diff --git a/morituri/common/checksum.py b/morituri/common/checksum.py
index cdd3a13..ecb78a9 100644
--- a/morituri/common/checksum.py
+++ b/morituri/common/checksum.py
@@ -30,6 +30,8 @@ import gst
 
 from morituri.common import task
 
+# checksums are not CRC's. a CRC is a specific type of checksum.
+
 FRAMES_PER_DISC_FRAME = 588
 SAMPLES_PER_DISC_FRAME = FRAMES_PER_DISC_FRAME * 4
 DISC_FRAMES_PER_SECOND = 75