diff --git a/include/minix/com.h b/include/minix/com.h
index c24df0c70..8c5c1ad0b 100644
--- a/include/minix/com.h
+++ b/include/minix/com.h
@@ -701,75 +701,78 @@
  *                Messages used between PM and VFS			     *
  *===========================================================================*/
 
-#define PM_RQ_BASE	0x900
-#define PM_RS_BASE	0x980
+#define VFS_PM_RQ_BASE	0x900
+#define VFS_PM_RS_BASE	0x980
 
-/* Requests from PM to VFS */
-#define PM_INIT		(PM_RQ_BASE + 0)	/* Process table exchange */
-#define PM_SETUID	(PM_RQ_BASE + 1)	/* Set new user ID */
-#define PM_SETGID	(PM_RQ_BASE + 2)	/* Set group ID */
-#define PM_SETSID	(PM_RQ_BASE + 3)	/* Set session leader */
-#define PM_EXIT		(PM_RQ_BASE + 4)	/* Process exits */
-#define PM_DUMPCORE	(PM_RQ_BASE + 5)	/* Process is to dump core */
-#define PM_EXEC		(PM_RQ_BASE + 6)	/* Forwarded exec call */
-#define PM_FORK		(PM_RQ_BASE + 7)	/* Newly forked process */
-#define PM_SRV_FORK	(PM_RQ_BASE + 8)	/* fork for system services */
-#define PM_UNPAUSE	(PM_RQ_BASE + 9)	/* Interrupt process call */
-#define PM_REBOOT	(PM_RQ_BASE + 10)	/* System reboot */
-#define PM_SETGROUPS	(PM_RQ_BASE + 11)	/* Tell VFS about setgroups */
+#define IS_VFS_PM_RQ(type) (((type) & ~0x7f) == VFS_PM_RQ_BASE)
+#define IS_VFS_PM_RS(type) (((type) & ~0x7f) == VFS_PM_RS_BASE)
+
+/* Requests from PM to VFS. */
+#define VFS_PM_INIT	(VFS_PM_RQ_BASE + 0)	/* Process table exchange */
+#define VFS_PM_SETUID	(VFS_PM_RQ_BASE + 1)	/* Set new user ID */
+#define VFS_PM_SETGID	(VFS_PM_RQ_BASE + 2)	/* Set group ID */
+#define VFS_PM_SETSID	(VFS_PM_RQ_BASE + 3)	/* Set session leader */
+#define VFS_PM_EXIT	(VFS_PM_RQ_BASE + 4)	/* Process exits */
+#define VFS_PM_DUMPCORE	(VFS_PM_RQ_BASE + 5)	/* Process is to dump core */
+#define VFS_PM_EXEC	(VFS_PM_RQ_BASE + 6)	/* Forwarded exec call */
+#define VFS_PM_FORK	(VFS_PM_RQ_BASE + 7)	/* Newly forked process */
+#define VFS_PM_SRV_FORK	(VFS_PM_RQ_BASE + 8)	/* fork for system services */
+#define VFS_PM_UNPAUSE	(VFS_PM_RQ_BASE + 9)	/* Interrupt process call */
+#define VFS_PM_REBOOT	(VFS_PM_RQ_BASE + 10)	/* System reboot */
+#define VFS_PM_SETGROUPS	(VFS_PM_RQ_BASE + 11)	/* Set groups */
 
