IS there any documents about psp system's memory & kerne

[wagon]

IS there any documents about psp system's memory & kernel?

programming on psp for few weeks. but i know nothing about
psp system's memory manage& kernel. how it works?
i just feel it like a dos os,can not run mutil task,can she surport mutil-thread? mutil-task? i really don't know.
what's kernel mode ,& what's user mode?
so many pzl.
my english is bad ,so there also many i still can't descripe.

any good man help me!thank you.

[jean]

my english is bad

I think your eyes are bad.... http://ps2dev.org/psp/Tutorials