QUOTE(teckyang97 @ Jan 24 2013, 10:26 PM)
By the way,what is kernel?
Here's some clarification regarding bootloader, kernel and rom. Hope it sheds some light.
Bootloader - the frontline code that get executed when you turn on any android device. It contains instructions to boot system kernel. Every bootloader is unique to every devices. Some may contain advanced options to mod or debug. It also serves as a checkpoint between partition, therefore that's why bootloaders are "locked" to restrict access to said partitions.
Kernel - the middle man between software and hardware. For anything, ANYTHING that you want doing on Android ( or all other popular OS ), kernel is involved. It translate hardware input to software, and translating it back for results.
Example : Waking screen.
Hardware input : Power button pressed -> Kernel: Trigger OS -> OS: Power button pushed, turning on screen -> Kernel : Send trigger to display digitizer -> Hardware : Voila, screen wakes
It effects all hardware aspects, brightness, digitizer, processor, memory, OTG controller etc. Hence why a well-written kernel can deliver high performance with minimal battery drain.
ROM - Your device operating system. How your devices ultimately look and work depends on them. TabletUI, PhabletUI, bloatware, adblocking are all ROM controlled. ROM cooks ( aka ROM developers ) also optimizing their ROMs by determinating which app should sit in memory, deodex / odex apk, and clearing out bloatware from stock ROMs.
Additional read :
BootloaderKernelRecovery ModeROMThis post has been edited by redlyfs: Jan 25 2013, 09:13 AM