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

[John Kelly]

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?

[Andy Hassall]

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

On Sun, 24 Sep 2006 21:28:06 +0000, John Kelly <jak@isp2dial.c omwrote:

>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-src/ext/session/session.c?r1=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-list/199911/3159.php

--
Andy Hassall :: andy@andyh.co.u k :: http://www.andyh.co.uk
http://www.andyhsoftware.co.uk/space :: disk and FTP usage analysis tool

[John Kelly]

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

On Sun, 24 Sep 2006 22:51:50 +0100, Andy Hassall <andy@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-src/ext/session/session.c?r1=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.