Patent ID: 7619912

Claim:
A memory module connectable to a computer system, the memory module comprising: a printed circuit board; a plurality of double-data-rate (DDR) memory devices mounted to the printed circuit board, the plurality of DDR memory devices having a first number of DDR memory devices arranged in a first number of ranks; a circuit mounted to the printed circuit board, the circuit comprising a logic element and a register, the logic element receiving a set of input control signals from the computer system, the set of input control signals comprising at least one row/column address signal, bank address signals, and at least one chip-select signal, the set of input control signals corresponding to a second number of DDR memory devices arranged in a second number of ranks, the second number of DDR memory devices smaller than the first number of DDR memory devices and the second number of ranks less than the first number of ranks, the circuit generating a set of output control signals in response to the set of input control signals, the set of output control signals corresponding to the first number of DDR memory devices arranged in the first number of ranks, wherein the circuit further responds to a first command signal and the set of input control signals from the computer system by generating and transmitting a second command signal and the set of output control signals to the plurality of memory devices, the first command signal and the set of input control signals corresponding to the second number of ranks and the second command signal and the set of output control signals corresponding to the first number of ranks; and a phase-lock loop device mounted to the printed circuit board, the phase-lock loop device operatively coupled to the plurality of DDR memory devices, the logic element, and the register.