0) "hello.c"

        int main(int argc, char **argv)
        {
            open("/dev/tty0", O_RDONLY, 0);
            open("/dev/tty0", O_WRONLY, 0);
            write(1, "Hello, world!\n", 14);
            return 0;
        }


        int write(int fd, const void *buf, size_t nbytes)
        {
            write_args_t args;
            args.fd = fd;
            args.buf = (void *) buf;
            args.nbytes = nbytes;
            return trap(SYS_write, (uint32_t) &args);
        }

1) Explain these command

        objdump --disassemble --section=".text" user/usr/bin/hello.exec > w
        objdump --disassemble --section=".text" -S user/usr/bin/hello.exec > x
        objdump --headers user/usr/bin/hello.exec > y
        xxd -g 1 user/usr/bin/hello.exec > z

2) Kernel 3 FAQ - Handle the first page fault:

        http://merlot.usc.edu/cs402-f20/projects/kernel/faq.html#q_debug_ptmap

3) Kernel 3 FAQ - Meaning of pagenum 

        http://merlot.usc.edu/cs402-f20/projects/kernel/faq.html#q_pagenum

4) Kernel 3 FAQ - What is the right number of page faults I should get when I run "/usr/bin/hello"?

        http://merlot.usc.edu/cs402-f20/projects/kernel/faq.html#q_hello_handle_pagefaults

5) Useful GDB commands:

        add-symbol-file user/usr/bin/hello.exec 0x08048094
        b __libc_static_entry
        b main
        b *0x12345678
        layout asm
        layout next
        si
        info registers
        kernel info vmmap_mapping_info curproc->p_vmmap

   Not-so-useful GDB command:

        kernel info pt_mapping_info curproc->p_pagedir