Crate

Abstract

Real-time collaborative editors are common tools for distributing work across space, time, and organizations. Unfortunately, mainstream editors such as Google Docs rely on central servers and raise privacy and scalability issues. Crate is a real-time decentralized collaborative editor that runs directly in web browsers thanks to WebRTC. Compared to state-of-the-art, Crate is the first real-time editor that only requires browsers in order to support collaborative editing and to transparently handle from small to large groups of users. Consequently, Crate can also be used in massive online lectures, TV shows or large conferences to allow users to share their notes. Crate's properties rely on two scientific results: (i) a replicated sequence structure with sub-linear upper bound on space complexity; this prevents the editor from running costly distributed garbage collectors, (ii) an adaptive peer sampling protocol; this prevent the editor from oversizing routing tables, hence from letting small networks pay the price of large networks. This paper describes Crate, its properties and its usage.

A conflict‐free replicated data type for collaborative annotation systems

“…CRDT 17,18 is a new framework of data structure where all concurrent updating operations must commute to ensure convergence in collaborative systems. Initially, the algorithm has been successfully applied to different data structures in collaborative systems 33,34 for linear data type, 35 tree document data type, 17 semistructured data type, 36 and JSON document 37 . Recently, many CRDT are proposed to support collaborative editing of semantic stores.…”

Breaking the Scalability Barrier of Causal Broadcast for Large and Dynamic Systems

“…These are not practical assumptions. In practice, processes may join and leave the system at any time; and processes may reconfigure their neighborhood at any time [4]. Figure 3 shows an example of message dissemination in dynamic settings where causal delivery is violated.…”

“…Causal broadcast [1] is a fundamental building block of many distributed applications [2] such as distributed social networks [3], distributed collaborative software [4,5], or distributed data stores [6,7,8,9,10]. Causal broadcast is a reliable broadcast where all connected processes deliver each broadcast message exactly once following the happen before relationship [11,12]: when Alice comments Bob's picture, everyone receives the comment after the picture; unrelated events are delivered in any order.…”

Verifying strong eventual consistency in distributed systems

“…As with OT, several CRDTs for text documents have been developed, including RGA [Roh et al 2011], Treedoc [Preguiça et al 2009], WOOT [Oster et al 2006b], Logoot , and LSEQ [Nédelec et al 2016[Nédelec et al , 2013. Other datatypes include registers and counters [Shapiro et al 2011a,b], maps [Baquero et al 2016], sets [Bieniusa et al 2012a,b], XML [Martin et al 2010], and JSON trees .…”