Applying the same validation ideas from DOS 3.3 to ProDOS's directory tree and volume-wide free-block bitmap
When your archive contains ProDOS disks alongside DOS 3.3, the validation strategy shifts. ProDOS replaces the flat catalog with a hierarchical directory tree, and its free-block map operates at a different scale.
Key Differences
- Directory Tree - Hierarchical instead of a single flat catalog
- Volume Bitmap - Tracks free blocks across the entire disk
- File Type Metadata - Rich file type and creator info
- Sanity Checks - Directory link validation, bitmap consistency
The core principle remains: what the filesystem claims must match what's actually allocated.