Content¶

• Read the chapter called I/O Devices (Chapter 36) in OSTEP
• Check out the course slides for a detailed investigation of these chapters!
• Review the important terms to find definitions of the terms associated with the assigned chapter

File Systems and Directories¶

Technical Questions¶

-Experts add their technical question here

Expert Added Content¶

• File Systems and Directories, File System Implementation and Network File Systems chapters in OSTEP
• Check out the course slides for a detailed investigation of these chapters!
• Click here to find definitions for key terms for the week's reading (chapters 39, 40 and 49)!

Data Integrity and Security¶

Technical Questions¶

-Experts add their technical question here

Expert Added Content¶

• Data Integrity and Protection and Intro Security chapters in OSTEP
• Check out the course slides for a detailed investigation of these chapters!
• Click here to find definitions for key terms for the week's reading (chapters 49 and 53)!

Distributed Systems¶

Technical Questions¶

-Experts add their technical question here

Expert Added Content¶

• Distributed Systems chapter in OSTEP
• Check out the course slides for a detailed investigation of these chapters!
• Click here to find definitions for key terms for the week's reading (chapters 48)!

Course Timeline¶

Return to top of the page

Important Terms¶

Introduction: Chapter 2¶

Processes: Chapter 4¶

Process API: Chapter 5¶

Direct Execution: Chapter 6¶

Memory API: Chapter 14¶

CPU Scheduling: Chapter 7¶

Lottery Scheduling: Chapter 9¶

Address Spaces: Chapter 13¶

Address Translation: Chapter 15¶

Segmentation: Chapter 16¶

Introduction To Paging: Chapter 18

1. Paging - the process's address space is split into a number of variable-sized units
2. Page Tables - operating system structure used to store per-process address space
3. Virtual Page Number (VPN) - virtual address that the process generates
4. Physical Frame Number (PFN) - where the virtual page number is indexed in the frames
5. Physical Page Number (PPN) - Same as PFN Return to Segmentation and Paging

Swapping Mechanisms: Chapter 21

1. High Watermark (HW) - a way the that the operating system keeps a small amount of memory free
2. Low Watermark (LW) - a way the that the operating system keeps a small amount of memory free
3. Swap Daemon - the process in which the operating system sorts LW amd HW to keep memory free Return to Swapping

Swapping Policies: Chapter 22

1. Average Memory Access Time (AMAT) - the number of cache hits and misses that a page is found
2. Temporal Locality - programs keep locality in their access streams when storing and accessing memory
3. Clock Algorithm - the way an operating system approximates LRU by randomly picking a page
4. Modified Bit - a bit that is used in the page-replacement process Return to Swapping

Concurrency and Threads: Chapter 26

1. Thread Control Blocks (TCBs) - stores the state of a thread in a process
2. Disassembler - shows what assembly instructions were used in the program
3. Transaction - grouping of many actions into a single atomic action
4. Critical Section - piece of code that when accesses a shared resource, usually a variable or data structure
5. Race Condition - arises if multiple threads of execution enter the critical section at roughly the same time Return to Concurrency

Thread API: Chapter 27

1. Function Pointer - looks for which function threads should start running in
2. Procedure Call - creates a thread or multiple threads
3. Critical Section - region of code that needs to be protected for operation Return to Thread API and Locks

Locks: Chapter 28

1. Spinning - a thread being told to wait before the action is executed based on a lock being in place
2. Mutual Exclusion: if one thread is in the critical section it excludes others from entering
3. Fairness: does each thread contending for the lock get an equal shot at it
4. Performance: time added by using the lock Return to Thread API and Locks

Condition Variables: Chapter 30

1. Condition variable: an explicit queue threads can put themselves on when some state of execution is less desirable than another thread. When it changes state the other threads can be woken up and allowed to continue
2. Wait/Signal: the actions used in a conditional variable. The thread waits on a specific condition to be met and then signals the sleeping threads to be executed
3. Bounded Buffer: a system of multiple producer threads and consumer threads which is shared Return to Variations of Locks

Semaphores: Chapter 31

1. Deadlock - A problem that occurs when a consumer thread is called before the producer when trying to use mutual exclusion
2. Throttling - An imposed limit to the number of threads that can be simultaneously executed on a piece of code. Used to keep the system from bogging down
3. Zemaphore - An easier-to-implement version of the semaphore where we don’t maintain the value of the semaphore, when negative, reflects the number of waiting threads
4. Hill’s Law - Sometimes simple and dumb is better. Just because you can make something sophisticated to solve a problem doesn’t mean it’s the best answer Return to Variations of Locks