 /* Replies from VFS to PM */
-#define PM_SETUID_REPLY	(PM_RS_BASE + 1)
-#define PM_SETGID_REPLY	(PM_RS_BASE + 2)
-#define PM_SETSID_REPLY	(PM_RS_BASE + 3)
-#define PM_EXIT_REPLY	(PM_RS_BASE + 4)
-#define PM_CORE_REPLY	(PM_RS_BASE + 5)
-#define PM_EXEC_REPLY	(PM_RS_BASE + 6)
-#define PM_FORK_REPLY	(PM_RS_BASE + 7)
-#define PM_SRV_FORK_REPLY	(PM_RS_BASE + 8)
-#define PM_UNPAUSE_REPLY	(PM_RS_BASE + 9)
-#define PM_REBOOT_REPLY	(PM_RS_BASE + 10)
-#define PM_SETGROUPS_REPLY	(PM_RS_BASE + 11)
+#define VFS_PM_SETUID_REPLY	(VFS_PM_RS_BASE + 1)
+#define VFS_PM_SETGID_REPLY	(VFS_PM_RS_BASE + 2)
+#define VFS_PM_SETSID_REPLY	(VFS_PM_RS_BASE + 3)
+#define VFS_PM_EXIT_REPLY	(VFS_PM_RS_BASE + 4)
+#define VFS_PM_CORE_REPLY	(VFS_PM_RS_BASE + 5)
+#define VFS_PM_EXEC_REPLY	(VFS_PM_RS_BASE + 6)
+#define VFS_PM_FORK_REPLY	(VFS_PM_RS_BASE + 7)
+#define VFS_PM_SRV_FORK_REPLY	(VFS_PM_RS_BASE + 8)
+#define VFS_PM_UNPAUSE_REPLY	(VFS_PM_RS_BASE + 9)
+#define VFS_PM_REBOOT_REPLY	(VFS_PM_RS_BASE + 10)
+#define VFS_PM_SETGROUPS_REPLY	(VFS_PM_RS_BASE + 11)
 
 /* Standard parameters for all requests and replies, except PM_REBOOT */
-#  define PM_PROC		m7_i1	/* process endpoint */
+#  define VFS_PM_ENDPT		m7_i1	/* process endpoint */
 
 /* Additional parameters for PM_INIT */
-#  define PM_SLOT		m7_i2	/* process slot number */
-#  define PM_PID		m7_i3	/* process pid */
+#  define VFS_PM_SLOT		m7_i2	/* process slot number */
+#  define VFS_PM_PID		m7_i3	/* process pid */
 
 /* Additional parameters for PM_SETUID and PM_SETGID */
-#  define PM_EID		m7_i2	/* effective user/group id */
-#  define PM_RID		m7_i3	/* real user/group id */
+#  define VFS_PM_EID		m7_i2	/* effective user/group id */
+#  define VFS_PM_RID		m7_i3	/* real user/group id */
 
 /* Additional parameter for PM_SETGROUPS */
-#  define PM_GROUP_NO		m7_i2	/* number of groups */
-#  define PM_GROUP_ADDR		m7_p1	/* struct holding group data */
+#  define VFS_PM_GROUP_NO	m7_i2	/* number of groups */
+#  define VFS_PM_GROUP_ADDR	m7_p1	/* struct holding group data */
 
 /* Additional parameters for PM_EXEC */
-#  define PM_PATH		m7_p1	/* executable */
-#  define PM_PATH_LEN		m7_i2	/* length of path including
+#  define VFS_PM_PATH		m7_p1	/* executable */
+#  define VFS_PM_PATH_LEN	m7_i2	/* length of path including
 					 * terminating null character
 					 */
-#  define PM_FRAME		m7_p2	/* arguments and environment */
-#  define PM_FRAME_LEN		m7_i3	/* size of frame */
-#  define PM_EXECFLAGS		m7_i4	/* PMEXEC_FLAGS */
-#  define PM_PS_STR		m7_i5	/* ps_strings pointer */
+#  define VFS_PM_FRAME		m7_p2	/* arguments and environment */
+#  define VFS_PM_FRAME_LEN	m7_i3	/* size of frame */
+#  define VFS_PM_EXECFLAGS	m7_i4	/* PMEXEC_FLAGS */
+#  define VFS_PM_PS_STR		m7_i5	/* ps_strings pointer */
 
 /* Additional parameters for PM_EXEC_REPLY and PM_CORE_REPLY */
-#  define PM_STATUS		m7_i2	/* OK or failure */
-#  define PM_PC			m7_p1	/* program counter */
-#  define PM_NEWSP		m7_p2	/* possibly-changed stack ptr */
-#  define PM_NEWPS_STR		m7_i5	/* possibly-changed ps_strings ptr */
+#  define VFS_PM_STATUS		m7_i2	/* OK or failure */
+#  define VFS_PM_PC		m7_p1	/* program counter */
+#  define VFS_PM_NEWSP		m7_p2	/* possibly-changed stack ptr */
+#  define VFS_PM_NEWPS_STR	m7_i5	/* possibly-changed ps_strings ptr */
 
