LearnViz CompSci
Home / Learn / Operating Systems / Processes

Beginner Topic 5 of 51 Operating Systems

Processes

Running instances of programs with their own resources.

How it works

A process is a running instance of a program with its own virtual address space containing code, data, heap and stack, plus resources such as open files, credentials and at least one thread. The OS tracks it in a process control block. Processes are isolated from each other, so one cannot read another's memory without explicit sharing, and they have a parent-child hierarchy.

Step-by-step walkthrough

  1. A program is only a file on disk.
  2. Starting it creates a process.
  3. The process gets its own address space of code, heap and stack.
  4. The scheduler gives it CPU time.
  5. It also holds open files and other resources.

Where it is used

Every application you launch is a process, and shells, web servers and compilers create many. Multi-process designs such as browsers isolate tabs for stability and security.

Common pitfall

Creating processes is heavier than creating threads, and communicating between them needs IPC. Zombie processes remain if parents do not wait for children, and orphaned processes are adopted by init. Leaked processes, runaway forks and unbounded memory use can exhaust system limits, so set ulimits and clean up children.

Where it fits in the course

Processes is topic 5 of 51 in Operating Systems, rated Beginner. It follows System Calls. The next topic is Process States.

Practice and explore

How to study this topic

  1. Read the explanation above and restate the definition in your own words.
  2. Open the interactive lesson and answer its mini quiz.
  3. Read the common pitfall, then write a short example that avoids it.
  4. Check your understanding in the Operating Systems quiz, and revisit the topic if you miss a question.

Frequently asked questions

What is Processes?
Running instances of programs with their own resources. It belongs to Operating Systems and is a beginner-level topic.
Where do people use Processes?
Every application you launch is a process, and shells, web servers and compilers create many.
What is the most common mistake with Processes?
Creating processes is heavier than creating threads, and communicating between them needs IPC.
What should I learn before this topic?
Start with System Calls, the topic just before it in Operating Systems.
How can I practice it?
Answer the mini quiz in the interactive lesson, then take the Operating Systems quiz.
Is Processes hard to learn?
It is a Beginner topic, so it works as an entry point. If the terms are new, read the explanation twice and try the visualizer before the quiz.
How long does it take to learn Processes?
Most learners can read the explanation and finish the interactive lesson in under an hour. Fluency comes from applying the idea, so plan a few short practice sessions with the quiz.
Which topics are related to Processes?
System Calls, Process States, User Mode vs Kernel Mode are closely connected. The full list is in the related topics section of this page.
What should I study after Processes?
Continue with Process States, the next topic in Operating Systems.

Related topics