This is the full lecture page: the lecture slides are embedded below with a summary of key points and references.

Lecture highlights (summary)

• The core problem of crash recovery: a crash can leave the file system in an inconsistent state (for example, directory entries pointing to uninitialized inodes).
• Common solution: write-ahead logging (journaling) so a transaction either fully completes or not at all.
• xv6 implementation notes: maintain log entries in memory, write and mark the log completed at commit, then install the blocks from the log to their target locations, and finally clear the log head.
• Design tradeoffs: correctness vs performance (logging causes blocks to be written twice), and tradeoffs with concurrency/log size (large transactions need splitting).

References

• Slides (embedded above)
• Detailed crash recovery notes: /mit6.1810/homework/l-crash.md
• xv6 source implementations for logging and the buffer cache: see fs.c, log.c, bio.c in the xv6 source repository

If you'd like, I can extract the original 2024 lecture notes and expand this into a more detailed Markdown lecture (including code snippets and examples) by incorporating homework/l-crash.md.