Date$ 1900 in OS X

Question

I like to place as much accuracy into my images as possible; so when scanning in old postcards that I have found along London markets I amend the date to reflect the year on the postcard. The problem is that anything before the 1900's is a problem for OS X. Apparently OS X can only go back to about 1970, something to do with Steve Jobs' birthday or some of the original workers I'm told.
I am told that this problem is embedded in OS X and that it would probably not get fixed, too hard.
Could an OS based on the ZFS system (up from HFS/HFS+) solve this problem? I don't know but if the change is integral its usual that long standing problems are fixed.
Either way, this complicated problem would be better sorted out as digital newspaper archives are being opened up and if you come from a country like the UK then there is a real need for dates to be recognised before 1900. I currently use Aperture to organise images from these periods but once exported that data will be modified and what of other formats?!

Answer 1

I don't know what all that means but it strange that UNIX set a deadline for itself, a time to expire.
First, many Unix implementations are starting to provide 64 bit time values (double the old 32 bit values) which are capable of a date range 292,471,208,677 years into the future and the past.
Mac OS X programs which have been compiled for 64 bits (gcc -m64) can access this 64 bit time value. But Mac OS X Leopard is still mostly compiled for 32 bits. Also the on-disk format most likely only has 32 bits reserved for the date. Change the on-disk format is not a simple recompile as your existing flies are in the way, so that requires some way of converting gigabytes of existing files.
HOWEVER, it will take awhile before every last bit of software is compiled as a 64 bit application. And it will also take time before every application is modified to be able to format dates that far into the future (or the past).
As to why Unix would choose a date format that ranges from 1902 - 2038, back in 1970 computers had memory sizes that ranged from 4 kilobytes to 64 kilobytes (10's of Thousands times smaller than the smallest Mac shipping today). Using a 32 bits time value was a major indulgence. The CPU Unix was developed on could do 16 bit math (and then only add and subtract, no multiple nor divide), so doing 32 bit math was much more difficult. Doing 64 bit math would have been even more difficult and taken a lot longer. And when I say it would have taken longer, consider that in those days CPUs ran at speeds less than 1 megahertz, where as today, they run at over 2 gigahertz (2000+ times faster), so every instruction Unix had to execute cost both in time as well as memory, neither of which were in great supply.
And just to put things in perspective, no Unix systems (nor Macs) had problems with the Y2K time problems that many PCs had (maybe some poorly written application, but not the OS). Some because they were still using DOS based applications which stored the year a 00 - 99, or because they had a computer BIOS with a year 99 limit. A lot of companies spent a lot of money upgrading computers and software in 1999 getting ready for New Year's 2000. Unix systems have another 29 years, and most of them have already started getting ready. By 2038, Unix should have be more than ready.
Message was edited by: BobHarris