{"id":"btree-page-zero-is-metadata","text":"Page 0 is always the metadata page (root_page, height, total_keys, next_free_page, free_list_head); the root page is never page 0.","truth_value":"IN","source":"entries/2026/05/28/b-tree-storage-engine-btree.md","source_url":"","source_hash":"","justifications":[],"dependents":[],"metadata":{"example":"# Page 0: root_page(4B), height(4B), total_keys(4B), next_free(4B), free_head(4B)\nMETA_FMT = \">5I\"\nself._f.seek(0)\nself._f.write(struct.pack(META_FMT, root, height, total_keys, next_free, free_head))"},"explanation":{"steps":[{"node":"btree-page-zero-is-metadata","truth_value":"IN","reason":"premise"}]}}