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Operating Systems from scratch - Part 1 (Udemy.com)

Learn the concepts of Operating Systems from scratch as Operating System forms the core of Computer Science

Created by: Vignesh Sekar

Last updated February 2023

Our take

Based on the ratings of 6,314 students, a sample of their written reviews and the syllabus, as the course stood in February 2023. No course pays to be reviewed.

Part 1 of Vignesh Sekar's operating systems series is a theory course for people starting from zero. It runs 8.3 hours across 66 lectures, and the syllabus shows where the time goes: nearly five hours on CPU scheduling (SJF, SRTF, FCFS, priority, HRRN), under two on memory allocation, plus short opening sections on what an operating system is. There are no quizzes or coding exercises. It is pitched at degree students and people preparing for interviews or exams like GATE, and 35,209 students have enrolled.

Reviewers mostly praise the teaching, with comments like clear voice, simple English, and explanations better than normal lectures. Of 6,314 ratings, 3,563 are five stars and 2,133 are four. The complaints are consistent too. One reviewer says half the videos can be fast forwarded if you know the topic, another mentions digressions and repeated points, and an experienced OS developer found it mostly frustrating, with the accent a problem at times. Two reviewers also spotted conceptual slips, such as a mix-up between short term and long term schedulers.

The course was last updated in February 2023, but this theory ages slowly, so that matters little. Know that it is only the first part. One reviewer notes it is split over several parts, so the exam promises in the description depend on the later ones. The price is modest for the length. It suits beginners and cramming students who want scheduling to finally click. Anyone who already knows the material, or wants to build something, should look elsewhere, and a textbook is worth keeping nearby to check details.

Best forStudents facing an OS exam who want scheduling algorithms and memory allocation explained simply, from zero.
Skip it ifYou already know OS basics, or want hands-on coding. Reviewers call it repetitive and purely theoretical.

Pros

  • Reviewers praise clear, simple English and explanations that work from zero knowledge
  • Nearly five hours go to CPU scheduling: SJF, SRTF, FCFS, priority and HRRN, with comparisons
  • Rated 4.6 from 6,314 reviews, with 3,563 of them five stars
  • Memory section covers allocation strategies and how a process moves from disk to RAM

Cons

  • Repetitive: reviewers say you can skip half the videos if you know the topic
  • Pure theory, with no quizzes or coding exercises to check understanding
  • A few reviewers flag errors, such as short term versus long term scheduler
He has explained in a very easy to understand way and in details.
Gautam Sarmah, a student

Fits true beginners and students. Basic binary sits beside harder material, so experienced people get bored.

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What you will learn

  • You will become very familiar with the core concepts of Operating Systems
  • You will be able to challenge the interviewer on questions related to Operating Systems
  • You will view Computer Science in a different dimension
  • You will be able to answer all questions of exams like GATE,PGEE,ISRO (after completing all parts of OS course
  • You will be able to get a top grade in your Operating systems course in your Bachelor's degree
  • Understand how Operating Systems work
  • Understand how a process is created
  • Understand how CPU scheduling is done in Operating Systems
  • Understand the various scheduling algorithms we have in Operating Systems
  • Understand how CPU , Memory and Disk work together
  • Understand Memory managment in Operating Systems
  • Understand how a process is moved from hard disk to RAM
  • understand memory allocation strategies used by operating systems

Course content

9 sections · 66 lectures · 8.4 hours of video 5 articles

  1. 1Introduction 1 free preview2 lectures · 3 min
  2. 2Introduction to Operating Systems 4 free previews4 lectures · 43 min
  3. 3Operating System Concepts5 lectures · 51 min
  4. 4CPU Scheduling Algorithms - SJF, SRTF, FCFS15 lectures · 1.9 hours
  5. 5Comparision of FCFS, SJF and SRTF - Advantages and Disadvantages4 lectures · 42 min
  6. 6CPU Scheduling Algorithms - LJF, LRTF, Priority-based, HRRN21 lectures · 2.1 hours
  7. 7Basics of Number System2 lectures · 14 min
  8. 8Memory Allocation Techniques12 lectures · 1.8 hours
  9. 9Bonus : How to proceed further1 lecture

