>From: Jeff Walther <[EMAIL PROTECTED]> > >> Date: Sat, 23 Jul 2005 11:41:29 +1000 >> From: David Elmo <[EMAIL PROTECTED]> > > >> I will get a new battery soon, but I simply do not understand this stuff and >> never have. I don't even know why it does not lose the date and time when >> you yank the battery out and replace it a minute later? Is there some >> capacitor maybe holding a bit of charge to keep it going temporarily. The >> pram circuit is a big secret, a huge mystery, even theologians would argue >> the toss on this for years... > > I missed the early discussion, so this may be a bit irrelevant... > > Both the PRAM and the NVRAM save some system settings (different for > each of them) which need to be available either before the OS loads > (before hard drive access) or for which it is convenient to be the > same no matter which volume you boot from. > > When there is no power to the machine, they are both maintained by > the PRAM battery. If there is power to the machine, but the machine > is off, then they are maintained by the 5V trickle. > > The PRAM physically resides in the CUDA chip ...
snip Thanks for this Jeff, good stuff and quite relevant. I have a habit of turning all power to the set up off, even yank the plug to guard against lightening etc. The issues you raise about firmware patches is particularly interesting to me. It is possible that in all my fiddling, I have lost necessary patches? Have been swapping HDs and stuff for ages... I use a Powerlogix g3/4 chip which may involve this stuff. I will think about it. David Elmo -- PCI-PowerMacs is sponsored by <http://lowendmac.com/> and... Small Dog Electronics http://www.smalldog.com | Refurbished Drives | -- Sonnet & PowerLogix Upgrades - start at $169 | & CDRWs on Sale! | Support Low End Mac <http://lowendmac.com/lists/support.html> PCI-PowerMacs list info: <http://lowendmac.com/lists/pci-powermacs.shtml> --> AOL users, remove "mailto:"; Send list messages to: <mailto:[email protected]> To unsubscribe, email: <mailto:[EMAIL PROTECTED]> For digest mode, email: <mailto:[EMAIL PROTECTED]> Subscription questions: <mailto:[EMAIL PROTECTED]> Archive:<http://www.mail-archive.com/pci-powermacs%40mail.maclaunch.com/> iPod Accessories for Less at 1-800-iPOD.COM Fast Delivery, Low Price, Good Deal www.1800ipod.com
