diff --git a/commands/service/service.c b/commands/service/service.c
index e8c965a0b..50c38bd40 100644
--- a/commands/service/service.c
+++ b/commands/service/service.c
@@ -419,8 +419,8 @@ int main(int argc, char **argv)
   memset(&m, 0, sizeof(m));
   switch(request) {
   case RS_UPDATE:
-      m.RS_LU_STATE = req_lu_state;
-      m.RS_LU_PREPARE_MAXTIME = req_lu_maxtime;
+      m.m_rs_update.state = req_lu_state;
+      m.m_rs_update.prepare_maxtime = req_lu_maxtime;
       /* fall through */
   case RS_UP:
   case RS_EDIT:
@@ -462,14 +462,14 @@ int main(int argc, char **argv)
       assert(config.rs_start.rss_priority < NR_SCHED_QUEUES);
       assert(config.rs_start.rss_quantum > 0);
 
-      m.RS_CMD_ADDR = (char *) &config.rs_start;
+      m.m_rs_req.addr = (char *) &config.rs_start;
       break;
   case RS_DOWN:
   case RS_REFRESH:
   case RS_RESTART:
   case RS_CLONE:
-      m.RS_CMD_ADDR = req_label;
-      m.RS_CMD_LEN = strlen(req_label);
+      m.m_rs_req.addr = req_label;
+      m.m_rs_req.len = strlen(req_label);
       break;
   case RS_SHUTDOWN:
       break;
diff --git a/drivers/filter/driver.c b/drivers/filter/driver.c
index 2664df76a..e4cf2128f 100644
--- a/drivers/filter/driver.c
+++ b/drivers/filter/driver.c
@@ -427,8 +427,8 @@ static void restart_driver(int which, int tell_rs)
 	if (tell_rs) {
 		/* Tell RS to refresh or restart the driver */
 		msg.m_type = RS_REFRESH;
-		msg.RS_CMD_ADDR = driver[which].label;
-		msg.RS_CMD_LEN = strlen(driver[which].label);
+		msg.m_rs_req.addr = driver[which].label;
+		msg.m_rs_req.len = strlen(driver[which].label);
 
 #if DEBUG
 		printf("Filter: asking RS to refresh %s..\n",
diff --git a/include/minix/com.h b/include/minix/com.h
index bafc7ab9b..32e4d9df0 100644
--- a/include/minix/com.h
+++ b/include/minix/com.h
@@ -487,25 +487,6 @@
 #define RS_INIT 	(RS_RQ_BASE + 20)	/* service init message */
 #define RS_LU_PREPARE	(RS_RQ_BASE + 21)	/* prepare to update message */
 
-#  define RS_CMD_ADDR		m1_p1		/* command string */
-#  define RS_CMD_LEN		m1_i1		/* length of command */
-#  define RS_PERIOD 	        m1_i2		/* heartbeat period */
-#  define RS_DEV_MAJOR          m1_i3           /* major device number */
-
-#  define RS_ENDPOINT		m1_i1		/* endpoint number in reply */
-
-#  define RS_NAME		m1_p1		/* name */
-#  define RS_NAME_LEN		m1_i1		/* namelen */
-
-#  define RS_INIT_RESULT        m7_i1           /* init result */
-#  define RS_INIT_TYPE          m7_i2           /* init type */
-#  define RS_INIT_RPROCTAB_GID  m7_i3           /* init rproc table gid */
-#  define RS_INIT_OLD_ENDPOINT  m7_i4           /* init old endpoint */
-
-#  define RS_LU_RESULT          m1_i1           /* live update result */
-#  define RS_LU_STATE           m1_i2           /* state required to update */
-#  define RS_LU_PREPARE_MAXTIME m1_i3           /* the max time to prepare */
-
 /*===========================================================================*
  *                Messages for the Data Store Server			     *
  *===========================================================================*/
diff --git a/include/minix/ipc.h b/include/minix/ipc.h
index cddaaf94d..97e6bfeae 100644
--- a/include/minix/ipc.h
+++ b/include/minix/ipc.h
@@ -1880,6 +1880,33 @@ typedef struct {
 } mess_lsys_kern_vsafecopy;
 _ASSERT_MSG_SIZE(mess_lsys_kern_vsafecopy);
 
