diff --git a/bin/dd/Makefile b/bin/dd/Makefile
index ab33aed85499..20f0522a5468 100644
--- a/bin/dd/Makefile
+++ b/bin/dd/Makefile
@@ -15,6 +15,7 @@ MAINTAINER=	green@FreeBSD.org
 test:	${PROG}
 	cc ${.CURDIR}/gen.c
 .for conv in ascii ebcdic ibm oldascii oldebcdic oldibm \
+    pareven parnone parodd parset \
     swab lcase ucase
 	@echo testing conv=${conv}
 	@./a.out | \
diff --git a/bin/dd/args.c b/bin/dd/args.c
index b629b3ad4e44..2b17f1e83999 100644
--- a/bin/dd/args.c
+++ b/bin/dd/args.c
@@ -299,6 +299,10 @@ static const struct conv {
 	{ "oldebcdic",	C_EBCDIC,	C_ASCII,	a2e_32V },
 	{ "oldibm",	C_EBCDIC,	C_ASCII,	a2ibm_32V },
 	{ "osync",	C_OSYNC,	C_BS,		NULL },
+	{ "pareven",	C_PAREVEN,	C_PARODD|C_PARSET|C_PARNONE, NULL},
+	{ "parnone",	C_PARNONE,	C_PARODD|C_PARSET|C_PAREVEN, NULL},
+	{ "parodd",	C_PARODD,	C_PAREVEN|C_PARSET|C_PARNONE, NULL},
+	{ "parset",	C_PARSET,	C_PARODD|C_PAREVEN|C_PARNONE, NULL},
 	{ "sparse",	C_SPARSE,	0,		NULL },
 	{ "swab",	C_SWAB,		0,		NULL },
 	{ "sync",	C_SYNC,		0,		NULL },
diff --git a/bin/dd/dd.1 b/bin/dd/dd.1
index 588b62f95b9b..31150fd9decb 100644
--- a/bin/dd/dd.1
+++ b/bin/dd/dd.1
@@ -231,6 +231,13 @@ and
 systems.
 .It Cm lcase
 Transform uppercase characters into lowercase characters.
+.It Cm pareven , parnone , parodd , parset
+Output data with the specified parity.
+The parity bit on input is stripped unless
+.Tn EBCDIC
+to
+.Tn ASCII
+conversions is also specified.
 .It Cm noerror
 Do not stop processing on an input error.
 When an input error occurs, a diagnostic message followed by the current
@@ -355,6 +362,19 @@ be written to the standard error output
 in the same format as the standard completion message and
 .Nm
 will exit.
+.Sh EXAMPLES
+Check that a disk drive contains no bad blocks:
+.Dl dd if=/dev/ad0 of=/dev/null bs=1m
+.Pp
+Do a refresh of a disk drive, in order to prevent presently
+recoverable read errors from progressing into unrecoverable read errors:
+.Dl dd if=/dev/ad0 of=/dev/ad0 bs=1m
+.Pp
+Remove parity bit from a file
+.Dl dd if=file conv=parnone of=file.txt
+.Pp
+Check for (even) parity errors on a file:
+.Dl dd if=file conv=pareven | cmp -x - file
 .Sh DIAGNOSTICS
 .Ex -std
 .Sh SEE ALSO
diff --git a/bin/dd/dd.c b/bin/dd/dd.c
index 9deac8a21a68..cb6127cd37a6 100644
--- a/bin/dd/dd.c
+++ b/bin/dd/dd.c
@@ -104,6 +104,16 @@ main(int argc __unused, char *argv[])
 	exit(0);
 }
 
+static int
+parity(u_char c)
+{
+	int i;
+
+	i = c ^ (c >> 1) ^ (c >> 2) ^ (c >> 3) ^ 
+	    (c >> 4) ^ (c >> 5) ^ (c >> 6) ^ (c >> 7);
+	return (i & 1);
+}
+
 static void
 setup(void)
 {
@@ -176,29 +186,52 @@ setup(void)
 		if (ftruncate(out.fd, out.offset * out.dbsz) == -1)
 			err(1, "truncating %s", out.name);
 
-	/*
-	 * If converting case at the same time as another conversion, build a
-	 * table that does both at once.  If just converting case, use the
-	 * built-in tables.
