Simple and scalable RAID XOR assist logic with overlapped operations

A RAID system, comprising:

• an exclusive OR (XOR) unit, including a first input and a first output, the XOR unit suitable for performing an exclusive OR (XOR) operation;
• a memory, including a first buffer and a second buffer, communicatively coupled to the XOR unit, the memory is suitable for storing a first item of data and a second item of data;
• a first register set before the XOR unit and communicatively coupled with the first input of the XOR unit and the memory and a second register set behind the XOR unit and communicatively coupled with the first output of the XOR unit and the memory, the first register and the second register being used for performing overlapped operations of the exclusive OR (XOR) unit;
• and
• an array of disk drives communicatively coupled to the exclusive OR (XOR) unit.

A method of generating parity utilizing an overlapped function in a RAID array, comprising:

• receiving an old data set from a data storage array and loading the data to a memory device coupled to an exlcusive OR (XOR) unit, a first register set before the XOR unit, and a second register set behind the XOR unit;
• receiving old parity from the data storage array, processing the old parity through the exclusive OR (XOR) unit with the old data set from the memory device to remove knowledge of the old data set from the old parity, and storing resultant intermediate parity to the memory device;
• and
• generating new parity, wherein the new parity is generated by reading a new data set and intermediate parity from the memory device through the exclusive OR (XOR) unit.