This part of GB/T 33523 specifies the term definitions of S1 and S2 software measurement standards (etalons) used for software calibration of measuring instruments. This part also specifies the file format of the S1 type software measurement standard. This section applies to the surface structure standard chain based on the area method, the profile surface structure defined by link G and the measurement standard for the calibration of the metrological characteristics of the area surface structure measuring instrument. Note: In this section, the term "software gauge" is an abbreviation for software measurement standard S1.