 /* Additional parameters for PM_FORK and PM_SRV_FORK */
-#  define PM_PPROC		m7_i2	/* parent process endpoint */
-#  define PM_CPID		m7_i3	/* child pid */
-#  define PM_REUID		m7_i4	/* real and effective uid */
-#  define PM_REGID		m7_i5	/* real and effective gid */
+#  define VFS_PM_PENDPT		m7_i2	/* parent process endpoint */
+#  define VFS_PM_CPID		m7_i3	/* child pid */
+#  define VFS_PM_REUID		m7_i4	/* real and effective uid */
+#  define VFS_PM_REGID		m7_i5	/* real and effective gid */
 
 /* Additional parameters for PM_DUMPCORE */
-#  define PM_TERM_SIG		m7_i2	/* process's termination signal */
+#  define VFS_PM_TERM_SIG	m7_i2	/* process's termination signal */
 
 /* Parameters for the EXEC_NEWMEM call */
 #define EXC_NM_PROC	m1_i1		/* process that needs new map */
diff --git a/servers/pm/alarm.c b/servers/pm/alarm.c
index c35ed62c2..94758644f 100644
--- a/servers/pm/alarm.c
+++ b/servers/pm/alarm.c
@@ -11,7 +11,6 @@
 #include "pm.h"
 #include <signal.h>
 #include <sys/time.h>
-#include <string.h>
 #include <minix/com.h>
 #include "mproc.h"
 #include "param.h"
diff --git a/servers/pm/exec.c b/servers/pm/exec.c
index 3fa75e889..a62b9ba39 100644
--- a/servers/pm/exec.c
+++ b/servers/pm/exec.c
@@ -24,7 +24,6 @@
 #include <minix/com.h>
 #include <minix/vm.h>
 #include <signal.h>
-#include <string.h>
 #include <libexec.h>
 #include <sys/ptrace.h>
 #include "mproc.h"
@@ -41,14 +40,15 @@ int do_exec()
 	message m;
 
 	/* Forward call to VFS */
-	m.m_type = PM_EXEC;
-	m.PM_PROC = mp->mp_endpoint;
-	m.PM_PATH = m_in.exec_name;
-	m.PM_PATH_LEN = m_in.exec_len;
-	m.PM_FRAME = m_in.frame_ptr;
-	m.PM_FRAME_LEN = m_in.msg_frame_len;
-	m.PM_EXECFLAGS = m_in.PMEXEC_FLAGS;
-	m.PM_PS_STR = (vir_bytes)m_in.m1_p4; /* ps_strings pointer into the frame. */
+	memset(&m, 0, sizeof(m));
+	m.m_type = VFS_PM_EXEC;
+	m.VFS_PM_ENDPT = mp->mp_endpoint;
+	m.VFS_PM_PATH = m_in.exec_name;
+	m.VFS_PM_PATH_LEN = m_in.exec_len;
+	m.VFS_PM_FRAME = m_in.frame_ptr;
+	m.VFS_PM_FRAME_LEN = m_in.msg_frame_len;
+	m.VFS_PM_EXECFLAGS = m_in.PMEXEC_FLAGS;
+	m.VFS_PM_PS_STR = (vir_bytes) m_in.m1_p4; /* strings ptr into frame */
 
 	tell_vfs(mp, &m);
 
diff --git a/servers/pm/forkexit.c b/servers/pm/forkexit.c
index 239766d6a..f697c8bc0 100644
--- a/servers/pm/forkexit.c
+++ b/servers/pm/forkexit.c
@@ -113,12 +113,13 @@ int do_fork()
   new_pid = get_free_pid();
   rmc->mp_pid = new_pid;	/* assign pid to child */
 
-  m.m_type = PM_FORK;
-  m.PM_PROC = rmc->mp_endpoint;
-  m.PM_PPROC = rmp->mp_endpoint;
-  m.PM_CPID = rmc->mp_pid;
-  m.PM_REUID = -1;	/* Not used by PM_FORK */
-  m.PM_REGID = -1;	/* Not used by PM_FORK */
+  memset(&m, 0, sizeof(m));
+  m.m_type = VFS_PM_FORK;
+  m.VFS_PM_ENDPT = rmc->mp_endpoint;
+  m.VFS_PM_PENDPT = rmp->mp_endpoint;
+  m.VFS_PM_CPID = rmc->mp_pid;
+  m.VFS_PM_REUID = -1;	/* Not used by VFS_PM_FORK */
+  m.VFS_PM_REGID = -1;	/* Not used by VFS_PM_FORK */
 
   tell_vfs(rmc, &m);
 
