Tiêu chuẩn quốc tế

• Số hiệu / Standard Number: ANSI/INCITS 22:1983
• Năm ban hành / Publication date: 1983
• Tình trạng / Status: A - Còn hiệu lực
• Tên tiếng Anh / Title in English: Information Systems - Recorded Magnetic Tape for Information Interchange (800 CPI, NRZI)
• Số trang / Page: 18

Phạm vi áp dụng / Scope of standard

Scope and Purpose

This standard provides specifications for format and recording
for l/2-inch, 9-track magnetic tape to be used for information
interchange among information processing systems, communication
systems, and associated equipment utilizing the American National
Standard Code for Information Interchange, (ASCII), ANSI X3.4-1977.
This standard deals solely with recording on magnetic tape and
supports and complements American National Standard for Information
Systems - Unrecorded Magnetic Tape for Information Interchange
(9-Track 800 CPI, NRZI; 1600 CPI, PE; and 6250 CPI, GCR), ANSI
X3.40-1983, in which the following sections are dealt with in
detail: general requirements, definitions, tape physical and
magnetic requirements, and tape reel requirements. Compliance with
the standard for unrecorded tape is a requirement for information
interchange.

CAUTION NOTICE: The user's attention is called to the
possibility that compliance with this standard may require 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. The patent holder has, however, 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.

This standard defines the requirements and supporting test
methods necessary to ensure interchange at acceptable performance
levels. It is distinct from a specification in that it delineates a
minimum of restrictions consistent with compatibility in
interchange transactions.

The performance levels contained in this standard represent the
minimum acceptable levels of performance for interchange purposes.
They, therefore, represent the performance levels that the
interchanged 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 must be
met or exceeded in order to comply with this standard are given. In
all cases, including those in which quantitative 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.

U.S. engineering units are the original dimensions in this
standard. Conversions of toleranced dimensions from customary U.S.
engineering units (similar to British Imperial Units) to SI units
have been incorporated in this standard according to Method A as
described in American National Standard Metric Practice, ANSI/ IEEE
268-1982, and in Toleranced Dimensions - Conversion from Inches
into Millimetres and Vice Versa, IS0 370-1975. Method A, as
described in ANSI/IEEE 268-1982, should be used to achieve economy
unless requirements for absolute assurance of fit justifies use of
Method B 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 tolerance.

Except as indicated in 1.4 above, interchange parties complying
with the applicable standards should be able to achieve
compatibility without need for additional exchange of technical
information.