Raid decoding architecture with reduced bandwidth

Abstract

A RAID decoding system which performs a Built in Self-Test (BIST) includes: a RAID decoder, including: a storage, for storing a syndrome of a first Reed-Solomon (RS) codeword, a syndrome of a second RS codeword, and parity data of the first RS codeword and the second RS codeword; and an RS decoder which performs decoding on the first RS codeword and the second RS codeword according to the parity data to generate an updated syndrome of the first RS codeword and an updated syndrome of the second RS codeword. A MUX inputs the first and the second RS codeword to the RS decoder in a first iteration, and inputs the parity data to the RS decoder in following iterations for updating the syndromes of the first and the second RS codeword. The updated syndromes are used to perform error correction on the first RS codeword and the second RS codeword.

What is claimed is: 
     
         1 . A RAID decoding system which performs a Built in Self-Test (BIST), the RAID decoding system comprising:
 a RAID decoder, comprising:
 a storage, for storing a syndrome of a first Reed-Solomon (RS) codeword, a syndrome of a second Reed-Solomon (RS) codeword, parity data of the first RS codeword and parity data of the second RS codeword; and 
 an RS decoder which stores the first RS codeword and the second RS codeword, and performs decoding on the first RS codeword according to the parity data to generate an updated syndrome of the first RS codeword and performs decoding on the second RS codeword according to the parity data to generate an updated syndrome of the second RS codeword; and 
   a MUX, coupled between the storage and the RS decoder, for inputting the first RS codeword and the second RS codeword to the RS decoder in a first iteration, and for inputting the parity data of the first RS codeword and the parity data of the second codeword to the RS decoder in following iterations for respectively updating the syndrome of the first RS codeword and the syndrome of the second RS codeword;   wherein the updated syndrome of the first RS codeword and the updated syndrome of the second RS codeword are used to perform error correction on the first RS codeword and the second RS codeword to generate an error-corrected first RS codeword and an error-corrected second RS codeword.   
     
     
         2 . The RAID decoding system of  claim 1 , wherein the second RS codeword is a mirror of the first RS codeword so that the parity data of the first RS codeword is equal to the parity data of the second RS codeword, and the storage only stores the parity data of one of the first RS codeword and the second RS codeword, and further stores one of the first RS codeword with errors and the second RS codeword with errors. 
     
     
         3 . The RAID decoding system of  claim 2 , wherein the MUX inputs the parity data of the first RS codeword and the parity data of the second codeword to the RS decoder by mirroring the parity data stored in the storage. 
     
     
         4 . The RAID decoding system of  claim 2 , further comprising:
 a Result Check block, coupled to the RAID decoder, for receiving the one of the first RS codeword with errors inserted and the second RS codeword with errors inserted and the error-corrected first RS codeword and the error-corrected second RS codeword, and determining correctness of the data.   
     
     
         5 . The RAID decoding system of  claim 1 , wherein the RS decoder comprises:
 a first RS decoder for storing the first RS codeword and for performing decoding on the first RS codeword according to the parity data to generate the updated syndrome of the first RS codeword; and   a second RS decoder for storing the second RS codeword and for performing decoding on the second RS codeword according to the parity data to generate the updated syndrome of the second RS codeword.   
     
     
         6 . The RAID decoding system of  claim 1 , further comprising:
 an Error Insertion block for inserting errors into the first RS codeword and the second RS codeword.   
     
     
         7 . The RAID decoding system of  claim 6 , further comprising:
 a Random Number Generator, for generating data to the Error Insertion block; and   a SEED pool, coupled between the Error Insertion block and the Random Number Generator, for storing values corresponding to the first RS codeword with errors inserted and the second RS codeword with errors inserted, and using those values to control the Random Number Generator to generate the first RS codeword with errors inserted and the second RS codeword with errors inserted when the updated syndrome of the first RS codeword and the updated syndrome of the second RS codeword both equal zero.   
     
     
         8 . The RAID decoding system of  claim 7 , further comprising:
 a Result Check block, coupled to the Random Number Generator and the RAID decoder, for receiving the first RS codeword with errors inserted and the second RS codeword with errors inserted and the error-corrected first RS codeword and the error-corrected second RS codeword, and determining correctness of the data.   
     
     
         9 . The RAID decoding system of  claim 1 , wherein the updated syndrome of the first RS codeword and the updated syndrome of the second RS codeword are used to perform error correction on the first RS codeword and the second RS codeword when the updated syndrome of the first RS codeword and the updated syndrome of the second RS codeword both equal zero.