DFIncBackup Pro make only multivolume zip files (WinZip format).
Main file - zip, parts - z01,z02,etc.
You always open main part (zip), other parts using by tool (DFIncBackup, WinZip, WinRar, etc).
DFIncBackup has 2 built-in tools:
1) Built-in zip Viewer - Fast and simple.
2) Built-in zip Browser - Slow,
but it works with incremental / Differential archives.
Solid large files (>2GB) is not used, because:
1) DVD ISO standard cannot use files > 2GB
2) USB flash and hard disks formatted in FAT32 mode does not support large files.
3) Network shared folders has a lot of problems with writing/opening large files:
freeze, lost connection to shared folder, locking files, etc.