Glossary of Tahoe-LAFS Terms

Foolscap

an RPC/RMI (Remote Procedure Call / Remote Method Invocation) protocol for use with Twisted

storage server

a Tahoe-LAFS process configured to offer storage and reachable over the network for store and retrieve operations

storage service

a Python object held in memory in the storage server which provides the implementation of the storage protocol

introducer

a Tahoe-LAFS process at a known location configured to re-publish announcements about the location of storage servers

fURLs

a self-authenticating URL-like string which can be used to locate a remote object using the Foolscap protocol (the storage service is an example of such an object)

NURLs

a self-authenticating URL-like string almost exactly like a fURL but without being tied to Foolscap

swissnum

a short random string which is part of a fURL/NURL and which acts as a shared secret to authorize clients to use a storage service

lease

state associated with a share informing a storage server of the duration of storage desired by a client

share

a single unit of client-provided arbitrary data to be stored by a storage server (in practice, one of the outputs of applying ZFEC encoding to some ciphertext with some additional metadata attached)

bucket

a group of one or more immutable shares held by a storage server and having a common storage index

slot

a group of one or more mutable shares held by a storage server and having a common storage index (sometimes “slot” is considered a synonym for “storage index of a slot”)

storage index

a 16 byte string which can address a slot or a bucket (in practice, derived by hashing the encryption key associated with contents of that slot or bucket)

write enabler

a short secret string which storage servers require to be presented before allowing mutation of any mutable share

lease renew secret

a short secret string which storage servers required to be presented before allowing a particular lease to be renewed