doesn't clear screen on boot

This bug has been copied automatically from: https://bugs.launchpad.net/qemu/+bug/922076

When I start Linux in Qemu via "qemu -kernel /vmlinuz ...", Qemu window
appears and it shows message "Starting Seabios (version 0.5.1-2010...)",
and then Linux writes messages like "Loading, please wait..." on top of
previous message!

For example, I can see "Loading, please wait...on 0.5.1-2010...)"

So, Qemu doesn't clean screan before booting OS.

Moreover, when I start Linux via "qemu /disk-image", Qemu shows "Starting
Seabios (version 0.5.1-2010...)", then switches to graphical mode, shows
GRUB, then switches back to text mode and shows "Starting Seabios" again!
And again Linux prints messages on top of Seabios messages, and we see a
mix of symbols on screen.

Also, I found another bug! I am learning now to write kernels. And I see
that operator "*(char *)0xb8000 = 0" in C code of kernel doesn't clean
first charaster of screen in Qemu in "-curses" mode! If I want to real
clean this charaster, I must type "*(char *)0xb8000 = ' '".

I attach a kernel (x86, multiboot) with this bug. Just type "make" (you
need gcc) and "qemu -curses -kernel kernel". You will see that screen is
not cleared, but kernel tries to clean it. If you change 0 to ' ', all
will work!