Unix why 1970

SteveHarrison It is, but it didn't start out that way — Reid. Add a comment. Notable excerpts from the Wikipedia page: The first edition Unix Programmer's Manual dated November 3, defines the Unix time as "the time since , Jan. Epoch reference date An epoch reference date is a point on the timeline from which we count time. Many epochs in use Why is 1 January considered the epoch time? No, not the epoch, an epoch. There are many epochs in use.

This choice of epoch is arbitrary. Many granularities Different systems use different granularity in counting time. ISO Because there is so much variance in the use of an epoch reference and in the granularities, it is generally best to avoid communicating moments as a count-from-epoch. Short answer: Why not? There's no great merit in choosing an arbitrary epoch just to be different. Because Unix was developed in and first released in and it was thus reasonable to assume that no machine would have to represent a system time earlier than As a developer of historical simulation games, it seems pretty silly that the designers of some time objects tend to assume all programs will only want to represent dates in the future or recent past.

Of course, we can program our own representations, or work in an adjustment factor, but still. The same pre-epoch issue applies to "practical" non-game uses, such as business spreadsheets, scientific data presentation, time machine UIs, etc. So it wasn't "silly" to make the most basic thing that worked. OP is correct on a meta-level, the schemes we work out for time have always been fairly arbitrary. The number of days in a year, number of days in the month, year "0", and the rules for leaps year are Every system is just a series of crappy compromises made because it was the best they could do with the available technology and worked well enough for their immediate use-case.

Which is true of all engineering projects : — Indolering. Show 3 more comments. The Overflow Blog. Does ES6 make JavaScript frameworks obsolete? Podcast Do polyglots have an edge when it comes to mastering programming Featured on Meta. Now live: A fully responsive profile. Linked See more linked questions.

Related Home » Other. See also How do I create a tmp folder in Linux? See also What came first Unix or Linux? See also What does more do in Unix? Like this post? Please share to your friends:. Ubuntu is a complete Linux operating system, freely available with both community and professional. Press the Windows logo on your keyboard, or click the Windows icon in the. If you have a Ford model. This site uses cookies to store data.

From Here needs free subscription :. Linux is following the tradition set by Unix of counting time in seconds since its official "birthday," -- called "epoch" in computing terms -- which is Jan. A more complete explanation can be found in this Wired News article. It explains that the early Unix engineers picked that date arbitrarily, because they needed to set a uniform date for the start of time, and New Year's Day, , seemed most convenient.

The Unix epoch is midnight on January 1, It's important to remember that this isn't Unix's "birthday" -- rough versions of the operating system were around in the s. Instead, the date was programmed into the system sometime in the early '70s only because it was convenient to do so, according to Dennis Ritchie, one of the engineers who worked on Unix at Bell Labs at its inception. Unix Time is represented by a 32 bit whole number an integer that can be positive or negative signed.

This is what is know as the Unix Epoch. A 32 bit signed integer can represent whole numbers between and Since Unix Time starts at 0, negative Unix Time values go back in time from the Epoch and positive numbers go forward in time. These dates represent the beginning, the pre-history and the end of Unix Time.

This is known as the "Year problem". Some believe this will be a more significant problem than the "Year problem". The fix for the Year problem is to store Unix Time in a 64 bit integer. This is already underway in most 64 bit Operating Systems but many systems may not be updated by Sign up to join this community.

The best answers are voted up and rise to the top. Stack Overflow for Teams — Collaborate and share knowledge with a private group. Create a free Team What is Teams? Learn more. Why does Unix time start at ? Ask Question. Asked 9 years, 11 months ago. Active 2 years, 2 months ago.