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Glossary

Baking​

Creation of new blocks on the Tezos blockchain by participants known as bakers , who are given a reward for each block that they bake. A baker may also be referred to as a delegate.

Block​

A set of operations for validation. A block contains, besides operations, information such as the current block number, information about the previous block, and also the time at which it was validated.

Cycle​

Period of time during which 16,384 blocks are created on the Tezos blockchain. Also used as a unit of time. It corresponds to roughly 2 days, 20 hours, and 16 minutes (based on 15 seconds per block created if no baker has missed their baking slots).

Delegation​

Every Tez holder can transfer the baking and voting rights associated with their Tez to a baker. The holder always retains control of their funds and may change delegate at any time.

Fitness​

Score representing the quality of the chain up to a given block. See https://tezos.gitlab.io/active/consensus.html#shell-protocol-interaction-revisited for more details.

Node​

A Tezos node is a peer (a machine) on the peer-to-peer network. It keeps a copy of the current state and propagates the blocks baked and operations performed to the other peers. A node is not necessarily a baker, but a baker is always associated with one or more nodes. Nodes are running in one of the following three modes, with respect to how they keep the chain history:

  • In archive mode, they keep the whole history of the chain. As of year-end 2020, an archive node takes up around 80GB.
  • In rolling mode, they keep the minimum data required to operate the chain, with the oldest information being deleted regularly.
  • In full mode (the default mode), they keep all the information in a rolling mode, plus the minimum data required to reconstitute the entire chain from the genesis block. Thus, the full mode combines elements of the archive and rolling modes.

Pre-attestation / Attestation​

In addition to creating new blocks, bakers may attest blocks made by other bakers. They are known as pre-attestations (1st approval phase) and attestations (2nd approval phase) of a block.

Roll​

An amount of tez (e.g. 6000ꜩ) serving as a minimal amount for a delegate to have baking and voting rights in a cycle. However since Ithaca and Jakarta amendment, rolls are not used anymore as a unit for baking or voting rights, these are based on the actual, non-approximated stake.

Round​

A period of time (made up of 3 phases) during which a given validator (selected to produce a block) proposes a block, obtains pre-attestations, and then attestations. If, for certain reasons it fails, we go to another round, and so on.

Stake​

To have the right to be recognized as a baker in a network, a Tez holder must possess at least one roll, in their staking balance (own balance + delegated balance). Voting rights are also indexed to the staking balance.

Slot​

A slot is an opportunity available for a block creation or an attestation: each cycle has 16,384 baking slots and 2,097,152 attestation slots. At the start of each cycle, the protocol assigns a list of bakers to each slot using a uniform law weighted by staking balance. The first baker on the list is tasked with baking or attesting as appropriate. If they don't, the next baker is given the task, etc.