Text 60653, 81 rader
Skriven 2010-04-25 08:36:00 av WAYNE CHIRNSIDE (1:123/140)
     Kommentar till en text av ED VANCE
Ärende: Re: BIOS cum CMOS ?
===========================
-=> ED VANCE wrote to JEAN PARROT <=-

 JP> EV> I use either of the terms BIOS or CMOS to mean that I am referring to
 JP> EV> the BIOS, which is on a IC chip made of a
 JP> EV> Complementry-Metal-Oxide-Semiconductor material.

 JP> Ed, you can not easily modify/replace the CMOS, it holds the BIOS, let us
g
 JP>our terms in agreement.

 EV> Jean,

 EV> IIRC Modern Days BIOSs are FLASH capable, the BIOS chip in my 486 box
 EV> isn't, I think the BIOS on that box is a ROM chip.

This 1998 boxes BIOS is writeable.

 EV> Not sure, mind you, but that is the impression that I have up in
 EV> "Ed's Head" TM.

 EV> Just reading over the few lines above, I would think that the BIOS in
 EV> the 486 box would probably store its self in low RAM memory when the
 EV> box was turned ON.

 EV> Otherwise none of the settings could be changed in the BIOS.

I do not believe it works _quite_ that way.

My understanding has always been that the CMOS and BIOS are
two entirely different chips however one (BIOS) is stored in
an electrically or UV erasable and rewritable PROM and the CMOS being stored 
in well, CMOS, extremely low power RAM working of those little lithium button 
cells.

 EV> But again, the BIOS chip WOULD HAVE TO have some RAM in it so that
 EV> Changes to the BIOS would be preserved so it would have the desired
 EV> settings when starting from a Cold Boot.


Two different chips interacting with one another is my understanding
with the CMOS selecting those values of the BIOS that the user has 
control over.

 EV> I suppose I better search for a "How Things Work" site on the internet
 EV> so I can make comments using some sence, instead of "Off The Top Of
 EV> Ed's Head", right?

Well if you find anything that contradicts what I say above, please 
let me know.

My stuff is off the top of Wayne's head.

 JP> EV> I've never heard of a parallel CMOS until today.    ;-)

 JP> If you go to the BIOS and modify any or all items, you still have a
numbere
 JP>line that says:  Load default settings. These are always present and will
se
 JP>you through a few errors on your part. My bad in calling it a parallel
CMOS,
 JP>is the options to default that I was trying to imply.

 EV> I'd guess that loading the Default settings for the BIOS would be done
 EV> by switching the data stored in RAM with the data on the BIOS chip.

My call is as above, the settings in CMOS, low power RAM, allows variables in
the BIOS
to be invoked by user selection in CMOS.

That's why we must replace those little lithium button cells every five years 
or so.

 EV> Hey!, Is there anyone else reading this series of messages I'm having
 EV> with Jean, that knows about this here BIOS CMOS stuff and can
 EV> straighten this thread out?
 
I did my best to my recollection as above.

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