When your turn on your computer, the first thing that loads is the Basic Input/Output System, or BIOS for short. It typically shows you a logo (to show that your monitor is working fine), initializes and checks the memory so that programs can use it, checks to make sure you have a keyboard, so you can interact with the system, and then goes about looking for an operating system. Which it loads into memory and runs.
There is a suggestion to replace this with a more complicated system. Why?
Well, for one, BIOSes must be specifically written for a particular make of motherboard, and have some hard limits that we're about to hit. A major crisis will occur when hard drives are over 2TB in size, as the BIOS will no longer report it correctly, and will start being unable to directly load the operating system. BIOSes also look very crude, being primarily CLI technology in an age when 99% of computers have a delightful graphical interface, with a pointing mouse, trackball, or touchpad.
The replacement system, UEFI, would be a mini-operating system with all the perks of the large thing. It would present a graphical interface that you could operate by mouse or computer. It would be universal (the U in the acronym) to all motherboards, and one writing could be reused in every board. It could be written in high level language, saving valuable programmer time. And it could have its variable sizes change as hard drives get better, eternally extending its ability to understand storage devices of ever-growing size.
On the down side, the bootup ROMs would have to be made way, way, way bigger. Which would be expensive. Oh well, nice try, guys.