diff --git a/docs/dj.1 b/docs/dj.1
index 1440ff4..a110166 100644
--- a/docs/dj.1
+++ b/docs/dj.1
@@ -181,22 +181,22 @@ option is specified, this could make written data nonsensical.
 
 Existing files are not truncated on ouput and are instead overwritten.
 
-Option variants that have uppercase and lowercase forms could be confused for
+Option variants that have lowercase and uppercase forms could be confused for
 each other. The former affects input and the latter affects output.
 
 The
 .B -B
 option could be mistaken for write size, meaning the count in bytes of data
-placed in the output. This conception is intuitive but incorrect; the amount of
-data read and output is controlled by the
+placed in the output. This conception is intuitive but incorrect, as the
 .B -c
-and
+option controls the number of blocks to read and the
 .B -b
-options. The latter sets the size of blocks to be read and the former sets the
-number of blocks to be read. The
+option sets the size of the blocks. The
 .B -B
 option is similar to the latter but sets the size of blocks to be written,
-regardless of the amount of data that will actually be written.
+regardless of the amount of data that will actually be written. In practice,
+this means the input buffer should be very large to make use of modern hardware
+input and output speeds.
 
 The skipped or sought bytes while processing irregular files, such as streams,
 are reported in the diagnostic output, because they were actually read or
@@ -223,3 +223,4 @@ Copyright \(co 2023 DTB. License AGPLv3+: GNU AGPL version 3 or later
 .SH SEE ALSO
 .BR dd (1p)
 .BR lseek (3p)
+.BR mm (1)