@@ -204,12 +205,13 @@ int do_srv_fork()
   new_pid = get_free_pid();
   rmc->mp_pid = new_pid;	/* assign pid to child */
 
-  m.m_type = PM_SRV_FORK;
-  m.PM_PROC = rmc->mp_endpoint;
-  m.PM_PPROC = rmp->mp_endpoint;
-  m.PM_CPID = rmc->mp_pid;
-  m.PM_REUID = m_in.m1_i1;
-  m.PM_REGID = m_in.m1_i2;
+  memset(&m, 0, sizeof(m));
+  m.m_type = VFS_PM_SRV_FORK;
+  m.VFS_PM_ENDPT = rmc->mp_endpoint;
+  m.VFS_PM_PENDPT = rmp->mp_endpoint;
+  m.VFS_PM_CPID = rmc->mp_pid;
+  m.VFS_PM_REUID = m_in.m1_i1;
+  m.VFS_PM_REGID = m_in.m1_i2;
 
   tell_vfs(rmc, &m);
 
@@ -321,12 +323,13 @@ int dump_core;			/* flag indicating whether to dump core */
   }
 
   /* Tell VFS about the exiting process. */
-  m.m_type = dump_core ? PM_DUMPCORE : PM_EXIT;
-  m.PM_PROC = rmp->mp_endpoint;
+  memset(&m, 0, sizeof(m));
+  m.m_type = dump_core ? VFS_PM_DUMPCORE : VFS_PM_EXIT;
+  m.VFS_PM_ENDPT = rmp->mp_endpoint;
 
   if (dump_core) {
-	m.PM_TERM_SIG = rmp->mp_sigstatus;
-	m.PM_PATH = rmp->mp_name;
+	m.VFS_PM_TERM_SIG = rmp->mp_sigstatus;
+	m.VFS_PM_PATH = rmp->mp_name;
   }
 
   tell_vfs(rmp, &m);
diff --git a/servers/pm/getset.c b/servers/pm/getset.c
index 4e7f757c1..f97c90936 100644
--- a/servers/pm/getset.c
+++ b/servers/pm/getset.c
@@ -102,6 +102,8 @@ int do_set()
   int r, i;
   int ngroups;
 
+  memset(&m, 0, sizeof(m));
+
   switch(call_nr) {
 	case SETUID:
 	case SETEUID:
@@ -111,10 +113,10 @@ int do_set()
 		if(call_nr == SETUID) rmp->mp_realuid = (uid_t) m_in.usr_id;
 		rmp->mp_effuid = (uid_t) m_in.usr_id;
 
-		m.m_type = PM_SETUID;
-		m.PM_PROC = rmp->mp_endpoint;
-		m.PM_EID = rmp->mp_effuid;
-		m.PM_RID = rmp->mp_realuid;
+		m.m_type = VFS_PM_SETUID;
+		m.VFS_PM_ENDPT = rmp->mp_endpoint;
+		m.VFS_PM_EID = rmp->mp_effuid;
+		m.VFS_PM_RID = rmp->mp_realuid;
 
 		break;
 
@@ -126,10 +128,10 @@ int do_set()
 		if(call_nr == SETGID) rmp->mp_realgid = (gid_t) m_in.grp_id;
 		rmp->mp_effgid = (gid_t) m_in.grp_id;
 
-		m.m_type = PM_SETGID;
-		m.PM_PROC = rmp->mp_endpoint;
-		m.PM_EID = rmp->mp_effgid;
-		m.PM_RID = rmp->mp_realgid;
+		m.m_type = VFS_PM_SETGID;
+		m.VFS_PM_ENDPT = rmp->mp_endpoint;
+		m.VFS_PM_EID = rmp->mp_effgid;
+		m.VFS_PM_RID = rmp->mp_realgid;
 
 		break;
 	case SETGROUPS:
@@ -159,18 +161,18 @@ int do_set()
 		}
 		rmp->mp_ngroups = ngroups;
 
