Relevant Terminologies

Block space

The capacity of each block. The amount of block space a blockchain has determines its throughput. Blockchains that suffer from high fees occur because the demand for block space exceeds supply.

Consensus

Consensus refers to a function of modular blockchains where the ordering of transactions is agreed upon by a set of validators. To agree on the order of transactions in a block, validators follow a consensus algorithm.

Data availability (DA)

Data availability answers the question of whether this data has been published. Specifically, a node will verify data availability when it receives a new block that is getting added to the chain. The node will attempt to download all the transaction data for the new block to verify availability. If the node can download all the transaction data, then it successfully verified data availability, proving that the block data was actually published to the network.

Data availability committee (DAC)

A data availability committee (DAC) is a permissioned group of nodes responsible for providing data availability to a blockchain.

Data availability sampling (DAS)

Data availability sampling is a mechanism for light nodes to verify data availability without having to download all data for a block. Data availability sampling (DAS) works by having light nodes conduct multiple rounds of random sampling for small portions of block data. As a light node completes more rounds of sampling for block data, it increases its confidence that data is available. Once the light node successfully reaches a predetermined confidence level (e.g. 99%) it will consider the block data as available.