1 files changed, 9 insertions, 0 deletions

diff --git a/docs/cronos-research.md b/docs/cronos-research.md
index ec074d7..4cc4da0 100644
--- a/docs/cronos-research.md
+++ b/docs/cronos-research.md
@@ -169,4 +169,13 @@ the `Base000` entry contains the record number for the table definition of the f
     ...
 
 
+## compressed records
+
+some records are compressed, the format is like this:
+
+    word16 size
+    byte   head[2] = { 8, 0 }
+    word32 crc32
+    byte   compdata[size-4]
+    byte   tail[3] = { 0, 0, 2 }