> Is the PRAM battery needed? newer macs, older macs…. please chime in:-) In > my understanding, this little battery does a whole lot more than just "set > my time and date".. honestly if that was the case, Apple would've got rid > of the thing a long time ago?? my 2 bits…. I'm interested in hearing your > thoughts/facts on the subject.
The original Mac used an existing Moto 68000 family part which performed two functions: 1) a real-time clock, and 2) a non-volatile RAM. The 3.6 volt battery supplied the power for both functions. As long as the NV-RAM remained powered, the various "persistent" settings were retained. As the Mac became more highly integrated, the entire function of this RTC/NV-RAM chip was brought inside the LSI, and the NV-RAM portion was expanded so that more paremeters could be retained when power was off. So, not only is the TOD clock retained, just about all system parameters are maintained as well. Such as: quite a number of settings which are set by System Preferences... Video resolution, among many others. The PeeCees had no similar requirement in the very beginning, but the PC/AT added essentially this very same chip to its architecture * , and the much more modern PeeCees of today still have the remnants of that RTC/NV-RAM chip. * It was perhaps fortuitous that Moto defined this chip so that it could be integrated into a conventional memory-mapped architecture (Moto-type) and a I/O-mapped architecture (Intel-type), so it was a no-brainer to incorporate this very same chip in the PC/AT. Later, Dallas Semiconductor made a clone of this chip and incorporated a very long lifetime battery into its package. It is the Dallas chip which eventually found its way into PC/AT clones. -- You received this message because you are a member of G-Group, a group for those using G3, G4, and G5 desktop Macs - with a particular focus on Power Macs. The list FAQ is at http://lowendmac.com/lists/g-list.shtml and our netiquette guide is at http://www.lowendmac.com/lists/netiquette.shtml To post to this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/g3-5-list
