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.
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.
In modern times usage of 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.
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.[1]
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.[2]
Standardization
ISO 8601 standardizes the representation of dates and times.[3] These standard representations are often used to construct timestamp values.
^Claudia Maria Bauzer Medeiros (19 September 2009). ADVANCED GEOGRAPHIC INFORMATION SYSTEMS -Volume I. EOLSS Publications. p. 59. ISBN978-1-905839-91-9.
^"ISO 8601:2004(E)" (PDF). ISO. 1 December 2004. Retrieved 7 March 2010. 3.5 Expansion … By mutual agreement of the partners in information interchange, it is permitted to expand the component identifying the calendar year, which is otherwise limited to four digits. This enables reference to dates and times in calendar years outside the range supported by complete representations, i.e. before the start of the year [0000] or after the end of the year [9999].
March 03, 2023
timestamp, unix, posix, timestamp, unix, time, timestamp, sequence, characters, encoded, information, identifying, when, certain, event, occurred, usually, giving, date, time, sometimes, accurate, small, fraction, second, have, based, some, absolute, notion, t. For Unix POSIX timestamp see Unix time 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 An actual time stamp from around 1960 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 In modern times usage of 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 Contents 1 Digital timestamps 2 Standardization 3 Examples 4 See also 5 Notes 6 ReferencesDigital timestamps EditThis 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 1 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 2 Standardization EditISO 8601 standardizes the representation of dates and times 3 These standard representations are often used to construct timestamp values Examples EditExamples of timestamps Thurs 01 01 2009 6 00 2005 10 30 T 10 45 UTC 2007 11 09 T 11 20 UTC Sat Jul 23 02 16 57 2005 2009 10 31T01 48 52Z ISO 8601 1256953732 Unix time equivalent to 2009 10 31T01 48 52Z 1969 07 21 T 02 56 UTC 07 38 11 December 2012 UTC 1985 102 T 10 15 UTC year 1985 day 102 12 April 1985 1985 W15 5 T 10 15 UTC year 1985 week 15 day 5 12 April 1985 20180203073000 a 3 February 2018 7 30 00 123478382 ns the nanoseconds since boot 17 minutes an arbitrary minute counter which increments every 1 minute since its last manual reset event Sequence number 21 a unitless counter which indicates only the relative order of events this is event 21 which comes after 20 and before 22 See also Edit Look up timestamp in Wiktionary the free dictionary Wikimedia Commons has media related to Timestamps Bates numbering Decentralized trusted timestamping on the blockchain Linked timestamping Timestamping computing Timestamp based concurrency control Trusted timestampingNotes Edit Used in Wayback Machine memento URLs References Edit Claudia Maria Bauzer Medeiros 19 September 2009 ADVANCED GEOGRAPHIC INFORMATION SYSTEMS Volume I EOLSS Publications p 59 ISBN 978 1 905839 91 9 Song Shaoxu Huang Ruihong Cao Yue Wang Jianmin May 2021 Cleaning timestamps with temporal constraints The VLDB Journal 30 3 425 446 doi 10 1007 s00778 020 00641 6 ISSN 1066 8888 S2CID 7559769 ISO 8601 2004 E PDF ISO 1 December 2004 Retrieved 7 March 2010 3 5 Expansion By mutual agreement of the partners in information interchange it is permitted to expand the component identifying the calendar year which is otherwise limited to four digits This enables reference to dates and times in calendar years outside the range supported by complete representations i e before the start of the year 0000 or after the end of the year 9999 Retrieved from https en wikipedia org w index php title Timestamp amp oldid 1132226739, wikipedia, wiki, book, books, library,
