[ubuntu] why can't we use embedded linux in PC's lik BIOS?

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http://ubuntuforums.org – hi! I'm a new user of linux (ubuntu). I've read an article in wikipedia about embedded linux. It was mentioned that linux operating systems were used in the form of embedded technology in mobile phones, media players etc. My question is why can't we embedded linux in our PC's like BIOS. won't it be easy for us??? I don know if this technology already exists... if so please tell me something about it ... thanks (Hardware)