• Source: Timestamp

A timestamp is a sequence of characters or encoded information identifying when a certain event occurred, usually giving date and time of day, sometimes accurate to a small fraction of a second. Timestamps do not have to be based on some absolute notion of time, however. They can have any epoch, can be relative to any arbitrary time, such as the power-on time of a system, or to some arbitrary time in the past.
A distinction is sometimes made between the terms datestamp, timestamp and date-timestamp:

Datestamp or DS: A date, for example 2024-11-26 according to ISO 8601
Timestamp or TS: A time of day, for example 00:27:02 using 24-hour clock
Date-timestamp or DTS: Date and time, for example 2024-11-26, 00:27:02




History



The term "timestamp" derives from rubber stamps used in offices to stamp the current date, and sometimes time, in ink on paper documents, to record when the document was received. Common examples of this type of timestamp are a postmark on a letter or the "in" and "out" times on a time card.
With the advent of digital data systems, the term has expanded to refer to digital date and time information attached to digital data. For example, computer files contain timestamps that tell when the file was last modified, and digital cameras add timestamps to the pictures they take, recording the date and time the picture was taken.




Digital timestamps



This data is usually presented in a consistent format, allowing for easy comparison of two different records and tracking progress over time; the practice of recording timestamps in a consistent manner along with the actual data is called timestamping.
Timestamps are typically used for logging events or in a sequence of events (SOE), in which case each event in the log or SOE is marked with a timestamp.
Practically all computer file systems store one or more timestamps in the per-file metadata.
In particular, most modern operating systems support the POSIX stat (system call), so each file has three timestamps associated with it:
time of last access (atime: ls -lu),
time of last modification (mtime: ls -l), and
time of last status change (ctime: ls -lc).
Some file archivers and some version control software, when they copy a file from some remote computer to the local computer, adjust the timestamps of the local file to show the date/time in the past when that file was created or modified on that remote computer, rather than the date/time when that file was copied to the local computer.
Timestamps are often found to be dirty in many cases. Without cleaning up inaccurate timestamps, time-related applications such as provenance analysis or pattern queries are not reliable. To evaluate the correctness of timestamps, temporal constraints can be applied, declaring distance limits between timestamps.




Standardization


ISO 8601 standardizes the representation of dates and times. These standard representations are often used to construct timestamp values.




Examples



Examples of date-timestamps:

Thurs 12/31/2009 1:35 p.m. — mixed-endian date, big-endian 12-hour clock
Thurs 31.12.2009 13:35 — same time as the above, different format with little-endian date and big-endian 24-hour clock
2005-10-30 T 10:45 UTC — ISO 8601 international order (big-endian) with time zone)
2007-11-09 T 11:20 UTC — same format as the above, hence easy to compare and perform alphanumeric sorting
Sat Jul 23 02:16:57 2005
2009-10-31T01:48:52Z — ISO 8601
2009-10-31 01:48:52Z — "Internet time" per RFC 3339, based on ISO 8601
1256953732 — Unix time, equivalent to 2009-10-31 T 01:48:52Z
1969-07-21 T 02:56 UTC
07:38, 11 December 2012 (UTC)
1985-102 T 10:15 UTC — year 1985, day number 102, i.e., 1985 April 12
1985-W15-5 T 10:15 UTC — year 1985, week number 15, weekday 5 = 1985 April 12
20180203073000 — used in Wayback Machine memento URLs, equals 3 February 2018 07:30:00
Examples of datestamps:

2025-05-25 — ISO 8601 international representation of 2025 May 25
Examples of timestamps:

17:30:23 — time of day in an afternoon
123478382 ns — the number of nanoseconds since boot
17 minutes — an arbitrary minute counter that increments every 1 minute since its last manual "reset" event
Sequence number:

21 — a unitless counter that indicates only the relative order of events; this is event #21, which comes after 20 and before 22




See also



Advanced electronic signature
Bates numbering
Decentralized trusted timestamping on the blockchain
Linked timestamping
Timestamping (computing)
Timestamp-based concurrency control
Trusted timestamping




References

Kata Kunci Pencarian:

• Stempel waktu terpercaya
• Sungai Kaia
• Sungai Panjo
• Muara Boe
• Sungai Pendolo
• Korps Marinir Republik Indonesia
• Kabupaten Lombok Timur
• Sungai Kodina
• Pulau Lombok
• Network Time Protocol
• Timestamp
• Internet Control Message Protocol
• Trusted timestamping
• Lamport timestamp
• Timestamp-based concurrency control
• Linked timestamping
• Unix time
• Timestamping (computing)
• OpenTimestamps
• Universally unique identifier