Bitcoin or 'blockchain': decentralized or distributed?

The eternal debate between each other bitcoin or other blockchains similar are decentralized or distributed is a constant in the Telegram group of Blockchain Spain. Bitcoin was born as an electronic cash or decentralized money managed between peers without the need to use intermediaries but, from a technological point of view, there is still no consensus in many cases if decentralized or distributed are the correct terms to use. It seems a secondary issue for those who do not follow this market on a daily basis, but it is revealing if we look at the way of thinking of the people who follow it.

What is the difference between decentralized systems or distributed from a technological point of view?

In the context of computing, a distributed system is a group of computers that are connected to each other through a standard communications protocol and that work as a single supercomputer offering a common service. Distributed systems can be classified into different types depending on the number of interconnected computers, the software that works in them or also how they are grouped.

For example, several computers can be connected through a local area network (cluster), where all the nodes are in the same place. These nodes can work with the same software and it is through a local communications protocol that one has access to each of the program components in any of the nodes. This is how the hardware and software resources of the network are used, and even if the appropriate configuration is made, high availability of the service and higher computing power can be guaranteed.

There is another type of distributed system in which the computers of the network do not have to be located in the same place (grid or mesh network). In this example, they connect to each other through a global communications protocol and form a heterogeneous system in which the nodes of the network do not have to have all the same software installed.

What examples of distributed networks exist?

One of the most popular distributed computing networks came into being in mid-1999, when the University of California at Berkeley launched the project SETI @ Home. You downloaded data packages obtained by the SETI to your computer's hard drive, and at times when your computer was inactive (when the screen saver jumped) a program that processed those data packages started running in the background. Upon completion, your computer returned the already processed packages and began downloading new packages of raw information to start over. This was done by users all over the world, in a totally disinterested way beyond collaboration with an interesting project.

Over the months the network grew, creating a huge network of computers and thus helping to achieve a common goal. In this case, the search for extraterrestrial intelligence was enhanced using the radio telescope of Arecibo (Puerto Rico), then the largest in the world. This project is still active today and has almost 300,000 active computers making calculations distributed all over the world.

Other similar projects were Einstein @ Home which aims to look for gravitational waves in the universe, or Rosetta @ Home that seeks to design new proteins with the collaboration of almost one million computers.

The bitcoin network is a distributed computing network that follows the same principles, but in it we can find two types of groupings of nodes. Mostly we will find a distributed network of type grid, where the nodes do not have to be located in the same geographic place and each node can be in a different point of the world. They are connected to each other through a communication protocol of their own and the same information is downloaded periodically. On the other hand, a minority part of the nodes forms a distributed network of type cluster, that is, computers connected to each other and located in the same place.

Most of them are computer clusters that process the information previously downloaded with the capacities they have available, usually the sum of the processors and ALU (arithmetic-logic unit). Finally, they share the result with the rest of the nodes of the global network, contributing through a consensus algorithm in the maintenance of a fairly secure information storage system, such as its own chain of blocks.

In a distributed network like that of bitcoin, all the nodes connected to the rest of the nodes do not have to be because it would be very complicated. In this case, it would be necessary to have open hundreds of thousands of bidirectional connections in all the nodes, which is not reasonable or effective. So in reality, bitcoin shares the same information replicated among all the nodes, where among many other data there are nodes participating in the network that is updated periodically. In this way, it is enough to establish communication with some nearby nodes that in turn will be connected to other nodes creating something similar to a neural network. Bitcoin is responsible for this as a protocol, the software that everything participant node In the network you must have installed and properly configured.

So is bitcoin distributed or decentralized?

Nowadays it can be said that the decentralized computer system by antonomasia is the one that uses bitcoin, since it does not have one or several central nodes that are in charge of storing and processing the information of the chain of blocks. If so, it would lose all its value, since trust in the consensus of most nodes is the main characteristic of the protocol. After all, it was created for that purpose; dispense with a centralized entity that could manipulate the recorded and stored information or censor the use of bitcoin. As explained before, all the nodes of the network participate in one way or another in making the network faster and more secure.

The main difference between a decentralized system and a distributed system is how and where the capture of decisions and how information is shared between the nodes of the system.

In a decentralized system there is no single decision point. Each node makes the decision that best suits it based on the consensus rules that the node operator has freely chosen. The result of the system as a whole is the collective response. The nodes in a decentralized system do not have knowledge of the state of the whole system, but they make the decisions that best suit them with the information they have. On the other hand, in a distributed system, the processing is shared among multiple nodes, but the decisions are centralized and they have knowledge of the total state of the system.

Have collaborated on this article: José Antonio Bravo, economist, founding member of AvalBit.org @AvalBit and co-administrator of Telegram forum of BlockchainEspana.com; Javier Domínguez Gómez, Node programmer and co-administrator of the Telegram forum of BlockchainEspana.com; Alex Preukschat he is the coordinating author of the book 'Blockchain: The Industrial Revolution of the Internet' Ediciones Gestión 2000 (Grupo Planeta) and the graphic novel'Bitcoin: the hunting of Satoshi Nakamoto'@BitcoinComic and node Coordinator of BlockchainEspana.com @BlockchainES, AllianceBlockchain.org @AlianzaBlock Y SSIMeetup.org @SSIMeetup.