Index: bin/dd/args.c
===================================================================
--- bin/dd/args.c
+++ bin/dd/args.c
@@ -317,6 +317,7 @@
 	u_int set, noset;
 	const u_char *ctab;
 } clist[] = {
+	/* ACHTUNG! keep this sorted in alphabetical order by conv.name */
 	{ "ascii",	C_ASCII,	C_EBCDIC,	e2a_POSIX },
 	{ "block",	C_BLOCK,	C_UNBLOCK,	NULL },
 	{ "ebcdic",	C_EBCDIC,	C_ASCII,	a2e_POSIX },
@@ -335,6 +336,7 @@
 	{ "sparse",	C_SPARSE,	0,		NULL },
 	{ "swab",	C_SWAB,		0,		NULL },
 	{ "sync",	C_SYNC,		0,		NULL },
+	{ "trim",	C_TRIM,		0,		NULL },
 	{ "ucase",	C_UCASE,	C_LCASE,	NULL },
 	{ "unblock",	C_UNBLOCK,	C_BLOCK,	NULL },
 };
Index: bin/dd/dd.h
===================================================================
--- bin/dd/dd.h
+++ bin/dd/dd.h
@@ -101,6 +101,7 @@
 #define	C_NOXFER	0x10000000
 #define	C_NOINFO	0x20000000
 #define	C_PROGRESS	0x40000000
+#define	C_TRIM		0x80000000
 
 #define	C_PARITY	(C_PAREVEN | C_PARODD | C_PARNONE | C_PARSET)
 
Index: bin/dd/dd.1
===================================================================
--- bin/dd/dd.1
+++ bin/dd/dd.1
@@ -308,6 +308,14 @@
 filling them with
 .Dv NUL Ns s ,
 resulting in a sparse file.
+.It Cm trim
+If one or more output blocks would consist solely of
+.Dv NUL
+bytes, trim (delete) corresponding block(s) of the output media by issuing
+appropriate
+.Xr ioctl 2
+instead of filling them with
+.Dv NUL Ns s .
 .It Cm swab
 Swap every pair of input bytes.
 If an input buffer has an odd number of bytes, the last byte will be
Index: bin/dd/dd.c
===================================================================
--- bin/dd/dd.c
+++ bin/dd/dd.c
@@ -507,6 +507,25 @@
 	}
 }
 
+static ssize_t
+dsk_trim(int d_fd, size_t size)
+{
+	off_t ioarg[2], npos;
+	int eval;
+
+	ioarg[0] = lseek(d_fd, (off_t)0, SEEK_CUR);
+	if (ioarg[0] < 0)
+		return (ioarg[0]);
+	ioarg[1] = size;
+	eval = ioctl(d_fd, DIOCGDELETE, ioarg);
+	if (eval != 0)
+		return (-1);
+	npos = lseek(d_fd, size, SEEK_CUR);
+	if (npos < 0)
+		return (npos);
+	return (npos - ioarg[0]);
+}
+
 void
 dd_out(int force)
 {
@@ -543,11 +562,11 @@
 		cnt = n;
 		do {
 			sparse = 0;
-			if (ddflags & C_SPARSE) {
+			if (ddflags & (C_SPARSE | C_TRIM)) {
 				/* Is buffer sparse? */
 				sparse = BISZERO(outp, cnt);
 			}
-			if (sparse && !force) {
+			if (sparse && !force && !(ddflags & C_TRIM)) {
 				pending += cnt;
 				nw = cnt;
 			} else {
@@ -565,8 +584,11 @@
 					pending = 0;
 				}
 				if (cnt) {
-					nw = write(out.fd, outp, cnt);
-					out.seek_offset = 0;
+                                        if (!sparse || !(ddflags & C_TRIM)) {
+						nw = write(out.fd, outp, cnt);
+					} else {
+						nw = dsk_trim(out.fd, cnt);
+					}
 				} else {
 					return;
 				}