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2.1.2 Block Format

The first 20 bytes of the block header format is the same for all types of blocks.

0 blk:id

The ID of this block.

4 blk:top-id

The ID of the root block of this tree.

8 blk:nxt-id

The ID of the next block in the chain (at same level as this one).

12 blk:time

The 32-bit time/date when this block was last modified.

16 blk:end

Two-byte length of data in block, including header.

18 blk:level

Block level; 0 is leaf.

19 blk:typ

Block type, one of:

• dir-typ Directory tree.
• ind-typ Other tree.
• seq-typ Sequential chain (unused).
• frl-typ Free-list chain.

20

Start of data for SEQ-TYP blocks. Data spans to blk:end.

20 leaf-split-key

22

Start of data for other block types. Data spans to blk:end.