Who it is for

The instructor says it suits

  • Anybody who needs to learn Operating Systems from scratch
  • Anybody who wants to pursue a career in Computer Science
  • Anybody who has Operating Systems in the Bachelor's degree
  • Anybody who is preparing for interview in product based companies
  • If you are preparing for exams like GATE , PGEE , BITS HD , ISRO ,..etc
  • If you are a Computer Science Engineer
  • If you are a software professional

What you need before you start

  • Have a PC with internet connection
  • Even ZERO knowledge in Operating Systems is fine - I'll teach you everything you need to know

How it compares

Against the other 1,182 rated Udemy courses in IT & Software on CourseDuck:

  • Rating4.6 out of 5higher than 67% of them
  • Reviews6,314#86 of 1,183 by number of reviews
  • Length8.3 hourslonger than 64% of them
  • Last updatedFebruary 2023earlier than 74% of them

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Course Description

You’ve just stumbled upon the most complete, in-depth Operating System course series online. With over 2700 students enrolled and hundreds of 5 star reviews to date, these comprehensive operating system tutorials cover everything you’ll ever need.

Whether you want to:

- build the skills you need to get started with computer science

- move to a top notch software company like google by cracking their interview questions on operating systems.

- get a top grade in semester exam

- or just learn computer science to be able to understand on how to build better apps. 

...this complete operating system series is the course you need to do all of this, and more.


Are you aiming to get your computer science degree with high level of expertise in core subjects ? or Are you aiming to get placed in a a top notch company like google, microsoft ? or Are you a college student struggling to understand the basics of computer science ? or Are you a software developer who would want to develop better apps by understanding the theory behind computer science ?

This course is designed to give you the operating system skills you need to crack the interview questions on operating system in top notch companies. By the end of the course you will understand Operating System Concepts extremely well and be able to start with any subject of computer science.

Lots of students with no zero knowledge of computer science have been successful with their college exams or interview by taking this course.
Here are some examples of students who found this course to do wonders for their college exams or interviews or software jobs.

"thank you , i finished the operating system course in the college with a good grade 85" by Moamen Medleg

"His way of explaining complex concept is Great. I started to understand little bit that this is base for all programming language. I have around 12 years of IT experience. Hope OS learning should be mandatory to all before starting their career in IT" by Happy.

"Very good explanation of all the learning materials. He is unlike many other instructors who just throws things out to you expecting you to absorb the things that are being thrown at you. He is someone who explains things in a manner that is understandable and absorbable even to O/S beginners with only limited knowledge or background in O/S. Two thumbs up from me! Thank you so much!" by Mike

"I really enjoyed this course. Instructor made it seems like he is standing there and wouldn't leave the screen until the concepts gets into your head. So much engaging and wherever he says, we will see this later. He make sure you will. I totally recommend" by Surbhi Vasudeva

"excellent course i had started with 0 knowledge now i had learned so much best lecturer super planning of schedule" by Harshavardhan Gupta

"I really enjoyed the course and the instructor provided a great overview of the fundamentals of the theory behind operating systems. In case you are confused, the course is theoretical as opposed to a walk through of how to use Windows, Mac, etc. Instead, he provides an overview of the algorithms used to move processes from RAM to the CPU. I look forward to Part 2" by John Simons

"Great, very detailed course. Ideal for non IT-educated students like me" by Michal Burdzy

"Great Teacher. Takes concepts slow and repeats definitions and meanings multiple times so there is no need to pause the video or rewind it to hear a definition. Uses this practice to reinforce the material in your mind and ensure you actually learn it rather than hear it" by Sam Debois

The course series (part 1 to 4) on operating systems is a whopping 46 hours long. Because the course is designed as a one stop shop for Operating System Concepts. And this 46 hours dedication will change your way of thinking towards computer science.

Why would you choose to learn Operating Systems ?

The reality is that there are a lot of computer science subjects out there. It's in the hundreds. Why would you choose the operating systems subject?

The reason is starting most of the subjects of computer science will become far more easier if you have a good understanding of operating systems. By learning this subject you are not only getting started with operating system but also getting started with computer science.

What textbook should I follow ?

I have used operating system concepts by Galvin. Its a great textbook. You can follow it. But I have referred lot of other textbooks like Tanenbaum, William Stallings, etc. So its upto you on which textbook you are comfortable with but follow a standard author book. If you complete this course, you will find it much easier to understand these textbooks. But anyway if you complete this course with good detailed notes, you don't need to read any textbook as I am reading them for you and giving the contents in an easy to understand manner.

