A recording medium such as a semiconductor recording medium is provided with: a data area in which data is recorded; and a management information area in which management information of the data recorded in the data area is recorded. The reference gas or gas mixture can include one or more of a target analyte and a background gas expected to be present during analysis of the target analyte. These tubes may be attached to one another, allowing tradespersons to further extend the range of the rails as the installation progresses. In other embodiments, different-order derivatives of a Gaussian pulse may be approximated by combining different numbers of Gaussian-like pulses. The bead core may be substantially centered in the bead portion, as determined by the material thickness at three locations about the bead core.