Sector #

The Sector is a fundamental “storage container” abstraction used in Filecoin Storage Mining. It is the basic unit of storage, and serves to make storage conform to a set of expectations.

New sectors are empty upon creation. As the miner receives client data, they fill or “pack” the piece(s) into an unsealed sector.

Once a sector is full, the unsealed sector is combined by a proving tree into a single root UnsealedSectorCID. The sealing process then encodes (using CBOR) an unsealed sector into a sealed sector, with the root SealedSectorCID.

This diagram shows the composition of an unsealed sector and a sealed sector.

Unsealed Sectors and Sealed Sectors
Unsealed Sectors and Sealed Sectors
import abi ""
import piece ""
import smarkact ""

type Bytes32 Bytes
type Commitment Bytes32  // TODO

type FaultSet CompactSectorSet
type StorageFaultType int

// SectorInDetail describes all the bits of information associated
// with each sector.
// - ID   - a unique identifier assigned once the Sector is registered on chain
// - Size - the size of the sector. there are a set of allowable sizes
// NOTE: do not use this struct. It is for illustrative purposes only.
type SectorInDetail struct {
    ID    abi.SectorID
    Size  abi.SectorSize

    Unsealed struct {
        CID     abi.UnsealedSectorCID
        Deals   [smarkact.StorageDeal]
        Pieces  [piece.Piece]
        // Pieces Tree<Piece> // some tree for proofs

    Sealed struct {
        CID              abi.SealedSectorCID
        RegisteredProof  abi.RegisteredProof

// SectorInfo is an object that gathers all the information miners know about their
// sectors. This is meant to be used for a local index.
type SectorInfo struct {
    ID                  abi.SectorID
    UnsealedInfo        UnsealedSectorInfo
    SealedInfo          SealedSectorInfo
    SealVerifyInfo      abi.SealVerifyInfo

// UnsealedSectorInfo is an object that tracks the relevant data to keep in a sector
type UnsealedSectorInfo struct {
    UnsealedCID  abi.UnsealedSectorCID  // CommD
    Size         abi.SectorSize
    PieceCount   UVarint  // number of pieces in this sector (can get it from len(Pieces) too)
    Pieces       [piece.PieceInfo]  // won't get externalized easy, -- it's big
    // Deals       [smarkact.StorageDeal]

// SealedSectorInfo keeps around information about a sector that has been sealed.
type SealedSectorInfo struct {
    SealedCID  abi.SealedSectorCID
    Size       abi.SectorSize
    SealArgs   SealArguments


  • describe sizing ranges of sectors
  • describe “storage/shipping container” analogy