📝 System Design Interview Classics · State Machine
File Sync States (Dropbox-style)
The states a file goes through in a sync client like Dropbox: detected, chunked, uploaded, synced, and conflict handling when two devices edit the same file.
Drawing diagram…
What this diagram shows
- Files are split into chunks so only changed parts upload
- A version check detects edits from another device
- Conflicts keep both copies instead of losing work
Prompt used
State machine for a file in a sync client: Detected when a change is seen, Chunking into 4 MB blocks, Uploading only new blocks, Committing the new version to the metadata server, Synced. If the server has a newer version from another device it becomes Conflict and a conflicted copy is saved. Network errors move to Waiting and retry.
Mermaid code
stateDiagram-v2 [*] --> Detected: Local change seen Detected --> Chunking Chunking --> Uploading: New blocks found Chunking --> Committing: No new blocks Uploading --> Committing: Blocks stored Uploading --> Waiting: Network error Waiting --> Uploading: Retry Committing --> Synced: Version accepted Committing --> Conflict: Server has newer version Conflict --> Synced: Conflicted copy saved Synced --> Detected: Edited again Synced --> [*]
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