View Full Version : Comparable BIOS Component in Mac?

Jan 24, 2005, 10:30 AM
Hey everyone,

I have a quite banal question concerning the inside of a Mac and hope you can help me out. Although I am an experienced Mac user for many years myself I couldn't answer this question when asked. Is there a comparable device inside a Mac that acts as the BIOS in a PC? If not, what is the reason the Mac doesn't need one? (I have been told before that such a thing is not needed.)

Thanks for any answer that will help me not to embarass myself again :P


Jan 24, 2005, 10:38 AM
The closest equivalent to the PC BIOS in Macs is Open Firmware. You can access it from a "New World" Mac by holding down Command+Option+O+F at startup. If it worked, you'll see an odd-looking command prompt like screen that doesn't look at all like Terminal. In here, you can make low-level hardware changes, such as resetting the NVRAM (reset-nvram), resetting everything (reset-all), continuing normal startup (mac-boot) or rebooting the Mac (reboot). The name in parentheses is the command you type at the Open Firmware prompt to achieve the described effect.

Jan 24, 2005, 10:46 AM
Open Firmware is much cooler than a BIOS!

It can be programmed to do some cool things like this (http://www.kernelthread.com/mac/apme/hanoi/).

Note that it mentions some of the cool things you can do in OF. A machine booted into OF can be telneted into for example (try that with a PC BIOS)!

Edit to add : Intro to Open Firmware (http://www.kernelthread.com/mac/osx/arch_boot.html)

This is even cooler. Skip to part II (http://www.kernelthread.com/publications/firmware/)

Jan 24, 2005, 04:32 PM
What a gr8 site!!

Tnx robbieduncan! :)

Jan 24, 2005, 10:45 PM
A machine booted into OF can be telneted into for example (try that with a PC BIOS)!

that is so cool. although I can't fathom the implications

Sun Baked
Jan 24, 2005, 10:51 PM
http://playground.sun.com/1275/ -- list of the mirrors

There is a manual on programming in OF, you can do some stuff that is quite interesting while in there.

Somewhere around is the .pdf manual to buy, could find where it is. Not free though.