-		m.m_type = PM_SETGROUPS;
-		m.PM_PROC = rmp->mp_endpoint;
-		m.PM_GROUP_NO = rmp->mp_ngroups;
-		m.PM_GROUP_ADDR = (char *) rmp->mp_sgroups;
+		m.m_type = VFS_PM_SETGROUPS;
+		m.VFS_PM_ENDPT = rmp->mp_endpoint;
+		m.VFS_PM_GROUP_NO = rmp->mp_ngroups;
+		m.VFS_PM_GROUP_ADDR = (char *) rmp->mp_sgroups;
 
 		break;
 	case SETSID:
 		if (rmp->mp_procgrp == rmp->mp_pid) return(EPERM);
 		rmp->mp_procgrp = rmp->mp_pid;
 
-		m.m_type = PM_SETSID;
-		m.PM_PROC = rmp->mp_endpoint;
+		m.m_type = VFS_PM_SETSID;
+		m.VFS_PM_ENDPT = rmp->mp_endpoint;
 
 		break;
 
diff --git a/servers/pm/main.c b/servers/pm/main.c
index 6f1e03810..3f05cee68 100644
--- a/servers/pm/main.c
+++ b/servers/pm/main.c
@@ -23,7 +23,6 @@
 #include <fcntl.h>
 #include <sys/resource.h>
 #include <sys/utsname.h>
-#include <string.h>
 #include <machine/archtypes.h>
 #include <env.h>
 #include <assert.h>
@@ -54,60 +53,38 @@ static int sef_cb_init_fresh(int type, sef_init_info_t *info);
 int main()
 {
 /* Main routine of the process manager. */
-  int result;
+  int ipc_status, result;
 
   /* SEF local startup. */
   sef_local_startup();
 
   /* This is PM's main loop-  get work and do it, forever and forever. */
   while (TRUE) {
-	  int ipc_status;
-
-	  /* Wait for the next message and extract useful information from it. */
-	  if (sef_receive_status(ANY, &m_in, &ipc_status) != OK)
-		  panic("PM sef_receive_status error");
-	  who_e = m_in.m_source;	/* who sent the message */
-	  if(pm_isokendpt(who_e, &who_p) != OK)
-		  panic("PM got message from invalid endpoint: %d", who_e);
-	  call_nr = m_in.m_type;	/* system call number */
-
-	  /* Process slot of caller. Misuse PM's own process slot if the kernel is
-	   * calling. This can happen in case of synchronous alarms (CLOCK) or or
-	   * event like pending kernel signals (SYSTEM).
-	   */
-	  mp = &mproc[who_p < 0 ? PM_PROC_NR : who_p];
-	  if(who_p >= 0 && mp->mp_endpoint != who_e) {
-		  panic("PM endpoint number out of sync with source: %d",
-				  			mp->mp_endpoint);
-	  }
-
-	/* Drop delayed calls from exiting processes. */
-	if (mp->mp_flags & EXITING)
-		continue;
+	/* Wait for the next message. */
+	if (sef_receive_status(ANY, &m_in, &ipc_status) != OK)
+		panic("PM sef_receive_status error");
 
 	/* Check for system notifications first. Special cases. */
 	if (is_ipc_notify(ipc_status)) {
-		if (who_p == CLOCK) {
+		if (_ENDPOINT_P(m_in.m_source) == CLOCK)
 			expire_timers(m_in.NOTIFY_TIMESTAMP);
-		}
 
