On Sunday 19 August 2007 10:42, William Case wrote: > Hi; > > I didn't want to steal a thread from someone who has a real problem, but > an issue was raised in the thread entitled 'Grub' by Marko Vojinovic > that has been bothering me for a long time. > > "And to my surprise, there the question was repeated, more > specific: "what happens between the points of pushing the power > button and the point when OS starts to load?" ;-) > > I was amazed !! The sequence of actions was explained in a way > that did not need any too technical background knowledge, while > at the same time it was extremely detailed. It started off along > the lines of "voltage on the circuitry rises, and the oscillator > starts ticking. The first few ticks activate a circuit that > sends a reset signal to the processor...". > > The moral of the story: it was way more complicated than I > thought, while the author was stating that the answer is > somewhat oversimplified..." > > I have been trying to find that answer for some time now. > > What happens in the micro-seconds between hitting the power button until > BIOS is loaded from CMOS into RAM memory? There is lots of information > available about what happens next. > > I have googled etc. for a source of this information. There is none > that I can find. As I said, lots of 'How BIOS works' none on 'How power > up/on works'. Any directions, recommended reading or explanations would > be warmly appreciated. > > -- > Regards Bill Years ago (like 30 years ago) I wanted to build a home system (the only way to get one) and read through the Intel CPU manuals and found a very good clear explanation of what happens to the CPU when power is applied. It was not simplified, was very clear and has since been the basis for my understanding of motherboard startup. The motherboard chipset powerup sequence was not covered but the CPU sequence, as far as I know, has changed little, if at all. Modifications have no doubt been made with the advent of multi-core and pipelining and predictive and conditional fetching and execution, but I would expect the core sequence to still be there somewhere. I found Intel a good and quite obliging information source; I phoned them and two weeks later printed manuals showed up in the mail - free, too! Dave -- The modern conservative is engaged in one of man's oldest exercises in moral philosophy; that is, the search for a superior moral justification for selfishness." - John Kenneth Galbraith
