diff --git a/src/bits.md b/src/bits.md
new file mode 100644
index 00000000..4a18c00a
--- /dev/null
+++ b/src/bits.md
@@ -0,0 +1,34 @@
+N |   MASK  | ENV       | TXN          | DB       | PUT       | DBI        | NODE    | PAGE     |
+--|---------|-----------|--------------|----------|-----------|------------|---------|----------|
+0 |0000 0001|           |TXN_FINISHED  |          |           |DBI_DIRTY   |F_BIGDATA|P_BRANCH
+1 |0000 0002|           |TXN_ERROR     |REVERSEKEY|           |DBI_STALE   |F_SUBDATA|P_LEAF
+2 |0000 0004|           |TXN_DIRTY     |DUPSORT   |           |DBI_FRESH   |F_DUPDATA|P_OVERFLOW
+3 |0000 0008|           |TXN_SPILLS    |INTEGERKEY|           |DBI_CREAT   |         |P_META
+4 |0000 0010|           |TXN_HAS_CHILD |DUPFIXED  |NOOVERWRITE|DBI_VALID   |         |P_DIRTY
+5 |0000 0020|           |              |INTEGERDUP|NODUPDATA  |DBI_USRVALID|         |P_LEAF2
+6 |0000 0040|           |              |REVERSEDUP|CURRENT    |DBI_DUPDATA |         |P_SUBP
+7 |0000 0080|           |              |          |ALLDUPS    |DBI_AUDITED |         |
+8 |0000 0100|           |              |          |           |            |         |
+9 |0000 0200|           |              |          |           |            |         |
+10|0000 0400|           |              |          |           |            |         |
+11|0000 0800|           |              |          |           |            |         |
+12|0000 1000|           |              |          |           |            |         |
+13|0000 2000|           |              |          |           |            |         |
+14|0000 4000|NOSUBDIR   |              |          |           |            |         |P_LOOSE
+15|0000 8000|           |              |DB_VALID  |           |            |         |P_KEEP
+16|0001 0000|SAFE_NOSYNC|TXN_NOSYNC    |          |RESERVE    |            |RESERVE  |
+17|0002 0000|RDONLY     |TXN_RDONLY    |          |APPEND     |            |APPEND   |
+18|0004 0000|NOMETASYNC |TXN_NOMETASYNC|CREATE    |APPENDDUP
+19|0008 0000|WRITEMAP   |<=            |          |MULTIPLE
+20|0010 0000|UTTERLY    |              |
+21|0020 0000|NOTLS      |<=            |
+22|0040 0000|EXCLUSIVE  |              |
+23|0080 0000|NORDAHEAD  |              |
+24|0100 0000|NOMEMINIT  |TXN_PREPARE   |
+25|0200 0000|COALESCE   |              |
+26|0400 0000|LIFORECLAIM|              |
+27|0800 0000|PAGEPERTURB|              |
+28|1000 0000|ENV_TXKEY  |TXN_TRY       |
+29|2000 0000|ENV_ACTIVE |              |
+30|4000 0000|ACCEDE     |SHRINK_ALLOWED|DB_ACCEDE
+31|8000 0000|FATAL_ERROR|              |