What is unix time stamp?
Unix time (also POSIX time or Unix epoch or Unix time or https://unixtimestamp.app/ is a system for describing moments in time adopted by Unix and other POSIX-compatible operating systems. Defined as the number of seconds elapsed since midnight (00:00:00 UTC) on Thursday, January 1, 1970; the time since then is called the Unix Epoch.
- 1 minute and 60 seconds
- 1 hour 3600 seconds
- 1 day 86400 seconds
- 1 week 604800 seconds
- 1 month (30.44 days) 2629743 seconds
- 1 year (365.24 days) 31556926 seconds
Unix Timestamp is a “fixed” time, a specific date stated in a number to the nearest second.
UTC (Coordinated Universal Time) is Coordinated Universal Time, which is “fixed” at the zero meridian (London) and from which geographic time zones are read off. The abbreviation UTC has no specific deciphering.
GMT – Greenwich Mean Time, or Greenwich Mean Time. Corresponds to a time zone of zero (UTC 0). – The mean solar time of the meridian passing through the former location of the Greenwich Royal Observatory near London.
Boundaries of Unix time
At the time 00:00:00 UTC on January 1, 1970 (Thursday) the Unix time is zero. Starting from that time, the number increases by a certain amount per day. So, for example, on September 16, 2004 at 00:00:00, 12677 days after unixtimestamp.app started counting, the time will be represented by the number 12677 × 86400 = 1095292800. The calculations can also be done in the opposite direction using negative numbers. For example, the date October 4th, 1957 00:00:00 which is 4472 days before counting is represented in Unix time by -4472 × 86400 = -386380800
Programs use the integer signed type to store unix timestamp. The 32-bit signed numbers can refer to time moments from Friday, December 13, 1901 20:45:52 to Tuesday, January 19, 2038 03:14:07 inclusive.
What is Unix time or Unix epoch or Unix time or POSIX time or Unix timestamp ?
UNIX time or POSIX time is a way of encoding time in UNIX and other POSIX-compatible operating systems.
It was started at midnight (UTC), December 31st, 1969, and then on January 1st, 1970, which is the Unix Epoch.
UNIX time is coordinated with UTC, in particular, when leap-second UTC is declared, the corresponding second numbers are repeated.
The way of storing time as a number of seconds is very convenient for comparing dates (to the nearest second) and for storing dates: if necessary, they can be converted to any readable format. Dates and times in this format also take up very little space (4 or 8 bytes, depending on the machine word size), so it makes sense to use it to store large amounts of dates. The disadvantages in performance may appear if date items, such as month numbers, etc., are accessed very often. But in most cases, it is more efficient to store time as a single value, rather than as a set of fields.
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