GYYMMDDSSSC

GYYMMDDSSSC is a fixed-length identifiers format sometimes used in data logging, file naming, and machine-to-machine messages. It is not a widely standardized timestamp, but rather a compact convention that packs date and a small time component into a single string, typically beginning with the letter G.

The structure maps as follows: G is a fixed prefix; YY is the two-digit year; MM is the month; DD is the day; SSS is a three-digit subfield representing a time-of-day component (often milliseconds since midnight or a similar subdivision); C is a single character used as a checksum or category code. The total length is eleven characters. Variants may assign different semantic meanings to SSS or end with different types of check characters, but the overall fixed-width design is a common feature.

Usage and interpretation: because it uses fixed width fields, the format lends itself to lexicographic sorting and easy truncation. It is used in environments where compact codes are preferred over verbose ISO-8601 strings, such as embedded systems, batch processing logs, or certain messaging protocols. There is no universal standard tying GYYMMDDSSSC to a single meaning; implementations vary by organization and application.

Example: an instance such as G231128012A could be interpreted as a record linked to 2023-11-28, with a time-subfield value of 012 and a trailing code A. The exact meaning of SSS and C depends on the defining system, so reader interpretation should reference local documentation.

See also: ISO 8601, datestamp, timestamp, fixed-length encoding.