+typedef struct {
+	int		result;
+	int		type;
+	cp_grant_id_t	rproctab_gid;
+	endpoint_t	old_endpoint;
+	uint8_t padding[40];
+} mess_rs_init;
+_ASSERT_MSG_SIZE(mess_rs_init);
+
+typedef struct {
+	int		result;
+	int		state;
+	int		prepare_maxtime;
+	uint8_t padding[44];
+} mess_rs_update;
+_ASSERT_MSG_SIZE(mess_rs_update);
+
+typedef struct {
+	int		len;
+	int		name_len;
+	endpoint_t	endpoint;
+	void		*addr;
+	const char	*name;
+	uint8_t padding[36];
+} mess_rs_req;
+_ASSERT_MSG_SIZE(mess_rs_req);
+
 typedef struct {
 	endpoint_t m_source;		/* who sent the message */
 	int m_type;			/* what kind of message is it */
@@ -2120,6 +2147,9 @@ typedef struct {
 		mess_lsys_vm_unmap_phys	m_lsys_vm_unmap_phys;
 		mess_lsys_kern_safecopy	m_lsys_kern_safecopy;
 		mess_lsys_kern_vsafecopy m_lsys_kern_vsafecopy;
+		mess_rs_init		m_rs_init;
+		mess_rs_update		m_rs_update;
+		mess_rs_req		m_rs_req;
 
 		mess_vfs_lchardriver_cancel	m_vfs_lchardriver_cancel;
 		mess_vfs_lchardriver_openclose	m_vfs_lchardriver_openclose;
diff --git a/lib/libc/sys-minix/minix_rs.c b/lib/libc/sys-minix/minix_rs.c
index c0c0d38b5..71b73603b 100644
--- a/lib/libc/sys-minix/minix_rs.c
+++ b/lib/libc/sys-minix/minix_rs.c
@@ -28,11 +28,11 @@ int minix_rs_lookup(const char *name, endpoint_t *value)
 	len_key = strlen(name)+1;
 
 	memset(&m, 0, sizeof(m));
-	m.RS_NAME = (char *) __UNCONST(name);
-	m.RS_NAME_LEN = len_key;
+	m.m_rs_req.name = name;
+	m.m_rs_req.name_len = len_key;
 
 	if (_syscall(RS_PROC_NR, RS_LOOKUP, &m) != -1) {
-		*value = m.RS_ENDPOINT;
+		*value = m.m_rs_req.endpoint;
 		return OK;
 	}
 
diff --git a/lib/libsys/sef_init.c b/lib/libsys/sef_init.c
index db1de9031..dae1935ef 100644
--- a/lib/libsys/sef_init.c
+++ b/lib/libsys/sef_init.c
@@ -66,7 +66,7 @@ static int process_init(int type, sef_init_info_t *info)
   memset(&m, 0, sizeof(m));
   m.m_source = sef_self_endpoint;
   m.m_type = RS_INIT;
-  m.RS_INIT_RESULT = result;
+  m.m_rs_init.result = result;
   r = sef_cbs.sef_cb_init_response(&m);
 
   return r;
@@ -111,10 +111,10 @@ int do_sef_init_request(message *m_ptr)
   sef_init_info_t info;
 
   /* Get init parameters from message. */
-  type = m_ptr->RS_INIT_TYPE;
-  info.rproctab_gid = m_ptr->RS_INIT_RPROCTAB_GID;
+  type = m_ptr->m_rs_init.type;
+  info.rproctab_gid = m_ptr->m_rs_init.rproctab_gid;
   info.endpoint = sef_self_endpoint;
-  info.old_endpoint = m_ptr->RS_INIT_OLD_ENDPOINT;
+  info.old_endpoint = m_ptr->m_rs_init.old_endpoint;
 
   /* Peform initialization. */
   r = process_init(type, &info);
diff --git a/lib/libsys/sef_liveupdate.c b/lib/libsys/sef_liveupdate.c
index 691a6c936..f1834b77f 100644
--- a/lib/libsys/sef_liveupdate.c
+++ b/lib/libsys/sef_liveupdate.c
@@ -87,7 +87,7 @@ int do_sef_lu_request(message *m_ptr)
 
   sef_lu_debug_cycle = 0;
   old_state = sef_lu_state;
-  state = m_ptr->RS_LU_STATE;
+  state = m_ptr->m_rs_update.state;
 
   /* Deal with prepare cancel requests first. */
   is_valid_state = (state == SEF_LU_STATE_NULL);
@@ -151,8 +151,8 @@ static void sef_lu_ready(int result)
    */
   m.m_source = sef_self_endpoint;
   m.m_type = RS_LU_PREPARE;
-  m.RS_LU_STATE = sef_lu_state;
-  m.RS_LU_RESULT = result;
+  m.m_rs_update.state = sef_lu_state;
+  m.m_rs_update.result = result;
   r = sef_cbs.sef_cb_lu_response(&m);
 