-	 */
-	if (ddflags & (C_LCASE | C_UCASE)) {
-		if (ddflags & (C_ASCII | C_EBCDIC)) {
-			if (ddflags & C_LCASE) {
-				for (cnt = 0; cnt <= 0377; ++cnt)
-					casetab[cnt] = tolower(ctab[cnt]);
-			} else {
-				for (cnt = 0; cnt <= 0377; ++cnt)
-					casetab[cnt] = toupper(ctab[cnt]);
-			}
+	if (ddflags & (C_LCASE  | C_UCASE | C_ASCII | C_EBCDIC | C_PARITY)) {
+		if (ctab != NULL) {
+			for (cnt = 0; cnt <= 0377; ++cnt)
+				casetab[cnt] = ctab[cnt];
 		} else {
-			if (ddflags & C_LCASE) {
-				for (cnt = 0; cnt <= 0377; ++cnt)
-					casetab[cnt] = tolower((int)cnt);
-			} else {
-				for (cnt = 0; cnt <= 0377; ++cnt)
-					casetab[cnt] = toupper((int)cnt);
-			}
+			for (cnt = 0; cnt <= 0377; ++cnt)
+				casetab[cnt] = cnt;
 		}
+		if ((ddflags & C_PARITY) && !(ddflags & C_ASCII)) {
+			/*
+			 * If the input is not EBCDIC, and we do parity
+			 * processing, strip input parity.
+			 */
+			for (cnt = 200; cnt <= 0377; ++cnt)
+				casetab[cnt] = casetab[cnt & 0x7f];
+		}
+		if (ddflags & C_LCASE) {
+			for (cnt = 0; cnt <= 0377; ++cnt)
+				casetab[cnt] = tolower(casetab[cnt]);
+		} else if (ddflags & C_UCASE) {
+			for (cnt = 0; cnt <= 0377; ++cnt)
+				casetab[cnt] = toupper(casetab[cnt]);
+		}
+		if ((ddflags & C_PARITY)) {
+			/*
+			 * This should strictly speaking be a no-op, but I
+			 * wonder what funny LANG settings could get us.
+			 */
+			for (cnt = 0; cnt <= 0377; ++cnt)
+				casetab[cnt] = casetab[cnt] & 0x7f;
+		}
+		if ((ddflags & C_PARSET)) {
+			for (cnt = 0; cnt <= 0377; ++cnt)
+				casetab[cnt] = casetab[cnt] | 0x80;
+		}
+		if ((ddflags & C_PAREVEN)) {
+			for (cnt = 0; cnt <= 0377; ++cnt)
+				if (parity(casetab[cnt]))
+					casetab[cnt] = casetab[cnt] | 0x80;
+		}
+		if ((ddflags & C_PARODD)) {
+			for (cnt = 0; cnt <= 0377; ++cnt)
+				if (!parity(casetab[cnt]))
+					casetab[cnt] = casetab[cnt] | 0x80;
+		}
+
 		ctab = casetab;
 	}
 
diff --git a/bin/dd/dd.h b/bin/dd/dd.h
index c6211d9fb766..fbe7ce06d96f 100644
--- a/bin/dd/dd.h
+++ b/bin/dd/dd.h
@@ -95,3 +95,9 @@ typedef struct {
 #define	C_UNBLOCK	0x80000
 #define	C_OSYNC		0x100000
 #define	C_SPARSE	0x200000
+#define C_PAREVEN	0x400000
+#define C_PARODD	0x800000
+#define C_PARSET	0x1000000
+#define C_PARNONE	0x2000000
+
+#define C_PARITY	(C_PAREVEN|C_PARODD|C_PARSET|C_PARNONE)
diff --git a/bin/dd/ref.pareven b/bin/dd/ref.pareven
new file mode 100644
index 000000000000..c64e63e30660
--- /dev/null
+++ b/bin/dd/ref.pareven
@@ -0,0 +1,18 @@
+$FreeBSD$
+00000000  00 81 82 03 84 05 06 87  88 09 0a 8b 0c 8d 8e 0f  |................|
+00000010  90 11 12 93 14 95 96 17  18 99 9a 1b 9c 1d 1e 9f  |................|
+00000020  a0 21 22 a3 24 a5 a6 27  28 a9 aa 2b ac 2d 2e af  |.!".$..'(..+.-..|
