Editing Hyphanet (section)

===Distributed storage and caching of data===
Like [[Winny]], [[Share (P2P)|Share]] and [[Perfect Dark (P2P)|Perfect Dark]], Freenet not only transmits data between nodes but actually stores them, working as a huge distributed cache. To achieve this, each node allocates some amount of disk space to store data; this is configurable by the node operator, but is typically several GB (or more).

Files on Freenet are typically split into multiple small blocks, with duplicate blocks created to provide [[Forward error correction|redundancy]].  Each block is handled independently, meaning that a single file may have parts stored on many different nodes.

Information flow in Freenet is different from networks like [[eMule]] or [[BitTorrent (protocol)|BitTorrent]]; in Freenet:

# A user wishing to share a file or update a freesite "inserts" the file "to the network"
# After "insertion" is finished, the publishing node is free to shut down, because the file is stored in the network. It will remain available for other users whether or not the original publishing node is online. No single node is responsible for the content; instead, it is replicated to many different nodes.

Two advantages of this design are high reliability and anonymity. Information remains available even if the publisher node goes offline, and is anonymously spread over many hosting nodes as encrypted blocks, not entire files.

The key disadvantage of the storage method is that no one node is responsible for any chunk of data. If a piece of data is not retrieved for some time and a node keeps getting new data, it will drop the old data sometime when its allocated disk space is fully used. In this way Freenet tends to 'forget' data which is not retrieved regularly (see also [[Freenet#Effect|Effect]]).

While users can insert data into the network, there is no way to delete data. Due to Freenet's anonymous nature the original publishing node or owner of any piece of data is unknown. The only way data can be removed is if users don't request it.