TOS Arno Puder 1 Demo Kernel /* tos/kernel/main.c */ #include - - PowerPoint PPT Presentation

1

TOS Arno Puder

Demo Kernel

2

/* tos/kernel/main.c */ #include <kernel.h> WINDOW window_top = {0, 0, 80, 12, 0, 0, ' '}; WINDOW window_bottom = {0, 12, 80, 13, 0, 0, ' '}; void kernel_main() { for (int x = 0; x < 80 * 25 * 2; x++) { poke_b(0xb8000 + x, 0); }

• utput_string(&window_top, "Hello World!");
• utput_string(&window_bottom, "TOS is fun!\n");
• utput_string(&window_bottom, "-----------");

while (1); }

TOS under Bochs

3

Internal parts of a 3½‑inch floppy disk

4

• 1. A hole that indicates a high-capacity disk.
• 2. The hub that engages with the drive motor.
• 3. A shutter that protects the surface when

removed from the drive.

• 4. The plastic housing.
• 5. A polyester sheet reducing friction against

the disk media as it rotates within the housing.

• 6. The magnetic coated plastic disk.
• 7. A schematic representation of one sector of

data on the disk; the tracks and sectors are not visible on actual disks.

• 8. The write protection tab (unlabeled) is upper

left.

https://en.wikipedia.org/wiki/Floppy_disk

USB Floppy Drive

5

http://a.co/3jvn7M5

Running TOS on Real Hardware

• How to make TOS run on real hardware?
• Recap:

– Makefile will create tos.img that contains the TOS kernel. – Makefile will create image/disk_image that contains a FAT formatted floppy disk image. – .bochsrc refers to disk_image via the floppya parameter.

• Inspecting disk_image:

# Size of disk_image is 1.44 MB ls -l image/disk_image # disk_image is a FAT-formatted image file image/disk_image # Create a mount point and mount disk_image sudo mkdir /mnt/tos sudo mount image/disk_image /mnt/tos df # Shows tos.img and stage2.bin ls –l /mnt/tos # Un-mount disk_image sudo umount /mnt/tos df

6

Creating a Boot Floppy

• Requires a physical floppy disk (e.g., USB-connected floppy disk)

and a floppy.

• File disk_image needs to be transferred to the floppy disk. This

cannot be done with the regular cp command! (why?)

• Ubuntu:

– Use dd (disk dump): dd if=image/disk_image of=/dev/fd0

• Windows:

– rawrite (http://www.chrysocome.net/rawwrite)

• Once disk_image is transferred for the first time, it is possible to

mount the floppy disk and just copy tos.img.

• The floppy can then used on an IBM PC compatible computer that

has a (USB) floppy drive.

• Note: might change in BIOS settings to allow booting from floppy!

7