This paper presents a file system and hardware architecture designed for byte-addressable, persistent memory technologies like phase change memory (PCM). The file system, BPFS, uses short-circuit shadow paging to provide atomic, fine-grained updates to persistent storage, offering strong reliability and performance guarantees. The hardware architecture enforces atomicity and ordering guarantees while leveraging the performance benefits of L1 and L2 caches. Evaluations show that BPFS outperforms traditional file systems on both DRAM and PCM, with significant improvements in speed and reliability. The paper also discusses design principles, hardware support, and limitations of the proposed system.This paper presents a file system and hardware architecture designed for byte-addressable, persistent memory technologies like phase change memory (PCM). The file system, BPFS, uses short-circuit shadow paging to provide atomic, fine-grained updates to persistent storage, offering strong reliability and performance guarantees. The hardware architecture enforces atomicity and ordering guarantees while leveraging the performance benefits of L1 and L2 caches. Evaluations show that BPFS outperforms traditional file systems on both DRAM and PCM, with significant improvements in speed and reliability. The paper also discusses design principles, hardware support, and limitations of the proposed system.