bigonotes

Read. Revise. Recall.

Everything you need to start as an engineer. In one place.

These are all my personal notes.

Built from real interviews at Amazon, Google, Microsoft, DoorDash and startups. Read the story →

The path

  1. 1Pick a blockChoose any topic below.
  2. 2Dig inRead its notes in order, one by one. In DSA, solve the questions at the top first. "Next" at the bottom of each note takes you on.
  3. 3ReviseLater, turn on Revision mode to glance through the short version of each note.
  4. 4Test yourselfPress "Quiz me with AI" on a note and paste it into an AI chat. It asks you multiple-choice, short-answer and explain-why questions.

Browse the library

DSA: Patterns & Python

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Python InternalsHow lists, dicts, strings and ints work under the hood.Hacks & Cheat SheetsIdioms, patterns and one-liners that speed up problem solving.Interview ApproachA repeatable flow for coding interviews, from clarifying to testing.+14 more topicsArrays & Hashing, Sliding Window, Stack and 11 more.→

CS Concepts

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OS FundamentalsThe OS basics: processes, threads, locks, scheduling and memory.OOPClasses, objects, inheritance and polymorphism, with Python examples.SOLID PrinciplesThe five SOLID principles and how they show up in real code.+2 more topicsDesign Patterns, LLD.→

System Design

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Getting StartedWhat system design is and how to think about it.Networking EssentialsProtocols, DNS, load balancing, latency and the network stack.API DesignREST, pagination, versioning, status codes and API security.+6 more topicsDatabases, Data Modeling, Caching & Scaling and 3 more.→

Cloud

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Cloud FundamentalsWhy cloud, service and deployment models, virtualization, shared responsibility, regions and zones.ComputeEC2 instances and images, auto scaling groups, serverless and Lambda.NetworkingVPCs, subnets and route tables, security groups and load balancers.+3 more topicsStorage and Databases, Identity (IAM), Messaging and Email.→

Engineering Practices

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Design DocsPlan the work and record the decisions and trade-offs.Git and Code ReviewBranches, merge and rebase, good pull requests and useful code reviews.TestingThe test pyramid, pytest, mocks, integration and contract tests.+4 more topicsCI/CD and Releases, DevOps and IaC, Observability and 1 more.→

Linux

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The SystemThe kernel, the boot process, the shell and the filesystem layout.Files and PermissionsFiles and links, redirection and pipes, permissions and sudo.Processes and ServicesProcesses and signals, disks, SSH, and services with systemd.Shell and EditorBash scripting basics and the vi editor.

Where I learned from

  • DSA

    My notes on the patterns, lessons and pitfalls, with extra questions I found in similar patterns. Try each problem first, then open the hints.

  • System Design

    For the interview itself, use Hello Interview's delivery framework: it is the best one out there. My notes are for learning the concepts, with deep dives into textbooks, search and Claude sessions.

    Hello Interview delivery framework ↗

  • Design Patterns

    The patterns themselves come from the Gang of Four (GoF) book, Design Patterns: Elements of Reusable Object-Oriented Software. The explanations and examples here are my own.

Listen & watch

NotebookLM overviews30 audio & video overviews of the notes. Play them on your commute or a walk.