The fundamentals round
Beside DSA and System Design, most interviews spend a round on how the machine and the network work. These are the 48 questions that round keeps asking, in three subjects. Each one links the lesson that answers it, and a lab where you can run the idea yourself. Read the lesson, then answer out loud without looking.
Networks 15 questions
What happens between your laptop and a server: names, addresses, the handshake, and the bytes on the wire.
- What a request actually says (HTTP)With a plan
- How the web outgrew the phone callWith a plan
- The whisper code (how a call goes private)With a plan
Operating systems 16 questions
What the kernel does for every program: walls between them, turns on the CPU, memory that is not where it says.
- Processes, Threads & the KernelWith a plan
- Processes, Threads & the KernelWith a plan
- Processes, Threads & the KernelWith a plan
- Whose turn, and who decidesWith a plan
- The address book every process carriesWith a plan
- Concurrency & the HardwareWith a plan
- Waiting without spinningWith a plan
- Four ways to get stuck: deadlockWith a plan
- Locks, Latches & TransactionsWith a plan
- Four ways to get stuck: deadlockWith a plan
- The program that starts programsWith a plan
Databases 17 questions
What a database promises, how it keeps the promise on disk, and why a query is fast or slow.
- TransactionsWith a plan
- TransactionsWith a plan
- Lab: Isolation levels
- B-Tree on DiskWith a plan
- Which shortcut to buildWith a plan
- Storage EnginesWith a plan
- Lab: LSM vs B-tree
- WAL & RecoveryWith a plan
- Lab: The write-ahead log
- MVCC & VacuumWith a plan
- Lab: The vacuum lag
- Locks, Latches & TransactionsWith a plan
- Data Models and Query LanguagesFree with an account
- Lab: The right book for the job
- ReplicationWith a plan
- Lab: The copy clerks
- PartitioningWith a plan
- Lab: Splitting the ledger
- Every fact in one place: normalisationWith a plan
- Which column names the row: keysWith a plan
Ticks follow you to any device you sign in on. A question ticks itself when you mark its lesson read. For the rest of the loop, the ten-week plan covers DSA and System Design a day at a time.