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Implement FAT12 Filesystem Writer: Create Files and Update FAT

hard6/10

Implement FAT12 Filesystem Reader: Parse Boot Sector and FAT Understand ext2 Filesystem Layout: Superblock, Inode Table, Block Groups

Language

Compiler

2.0s Limit 256MB

Implementation

Implement FAT12 writer.

Requirements:

Open disk image for writing
Find free cluster in FAT
Write data to cluster in data area
Update FAT table (allocate, link, mark end)
Create directory entry with correct format
Write directory entry to root directory
Handle extending files (append data)
Error checking: disk full, directory full
Flush changes to disk

Test:

Create new file
Write file data
Update FAT correctly
Create directory entry
Verify with hexdump or fsck

Why This Matters

Every field you pack here — the space-padded 8.3 filename, the 0xFFF end-of-chain marker — matches exactly what tools like mkfs.fat and fsck.fat validate, and what real DOS and early Windows machines wrote to floppies for two decades. Forgetting to write the FAT back to disk after updating it in memory is a classic bug that silently corrupts the whole filesystem on the next mount.

Hints

0 / 3 revealed

Validation Suite

main.c

Workspace 1.0