Why should you take this course?

It's been a best seller since it's release on Udemy, you would be joining over 2700 students who are already enrolled in the course.

There are close to 500 reviews left by students. It's rated as the best course to learn operating system for beginners.

What makes this course a bestseller?

Like you, thousands of others were frustrated and fed up with incomplete Youtube tutorials which assume you already know a bunch of stuff and also bulk textbooks able to send even the most intuitive person to sleep.

Like you, they were tired of low-quality lessons, poorly explained topics and all-round confusing info presented in the wrong way. That’s why so many find success in this complete Operating System course. It’s designed in a simple manner so that anybody with no prior knowledge of operating system/computer science will be able to understand.

What if I have questions?

You can ask questions anytime using the Q/A section or through personal messages. I take it very seriously and answer these questions in a detailed manner with simple english words so that anybody can understand it.

Student Quote: “Everything you always wanted to know about OS but were afraid to ask"...And Vignesh Sekar gives the right answers” by Claus Kaliba.

There’s no risk either!

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Instructor Details

Vignesh Sekar

Hi! I'm Vignesh. I have a degree in Computer Science, work experience in a multi national company and you might call me a bit of Computer Science enthusiast who is highly passionate in teaching Mathematics and Computer Science 

After working for a successful multinational company for an year, I resigned the job to follow my passion of teaching students. I have been teaching online for more than 4 years in platforms like youtube where I have a happy bunch of Engineers who are my main motivating factor in following my passion.



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Reviews

4.6

6,314 ratings on Udemy

Select a bar to show only those reviews.Select the bar again to show every rating.

By Ngọc Châu Giang Nguyễn on 9/9/2026

He explains things very clearly, but sometimes the lectures contain contradictions that confuse beginners. For instance, he initially states that the CPU cannot directly access the harddisk, yet later mentions that if a program is not in RAM, it must be located on the harddisk—a time-consuming process

By Nooruldeen Qutaiba Ismaeel on 8/3/2026

The explanation is good and the course is helpful and useful. however, the approach for explaining each topic does not follow a clear, direct path toward the main point. Instead, it includes unnecessary digressions and repeated explanations of certain points, which can be distracting and make it harder to stay focused on the main idea. The language needs improvement. Nevertheless, a great deal of effort has clearly been invested in preparing the content. Thank you to the instructor for the hard work and dedication.

By Riju Jain on 6/23/2026

Yes, the course content is good. The topics are explained in depth.

By C Karthik on 7/27/2023

Best course on Operating System. You will learn all the fundamentals of operating system. The instructor takes a lot of time explaining each and every concept in detail. This course is highly recommended to people who want to learn Operating system from scratch.

By Siddhartha Shyam Vyas on 2/9/2023

The explanation was great as if it is one-on-one tutoring. Complete! Clear! - Its amazing the way the course has been taught and explained. I would personally rate this course as one of the best courses available in Udemy. It's worth purchasing this course.

By yash tarekar on 12/20/2020

It's a really good course. Even though I am from a non-CS background, I am getting a really good understanding of OS.

By Sathya Prabu Sivakumar on 12/13/2020

Great learning with someone from same English accent.

By Tanoy Bhowmick on 12/6/2020

very impressed with the technique of teaching, felt like he is teaching me personally. Very impressed.

By Rajat Sharma on 12/6/2020

Completely understood every theory and numerical. Would have given 0.5 starts more had there been more numericals and timely response to the queries.
But you are awesome sir. Enrolling for part 2 now !

By Stuart Stevenson on 12/6/2020

Yes. I'm enjoying the content of the course so far.

By Luis Garcia on 11/21/2020

I am a native Spanish speaker with very good English as well and I had no problems understanding the instructors English. The accent wasn't an issue at all, - and he repeats the concept a few different ways to compensate so it was easy to understand the concepts. He is very thorough. I'm looking forward to continuing on all 4 courses of his.

By Marli Cummings on 11/11/2020

It was very well explained, exactly what I need!

Showing 12 of 285 reviews

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Quality Score

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Overall Score : 92 / 100