CST 334 Week 5 Journal Entry

-


Concurrency

This week, we learned about the importance of threads in a process. A thread is a point of execution for a single running process. When a program is running, it can have more than one thread running at a time. Each thread has its own stack to store local variables and function calls, but resources such as code and heap can be shared from the program. Threads are like separate processes, except they share the same address space. When we switch between threads, thread control blocks are used to store and restore the state of the thread. This is a quick action as the threads share the same address space. Threads can help run tasks parallel to each other on different CPUs or run concurrently on the same CPU. 

When more than one thread runs concurrently, it is important to take some precautions to avoid a race condition. A race condition occurs when threads in a program access critical sections of code concurrently. This can lead to the program being indeterminate, which is when the program produces different results for each run. The critical section is where shared resources are accessed, so it is important that a thread that accesses this area of code finishes it before another thread accesses it. Failure to do so will result in indeterminate results. 

We can prevent race conditions by making sure a critical section is accessed by a thread one at a time (mutually exclusive), each thread has its own chance to run the critical section, and the time overhead is maintained. This is done by using locks, conditional variables, and synchronization primitives offered by the hardware. Locks allow threads to be owners of a critical section until completion and prevent other threads from interfering until the lock is released. Conditional variables allow threads to wait for the critical section to be released. When it is released, a conditional variable gives a signal to another thread to give it access to the critical section. Using a combination of locks and conditional variables, we can develop different types of locks, such as the Spin Lock with Test and Set and the Ticket Lock. These locks can also be applied to data structures such as linked lists and hash maps. 

Comments

Post a Comment

Popular posts from this blog

CST 300 - Week 8

-
 Part 1: Review of other team's final video projects Final Video Project Review # 1: Otter This World The video project from Otter This World is about Genomics. They describe how genomics is important and what advances we have made in this area. The topic is well-covered, and the presentation is clear. They cover each section described at the beginning of the video and provide various videos that go along with those sections. The quality of the research and video project is well done. They provide definitions and statistics with references. The video has a lot of visuals and could have used some slides with text at the beginning of each section. The information is being provided via audio, and there should be some text to supplement it. Also, the General Public video cuts off at the end with no conclusion. The video is engaging and interesting. They made a nice choice of visuals for each section. Team work is evident as each person had a section they covered. Overall, the video is
Read more

CST 300 - Week 5

-
Image
Part 1: Support and Comments on Teammates' Goals Victoria's Comment Guillermo's Comment Part 2: Possible Capstone Ideas Some ideas for capstone that I have are in the area of education with a focus on classroom management and video game design.  My first idea is to create a seating chart generator app for teachers to use in their classrooms. As a teacher, creating a seating chart can be a challenge. Whether you have a challenging class or are just looking to mix seats up, this app will help create the perfect seating chart. The app will give the teacher a variety of options to create a seating chart: individual, partner, or grouping (3 or more). The teacher can create a seating chart or groupings based on current grade in class, on an assignment, IEP requirements, or behavioral issues.  My second idea is to create a school environment application or website. With technology in the classroom becoming more and more popular, students are having to manage their own apps, homewo
Read more

CST 300 - Week 4

-
Image
 Part 1: Educational Goals My primary educational goal in the CS program is to graduate with my Bachelor's in Computer Science in December 2025 with experience in the field from internships and our service learning class. Another goal I have by the end of the program is to create projects that will showcase my experience and skill set and have them on display on my GitHub. Furthermore , my secondary goal is to graduate with my Master's degree  with a focus on Artificial Intelligence or Computer and Network Security.  from Stanford University in December 2027.  Part 2: Career Goals My career goal is to work in the field of computer science as a backend developer in cybersecurity or software development once I graduate from the CS Online program or the Computer Science Master's Degree program at Stanford University. I want to work with a company that strives to create products that will improve the quality of life while keeping user's data safe and secure.  Part 3: Percen
Read more