Operating Systems is the course every CSE/IT syllabus shares and every product interview still asks about. This course covers the full university core in eight compact lessons: process models and PCBs, FCFS through Round Robin with Gantt-chart arithmetic, critical sections with mutexes and semaphores, the classic producer-consumer and deadlock conditions, paging with TLB math, page replacement including Belady and thrashing, file inodes and allocation, and disk scheduling with RAID.

Every lesson uses the nine-block structure (objectives, hook, concept, worked example, practice, common mistakes, exam angle, graded quiz, summary). A 30-question bank feeds a 15-question timed final. Passing earns a verifiable TieEdu certificate.

**Who this is for:** second- and third-year CSE/IT students preparing for university exams, GATE fundamentals, and placement interviews that ask OS questions.

**What you need:** pen and paper for Gantt charts and fault counts; a browser for the quizzes.

Processes, scheduling, concurrency, deadlock, memory, paging, virtual memory and file systems — exam + interview core

Operating Systems

Most courses teach you C syntax and stop. This one teaches you the *machine*: what a compiler actually does, how memory is laid out, why pointers behave the way they do, and how to reason about a program that has no garbage collector and no safety net.

Fifteen modules take you from writing and compiling your first program through types, control flow, functions, arrays, pointers, dynamic memory, structs, files, the preprocessor, and the standard library — then close with two capstones (a reusable dynamic string and string map, and a recursively destroyed binary search tree) and a cumulative final assessment.

Every lesson is short, runs real compilable C, and is paired with interactive visualisations: watch the stack and heap change step by step, trace a program line by line, see bytes and bit-fields laid out, and follow arguments across a function call. There is no sign-up wall and no paid tier — finish the modules, pass the quizzes, and you earn a verifiable TieEdu certificate plus XP on the leaderboard.

**Who this is for:** students who have finished Coding Foundations or written a little code in any language, and anyone preparing for placements who needs to be able to read and write C with confidence.

**What you need:** a terminal and a C compiler (gcc or clang). Module 1 walks you through installing one in about five minutes.

A free, deep, hands-on C course — the language underneath almost everything else

C Programming: From First Program to Pointers and Data Structures

DBMS is one of the highest-weight subjects in every CSE university paper and a favourite of placement interviewers. This course covers the full core in eight compact lessons: ER diagrams and their relational mapping, keys and relational algebra including division, SQL core with joins and aggregation, subqueries/views/indexes, functional dependencies with attribute closure, normalization from 1NF through BCNF with lossless-join checks, transactions with ACID and serializability, and concurrency control with 2PL plus write-ahead-logging recovery.

Every lesson uses the nine-block structure (objectives, hook, concept, worked example, practice, common mistakes, exam angle, graded quiz, summary). A 30-question bank feeds a 15-question timed final. Passing earns a verifiable TieEdu certificate.

**Who this is for:** second- and third-year CSE/IT students preparing for university exams, GATE fundamentals, and placement interviews that ask database questions.

**What you need:** pen and paper for closures, normal forms and precedence graphs; a browser for the quizzes.

ER models, SQL, normalization, transactions, concurrency control and crash recovery — exam + interview core

DBMS

Computer Networks is the CSE subject that shows up in university exams, GATE and every infrastructure or backend interview. This course covers the full core in eight compact lessons: layered models and encapsulation, MAC/IP/port addressing with ARP, framing and CRC, switches and routers, IPv4 subnetting arithmetic, distance-vector vs link-state routing, the TCP handshake with flow and congestion control, DNS/HTTP/DHCP, TLS with firewalls, and wireless/SDN/CDN for modern context.

Every lesson uses the nine-block structure (objectives, hook, concept, worked example, practice, common mistakes, exam angle, graded quiz, summary). A 30-question bank feeds a 15-question timed final. Passing earns a verifiable TieEdu certificate.

**Who this is for:** second- and third-year CSE/IT students preparing for university exams, GATE fundamentals, and placement interviews that ask networking questions.

