Bi-directional decodable Reed-Solomon codes

A method of processing a code word stored on a storage device, the code word comprising symbols stored in a forward order, the method comprising:

• reading symbols of the code word from a storage device in the forward order or in a reverse order that is opposite the forward order;
• and
• decoding the code word;
• wherein, in a case that the symbols are read in the reverse order, the code word is decoded by processing the symbols in the reverse order, decoding being performed using a single syndrome generator that is operable on both reverse order symbols and forward order symbols.

A storage controller comprising:

• a controller which reads a code word from a storage device in either a forward or a reverse direction;
• and
• a decoder which decodes the code word in either the forward direction or the reverse direction;
• wherein, if the controller reads the code word from the storage device in the reverse direction, the decoder decodes the code word by processing data from the code word ordered in the reverse direction, decoding being performed using a single syndrome generator that is operable on both reverse order symbols and forward order symbols.

A data storage system comprising:

• a storage device;
• a controller which reads a code word from the storage device in either a forward or a reverse direction;
• and
• a decoder which decodes the code word as it is read from the storage device in either the forward direction or the reverse direction;
• wherein, if the controller reads the code word in the reverse direction, the decoder decodes the code word by processing data from the code word ordered in the reverse direction, decoding being performed using a single syndrome generator that is operable on both reverse order symbols and forward order symbols.

A method comprising:

• receiving, from a storage device, symbols of a Reed-Solomon code word in a reverse order, the symbols being stored on the storage device in a forward order that is opposite the reverse order, the symbols received in the reverse order comprising reverse order symbols;
• and
• performing a decoding procedure on the reverse order symbols by processing the symbols in the reverse order, the decoding procedure being performed using a single syndrome generator that is operable on both reverse order symbols and forward order symbols;
• wherein the decoding procedure comprises:
• generating reverse directional syndrome values based on the reverse order symbols;
• and
• converting the reverse directional syndrome values to syndrome values that correspond to syndrome values that would be generated if the reverse order symbols were received in forward order.