What is the physical location of Blockchain

Question

 I am new to this technology and I am confused. Please clear my few doubts. Thanks in advance.

Blockchain consists of Blocks but where these blocks are stored, I mean what is the physical location of the blocks. As per my theoretical knowledge blockchain exists in a network but in which network do we need to create our own network or is there any third party those who provide a network for our application.

Suppose I have to develop a land registry application. I need some space somewhere where I can store my blocks. if I store all blocks in my system itself then how it will behave like a decentralised.

Does Ethereum store our blocks in his network?

Blockchain itself is a database but how we can manage the data?

Answer 1

Blockchain is shared among all the p2p networks hosting it. So basically blockchain is stored in many simple HDDs all around the world.

1. If you want to create a totally new blockchain, you create your own network. If you want, for example, to use Ethereum network to run your token, then you'll use Ethereum network (which has been created for Ethereum at the first place)

2. That's what the blockchain and its protocol do. Store datas in multiple places and handle the integrity and safety of the datas. You need to have multiple agents in your network to be decentralised. You alone are centralised.

3. Yes, or more exactly, Ethereum users store datas in their storages for the Ethereum network

4. You can imagine different forms of blockchain, but speaking about the first one, Bitcoin, when the p2p network is launched and used, you can't manage datas by yourself. The network will handle it, and the only way you can manage datas is by having more than 50% of the mining power (in another way the network let users manage datas in an normal use case, for example, send your bitcoin is a normal use case, steal someone is not)