Diskette test linearity

Abstract

Test linearity occurs when results obtained using any test system agree with those obtained using the master test system used to prepare reference material. Linearity is necessary to obtain correlation within the diskette industry. Non-linearity can occur if other reference disks are substituted for PTB secondary reference material. Even when the test system is calibrated using proper reference material, that calibration is valid only for test results having values close to those of the reference disk. System non-linearities can affect results when test values can depart significantly from reference values. This causes poor correlation between test equipment which leads to confusion about conformance to specifications. Results of this investigation demonstrate non-linearity for the four most popular types of diskettes and suggest that the test drive is a major source of non-linearity. Since the average test facility may not have the proper technical resources for linearity measurements, the manufacturers of diskette test equipment must supply linear test drives to users of their equipment.