... a protocol that allows independent blockchains to exchange information.

... an interoperability layer, that enforces order and the validity of the messages between the chains

Parachains are separate chains run in and with direct knowledge of polkadot.

& bridges allow interactions with 3rd Party chains.

Polkadot is an interoperability protocol with multi-chain collaboration at the core of its design

... is a Polkadot compatible, general purpose blockchain development kit in rust

... allows hot-upgrades of the internal runtime through WebAssembly ("WASM")

... is log of state transitions

... the specifics depend on that particular blockchain

... transitions are bundled in blocks, where every block references its parent ("chain")

e.g. which crypto, consensus, network protocol or transitions are available

This is where the magic happens

Substrate

Chain Runtime

execute_block

Substrate provided Key-Value-Store

:code

.. is a web standard for an assembly like compile-target to run code in Web Browsers as almost native speed

.. is execute in a sandboxed virtual environment

.. can be compiled to from many system languages (C, C++, rust, ...)

let code = get_state(":code");

let executor = {
  if native.can_call_with(code.runtime_version) {
    native::executor
  } else {
    in_wasm_module_executor(code)
  }
};

executor.execute_block(   );

let code = get_state(":code");

let executor = {
  if native.can_call_with(code.runtime_version) {
    native::executor
  } else {
    in_wasm_module_executor(code)
  }
};

executor.execute_block(   );

impl RuntimeVersion {
  pub fn can_call_with(&self, other: &RuntimeVersion) -> bool {
    self.spec_name == other.spec_name &&

    self.spec_version == other.spec_version    

  }
}

set_state(":code",    )

+1