1) What is EOS

 
Basically it is a really powerful "framework" for DAPPS (Decentralized applications). Someone like to call it a "Operative System" for dapps on blockchain technology, but it's more like a framework where anyone can build a DAPP on it. So EOS will be the backbone that give a DAPP some powerful features like smart contracts that can evolve, a lot of transactions per seconds, parallel performance and more...

The creator of EOS is Dan Larimer, the same creator of STEEM and BitShares, the 2 most used blockchains.

2) What EOS gives to DAPPS

 

• Support Millions of Users - it Is designed to handle more than 10 millions active users
• free usage - users don’t have to pay fees
• Easy upgrade and bug recovery - it allows to software to to fix bugs when they inevitably occur.
• Low latency - transactions are really fast
• Parallel performance - the workload is distributed across multiple CPUs and computers.
• Fine tuned permissions

3) EOS consensus algorithm

 
The consensus algorithm that EOS use is called “Delegated proof of stake” (DPOS). Under this algorithm, those who hold tokens may select block producers through a continuous approval voting system .Anyone can participate in block production and will be given an opportunity to produce blocks proportional to the total votes they have received relative to all other producers. Each block should be produced every 3 seconds. Blocks are produced in rounds of 21.

4) Transactions on EOS

 
A transaction can be considered confirmed after an average of 1.5 seconds from time of broadcast. By default all nodes will consider a block confirmed by 15 of 21 producers irreversible and this will take an average of 45 seconds under normal circumstances.

Every transaction should include the hash of a recent block header. This is done in order to prevent replay of transactions in different forks and to notify that a user is in a certain fork.

5) EOS smart contracts

 
Each account can define a custom message handler script when a message arrives. Those script can send message to other accounts and can access a private database that Eos provide for each account. These automated message handler is called smart contracts in EOS.

6) EOS supports multiples virtual machines

 
EOS is designed to support different virtual machines. There are two virtual machines that are currently being evaluated for use with an EOS.IO: Web Assembly (WASM) and the EVM (Ethereum virtual machine).