maybe it's not obvious that the block size can't be turned into a "mutt".  :-)

Reference: /n/atom/patch/applied/fosmuttable
Date: Thu Mar 20 18:16:43 CET 2014
Signed-off-by: quanstro@quanstro.net

--- /sys/src/cmd/fossil/disk.c	Thu Mar 20 18:16:40 2014
+++ /sys/src/cmd/fossil/disk.c	Thu Mar 20 18:16:40 2014
@@ -255,7 +255,7 @@
 int
 diskBlockSize(Disk *disk)
 {
-	return disk->h.blockSize;	/* immuttable */
+	return disk->h.blockSize;	/* immutable */
 }
 
 int