+00000030  30 b1 b2 33 b4 35 36 b7  b8 39 3a bb 3c bd be 3f  |0..3.56..9:.<..?|
+00000040  c0 41 42 c3 44 c5 c6 47  48 c9 ca 4b cc 4d 4e cf  |.AB.D..GH..K.MN.|
+00000050  50 d1 d2 53 d4 55 56 d7  d8 59 5a db 5c dd de 5f  |P..S.UV..YZ.\.._|
+00000060  60 e1 e2 63 e4 65 66 e7  e8 69 6a eb 6c ed ee 6f  |`..c.ef..ij.l..o|
+00000070  f0 71 72 f3 74 f5 f6 77  78 f9 fa 7b fc 7d 7e ff  |.qr.t..wx..{.}~.|
+00000080  00 81 82 03 84 05 06 87  88 09 0a 8b 0c 8d 8e 0f  |................|
+00000090  90 11 12 93 14 95 96 17  18 99 9a 1b 9c 1d 1e 9f  |................|
+000000a0  a0 21 22 a3 24 a5 a6 27  28 a9 aa 2b ac 2d 2e af  |.!".$..'(..+.-..|
+000000b0  30 b1 b2 33 b4 35 36 b7  b8 39 3a bb 3c bd be 3f  |0..3.56..9:.<..?|
+000000c0  c0 41 42 c3 44 c5 c6 47  48 c9 ca 4b cc 4d 4e cf  |.AB.D..GH..K.MN.|
+000000d0  50 d1 d2 53 d4 55 56 d7  d8 59 5a db 5c dd de 5f  |P..S.UV..YZ.\.._|
+000000e0  60 e1 e2 63 e4 65 66 e7  e8 69 6a eb 6c ed ee 6f  |`..c.ef..ij.l..o|
+000000f0  f0 71 72 f3 74 f5 f6 77  78 f9 fa 7b fc 7d 7e ff  |.qr.t..wx..{.}~.|
+00000100
diff --git a/bin/dd/ref.parnone b/bin/dd/ref.parnone
new file mode 100644
index 000000000000..fba31c142448
--- /dev/null
+++ b/bin/dd/ref.parnone
@@ -0,0 +1,18 @@
+$FreeBSD$
+00000000  00 01 02 03 04 05 06 07  08 09 0a 0b 0c 0d 0e 0f  |................|
+00000010  10 11 12 13 14 15 16 17  18 19 1a 1b 1c 1d 1e 1f  |................|
+00000020  20 21 22 23 24 25 26 27  28 29 2a 2b 2c 2d 2e 2f  | !"#$%&'()*+,-./|
+00000030  30 31 32 33 34 35 36 37  38 39 3a 3b 3c 3d 3e 3f  |0123456789:;<=>?|
+00000040  40 41 42 43 44 45 46 47  48 49 4a 4b 4c 4d 4e 4f  |@ABCDEFGHIJKLMNO|
+00000050  50 51 52 53 54 55 56 57  58 59 5a 5b 5c 5d 5e 5f  |PQRSTUVWXYZ[\]^_|
+00000060  60 61 62 63 64 65 66 67  68 69 6a 6b 6c 6d 6e 6f  |`abcdefghijklmno|
+00000070  70 71 72 73 74 75 76 77  78 79 7a 7b 7c 7d 7e 7f  |pqrstuvwxyz{|}~.|
+00000080  00 01 02 03 04 05 06 07  08 09 0a 0b 0c 0d 0e 0f  |................|
+00000090  10 11 12 13 14 15 16 17  18 19 1a 1b 1c 1d 1e 1f  |................|
+000000a0  20 21 22 23 24 25 26 27  28 29 2a 2b 2c 2d 2e 2f  | !"#$%&'()*+,-./|
+000000b0  30 31 32 33 34 35 36 37  38 39 3a 3b 3c 3d 3e 3f  |0123456789:;<=>?|
+000000c0  40 41 42 43 44 45 46 47  48 49 4a 4b 4c 4d 4e 4f  |@ABCDEFGHIJKLMNO|
+000000d0  50 51 52 53 54 55 56 57  58 59 5a 5b 5c 5d 5e 5f  |PQRSTUVWXYZ[\]^_|
+000000e0  60 61 62 63 64 65 66 67  68 69 6a 6b 6c 6d 6e 6f  |`abcdefghijklmno|
+000000f0  70 71 72 73 74 75 76 77  78 79 7a 7b 7c 7d 7e 7f  |pqrstuvwxyz{|}~.|
+00000100
diff --git a/bin/dd/ref.parodd b/bin/dd/ref.parodd
new file mode 100644
index 000000000000..f0bc449e3648
--- /dev/null
+++ b/bin/dd/ref.parodd
@@ -0,0 +1,18 @@
+$FreeBSD$
