YOUR BRIEF
What to work through
Work through an over-the-air update system as a spoken system design interview. Start by clarifying the scope, sketch a working design and explain the trade-offs behind your choices.
- Publish a new software version and choose which cars get it
- Roll it out in stages, and pause or stop a rollout
- Cars download the update in the background and resume after a dropped link
- Cars check the update is genuine before installing, and fall back to the old version if it fails
- Report each car’s version and update state
BEFORE YOU START
Constraints to discuss
- An update never leaves a car unable to start
- Only software signed by the company installs
- A dropped link costs one byte range, about 1 MB, not the whole download
- Installs never interrupt a driver
- Send as few bytes as possible over metered cellular links
Need a starting point?
Watch for these common gaps as you prepare:
- Sending a release to the whole fleet at once
- Restarting a dropped download from the first byte
- Installing over the running system with no copy to fall back to
- Trusting the encrypted connection alone instead of signed metadata checked on the car
- Counting a finished download as success instead of a confirmed boot
Why this question is in the collection
These sources connect the problem to company interview reports or preparation guides. They do not guarantee what a company will ask you.