BIOS and CMOS

Oh man! Ad-blocking software has been detected! :'(

This website is run by the community, for the community... and it needs advertisements in order to keep running. Blocking our ads means your killing our stats!
Please disable your ad-block, or become a premium member to hide all advertisements and this notice.

whilst working in IT, the explanation between both has varied, I am wondering whether there is an official distinction between the both of these terms that the majority agree on, opinions vary across websites also. Am I right in saying BIOS is the software that sits on the CMOS chip? and when people say "BIOS chip" they are actually referring to the CMOS chip?

 

CMO stands for Complimentary Metal Oxide. Its a type of silicon chip that used to be made. https://en.wikipedia.org/wiki/CMOS
In fact most semiconductors are silicon 'doped' with a metal so doesn't mean much to most people.

BIO's stands for Basic Input Output System.
The BIOS is the firmware for a PC, it contains the routines used to boot the system and drive a VGA screen and keyboard and IO ports.

The BIOS used to be stored on an EEPROM, but now its normally Flash RAM.

The CMOS chip used to contain the BIOS settings, and part of the chip was battery backed ram. BIO's settings can also now be stored in flash RAM, negating the battery.
https://www.computerhope.com/issues/ch001360.htm
https://www.quora.com/What-is-the-difference-between-CMOS-and-RTC
The original meaning of the CMOS manufacturing process bears litter relevance to the technology in your computer. Its an anachronism. So its unlikely your 'CMOS' chip is CMOS. You just have a southbridge chip with some FlashRAM I expect.

I think things are somewhat more complicated now. The PC has continually evolved over ~30 years.
In reality many BIOS routines aren't used anymore and windows loads its system routines into RAM on startup and creates a table called System Service Dispatch Table SSDT.
http://resources.infosecinstitute.com/hooking-system-service-dispatch-table-ssdt/

Lately we've had the Unified Extensible Firmware Interface (UEFI). Which aims to try to sort all this mess out.
http://www.alphr.com/features/381565/uefi-bios-explained