ADR-0004 — Native NTFS implementation

Status: accepted · Date: 2026-09

Context

NTFS is the first filesystem PHOINIX must recover from. Undelete needs evidence (fixup validity, runlist completeness, $Bitmap state, stale parent sequence numbers) that generic filesystem libraries do not expose.

Decision

phoinix-fs-ntfs implements NTFS natively: boot sector, update sequence fixups, FILE records, attributes, runlists, $FILE_NAME, $STANDARD_INFORMATION, resident and non-resident $DATA, $Bitmap and parent-based path reconstruction. No TSK, TestDisk or ntfs-3g code is required in the recovery path.

Consequences

PHOINIX controls the evidence model end to end.
Compression and EFS are detected and reported as unsupported rather than silently mis-recovered until implemented.
External tools remain valuable as comparison references in tests.