Bios/cmos

[Ramses2]

HI,
Can anyone answer PLse .
I have read about the CMOS RAM chip holding the set up configuratoin of the computer. It is battery powered. It is a separate chip on its own. Is that true? How can we locate it on the motherboard? If this chip fails completely, can we boot the computer? Can we replace it?
I have also read at http://internal.vusd.solanocoe.k12.c...nks_to_explore)
that the newer computers have motherboards that have the CMOS RAM on the BIOS chip itself? How can two technologies (CMOS is RAM and BIOS is ROM) be put on a single chip? That is CMOS info is changing, but BIOS (ROM) must be flashed to delete contents.
Thank you for your answers.

[bailey]

I think you are just confuseing yourself.
bios is software that is stored on a chip.
the chip can be of many differant types dateing back to the older rom chips
up to todays newer eerom chips that are of the type that can be flashed with a newer bios or rewritten with a newer version of the software.

with out the bios, the computer will be dead, nothing will happen

yes the chip is replaceable but then it is not a recommended thing for a novice to do.

[mrmister1]

The CMOS chip can operate without a battery, but it will not save your settings

[Cricket]

CMOS (complementary metal oxide semiconductor) is hardware (the non-volatile memory chip on the motherboard).

BIOS (basic input/output system) is software (the basic operating system your computer uses to boot up).

The BIOS is stored in the CMOS.

Cricket

[pizzapie]

it is simple. I dont fully understand how bios works but i can make you understand. Bois is like a program that is stored on your comp in a chip that you can pull out if you want, it runs the base system where cmos is a place where you can change some settins like boot sequence (hdd first, floppy second wateva) and things like power saving. It is the setup. get it? you can fuk with cmos but not so easy to fuk with bios

[Ramses2]

That much I understand, that the BIOS is a software. But that software is stored on a ROM chip (or EEPROM if u prefer). The chip can be easily located on the motherboard: written on it is the manufacturer's name like AMI BIOS or PHOENIX BIOS.
The question is: Is the configuration setting of the PC also stored on this BIOS chip together with the BIOS program or is the setting stored on a SEPARATE chip which is the CMOS RAM chip? If so, how can we locate this CMOS RAM chip on the motherboard?
Also, if the configuration setting is actually on the BIOS EEPROM chip and the setting changes (which can happen often), how is the update done? Is the EEPROM flashed each time the setting changes? Remember that one of the data stored in CMOS is date and time which are CONTINUOUSLY changing.

[pizzapie]

i dont think that the cmos's data is stored in the bios as the bios isn't meant to be changed. Yes, i think that its in a different chip altogether, maybe its even stored in the chipset, i don't know much about chipsets.

[rave]

the BIOS controls the basic function of the system, its like your subconcious or your nervous system. the BIOS is placed on a EEPROM chip that can be flashed/changed if you want your motherboard to be "upgraded". The CMOS is just a battery that makes sure when you change something in the BIOS the change stays even after you turn off your PC and unplug it from the socket.
if your CMOS has run out of power the most obvious sign is the Windows clock will be out of sync (that is if you dont sync with a time server)

[Cricket]

Originally Posted by Ramses2 The question is: Is the configuration setting of the PC also stored on this BIOS chip together with the BIOS program or is the setting stored on a SEPARATE chip which is the CMOS RAM chip?

The PC configuration is stored in the CMOS chip which is where the BIOS is stored...there is no separate "BIOS chip".

Originally Posted by Ramses2 Also, if the configuration setting is actually on the BIOS EEPROM chip and the setting changes (which can happen often), how is the update done?

Everytime you boot up your computer, the BIOS does a quick inventory of your system to see if it matches what it has stored in memory. If everything is fine, you get the 1 good POST beep. If things have been changed, it makes note of that change by writing it to the ESCD (extended system configuration data) information.

Originally Posted by Ramses2 Is the EEPROM flashed each time the setting changes?

No, it's not "flashed"...the CMOS is basically a semiconductor that has a clock built into it, that is partly what the motherboard battery is for. It powers this clock.

Originally Posted by rave the BIOS controls the basic function of the system, its like your subconcious or your nervous system. the BIOS is placed on a EEPROM chip that can be flashed/changed if you want your motherboard to be "upgraded". The CMOS is just a battery that makes sure when you change something in the BIOS the change stays even after you turn off your PC and unplug it from the socket. if your CMOS has run out of power the most obvious sign is the Windows clock will be out of sync (that is if you dont sync with a time server)

The CMOS is not the motherboard battery. The BIOS is stored in the CMOS.

CMOS: Short for complementary metal oxide semiconductor. Pronounced see-moss, CMOS is a widely used type of semiconductor. CMOS semiconductors use both NMOS (negative polarity) and PMOS (positive polarity) circuits. Since only one of the circuit types is on at any given time, CMOS chips require less power than chips using just one type of transistor. This makes them particularly attractive for use in battery-powered devices, such as portable computers. Personal computers also contain a small amount of battery-powered CMOS memory to hold the date, time, and system setup parameter.

Originally Posted by pizzapie i dont think that the cmos's data is stored in the bios as the bios isn't meant to be changed. Yes, i think that its in a different chip altogether, maybe its even stored in the chipset, i don't know much about chipsets.

The chip where the BIOS is stored is the CMOS. The CMOS contains EEPROM (electrically eraseable programmable read-only memory) which is where the BIOS is stored. EEPROM chips are "flashable" and this allows the BIOS to be updated.

BIOS: Acronym for basic input/output system, the built-in software that determines what a computer can do without accessing programs from a disk. On PCs, the BIOS contains all the code required to control the keyboard, display screen, disk drives, serial communications, and a number of miscellaneous functions.

The BIOS is typically placed in a ROM chip that comes with the computer (it is often called a ROM BIOS). This ensures that the BIOS will always be available and will not be damaged by disk failures. It also makes it possible for a computer to boot itself. Because RAM is faster than ROM, though, many computer manufacturers design systems so that the BIOS is copied from ROM to RAM each time the computer is booted. This is known as shadowing.

Many modern PCs have a flash BIOS, which means that the BIOS has been recorded on a flash memory chip, which can be updated if necessary.

The PC BIOS is fairly standardized, so all PCs are similar at this level (although there are different BIOS versions). Additional DOS functions are usually added through software modules. This means you can upgrade to a newer version of DOS without changing the BIOS.

PC BIOSes that can handle Plug-and-Play (PnP) devices are known as PnP BIOSes, or PnP-aware BIOSes. These BIOSes are always implemented with flash memory rather than ROM.

Cricket

[rave]

Originally Posted by Cricket The CMOS is not the motherboard battery. The BIOS is stored in the CMOS.

sorry...my bad

[Ramses2]

Sorry but have read in standard text books.
CMOS RAM chip is a small chip that contains as little as 64 bytes of information with the first 14 bytes for clock information and the rest for the computer setting.
The CMOS memory exists outside of the normal address space and cannot
contain directly executable code. BIOS is a program which is directly executable.
So CMOS chip cannot contain BIOS program because (1) that program is larger than 64 bytes and (2) BIOS is directly executable program.
Really a lot of confusion!!!

[bailey]

you need to get a newer book, the chips today have 2 meg of space