 #if SEF_LU_DEBUG
diff --git a/servers/rs/main.c b/servers/rs/main.c
index adcb8df4d..5c5cd154f 100644
--- a/servers/rs/main.c
+++ b/servers/rs/main.c
@@ -646,7 +646,7 @@ endpoint_t endpoint;
   if(m.m_type != RS_INIT) {
       panic("unexpected reply from service: %d", m.m_source);
   }
-  result = m.RS_INIT_RESULT;
+  result = m.m_rs_init.result;
   rp = rproc_ptr[_ENDPOINT_P(m.m_source)];
 
   /* Check result. */
diff --git a/servers/rs/manager.c b/servers/rs/manager.c
index 689360b6d..0cadf95c0 100644
--- a/servers/rs/manager.c
+++ b/servers/rs/manager.c
@@ -257,7 +257,7 @@ void update_period(message *m_ptr)
 
       /* Prepare cancel request. */
       m.m_type = RS_LU_PREPARE;
-      m.RS_LU_STATE = SEF_LU_STATE_NULL;
+      m.m_rs_update.state = SEF_LU_STATE_NULL;
       if(rpub->endpoint == RS_PROC_NR) {
           /* RS can process the request directly. */
           do_sef_lu_request(&m);
diff --git a/servers/rs/request.c b/servers/rs/request.c
index 5345e9c98..c951d9454 100755
--- a/servers/rs/request.c
+++ b/servers/rs/request.c
@@ -35,7 +35,7 @@ message *m_ptr;					/* request message pointer */
   rpub = rp->r_pub;
 
   /* Copy the request structure. */
-  r = copy_rs_start(m_ptr->m_source, m_ptr->RS_CMD_ADDR, &rs_start);
+  r = copy_rs_start(m_ptr->m_source, m_ptr->m_rs_req.addr, &rs_start);
   if (r != OK) {
       return r;
   }
@@ -93,8 +93,8 @@ int do_down(message *m_ptr)
   char label[RS_MAX_LABEL_LEN];
 
   /* Copy label. */
-  s = copy_label(m_ptr->m_source, m_ptr->RS_CMD_ADDR,
-      m_ptr->RS_CMD_LEN, label, sizeof(label));
+  s = copy_label(m_ptr->m_source, m_ptr->m_rs_req.addr,
+      m_ptr->m_rs_req.len, label, sizeof(label));
   if(s != OK) {
       return s;
   }
@@ -143,8 +143,8 @@ int do_restart(message *m_ptr)
   char script[MAX_SCRIPT_LEN];
 
   /* Copy label. */
-  s = copy_label(m_ptr->m_source, m_ptr->RS_CMD_ADDR,
-      m_ptr->RS_CMD_LEN, label, sizeof(label));
+  s = copy_label(m_ptr->m_source, m_ptr->m_rs_req.addr,
+      m_ptr->m_rs_req.len, label, sizeof(label));
   if(s != OK) {
       return s;
   }
@@ -191,8 +191,8 @@ int do_clone(message *m_ptr)
   char label[RS_MAX_LABEL_LEN];
 
   /* Copy label. */
-  s = copy_label(m_ptr->m_source, m_ptr->RS_CMD_ADDR,
-      m_ptr->RS_CMD_LEN, label, sizeof(label));
+  s = copy_label(m_ptr->m_source, m_ptr->m_rs_req.addr,
+      m_ptr->m_rs_req.len, label, sizeof(label));
   if(s != OK) {
       return s;
   }
@@ -237,7 +237,7 @@ int do_edit(message *m_ptr)
   char label[RS_MAX_LABEL_LEN];
 
   /* Copy the request structure. */
-  r = copy_rs_start(m_ptr->m_source, m_ptr->RS_CMD_ADDR, &rs_start);
+  r = copy_rs_start(m_ptr->m_source, m_ptr->m_rs_req.addr, &rs_start);
   if (r != OK) {
       return r;
   }
@@ -327,8 +327,8 @@ int do_refresh(message *m_ptr)
   char label[RS_MAX_LABEL_LEN];
 
   /* Copy label. */
-  s = copy_label(m_ptr->m_source, m_ptr->RS_CMD_ADDR,
-      m_ptr->RS_CMD_LEN, label, sizeof(label));
+  s = copy_label(m_ptr->m_source, m_ptr->m_rs_req.addr,
+      m_ptr->m_rs_req.len, label, sizeof(label));
   if(s != OK) {
       return s;
   }
@@ -398,7 +398,7 @@ int do_init_ready(message *m_ptr)
 
   is_rs = (m_ptr->m_source == RS_PROC_NR);
   who_p = _ENDPOINT_P(m_ptr->m_source);
-  result = m_ptr->RS_INIT_RESULT;
+  result = m_ptr->m_rs_init.result;
 
