By using this site, you agree to our updated Privacy Policy and our Terms of Use. Manage your Cookies Settings.
429,365 Members | 3,095 Online
Bytes IT Community
+ Ask a Question
Need help? Post your question and get tips & solutions from a community of 429,365 IT Pros & Developers. It's quick & easy.

epoch date -- Expires: Thu, 19 Nov 1981 08:52:00

P: n/a
Pardon me if this is a FAQ. I searched, but got far too many hits to
find the answer. Question:

Why is the date: Thu, 19 Nov 1981 08:52:00 GMT used as the value for
anti-caching Expires: headers?

Why not use the UNIX epoch of Thu, 01 Jan 1970 00:00:00 GMT?

The IBM PC debuted in 1981, but that was August 12, not November 19.
Is there a PC clock "epoch" related to the November 19 date used by
PHP?
Sep 24 '06 #1
Share this Question
Share on Google+
2 Replies


P: n/a
On Sun, 24 Sep 2006 21:28:06 +0000, John Kelly <ja*@isp2dial.comwrote:
>Pardon me if this is a FAQ. I searched, but got far too many hits to
find the answer. Question:

Why is the date: Thu, 19 Nov 1981 08:52:00 GMT used as the value for
anti-caching Expires: headers?

Why not use the UNIX epoch of Thu, 01 Jan 1970 00:00:00 GMT?

The IBM PC debuted in 1981, but that was August 12, not November 19.
Is there a PC clock "epoch" related to the November 19 date used by
PHP?
It was added in this revision:
http://cvs.php.net/viewvc.cgi/php-sr...1=1.80&r2=1.81

... by CVS user "sas", who is Sascha Schumann. The date appears to be Sascha's
birthday:

http://www.phpbuilder.com/lists/php3...99911/3159.php

--
Andy Hassall :: an**@andyh.co.uk :: http://www.andyh.co.uk
http://www.andyhsoftware.co.uk/space :: disk and FTP usage analysis tool
Sep 24 '06 #2

P: n/a
On Sun, 24 Sep 2006 22:51:50 +0100, Andy Hassall <an**@andyh.co.uk>
wrote:
>>Why is the date: Thu, 19 Nov 1981 08:52:00 GMT used as the value for
anti-caching Expires: headers?
It was added in this revision:
http://cvs.php.net/viewvc.cgi/php-sr...1=1.80&r2=1.81

... by CVS user "sas", who is Sascha Schumann. The date appears to be Sascha's
birthday:

http://www.phpbuilder.com/lists/php3...99911/3159.php
Andy, thanks for the answer.

I'm glad to know the reason, silly though it is.
Sep 25 '06 #3

This discussion thread is closed

Replies have been disabled for this discussion.