Patent ID: 11914475
Assignee: INSTITUT MINES TELECOM
Field: Computer technology (Electrical engineering)
Classification: CPC G  H | IPC G  H

Claim 8:
9. A method for reconstructing a content of a storage device out of a plurality of devices storing k data blocks ai in k systematic storage devices Ni, i∈{I, . . . , k}, and r parity functions fj(a) in r parity storage devices Ni, i ∈{k+1, . . . , k+r}, said k data blocks and r parity functions being obtained according to the method of claim 1, the reconstruction method comprising:
determining whether the storage device for which to reconstruct the content is a systematic or parity storage device;
if said device is a systematic storage device Ni, i∈{1, . . . , k},
determining to which subset of data Sj the data block of said device belongs;
retrieving the primary and secondary parity functions stored in the parity storage devices k+1 and k+1+j;
computing the linear function gj(a) associated with the subset Sj;
retrieving the data blocks of the subset Sj except for the block ai; and
reconstructing the content of said systematic storage device Ni, i∈{1, . . . , k},
if said device is a parity storage device Ni, i∈{k+1, . . . , k+r}, determining the index i identifying said storage device;
if the index i is equal to k+1:
retrieving the secondary parity function f1(a) stored in the parity storage device of index i=k+2 and the data blocks ai of the subset S1;
computing the linear function g1(a) associated with the subset S1 and decoding the primary parity function f0(a); and
reconstructing the content of said parity device of index i=k+1;
if the index i is greater than k+1:
retrieving the primary parity function f0(a) stored in the parity storage device of index i=k+1 and the data blocks ai of the subset Si−k+1;
computing the linear function gi−k+1 (a) associated with the subset Si−k+1 and decoding the secondary parity function f1−k+1 (a); and
reconstructing the content of said parity device of index i>k+1.