I/O Devices: Chapter 36

1. DMA (direct memory access) - a device within a system that orchestrates transfers between devices and memory without much CPU intervention
2. Memory-mapped I/O - Another method to interact with devices. With this version the hardware makes device registers available as if they were memory locations Helpful because no new instructions are needed to support it
3. Hardware Interface - The way for the software to communicate and interact with the hardware system
4. Internal Structure - Responsible for implementing the abstraction the device presents to the system Return to I/O Devices

Files and Directories: Chapter 39

1. Persistent Storage - A permanent storage device that keeps information intact after a loss of power
2. File - An array of bytes that can be created, read, written and deleted. Low level name is i-number
3. Directory - An array of tuples, each containing a human-readable and low-level name to which it is mapped
4. Directory Tree - Organizes all files into a tree, starting with the root.
5. Hard Link - An entry in the file system tree. Takes two arguments (old path name and new) and creates another way to refer to that same file
6. Symbolic (soft) Link - Different type of link that allows links to files in other disk partitions than the one the original file is in Return to File Systems and Directories

File System Implementation: Chapter 40

1. vsfs (Very Simple File System) A simplified version of UNIX and utilizes basic on-disk structures, access methods, and multiple file system
2. Access Methods The methods which allow for calls to be made. They include actions such as open(), read(), and write()
3. Metadeta Types of data about data. Mainly consists of data about data blocks, file size, owner and access rights, etc.
4. Inode A series of nodes arranged in an array and indexed into when the user is accessing a specific inode.
5. Indirect Pointer A type of pointer that points to other pointers which direct the program to a specific memory address or another pointer
6. Fixed-Size Cache A small amount of fast memory inside of a processor to improve the speed of which computational tasks are completed Return to File Systems and Directories

Network File Systems: Chapter 49

1. Stateless Protocol Simplistic crash recovery process where the server restarts and works as it did previously
2. Recovery Protocol A specific protocol where there's enough memory available to tell the server what it needs to know
3. Mount Protocol The first process through which the clients and servers connect together
4. Virtual File System (VFS) Allows for the use of multiple file systems to be utilized for a given operating system
5. Write Buffering The delayed sending of the clients data to the server. The submitted data to the network is first held locally in the client's cache Return to File Systems and Directories

Data Integrity and Protection: Chapter 45

1. Fail-Stop An early feature of RAID systems where either the disk is working or not at all
2. Silent Faults When the storage drive disk doesn't give any appearance of a problem when the data returned is corrupted
3. Misdirected Write When data is written correctly to the disk storage but in the wrong memory address
4. Cyclic Redundancy Check (CRC) Remainder of binary division between a large binary number (D) and an agreed value of (k)
5. Lost Write The device doesn't inform the upper layer that a write finished but the new changes never persisted into the next state, thus exposing the past state before the write Return to Data Integrity and Security

Intro Security: Chapter 53

1. Trusted Platform Module (TPM) Authenticated to users that they were starting up the operating system and version they had intended to do so
2. Access Control Mechanisms The process through which an operating system determines if the user has the proper authorization to perform the requested action
3. Non-Repudiation The authentication of prior actions in the operating system that cannot be forged
4. Security Policies A list of rules and specifications for ensuring security in an operating system environment Return to Data Integrity and Security

Distributed Systems: Chapter 48

1. Checksums Method to detect memory corruption quickly
2. End-to-end argument Method through which packet loss, aka data loss, is avoided
3. UDP/IP Common networking stack that involves the use of sockets to communicate with an endpoint, and send datagrams which are short messages
4. Distributed Shared Memory (DSM) Allows for multiple computers on the network to share large virtual address space, akin to how processors have multiple cores which allow for the use of threading
5. Remote Procedure Call (RPC) Simple and easy way to execute code on a remote machine Return to Distributed Systems

Learning Opportunities¶

Interested in learning more about any of the topics on this schedule? If you are, then make sure to connect with members of the OS Sketch community for more learning opportunities. Remember, this course emphasizes building mastery of the course's learning objectives through the process of "learning by doing" As such, you can best understand the content on this schedule by completing all of the projects on this site!