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local-first-sync

local-first sync

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SystemTechniques · 11Primitives · 52 local-first-sync CRDTsdistributed · medium: Data types whose replicas accept writes independently and always converge by merging, with no coordination: counters, sets, maps, registers, text.›Deterministic simulation testingdistributed · medium: Run the whole system in one thread under a seeded scheduler with simulated network, disk and clock, so every failure replays from its seed.›Primary-backup replicationdistributed · medium: One node orders all writes and ships them to standbys; the acknowledgement rule (none, one, all) sets what a crash loses, and an external arbiter decides who takes over.›NAT traversal (STUN, ICE, TURN)media · medium: Learn your public address with STUN, swap candidate addresses over signalling, test pairs with ICE checks, and fall back to a TURN relay if no direct path works.›Coverage-guided fuzzingsecurity · medium: Mutate inputs, run an instrumented target, and keep any input that reaches a new code edge; feedback turns blind guessing into incremental search.›Point-in-time recoverystorage · medium: Periodic base backups plus a continuously archived change log let you rebuild the state as of any instant, then branch from there.›Delta debuggingcompilers · medium: Ddmin minimization of failing inputs or change setsLamport clocksdistributed · low: One integer per process, max-plus-one on receive; gives a total order consistent with causality using 8 bytes per timestamp.›Vector clocksdistributed · low: One counter per node; comparing two vectors tells whether events are ordered or concurrent, which is exactly what conflict detection needs.›Write-ahead logstorage · low: Append each change to a checksummed sequential log and fsync it before touching data pages; the basis of crash durability in nearly every database.›Delta encodingcompression · low: Store differences between consecutive values instead of the values, turning sorted IDs, timestamps and counters into small numbers that pack into few bits.›Run length encodingcompression · low: Run-length encoding of repeated values, often combined with delta and bit packingVarint (LEB128)compression · low: Variable-length integers in 7-bit groups with a continuation bit; small numbers take 1 byte, the wire format of Protobuf, WebAssembly and DWARF.›Bloom filterdata-structures · low: Bit array answering "definitely not present" or "probably present" in about 10 bits per key for 1 % false positives; inserts are cheap, deletes impossible.›Hdr histogramdata-structures · low: Log-linear bucketed histograms with bounded relative error for latency percentilesMerkle treedata-structures · low: Hash tree for verifying and diffing large datasets with logarithmic proofsRopegraphics · low: A balanced tree of small string chunks with cached byte and newline counts, so seek, insert, delete and snapshot cost O(log n) instead of O(n).›Process supervisionhardware-os · low: A parent process starts services, reaps their exits and restarts them under a delay and burst-limit policy, then stops them with SIGTERM before SIGKILL.›WebSocketsnetworking · low: Full-duplex message framing over one upgraded HTTP connection; the standard way to push real-time data to browsers.›AEAD (AES-GCM, ChaCha20-Poly1305)security · low: Authenticated encryption that encrypts and detects tampering in one call; the only kind of symmetric encryption you should use.›Cryptographic hashes (SHA-2, BLAKE3)security · low: Collision-resistant fingerprints of data; SHA-256 for interoperability, BLAKE3 for speed, HMAC/HKDF for keyed uses.›ECDH key exchange (X25519, P-256)security · low: Each side multiplies the other's public curve point by its own scalar and both get the same point; always validate the peer key and run the result through a KDF.›Mutual TLSsecurity · low: TLS where the client also proves a certificate key, so every connection carries a verified, rotatable machine identity.›+ 4 more techniques+ 36 more primitives

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