on 15.02.2003 17:27, Jeff Walther at [EMAIL PROTECTED] wrote:
> These
> storage areas achieve "non-volatile" status by virtue of the
> motherboard battery. Without the battery or the trickle from the
> power supply, their contents evaporate. Which is why unplugging the
> machine and removing the battery for several hours is a useful
> troubleshooting technique.
>
> Chips such as ROMs, EPROMs, EEPROMs and Flash Memory truly are
> non-volatile (retain their contents without power) but they are
> slower and more difficult (or impossible) to write to.
Jeff,
Good point. This is precisely the distinction between "non-volatile" and
"volatile."
By way of analogy: {RAM, NVRAM, EPROM, EEPROM} :: {'virtual memory', 'RAM
disk', CD-R, CD-RW}.
What I was trying to get at, though, was that CUDA is a subsystem of the
MOBO, as are the so-called NVRAM and PRAM.
Here's a reference to what is currently stored in PRAM:
<http://docs.info.apple.com/article.html?artnum=86194>
[Unfortunately, I have failed to find clear references to what is stored in
PRAM under previous operating systems, and must needs (sic) refer to
"wetware" =8^) ]
Here's a reference to the distinction between PRAM and NVRAM [but does _not_
elaborate on the contents of the latter]:
<http://docs.info.apple.com/article.html?artnum=2238>
FWIW, I too have experienced the differing results when pressing cmd-opt-p-r
at different times in the boot sequence, but have yet to find "official"
documentation for this.
Here's a reference, FWIW, to what the "CUDA chip" is responsible for on the
MOBO for an Apple G4:
<http://docs.info.apple.com/article.html?artnum=95065>
Clear as mud ;-) Here again, references to earlier MOBOs are, might I say,
volatile <ducking>.
I have noted that "zapping" the CUDA does _not_ change the time zone setting
on a UMAX box, but _does_ change the time. [Experience contrary to mine is,
indeed, welcome.]
Contrast that with this:
<http://docs.info.apple.com/article.html?artnum=24385>
Do your own research: Draw your own conclusions.
HTH,
paul
--
Paul F. Henegan
<[EMAIL PROTECTED]>
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