**What you need:** pen and paper for subnetting and handshake diagrams; a browser for the quizzes.

OSI to TCP/IP, subnetting, TCP internals, DNS/HTTP/DHCP, TLS security and modern delivery — exam + interview core

Computer Networks

Most Python courses teach you syntax and stop. This one teaches you the *model*: what an object is, what a name binds to, why assignment never copies, what a closure captures, when a generator beats a list, and why most of the "gotchas" you have heard about are really consequences of four rules you can hold in your head.

Fifteen modules take you from running your first script and reading a traceback bottom-up, through types and operators, strings, lists, tuples, dictionaries and sets, control flow, functions, recursion, scope and closures, comprehensions and lazy iteration, exceptions — then files, JSON, the import system, classes, dataclasses and the standard library, testing and honest performance work. It closes with a capstone you would actually ship: a command-line task tracker with a proper package layout, JSON persistence, `argparse`, input validation and a test suite.

Every lesson runs real, correct Python and is paired with interactive visualisations: step through the bytecode pipeline from `.py` file to printed output, trace a program line by line with a live variable table, watch arguments bind across a call, unwind a recursive call stack, watch a generator suspend at a `yield`, and follow an exception up through four frames into one traceback.

**Who this is for:** absolute beginners who want one language taken seriously, students who have finished Coding Foundations, and anyone preparing for placements who needs to read and write idiomatic Python with confidence.

**What you need:** nothing. Python runs from a single installer, every example in the course is self-contained, and the interactive visualisations run in this page.

A free, deep, hands-on Python course — the language the industry actually runs on

Python Programming: From First Script to Packages, Classes and Testing

Most placement prep assumes you can already read code. This course starts one step earlier and walks the whole loop: what a program *is*, how a computer stores and moves data, how to express a problem as instructions, and how to debug when it does not work.

Every lesson is short, written in plain language, and ends with something you can check yourself. There is no sign-up wall, no trial, and no paid tier — finish all four modules and you get a verifiable TieEdu certificate plus your XP on the leaderboard.

**Who this is for:** first-year and second-year students, commerce and arts students switching into tech, and anyone who has been copying code without understanding it.

**What you need:** nothing. A browser and a sense of curiosity.

A free, end-to-end introduction to how programs actually work

Coding Foundations: From Zero to Your First Program

Most data-structure teaching stops at "a hash map is O(1), a tree is O(log n)" and leaves you to guess which one your problem needs. This course is about the second half: the part where the constraints decide, the constant factors show up in a profile, and you have to defend the choice.

Every structure here is implemented from scratch in TypeScript — the hash table with resizing, the red-black tree with all three fix-up cases, the array-backed binary heap, BFS and Dijkstra — and then measured rather than asserted about. The questions are the ones that actually come up: why adversarial hash collisions are a denial-of-service vector, when a binary search loses to a linear scan on cache behaviour, and when an adjacency matrix is genuinely the right answer.

It is a paid course because it assumes you can already program and already have the C course's grounding in pointers and memory. If you are not comfortable reading a loop that walks a linked structure, start with C Programming first.

Hashing, trees, heaps and graphs — built, benchmarked, and chosen with a procedure you can defend

Advanced Data Structures: Choosing Well Under Real Constraints

Data structures and algorithms remain the single highest-leverage filter in engineering hiring. This course teaches the patterns interviewers actually use, not a tour of every exotic structure: Big-O fluency and constraint budgets, two pointers and sliding windows, hashing and monotonic stacks, linked-list surgery, trees and BSTs, heaps and greedy proofs, graph templates (BFS, DFS, Dijkstra, topological sort), and a dynamic-programming recipe that turns "hard" problems into state-recurrence work. A final lesson covers the 45-minute interview conversation itself — clarify, example, brute force, optimize, code, test.

Four modules, eight lessons on the nine-step standard: objective, hook, concept, worked example, practice, common mistakes, exam angle, server-graded quiz and revision summary. A 30-question bank feeds the timed final; passing earns a verifiable TieEdu certificate.

**Who this is for:** students preparing for campus placements, off-campus OAs and interviews at product and service companies. Assumes you can write basic code in any language; every pattern is shown with complexity and edge cases called out.

**What you need:** a language you can code in during practice. No prior competitive programming is required.

Courses for CSE students