LC

Use BIOS Disk Services to Read Sectors from Disk

medium2/8

Use BIOS Interrupts to Read Keyboard Input and Display Text Create Simple UEFI Application that Prints Hello World

Language

Compiler

2.0s Limit 256MB

Implementation

Demonstrate BIOS disk sector reading operations.

Requirements:

Use INT 0x13, AH=0x02 to read disk sectors
Implement CHS (Cylinder-Head-Sector) addressing
Read the boot sector (cylinder 0, head 0, sector 1)
Display the first bytes of the boot sector
Check for boot signature (0x55AA at offset 510)
Handle disk read errors
Print disk geometry (cylinders, heads, sectors)
Demonstrate understanding of disk addressing

Why This Matters

INT 0x13 is literally how GRUB's stage-1 boot sector and MS-DOS's MBR code have loaded the next boot stage from disk since the original IBM PC, and the 0x55AA boot signature check you implement here is the same one every BIOS performs before jumping to 0x7C00. CHS-vs-LBA addressing bugs in this exact code path are why old bootloaders silently failed on drives larger than 8GB.

Hints

0 / 3 revealed

Validation Suite

main.c

Workspace 1.0