ISO 6093:1985

Overview

ISO 6093:1985 specifies standardized ways to represent numerical values in machine‑readable character strings for information interchange between data processing systems. It defines three allowed formats (NR1, NR2, NR3), the permitted character subset (from ISO 646), rules for signs, decimal marks, field lengths and semantics, and guidance for programming‑language and implementation support. The standard applies only to base‑10 numbers composed of a finite number of digits, with or without a decimal mark.

Key topics and technical requirements

• Three numeric representations
  • NR1 (implicit‑point / implicit scaling): Positional notation where the decimal point is implicit and its position is fixed by field description. Signed and unsigned forms allowed; at least one digit required.
  • NR2 (explicit‑point / unscaled): Positional notation with an explicit decimal mark (FULL STOP or COMMA). Signed and unsigned forms allowed; decimal mark must appear in the field.
  • NR3 (significand + exponent / scaled): Significand and exponent form (A E B), where value = significand × 10^exponent. Exponent uses E or e followed by signed digits; normalized form requires significand in 0.1 < |s| < 1 for uniqueness.
• Character set and symbols
  • Subset of ISO 646: digits 0–9, sign characters (+/−), decimal mark (COMMA or FULL STOP), exponent mark (E/e), and SPACE.
  • Default decimal mark: FULL STOP is assumed unless the conformance statement specifies COMMA.
• Field and syntax rules
  • Each numeric instance must fit a defined field length; field description in interchange documentation must state length and representation.
  • Rules for leading spaces, allowed omission of plus sign (can be represented by SPACE), no embedded or trailing spaces in fields, and how zero is represented in signed forms.
• Conformance and documentation
  • A conformance statement must identify which NR is used and which decimal mark applies.
• Guidance for implementations
  • Annexes provide a syntax specification method, rationale for including COMMA as decimal mark, and programming‑language application examples (including COBOL PICTURE guidance).

Applications and users

• System integrators and architects designing cross‑system data interchange formats.
• Developers of programming language standards and compilers/runtime libraries that parse or produce numeric text (COBOL, FORTRAN, BASIC, ETL tools).
• Database, ETL and file‑exchange implementers who require human‑readable, machine‑parsable numeric formats.
• International data exchange projects needing consistent rules for decimal marks, signs and exponent notation.

Related standards

• ISO 646 (7‑bit coded character set)
• ISO 2022 (code extension techniques)
• ISO 4873 (8‑bit coded character set)

Keywords: ISO 6093, numeric representation, NR1 NR2 NR3, character strings, decimal mark, COMMA, FULL STOP, information interchange, programming languages, ISO 646.