 		/* done, continue */
 		continue;
 	}
 
-	switch(call_nr)
-	{
-	case PM_SETUID_REPLY:
-	case PM_SETGID_REPLY:
-	case PM_SETSID_REPLY:
-	case PM_EXEC_REPLY:
-	case PM_EXIT_REPLY:
-	case PM_CORE_REPLY:
-	case PM_FORK_REPLY:
-	case PM_SRV_FORK_REPLY:
-	case PM_UNPAUSE_REPLY:
-	case PM_REBOOT_REPLY:
-	case PM_SETGROUPS_REPLY:
+	/* Extract useful information from the message. */
+	who_e = m_in.m_source;	/* who sent the message */
+	if (pm_isokendpt(who_e, &who_p) != OK)
+		panic("PM got message from invalid endpoint: %d", who_e);
+	mp = &mproc[who_p];	/* process slot of caller */
+	call_nr = m_in.m_type;	/* system call number */
+
+	/* Drop delayed calls from exiting processes. */
+	if (mp->mp_flags & EXITING)
+		continue;
+
+	if (IS_VFS_PM_RS(call_nr)) {
 		if (who_e == VFS_PROC_NR)
 		{
 			handle_vfs_reply();
@@ -115,11 +92,8 @@ int main()
 		}
 		else
 			result= ENOSYS;
-		break;
-	default:
-		/* Else, if the system call number is valid, perform the
-		 * call.
-		 */
+	} else {
+		/* If the system call number is valid, perform the call. */
 		if ((unsigned) call_nr >= NCALLS) {
 			result = ENOSYS;
 		} else {
@@ -130,7 +104,6 @@ int main()
 			result = (*call_vec[call_nr])();
 
 		}
-		break;
 	}
 
 	/* Send reply. */
@@ -259,17 +232,20 @@ static int sef_cb_init_fresh(int UNUSED(type), sef_init_info_t *UNUSED(info))
 		rmp->mp_endpoint = ip->endpoint;
 
 		/* Tell VFS about this system process. */
-		mess.m_type = PM_INIT;
-		mess.PM_SLOT = ip->proc_nr;
-		mess.PM_PID = rmp->mp_pid;
-		mess.PM_PROC = rmp->mp_endpoint;
+		memset(&mess, 0, sizeof(mess));
+		mess.m_type = VFS_PM_INIT;
+		mess.VFS_PM_SLOT = ip->proc_nr;
+		mess.VFS_PM_PID = rmp->mp_pid;
+		mess.VFS_PM_ENDPT = rmp->mp_endpoint;
   		if (OK != (s=send(VFS_PROC_NR, &mess)))
 			panic("can't sync up with VFS: %d", s);
   	}
   }
 
   /* Tell VFS that no more system processes follow and synchronize. */
-  mess.PR_ENDPT = NONE;
+  memset(&mess, 0, sizeof(mess));
+  mess.m_type = VFS_PM_INIT;
+  mess.VFS_PM_ENDPT = NONE;
   if (sendrec(VFS_PROC_NR, &mess) != OK || mess.m_type != OK)
 	panic("can't sync up with VFS");
 
@@ -338,10 +314,10 @@ static void handle_vfs_reply()
   endpoint_t proc_e;
   int r, proc_n, new_parent;
 
-  /* PM_REBOOT is the only request not associated with a process.
+  /* VFS_PM_REBOOT is the only request not associated with a process.
    * Handle its reply first.
    */
-  if (call_nr == PM_REBOOT_REPLY) {
+  if (call_nr == VFS_PM_REBOOT_REPLY) {
 	/* Ask the kernel to abort. All system services, including
 	 * the PM, will get a HARD_STOP notification. Await the
 	 * notification in the main loop.
@@ -352,7 +328,7 @@ static void handle_vfs_reply()
   }
 
   /* Get the process associated with this call */
-  proc_e = m_in.PM_PROC;
+  proc_e = m_in.VFS_PM_ENDPT;
 
   if (pm_isokendpt(proc_e, &proc_n) != OK) {
 	panic("handle_vfs_reply: got bad endpoint from VFS: %d", proc_e);
@@ -372,40 +348,41 @@ static void handle_vfs_reply()
 
   /* Call-specific handler code */
   switch (call_nr) {
-  case PM_SETUID_REPLY:
-  case PM_SETGID_REPLY:
-  case PM_SETGROUPS_REPLY:
+  case VFS_PM_SETUID_REPLY:
+  case VFS_PM_SETGID_REPLY:
+  case VFS_PM_SETGROUPS_REPLY:
 	/* Wake up the original caller */
 	reply(rmp-mproc, OK);
 
 	break;
 
-  case PM_SETSID_REPLY:
+  case VFS_PM_SETSID_REPLY:
 	/* Wake up the original caller */
 	reply(rmp-mproc, rmp->mp_procgrp);
 
 	break;
 
