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Three comma club
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drewstone authored Sep 13, 2018
commit f569de2e6fdf969912d563c344cdf6af6dde531c
8 changes: 4 additions & 4 deletions README.adoc
Original file line number Diff line number Diff line change
Expand Up @@ -12,17 +12,17 @@ Next-generation framework for blockchain innovation.

At its heart, Substrate is a combination of three technologies: WebAssembly, Libp2p and AfG Consensus. It is both a library for building new blockchains and a "skeleton key" of a blockchain client, able to synchronise to any Substrate-based chain.

Substrate chains have three distinct features that make them "next-generation": a dynamic, self-defining state-transition function, light-client functionality from day one, and a progressive consensus algorithm with fast block production and adaptive, definite finality. The STF, encoded in WebAssembly, is known as the "runtime". This defines the `execute_block` function, and can specify everything from the staking algorithm, transaction semantics, logging mechanisms and procedures for replacing any aspect of itself or of the blockchain's state ("governance"). Because the runtime is entirely dynamic all of these can be switched out or upgraded at any time. A Substrate chain is very much a "living organism".
Substrate chains have three distinct features that make them "next-generation": a dynamic, self-defining state-transition function, light-client functionality from day one and a progressive consensus algorithm with fast block production and adaptive, definite finality. The STF, encoded in WebAssembly, is known as the "runtime". This defines the `execute_block` function, and can specify everything from the staking algorithm, transaction semantics, logging mechanisms and procedures for replacing any aspect of itself or of the blockchain's state ("governance"). Because the runtime is entirely dynamic all of these can be switched out or upgraded at any time. A Substrate chain is very much a "living organism".

== Usage

Substrate is still an early stage project, and while it has already been used as the basis of major projects like Polkadot, using it is still a significant undertaking. In particular, you should have a good knowledge of blockchain concepts and basic cryptography. Terminology like header, block, client, hash, transaction, and signature should be familiar. At present you will need a working knowledge of Rust to be able to do anything interesting (though eventually, we aim for this not to be the case).
Substrate is still an early stage project, and while it has already been used as the basis of major projects like Polkadot, using it is still a significant undertaking. In particular, you should have a good knowledge of blockchain concepts and basic cryptography. Terminology like header, block, client, hash, transaction and signature should be familiar. At present you will need a working knowledge of Rust to be able to do anything interesting (though eventually, we aim for this not to be the case).

Substrate is designed to be used in one of three ways:

1. Trivial: By running the Substrate binary `substrate` and configuring it with a genesis block that includes the current demonstration runtime. In this case, you just build Substrate, configure a JSON file and launch your own blockchain. This affords you the least amount of customisability, primarily allowing you to change the genesis parameters of the various included runtime modules such as balances, staking, block-period, fees and governance.

2. Modular: By hacking together modules from the Substrate Runtime Module Library into a new runtime and possibly altering or reconfiguring the Substrate client's block authoring logic. This affords you a very large amount of freedom over your own blockchain's logic, letting you change datatypes, add or remove modules, and, crucially, add your own modules. Much can be changed without touching the block-authoring logic (since it is generic). If this is the case, then the existing Substrate binary can be used for block authoring and syncing. If the block authoring logic needs to be tweaked, then a new altered block-authoring binary must be built as a separate project and used by validators. This is how the Polkadot relay chain is built and should suffice for almost all circumstances in the near to mid-term.
2. Modular: By hacking together modules from the Substrate Runtime Module Library into a new runtime and possibly altering or reconfiguring the Substrate client's block authoring logic. This affords you a very large amount of freedom over your own blockchain's logic, letting you change datatypes, add or remove modules and crucially add your own modules. Much can be changed without touching the block-authoring logic (since it is generic). If this is the case, then the existing Substrate binary can be used for block authoring and syncing. If the block authoring logic needs to be tweaked, then a new altered block-authoring binary must be built as a separate project and used by validators. This is how the Polkadot relay chain is built and should suffice for almost all circumstances in the near to mid-term.
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definitely keep these twoor exchange them for m-dashes.


3. Generic: The entire Substrate Runtime Module Library can be ignored and the entire runtime designed and implemented from scratch. If desired, this can be done in a language other than Rust, providing it can target WebAssembly. If the runtime can be made to be compatible with the existing client's block authoring logic, then you can simply construct a new genesis block from your Wasm blob and launch your chain with the existing Rust-based Substrate client. If not, then you'll need to alter the client's block authoring logic accordingly. This is probably a useless option for most projects right now, but provides complete flexibility allowing for a long-term far-reaching upgrade path for the Substrate paradigm.

Expand Down Expand Up @@ -87,7 +87,7 @@ The Substrate Runtime Module Library includes functionality for timestamps and s

=== Block-authoring Logic

In Substrate, there is a major distinction between blockchain *syncing* and block *authoring* ("authoring" is a more general term for what is called "mining" in Bitcoin). The first case might be referred to as a "full node" (or "light node" - Substrate supports both): authoring necessarily requires a synced node, and, therefore, all authoring clients must necessarily be able to synchronise. However, the reverse is not true. The primary functionality that authoring nodes have, which is not in "sync nodes", is threefold: transaction queue logic, inherent transaction knowledge, and BFT consensus logic. BFT consensus logic is provided as a core element of Substrate and can be ignored since it is only exposed in the SDK under the `authorities()` API entry.
In Substrate, there is a major distinction between blockchain *syncing* and block *authoring* ("authoring" is a more general term for what is called "mining" in Bitcoin). The first case might be referred to as a "full node" (or "light node" - Substrate supports both): authoring necessarily requires a synced node and, therefore, all authoring clients must necessarily be able to synchronise. However, the reverse is not true. The primary functionality that authoring nodes have, which is not in "sync nodes", is threefold: transaction queue logic, inherent transaction knowledge and BFT consensus logic. BFT consensus logic is provided as a core element of Substrate and can be ignored since it is only exposed in the SDK under the `authorities()` API entry.

Transaction queue logic in Substrate is designed to be as generic as possible, allowing a runtime to express which transactions are fit for inclusion in a block through the `initialize_block` and `apply_extrinsic` calls. However, more subtle aspects like prioritisation and replacement policy must currently be expressed, "hard coded", as part of the blockchain's authoring code. That said, Substrate's reference implementation for a transaction queue should be sufficient for an initial chain implementation.

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