Abstract: According to one embodiment, a memory system includes a controller for controlling a data transfer between a nonvolatile memory and a host device. The controller writes, to the nonvolatile memory, management information to be used in the data transfer, a multiplexed pointer indicating a storage position, and a log indicating whether the writing of the pointer is successful, determines whether the multiplexing the pointer by the predetermined number is maintained according to at least one of the pointer and the log, and rewrites the multiplexed pointers to the nonvolatile memory when determining that the multiplexing the pointer by the predetermined number is not maintained.

Abstract: According to one embodiment, a memory system includes a controller for controlling a data transfer between a nonvolatile memory and a host device. The controller writes, to the nonvolatile memory, management information to be used in the data transfer, a multiplexed pointer indicating a storage position, and a log indicating whether the writing of the pointer is successful, determines whether the multiplexing the pointer by the predetermined number is maintained according to at least one of the pointer and the log, and rewrites the multiplexed pointers to the nonvolatile memory when determining that the multiplexing the pointer by the predetermined number is not maintained.

Abstract: In a wavelength division multiplexed optical transmission system wherein the zero dispersion wavelength of the optical fiber transmission path 224 is in the 1550 nm region, among multiplexed optical signals, the wavelengths of either of at least two optical signals are allocated between 1450 nm and 1530 nm, or between 1570 nm and 1650 nm.

Abstract: In a wavelength division multiplexed optical transmission system wherein the zero dispersion wavelength of the optical fiber transmission path 224 is in the 1550 nm region, among multiplexed optical signals, the wavelengths of either of at least two optical signals are allocated between 1450 nm and 1530 nm, or between 1570 mn and 1650 nm.

Abstract: In a wavelength division multiplexed optical transmission system wherein the zero dispersion wavelength of the optical fiber transmission path 224 is in the 1550 nm region, among multiplexed optical signals, the wavelengths of either of at least two optical signals are allocated between 1450 nm and 1530 nm, or between 1570 nm and 1650 nm.

Abstract: In a transmitter side in an optical transmission system, an input binary signal is converted into a duobinary signal, and the duobinary signal is applied to an optical modulation device which provides an optical intensity modulation signal, wherein the optical intensity for a center value of the duobinary signal is a minimum, the optical intensity for the other two values of the duobinary signal is a maximum, and an optical phase for those two values is opposite to each other. In a receiver side, simple direct detection is carried out for receiving optical signal through an optical transmission line to provide a demodulated binary signal. Thus, an original binary signal is recovered without a duobinary decoder and receiver sensitivity degradation.