HAL : hal-00717235, version 2
 Versions disponibles : v1 (17-07-2012) v2 (23-08-2012)
 Linear Space Boostrap Communication Scheme
 (21/05/2012)
 We consider a system of $n$ processes with ids not a priori known, that are drown from a large space, potentially unbounded. How can these $n$ processes communicate to solve a task? We show that $n$ a priori allocated Multi-Writer Multi-Reader (MWMR) registers are both needed and sufficient to solve any read-write wait-free solvable task. This contrasts with the existing possible solution borrowed from adaptive algorithms that require $\Theta(n^2)$ MWMR registers. To obtain these results, the paper shows how the processes can \emph{non-blocking} emulate a system of $n$ Single-Writer Multi-Reader (SWMR) registers on top of $n$ MWMR registers. It is impossible to do such an emulation with $n-1$ MWMR registers. Furthermore, we want to solve a sequence of tasks (potentially infinite) that are sequentially dependent (processes need the previous task's outputs in order to proceed to the next task). A non-blocking emulation might starve a processor forever. By doubling the space complexity, using $2n-1$ rather than just $n$ registers, processes can erase each other's write operation, just a bounded number of times, and consequently the computation is wait-free rather than non-blocking.
 1 : Laboratoire d'informatique Algorithmique : Fondements et Applications (LIAFA) CNRS : UMR7089 – Université Paris VII - Paris Diderot 2 : Computer Science Department [Los Angeles] (UCLA) University of California, Los Angeles 3 : Instituto de Matematicas [México] UNIVERSIDAD NACIONAL AUTÓNOMA DE MÉXICO
 Domaine : Sciences cognitives/Informatique
 Mots Clés : shared memory – read/write registers – distributed algorithms – wait-free – space complexity – renaming.
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 hal-00717235, version 2 http://hal.archives-ouvertes.fr/hal-00717235 oai:hal.archives-ouvertes.fr:hal-00717235 Contributeur : Carole Delporte-Gallet <> Soumis le : Mardi 21 Août 2012, 12:13:35 Dernière modification le : Jeudi 23 Août 2012, 14:29:18