ANSI INCITS 179

Abstract

This standard provides the mechanical, physical and magnetic properties of a low-friction disk with a diameter of 95 mm (3.740 inches) and with a typical recording density of 3 1.5 tracks per millimeter (tpmm) (800 tracks per inch (tpi)) with 567 flux transitions per millimeter (ftpmm) (14 400 flux transitions per inch (ftpi)) at a radius of 23 mm (0.900 inch). This standardd efines the requirementsa nd supportingt est methodsn ecessaryto ensurea cceptable performancel evels in the context of the general application referencedi n 1.1. It is distinct from a specification in that it delineates a minimum of restrictions consistent with compatibility of media characteristics. The performance levels contained in this standard representt he minimum acceptablele vels of performance for typical applications. They, therefore, represent the performance levels that the media should meet. The performancel evels in theses tandardsa re intended as guidelines to prospective users and should not be employed as substitutes for purchase specifications. Quantitativep erformancel evels that must be met or exceededin order to comply with this standarda re given wherever possible. In all cases, including those in which quantitative limits for requirementsf alling within the scope of this standard are not stated but are left to agreementb etweeni nteracting parties, standard test methodsa nd measuremenpt roceduress hall be used to determine such quantities. SI units are the original dimension in this standard. Conversions of toleranced dimensions to customary U.S. engineering units (similar to British Imperial units) have been done in this standard according to Method A of International Standard for Toleranced Dimensions - Conversions from Inches into Millimeters and Vice Versa, ISO 370-1975, except as noted. Method A should be used for economy unless a requirementf or absolute assurance of a fit justifies use of Method B. In the national standards of ISO member nations, additional rounding may be done to produce “preferred” values. These values should lie within or close to the original tolerance ranges