Information Systems – Helical-Scan Digital Computer Tape Cartridge@ for Information Interchange (3.81 -mm (0.150-in) Digital Data Storage (DDS) Recorded Format)
This standard provides the requirements for the helical-scan recording method and the Digital Data Storage (DDS) recorded format of a 3.81-mm (0.150-in) magnetic tape cartridge to be used for information interchange between information processing systems. Information interchange between information processing systems requires the use of this standard in conjunction with the unrecorded tape and cartridge requirements provided by American National Standard for Information systems - Unrecorded helical-scan digital computer tape cartridge for information interchange@ 3.87-mm (0.150 in)@ ANSI X3.206.??) Additionally@ information interchange requires@ at a minimum@ the utilization of a labeling and file structure and an interchange code as agreed upon by the interchange parties. It is not within the scope of this standard to describe unrecorded tape and cartridge requirements@ labeling and file structure requirements@ or interchange code requirements. CAUTION:The user??s attention is called to the possibility that compliance with this standard may require the use of an invention covered by patent rights. By publication of this standard@ no position is taken with respect to the validity of this claim or of any patent rights in connection therewith. However@ the patent holder has filed a statement of willingness to grant a license under these rights on reasonable and nondiscriminatory terms and conditions to applicants desiring to obtain such a license. Details may be obtained from the publisher@ No representation or warranty is made or implied that this is the only license that may be required to avoid infringement in the use of this standard Purpose This standard defines the requirements necessary to ensure information interchange at acceptable performance levels It is distinct from a specification in that it delineates a minimum number of restrictions consistent with compatibility in interchange transactions. The performance levels in this standard represent the minimum acceptable levels of performance for interchange purposes. They@ therefore@ represent the performance levels that the interchange items should meet or surpass during their useful life and thus define end-of-life criteria for interchange purposes The performance levels in this standard are not intended to be employed as substitutes for purchase specifications. Wherever feasible@ quantitative performance levels that shall be met or exceeded in order to comply with this standard are given. In all cases@ including those in which quantitiative limits for requirements falling within the scope of this standard are not stated but left to agreement between interchange parties@ standard test methods and measurement procedures shall be used to determine such limits. The original dimensions and quantities for all numeric values in this standard are in the International System of Units (SI). Conversions of these units to U.S. Customary engineering units (similiar to British Imperial units) and centimeter-gram-second electromagnetic units (cgs-emu) have been incorporated in accordance with the procedures described in American National Standard Metric practice@ ANSI/IEEE 268. Units of either of the two measurement systems may be referred to but the two systems should not be intermixed or reconverted. Conversions of toleranced dimensions and quantities in this standard have been performed in accordance with Method A of ANSI/IEEE 268 and International Standard for Toleranced dimensions - Conversions from inches to millimetres and vice versa@ IS0 370@ to maintain the implied correspondence between the accuracy of the original data and the number of significant digits and rounding of the converted values. In the national standards of IS0 member bodies@ additional rounding may be done to produce ??preferred?? values. These values should lie within or close to the original tolerances. Except as indicated above@ the interchange parties complying with the applicable standards should be able to achieve compatibility without the need for additional exchange of technical information.