The PRAM batteries used in PowerMacs are not rechargeable nor does the logicboard provide power to the battery terminals when the machine is plugged in.
My Macs lose time and date the second the power cord is unplugged... spite the fact i bought a brand new battery for the eMac a week after i bought it it was dead a few months later.... Any reason why Mac OS X falls back to 12/6/1969? Macs let alone the computers we know today didn't even exist back then!
All I can do is repeat my experience, although I realize it's anecdotal...
Is it possible that there was a capacitor in the PSU holding enough residual power to keep the clock going in my cases?
As I said, there was no internet connection at the time. No airport card and no Ethernet.You may have enabled the "Set date & time automatically" option in System Preferences. If yes, your Mac did set the time from the web during the boot process, and you didn't notice it had lost it because of that. Happened with my G5 every day as I unplugged the machine every day and had no PRAM battery.
As I said, there was no internet connection at the time. No airport card and no Ethernet.
You may have enabled the "Set date & time automatically" option in System Preferences. If yes, your Mac did set the time from the web during the boot process, and you didn't notice it had lost it because of that. Happened with my G5 every day as I unplugged the machine every day and had no PRAM battery.
Even so, 12/6/1969? Usually (at least in the Americas), it would reset to 12/31/1969, not 12/6/1969, anywhere from about 3-7 PM. As you correctly stated, Mac OS X is Unix-based, and the "beginning of time" for Unix is January 1, 1970, at 12:00 midnight GMT. So if you are in (say) US Pacific Time, 8 hours behind GMT, a reboot with a dead PRAM battery would start up showing 12/31/1969 at 4 PM until an automatic network reset of time and date fixed it.It's Unix related - the time/date format counts the number of seconds elapsed from 1st January 1970.
Hence why a bad PRAM battery resets the clock to zero.
Date sets to 12/31/1969 my mistake sorryEven so, 12/6/1969? Usually (at least in the Americas), it would reset to 12/31/1969, not 12/6/1969, anywhere from about 3-7 PM. As you correctly stated, Mac OS X is Unix-based, and the "beginning of time" for Unix is January 1, 1970, at 12:00 midnight GMT. So if you are in (say) US Pacific Time, 8 hours behind GMT, a reboot with a dead PRAM battery would start up showing 12/31/1969 at 4 PM until an automatic network reset of time and date fixed it.
And as an aside, until the migration from 32-bit Unix to 64-bit Unix took hold, Unix had a "Y2.038K problem" -- basically, the number of seconds from the "Unix Big Bang" (1/1/1970) until the overflow of a 32-bit time register would occur in 2038. Thankfully, pretty much all critical Unix-based systems are at least on 64-bit time now, and won't suffer this problem for a very long time.
I believe the reason some Macs reset to just before the beginning of epoch is that the programmer of OpenFirmware or someone else's birthday is that time.
Even so, 12/6/1969? Usually (at least in the Americas), it would reset to 12/31/1969, not 12/6/1969, anywhere from about 3-7 PM. As you correctly stated, Mac OS X is Unix-based, and the "beginning of time" for Unix is January 1, 1970, at 12:00 midnight GMT. So if you are in (say) US Pacific Time, 8 hours behind GMT, a reboot with a dead PRAM battery would start up showing 12/31/1969 at 4 PM until an automatic network reset of time and date fixed it.
And as an aside, until the migration from 32-bit Unix to 64-bit Unix took hold, Unix had a "Y2.038K problem" -- basically, the number of seconds from the "Unix Big Bang" (1/1/1970) until the overflow of a 32-bit time register would occur in 2038. Thankfully, pretty much all critical Unix-based systems are at least on 64-bit time now, and won't suffer this problem for a very long time.
No, it was made by Sun and used in some of their Sun workstations and servers.
It's more flexible and powerful than the standard and rigid BIOS.