-  case PM_EXEC_REPLY:
-	exec_restart(rmp, m_in.PM_STATUS, (vir_bytes)m_in.PM_PC,
-		(vir_bytes)m_in.PM_NEWSP, (vir_bytes)m_in.PM_NEWPS_STR);
+  case VFS_PM_EXEC_REPLY:
+	exec_restart(rmp, m_in.VFS_PM_STATUS, (vir_bytes)m_in.VFS_PM_PC,
+		(vir_bytes)m_in.VFS_PM_NEWSP,
+		(vir_bytes)m_in.VFS_PM_NEWPS_STR);
 
 	break;
 
-  case PM_EXIT_REPLY:
+  case VFS_PM_EXIT_REPLY:
 	exit_restart(rmp, FALSE /*dump_core*/);
 
 	break;
 
-  case PM_CORE_REPLY:
-	if (m_in.PM_STATUS == OK)
+  case VFS_PM_CORE_REPLY:
+	if (m_in.VFS_PM_STATUS == OK)
 		rmp->mp_sigstatus |= DUMPED;
 
 	exit_restart(rmp, TRUE /*dump_core*/);
 
 	break;
 
-  case PM_FORK_REPLY:
+  case VFS_PM_FORK_REPLY:
 	/* Schedule the newly created process ... */
 	r = OK;
 	if (rmp->mp_scheduler != KERNEL && rmp->mp_scheduler != NONE) {
@@ -434,12 +411,12 @@ static void handle_vfs_reply()
 
 	break;
 
-  case PM_SRV_FORK_REPLY:
+  case VFS_PM_SRV_FORK_REPLY:
 	/* Nothing to do */
 
 	break;
 
-  case PM_UNPAUSE_REPLY:
+  case VFS_PM_UNPAUSE_REPLY:
 	/* The target process must always be stopped while unpausing; otherwise
 	 * it could just end up pausing itself on a new call afterwards.
 	 */
diff --git a/servers/pm/misc.c b/servers/pm/misc.c
index 00f937472..612d78a7b 100644
--- a/servers/pm/misc.c
+++ b/servers/pm/misc.c
@@ -24,7 +24,6 @@
 #include <minix/type.h>
 #include <minix/vm.h>
 #include <minix/ds.h>
-#include <string.h>
 #include <machine/archtypes.h>
 #include <lib.h>
 #include <assert.h>
@@ -239,7 +238,8 @@ int do_reboot()
   sys_stop(INIT_PROC_NR);		   /* stop init, but keep it around */
 
   /* Tell VFS to reboot */
-  m.m_type = PM_REBOOT;
+  memset(&m, 0, sizeof(m));
+  m.m_type = VFS_PM_REBOOT;
 
   tell_vfs(&mproc[VFS_PROC_NR], &m);
 
diff --git a/servers/pm/pm.h b/servers/pm/pm.h
index b362115b5..148410ccf 100644
--- a/servers/pm/pm.h
+++ b/servers/pm/pm.h
@@ -11,6 +11,7 @@
 
 #include <fcntl.h>
 #include <unistd.h>
+#include <string.h>
 #include <minix/syslib.h>
 #include <minix/sysutil.h>
 #include <minix/timers.h>
diff --git a/servers/pm/signal.c b/servers/pm/signal.c
index b2e727203..f2e5d1dfc 100644
--- a/servers/pm/signal.c
+++ b/servers/pm/signal.c
@@ -27,7 +27,6 @@
 #include <minix/vm.h>
 #include <signal.h>
 #include <sys/resource.h>
-#include <string.h>
 #include <assert.h>
 #include "mproc.h"
 #include "param.h"
@@ -293,7 +292,7 @@ int process_ksig(endpoint_t proc_nr_e, int signo)
   int proc_nr;
   pid_t proc_id, id;
 
-  if(pm_isokendpt(proc_nr_e, &proc_nr) != OK || proc_nr < 0) {
+  if(pm_isokendpt(proc_nr_e, &proc_nr) != OK) {
 	printf("PM: process_ksig: %d?? not ok\n", proc_nr_e);
 	return EDEADEPT; /* process is gone. */
   }
@@ -747,8 +746,9 @@ struct mproc *rmp;		/* which process */
   if (!(rmp->mp_flags & PROC_STOPPED) && !stop_proc(rmp, TRUE /*may_delay*/))
 	return FALSE;
 
