IITM BS Operating System (BSCS4022): Syllabus and Tips

Operating System (BSCS4022) is a level 4 elective in the IITM BS in Data Science. It explains what happens under your programs: booting, memory, processes, system calls, scheduling, file systems and OS security. The handbook gives it 4 credits. You must pass Computer Systems Design (BSCS3031) before you can register. It is one of the three courses of the Minor in Computer Systems.

Operating System at a glance

The instructor is Prof. Chester Rebeiro of IIT Madras. The handbook table calls the course "Operating Systems", lists it as "L4_DEGREE" with the tag "BP", and gives the same prerequisite.

Mismatches to know:

• The course page leaves the credits and the course type blank. The 4 credits come from the DS handbook.
• The ES handbook lists Operating Systems (as CS4022) among DS courses proposed as open electives for Electronic Systems students, with no prerequisite. The DS page and DS handbook both require Computer Systems Design.

The DS handbook table (updated 18 March 2026) marks it as offered in September 2026 and January 2027, but not in May 2026.

What you learn in Operating System

• Weeks 1 and 2: starting the machine. How a computer system is organised, how it boots, and how the OS manages memory.
• Weeks 3 to 5: processes. What a process is and how programs ask the OS for help through system calls. How the first process starts, and how fork, exit, wait and exec create and replace processes. How executable files are laid out, using the ELF format.
• Weeks 6 to 8: sharing the CPU. Interrupts and how they are handled, scheduling, and synchronisation between tasks that run at the same time.
• Weeks 9 and 10: more building blocks. Deadlocks, threads and file systems.
• Weeks 11 and 12: security. OS security, side channel attacks, trusted execution environments (TEEs) and buffer overflows.

The suggested reading is a book on a simple Unix-like teaching operating system by Russ Cox, Frans Kaashoek and Robert Morris.

How it is assessed

The course page does not spell out the assessment for this course. It only points to the programme's standard course structure. Check the course portal at the start of the term.

Where it counts

• Computer Systems minor. It is one of the three minor courses, with Computer Systems Design and Computer Networks. See the Minor in Computer Systems.
• BS level stream requirement. It is level 4 and tagged BP. BP appears to mean the programming stream, so it may count as one of the two level 4 or higher programming courses at the BS degree level. Confirm this with support.

Who finds it hard and how to prepare

This course sits right on top of C and hardware. If pointers and memory still confuse you, or you rushed through the CPU weeks of Computer Systems Design, the process and memory weeks will be tough.

• Be solid on C memory first. Revise pointers, arrays and dynamic memory from Programming in C (BSCS3005). The buffer overflow week also builds on this.
• Revise the CPU weeks of Computer Systems Design (BSCS3031). Instruction sets and CPU design help with booting and interrupts.
• Write small process programs. On Linux, write a C program that uses fork, exec and wait, and print process IDs to see who runs when.
• Draw scheduling timelines. For each scheduling method, draw which process runs at each time step. Do the same for a deadlock example.
• Use the Linux shell. The System Commands (BSSE2001) course showed you how to manage running programs from the command line. Watching real processes makes the theory concrete.

What to take before and after

Before: Programming in C, then Computer Systems Design. After or alongside: Computer Networks, which completes the minor and needs Programming in C.

Common questions

Is it "Operating System" or "Operating Systems"?

Both names are used for the same course. The course page says "Operating System" and the handbook says "Operating Systems". The code BSCS4022 is the same.

Can I take Operating System in the same term as Computer Systems Design?

No. Computer Systems Design is a prerequisite, not a corequisite. You must pass it in an earlier term.

Can Electronic Systems students take this course?

The ES handbook lists it as a proposed open elective from the DS programme, with no prerequisite shown. Since the DS page lists Computer Systems Design as a prerequisite, confirm with support before you register.

Do I need Linux on my own laptop?

The course page does not say. Having Linux ready helps you try the system calls yourself, and the DS programme's System Commands course already uses Linux.