   /* Check for RS failing initialization first. */
   if(is_rs && result != OK) {
@@ -490,7 +490,7 @@ int do_update(message *m_ptr)
   int prepare_maxtime;
 
   /* Copy the request structure. */
-  s = copy_rs_start(m_ptr->m_source, m_ptr->RS_CMD_ADDR, &rs_start);
+  s = copy_rs_start(m_ptr->m_source, m_ptr->m_rs_req.addr, &rs_start);
   if (s != OK) {
       return s;
   }
@@ -522,13 +522,13 @@ int do_update(message *m_ptr)
       return s;
 
   /* Retrieve live update state. */
-  lu_state = m_ptr->RS_LU_STATE;
+  lu_state = m_ptr->m_rs_update.state;
   if(lu_state == SEF_LU_STATE_NULL) {
       return(EINVAL);
   }
 
   /* Retrieve prepare max time. */
-  prepare_maxtime = m_ptr->RS_LU_PREPARE_MAXTIME;
+  prepare_maxtime = m_ptr->m_rs_update.prepare_maxtime;
   if(prepare_maxtime) {
       if(prepare_maxtime < 0 || prepare_maxtime > RS_MAX_PREPARE_MAXTIME) {
           return(EINVAL);
@@ -658,7 +658,7 @@ int do_upd_ready(message *m_ptr)
 
   who_p = _ENDPOINT_P(m_ptr->m_source);
   rp = rproc_ptr[who_p];
-  result = m_ptr->RS_LU_RESULT;
+  result = m_ptr->m_rs_update.result;
   is_rs = (m_ptr->m_source == RS_PROC_NR);
 
   /* Make sure the originating service was requested to prepare for update. */
@@ -906,14 +906,14 @@ message *m_ptr;
 	struct rproc *rrp;
 	struct rprocpub *rrpub;
 
-	len = m_ptr->RS_NAME_LEN;
+	len = m_ptr->m_rs_req.name_len;
 
 	if(len < 2 || len >= sizeof(namebuf)) {
 		printf("RS: len too weird (%d)\n", len);
 		return EINVAL;
 	}
 
-	if((r=sys_datacopy(m_ptr->m_source, (vir_bytes) m_ptr->RS_NAME,
+	if((r=sys_datacopy(m_ptr->m_source, (vir_bytes) m_ptr->m_rs_req.name,
 		SELF, (vir_bytes) namebuf, len)) != OK) {
 		printf("RS: name copy failed\n");
 		return r;
@@ -927,7 +927,7 @@ message *m_ptr;
 		return ESRCH;
 	}
 	rrpub = rrp->r_pub;
-	m_ptr->RS_ENDPOINT = rrpub->endpoint;
+	m_ptr->m_rs_req.endpoint = rrpub->endpoint;
 
 	return OK;
 }
diff --git a/servers/rs/utility.c b/servers/rs/utility.c
index 6a40c7a1a..62f3dd14c 100644
--- a/servers/rs/utility.c
+++ b/servers/rs/utility.c
@@ -43,9 +43,9 @@ int type;					/* type of initialization */
 
   /* Send initialization message. */
   m.m_type = RS_INIT;
-  m.RS_INIT_TYPE = type;
-  m.RS_INIT_RPROCTAB_GID = rinit.rproctab_gid;
-  m.RS_INIT_OLD_ENDPOINT = old_endpoint;
+  m.m_rs_init.type = type;
+  m.m_rs_init.rproctab_gid = rinit.rproctab_gid;
+  m.m_rs_init.old_endpoint = old_endpoint;
   r = asynsend(rpub->endpoint, &m);
 
   return r;
diff --git a/servers/vm/main.c b/servers/vm/main.c
index cc738ab94..73cf0e2c4 100644
--- a/servers/vm/main.c
+++ b/servers/vm/main.c
@@ -177,7 +177,7 @@ static int do_rs_init(message *m)
 	static struct rprocpub rprocpub[NR_BOOT_PROCS];
 
 	/* Map all the services in the boot image. */
-	if((s = sys_safecopyfrom(RS_PROC_NR, m->RS_INIT_RPROCTAB_GID, 0,
+	if((s = sys_safecopyfrom(RS_PROC_NR, m->m_rs_init.rproctab_gid, 0,
 		(vir_bytes) rprocpub, sizeof(rprocpub))) != OK) {
 		panic("vm: sys_safecopyfrom (rs) failed: %d", s);
 	}
@@ -191,7 +191,7 @@ static int do_rs_init(message *m)
 	}
 
 	/* RS expects this response that it then again wants to reply to: */
-	m->RS_INIT_RESULT = OK;
+	m->m_rs_init.result = OK;
 	ipc_sendrec(RS_PROC_NR, m);
 
 	return(SUSPEND);