QUERY: kernel-mode & user-mode... woes...

I came across this twice:

sness9X (http://yoyofr92.free.fr/psp/snespsp.html) has two versions, user-mode & kernel-mode (codename ME)
CPS2PSP (http://dl.qj.net/Emulators-PSP-/catid/111) has two versions, 3.xx user-mode & 1.50 kernel-mode

What is the difference between user-mode & kernel-mode? Why is it called user-mode & kernel-mode? What does ME stand for regarding snes9X emulator?

The CPS2PSP (Capcom PlaySystem 2) emulator readme files is all in japanese. Can someone help me locate the official homepage website & author email address as I would like to talk to the programmer.

user mode is like what official sony programs use. Kernel mode is the same, but it has more memory and has more access to the psp, making it work better. It does have some compatability issues at times, but if you have a custom firmware, there is no problem.
user mode homebrews go in X:/PSP/GAME3XX/ (The 3XX depends on what custom firmware you are on. if you are on 3.52 m33, it would be GAME352)
kernel mode, or 1.50 homebrews go in X:/PSP/GAME150 (That one is the same on all custom firmwares)

ME stands for Media Engine, if something is coded in ME it runs the audio under the psp Media Engine which is accessible under kernel mode. It helps improve the emulators performance. Correct me if I am wrong but I think thats what it is.

http://img.qj.net/uploads/articles_m...mall_small.jpg