why pos

Ethereum switched on its proof-of-stake mechanism in 2022 because it is more secure, less energy-intensive, and better for implementing new scaling solutions compared to the previous proof-of-work architecture.

Terms

Parser:

PMD uses JavaCC and JJTree to generate source code parser.
When parsing java source file with the generated parser, it produces an AST tree with ASTCompilationUnit as root node.
See https://javacc.github.io/javacc/documentation/jjtree.html.

IT的不可能三角：在固定生产力水平下，开发效率、资源利用率、稳定性三者不可能同时达到最优。

2017年，以太坊主网拥剧烈拥堵，容量成为限制以太坊发展的重大瓶颈，亟需寻找扩容方案。
现在，四年过去了，以太坊的扩容之路，走得怎么样了？

steps

choco install rustup
rustup toolchain install stable-x86_64-pc-windows-gnu
rustup toolchain remove stable-x86_64-pc-windows-msvc
rustup target add x86_64-pc-windows-gnu
rustup default stable-x86_64-pc-windows-gnu

Abstract

Substrate is a modular framework that enables you to create purpose-built blockchains by composing custom or pre-built components.

Overview

Substrate takes a modular approach to blockchain development and defines a rich set of primitives that allows developers to make use of powerful, familiar programming idioms.

How to Use

1. Substrate Node: create a new blockchain with a JSON file.
2. Substrate FRAME: create a new blockchain with customized login.
3. Substrate core: build your own blockchain from scratch.

Architecture

Key Concepts

In Substrate-based chains, the runtime is referred to as the “state transition function”.

Core Primitives

1. Hash
2. DigestItem
3. Digest
4. Extrinsic. Data out of chain, that could be recognized by the chain.
5. Header. Similar to BTC blockchain header.
6. Block
7. BlockNumber. Similar to BTC height. 32bit.

FRAME Primitives

1. Call.
2. Origin. Where the call came from
3. Index.
4. Hashing. The hashing system used, e.g. Blake2
5. AccountId. User account identifier.
6. Event
7. Version
   

简介

可伸缩异构多链系统
政府和尿布都得经常换，而且理由都一样。

简介

历史

远古时期：分时系统和最早的虚拟化理论

互联网早期：虚拟化技术的成熟

第一代真正的云计算市场

从容器到云原生

概念

1. 云计算=将计算服务当做一种服务提供出去
2. 服务类型：IaaS，PaaS，ServerLess，SaaS，FaaS
3. IaaS：租用IT基础结构，比如服务器和虚拟机、存储空间、网络、防火墙、低层安全设施
4. PaaS：租用操作系统、开发工具、数据库管理系统、BI、大数据系统等
5. ServerLess：开发者不再管理基础结构，云服务提供商自动预配、缩放和管理运行代码所需的基础结构
6. FaaS：ServerLess的一种场景，不再有应用的概念，开发人员仅专注于功能；FaaS只是特殊场景，ServerLess的含义更加广泛
7. SaaS：直接租用托管的软件系统
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