Disk · BPM · Frame
BPM sits in the middle. Left is durable 8 KB. Right is the pinned copy. Read each band — header, slots, free, tuples.
idle · t 0.0s
Three vertical 8 KB pages on disk. Frames are empty desks.
Open. Anyone may ask which frame holds a page_id — nobody is rewriting the catalog.
header + slots↓ + free + tuples↑ · BusTub TablePage
Space / ← → · Theatre.js clock
PageGuard, pin & two latches