1. Introduction to Concurrency: Threads and Processes

Learning Objectives Define concurrency and parallelism, and articulate the key difference between them. Differentiate between a process and a thread, using the analogy of memory space. Explain how threads share memory within a single process, while processes have isolated memory. Identify the primary benefits of concurrent programming, such as improved application responsiveness and performance. Analyze a simple computational problem and determine if it is suitable for a concurrent or parallel solution. Conceptually trace the interleaved execution of multiple threads on a single CPU core. How does your computer play music, let you browse the web, and download a file all at the same time? 🤔 It's not magic, it's concurrency! In this lesson, you will learn the funda...

TermDefinitionExample ConcurrencyThe ability of a system to manage and make progress on multiple tasks over the same period of time. Tasks can be interleaved on a single CPU core, giving the illusion of simultaneous execution.On a single-core CPU, a word processor saves your document in the background. It might type a few characters, then save a small chunk to the disk, then type a few more characters. The tasks are interwoven, not running at the same exact instant. ParallelismThe ability of a system to execute multiple tasks at the exact same time. This requires hardware with multiple processing units, such as a multi-core CPU.On a quad-core CPU, a video encoding program can process four different frames of a video simultaneously, with each core handling one frame. This is true simultane...

Process Memory Isolation Memory(Process A) ∩ Memory(Process B) = ∅ The memory spaces of two different processes are completely separate. One process cannot directly access, read, or write to the memory of another. This is a fundamental security and stability feature of modern operating systems. Thread Memory Sharing Threads within Process A share Memory(Process A) All threads that are created within a single process share the same memory space (like global variables and the heap). This makes communication between threads very fast and efficient but requires careful programming to avoid conflicts. The Parallelism Condition Parallelism requires Num_Threads ≤ Num_Cores True parallelism, the simultaneous execution of tasks, can only occur if the number of active threads...