-The number of kilobytes per dump record. The default blocksize is 10
-and the maximal value is 1024.
+The number of kilobytes per dump record. The default blocksize is 10,
+unless the
+.B \-d
+option has been used to specify a tape density of 6250BPI or more,
+in which case the default blocksize is 32. Th maximal value is 1024.