DEC STD 112

DEC Standard 112, Revision B, establishes a standardized date format for output to ensure unambiguous interpretation by readers worldwide, minimize misinterpretation, and achieve consistency across DEC-produced software and documents.

The standard was created to address confusion arising from differing interpretations of date components (e.g., month vs. day order) and to provide a format that is well human-engineered, terse, and easy for computer systems to produce. It clarifies that previous standardization efforts were either too rigid (like ANSI/ISO formats) or unenforced.

Key definitions for date components:

• Month: Can be the full English name (e.g., "January") or a three-letter abbreviation (e.g., "Jan"). The first letter must be capitalized.
• Year: Can be two or four digits. Two-digit years are only allowed if unambiguous regarding the century and if the month is abbreviated. Four-digit years are required if the full month name is used. A leading zero for two-digit years must be preserved.
• Day: Can be one or two digits. A leading zero (e.g., "04") is preferred to be suppressed or converted to a space.

The standard defines three allowed date formats:

1. Day-Month-Year (e.g., 4-Jan-74, 04-Jan-74, 4-January-1974): This is the preferred format for computer program output.
2. Day Month Year (e.g., 4 Jan 74): Preferred for memos and letters that do not follow the first format.
3. Month Day, Year (e.g., January 4, 1974): This format requires the month and year to be spelled out in full.