+00000000  80 01 02 83 04 85 86 07  08 89 8a 0b 8c 0d 0e 8f  |................|
+00000010  10 91 92 13 94 15 16 97  98 19 1a 9b 1c 9d 9e 1f  |................|
+00000020  20 a1 a2 23 a4 25 26 a7  a8 29 2a ab 2c ad ae 2f  | ..#.%&..)*.,../|
+00000030  b0 31 32 b3 34 b5 b6 37  38 b9 ba 3b bc 3d 3e bf  |.12.4..78..;.=>.|
+00000040  40 c1 c2 43 c4 45 46 c7  c8 49 4a cb 4c cd ce 4f  |@..C.EF..IJ.L..O|
+00000050  d0 51 52 d3 54 d5 d6 57  58 d9 da 5b dc 5d 5e df  |.QR.T..WX..[.]^.|
+00000060  e0 61 62 e3 64 e5 e6 67  68 e9 ea 6b ec 6d 6e ef  |.ab.d..gh..k.mn.|
+00000070  70 f1 f2 73 f4 75 76 f7  f8 79 7a fb 7c fd fe 7f  |p..s.uv..yz.|...|
+00000080  80 01 02 83 04 85 86 07  08 89 8a 0b 8c 0d 0e 8f  |................|
+00000090  10 91 92 13 94 15 16 97  98 19 1a 9b 1c 9d 9e 1f  |................|
+000000a0  20 a1 a2 23 a4 25 26 a7  a8 29 2a ab 2c ad ae 2f  | ..#.%&..)*.,../|
+000000b0  b0 31 32 b3 34 b5 b6 37  38 b9 ba 3b bc 3d 3e bf  |.12.4..78..;.=>.|
+000000c0  40 c1 c2 43 c4 45 46 c7  c8 49 4a cb 4c cd ce 4f  |@..C.EF..IJ.L..O|
+000000d0  d0 51 52 d3 54 d5 d6 57  58 d9 da 5b dc 5d 5e df  |.QR.T..WX..[.]^.|
+000000e0  e0 61 62 e3 64 e5 e6 67  68 e9 ea 6b ec 6d 6e ef  |.ab.d..gh..k.mn.|
+000000f0  70 f1 f2 73 f4 75 76 f7  f8 79 7a fb 7c fd fe 7f  |p..s.uv..yz.|...|
+00000100
diff --git a/bin/dd/ref.parset b/bin/dd/ref.parset
new file mode 100644
index 000000000000..baa1c57163a2
--- /dev/null
+++ b/bin/dd/ref.parset
@@ -0,0 +1,18 @@
+$FreeBSD$
+00000000  80 81 82 83 84 85 86 87  88 89 8a 8b 8c 8d 8e 8f  |................|
+00000010  90 91 92 93 94 95 96 97  98 99 9a 9b 9c 9d 9e 9f  |................|
+00000020  a0 a1 a2 a3 a4 a5 a6 a7  a8 a9 aa ab ac ad ae af  |................|
+00000030  b0 b1 b2 b3 b4 b5 b6 b7  b8 b9 ba bb bc bd be bf  |................|
+00000040  c0 c1 c2 c3 c4 c5 c6 c7  c8 c9 ca cb cc cd ce cf  |................|
+00000050  d0 d1 d2 d3 d4 d5 d6 d7  d8 d9 da db dc dd de df  |................|
+00000060  e0 e1 e2 e3 e4 e5 e6 e7  e8 e9 ea eb ec ed ee ef  |................|
+00000070  f0 f1 f2 f3 f4 f5 f6 f7  f8 f9 fa fb fc fd fe ff  |................|
+00000080  80 81 82 83 84 85 86 87  88 89 8a 8b 8c 8d 8e 8f  |................|
+00000090  90 91 92 93 94 95 96 97  98 99 9a 9b 9c 9d 9e 9f  |................|
+000000a0  a0 a1 a2 a3 a4 a5 a6 a7  a8 a9 aa ab ac ad ae af  |................|
+000000b0  b0 b1 b2 b3 b4 b5 b6 b7  b8 b9 ba bb bc bd be bf  |................|
+000000c0  c0 c1 c2 c3 c4 c5 c6 c7  c8 c9 ca cb cc cd ce cf  |................|
+000000d0  d0 d1 d2 d3 d4 d5 d6 d7  d8 d9 da db dc dd de df  |................|
+000000e0  e0 e1 e2 e3 e4 e5 e6 e7  e8 e9 ea eb ec ed ee ef  |................|
+000000f0  f0 f1 f2 f3 f4 f5 f6 f7  f8 f9 fa fb fc fd fe ff  |................|
+00000100