Introduction

LINC

LINC is a middleware for building applications over a distributed system (possibly over a large-scale distributed system) comprising software components, sensors and actuators. The paradigm of resources is used to simplify the integration of these components.

Motivation

Where distributed applications are concerned, whether it be components running on the same machine or components running on machines spread over different continents, the problems to solve are the same:

  • To share data
  • To synchronize « entities »
  • To manage concurrent accesses
  • To define conditions
  • To ensure consistency on the « global state » of the « system »

However until now each level was defining its own way to solve (or not) the issues with differing points of view.

LINC offers a unified view of the problem through a resources-oriented approach.

LINC: A resource based middleware

A very high-level description of LINC is presented here. For more details please follow the link.

What is a component in LINC ?

In a first approach, consider that ''a component is a set of bags containing resources''.

What is a resource in LINC ?

  • a directory, a file,
  • a document, a paragraph, a line of the document,
  • the author of the document,
  • the office of the author, his/her chair
  • the authorization to access the document
  • a disk, a computer,
  • the room where the computer is located
  • the socket where the computer is plugged in
  • the power line, the power plan,
  • the town, the Earth, the galaxy, the universe
  • Richard Stallman

and

  • “you” who are reading these lines

What is an application in LINC

''An application is a set of rules that try to find some specific resources in the LINC world (the different bags) and once these resources are present, they can be consumed or combined in order to create new resources that are, in turn, inserted in the LINC world.''

This is nothing more than what was introduced by Anaxagore de Clazomènes:

"Rien ne naît ni ne périt, mais des choses déjà existantes se combinent, puis se séparent de nouveau". This was reworded by Antoine Lavoisier under the form "Rien ne se perd, rien ne se crée, tout se transforme". This last sentence has been engraved in the memories of French schoolchildren for centuries.