procfs doubts

[Dattatray Kulkarni]

Hi,
I have some doubts regarding proc file system in linux.
1. read_proc & get_info have similar functionality. when i do cat
/proc/net/some_procfile, read_info function is called. then how & when
get_info function is called?
2. What is the exact difference between proc_create_entry &
proc_register?  Is it necessary to write both of these functions?
3 . How the function write_proc works? and when that function is called
by the kernel?
regards,
dattatray.