Hello World Module not working
 

Hi all
I wrote a Hello World module . Does n't seem to work - compiles but i cant insmod the same.
The program is #define MODULE
#include <linux/version.h>
#include <linux/init.h>
#include <linux/module.h>

MODULE_LICENSE("Dual BSD/GPL");

static int hello_init(void)
{
printk("Hello World!");
return 0;
}

static void hello_exit(void)
{
printk("Good Bye");

}

module_init(hello_init);
module_exit(hello_exit);



Now this is the way i compile it

#gcc -c hello.c
#insmod hello.o
This isthe error i get

hello.o : kernel - module version mismatch.
hello.o was compiled for kernel version 2.4.20
while this kernel is version 2.4.22-1.2115.ntpl

Another question , how to use KERN_ALERT in printk? What should the include file be?

And finally , what is .ko for example xyz.ko . How is it different from xyz.o??
Please help

Maybe this will help: http://www.linuxhq.com/lkprogram.html