diff --git a/sys/conf/NOTES b/sys/conf/NOTES
index c9a38ac0b89e..a6109c40ee5e 100644
--- a/sys/conf/NOTES
+++ b/sys/conf/NOTES
@@ -1038,6 +1038,9 @@ options 	LIBICONV
 # Size of the kernel message buffer.  Should be N * pagesize.
 options 	MSGBUF_SIZE=40960
 
+# Maximum size of a tty or pty input buffer.
+options 	TTYHOG=8193
+
 
 #####################################################################
 # HARDWARE DEVICE CONFIGURATION
diff --git a/sys/conf/options b/sys/conf/options
index e097828b9336..622bc14d99d8 100644
--- a/sys/conf/options
+++ b/sys/conf/options
@@ -141,6 +141,7 @@ SYSVSHM		opt_sysvipc.h
 VFS_AIO
 WLCACHE		opt_wavelan.h
 WLDEBUG		opt_wavelan.h
+TTYHOG		opt_tty.h
 
 # POSIX kernel options
 _KPOSIX_PRIORITY_SCHEDULING	opt_posix.h
diff --git a/sys/dev/dgb/dgb.c b/sys/dev/dgb/dgb.c
index e77e2f1ca196..ef6ba67e87b0 100644
--- a/sys/dev/dgb/dgb.c
+++ b/sys/dev/dgb/dgb.c
@@ -58,6 +58,7 @@
 
 #include "opt_compat.h"
 #include "opt_dgb.h"
+#include "opt_tty.h"
 
 #include "dgb.h"
 
diff --git a/sys/dev/nmdm/nmdm.c b/sys/dev/nmdm/nmdm.c
index 8f5af4636df2..7b5ec78ea521 100644
--- a/sys/dev/nmdm/nmdm.c
+++ b/sys/dev/nmdm/nmdm.c
@@ -39,6 +39,8 @@
  */
 
 #include "opt_compat.h"
+#include "opt_tty.h"
+
 #include <sys/param.h>
 #include <sys/systm.h>
 #if defined(COMPAT_43) || defined(COMPAT_SUNOS)
diff --git a/sys/dev/rc/rc.c b/sys/dev/rc/rc.c
index 07c0c5b913c7..aafb3fda68f3 100644
--- a/sys/dev/rc/rc.c
+++ b/sys/dev/rc/rc.c
@@ -35,6 +35,8 @@
 
 /*#define RCDEBUG*/
 
+#include "opt_tty.h"
+
 #include <sys/param.h>
 #include <sys/systm.h>
 #include <sys/bus.h>
diff --git a/sys/dev/si/si.c b/sys/dev/si/si.c
index d96266ce069e..ed79741a6c3f 100644
--- a/sys/dev/si/si.c
+++ b/sys/dev/si/si.c
@@ -41,6 +41,7 @@ static const char si_copyright1[] =  "@(#) Copyright (C) Specialix International
 
 #include "opt_compat.h"
 #include "opt_debug_si.h"
+#include "opt_tty.h"
 
 #include <sys/param.h>
 #include <sys/systm.h>
diff --git a/sys/i386/isa/istallion.c b/sys/i386/isa/istallion.c
index 9397d593e9cd..e94277299a2e 100644
--- a/sys/i386/isa/istallion.c
+++ b/sys/i386/isa/istallion.c
@@ -39,6 +39,7 @@
 /*****************************************************************************/
 
 #include "opt_compat.h"
+#include "opt_tty.h"
 
 #define	TTYDEFCHARS	1
 
diff --git a/sys/i386/isa/stallion.c b/sys/i386/isa/stallion.c
index 52185478ea3c..79cd0ff5b418 100644
--- a/sys/i386/isa/stallion.c
+++ b/sys/i386/isa/stallion.c
@@ -41,6 +41,7 @@
 #define	TTYDEFCHARS	1
 
 #include "opt_compat.h"
+#include "opt_tty.h"
 
 #include <sys/param.h>
 #include <sys/systm.h>
diff --git a/sys/kern/tty.c b/sys/kern/tty.c
index 8cbcb656b490..c0ad4a293a83 100644
--- a/sys/kern/tty.c
+++ b/sys/kern/tty.c
@@ -76,6 +76,7 @@
  */
 
 #include "opt_compat.h"
+#include "opt_tty.h"
 
 #include <sys/param.h>
 #include <sys/systm.h>
diff --git a/sys/kern/tty_pty.c b/sys/kern/tty_pty.c
index d3ba47ab959e..da408fc1e64e 100644
--- a/sys/kern/tty_pty.c
+++ b/sys/kern/tty_pty.c
@@ -39,6 +39,7 @@
  * (Actually two drivers, requiring two entries in 'cdevsw')
  */
 #include "opt_compat.h"
+#include "opt_tty.h"
 #include <sys/param.h>
 #include <sys/systm.h>
 #include <sys/lock.h>
diff --git a/sys/modules/nmdm/Makefile b/sys/modules/nmdm/Makefile
index d74b7d3d6ac7..4982c382a45f 100644
--- a/sys/modules/nmdm/Makefile
+++ b/sys/modules/nmdm/Makefile
@@ -4,9 +4,12 @@
 
 KMOD=	nmdm
 SRCS=	nmdm.c
-SRCS+=	opt_compat.h vnode_if.h
+SRCS+=	opt_compat.h opt_tty.h vnode_if.h
 
 opt_compat.h:
 	echo "#define COMPAT_43 1" >opt_compat.h
 
+opt_tty.h:
+	echo "#define TTYHOG 8192" >opt_tty.h
+
 .include <bsd.kmod.mk>
diff --git a/sys/modules/rc/Makefile b/sys/modules/rc/Makefile
index ffa6163afa83..9cc8f0306552 100644
--- a/sys/modules/rc/Makefile
+++ b/sys/modules/rc/Makefile
@@ -3,6 +3,9 @@
 .PATH: ${.CURDIR}/../../dev/rc
 
 KMOD=	rc
-SRCS=	rc.c device_if.h bus_if.h isa_if.h
+SRCS=	rc.c device_if.h bus_if.h isa_if.h opt_tty.h
+
+opt_tty.h:
+	echo "#define TTYHOG 8192" >opt_tty.h
 
 .include <bsd.kmod.mk>