| 2014-06-02 12:54:21 |
Askar Safin |
description |
When I start Linux in Qemu via "qemu -kernel /vmlinuz ...", opens Qemu window, 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! |
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! |
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