-  m.m_type = PM_UNPAUSE;
-  m.PM_PROC = rmp->mp_endpoint;
+  memset(&m, 0, sizeof(m));
+  m.m_type = VFS_PM_UNPAUSE;
+  m.VFS_PM_ENDPT = rmp->mp_endpoint;
 
   tell_vfs(rmp, &m);
 
diff --git a/servers/pm/utility.c b/servers/pm/utility.c
index b41da9526..ea92f6c06 100644
--- a/servers/pm/utility.c
+++ b/servers/pm/utility.c
@@ -23,7 +23,6 @@
 
 #include <minix/config.h>
 #include <minix/timers.h>
-#include <string.h>
 #include <machine/archtypes.h>
 #include "kernel/const.h"
 #include "kernel/config.h"
@@ -120,11 +119,11 @@ int nice_to_priority(int nice, unsigned* new_q)
 int pm_isokendpt(int endpoint, int *proc)
 {
 	*proc = _ENDPOINT_P(endpoint);
-	if(*proc < -NR_TASKS || *proc >= NR_PROCS)
+	if (*proc < 0 || *proc >= NR_PROCS)
 		return EINVAL;
-	if(*proc >= 0 && endpoint != mproc[*proc].mp_endpoint)
+	if (endpoint != mproc[*proc].mp_endpoint)
 		return EDEADEPT;
-	if(*proc >= 0 && !(mproc[*proc].mp_flags & IN_USE))
+	if (!(mproc[*proc].mp_flags & IN_USE))
 		return EDEADEPT;
 	return OK;
 }
diff --git a/servers/vfs/main.c b/servers/vfs/main.c
index c8433ca45..4c18a3276 100644
--- a/servers/vfs/main.c
+++ b/servers/vfs/main.c
@@ -301,15 +301,15 @@ static int sef_cb_init_fresh(int UNUSED(type), sef_init_info_t *info)
 	if ((s = sef_receive(PM_PROC_NR, &mess)) != OK)
 		panic("VFS: couldn't receive from PM: %d", s);
 
-	if (mess.m_type != PM_INIT)
+	if (mess.m_type != VFS_PM_INIT)
 		panic("unexpected message from PM: %d", mess.m_type);
 
-	if (NONE == mess.PM_PROC) break;
+	if (NONE == mess.VFS_PM_ENDPT) break;
 
-	rfp = &fproc[mess.PM_SLOT];
+	rfp = &fproc[mess.VFS_PM_SLOT];
 	rfp->fp_flags = FP_NOFLAGS;
-	rfp->fp_pid = mess.PM_PID;
-	rfp->fp_endpoint = mess.PM_PROC;
+	rfp->fp_pid = mess.VFS_PM_PID;
+	rfp->fp_endpoint = mess.VFS_PM_ENDPT;
 	rfp->fp_grant = GRANT_INVALID;
 	rfp->fp_blocked_on = FP_BLOCKED_ON_NONE;
 	rfp->fp_realuid = (uid_t) SYS_UID;
@@ -569,67 +569,67 @@ void service_pm_postponed(void)
   memset(&m_out, 0, sizeof(m_out));
 
   switch(job_call_nr) {
-  case PM_EXEC:
-	proc_e = job_m_in.PM_PROC;
-	exec_path = (vir_bytes)job_m_in.PM_PATH;
-	exec_path_len = (size_t)job_m_in.PM_PATH_LEN;
-	stack_frame = (vir_bytes)job_m_in.PM_FRAME;
-	stack_frame_len = (size_t)job_m_in.PM_FRAME_LEN;
-	ps_str = (vir_bytes)job_m_in.PM_PS_STR;
+  case VFS_PM_EXEC:
+	proc_e = job_m_in.VFS_PM_ENDPT;
+	exec_path = (vir_bytes) job_m_in.VFS_PM_PATH;
+	exec_path_len = (size_t) job_m_in.VFS_PM_PATH_LEN;
+	stack_frame = (vir_bytes) job_m_in.VFS_PM_FRAME;
+	stack_frame_len = (size_t) job_m_in.VFS_PM_FRAME_LEN;
+	ps_str = (vir_bytes) job_m_in.VFS_PM_PS_STR;
 
 	assert(proc_e == fp->fp_endpoint);
 
 	r = pm_exec(exec_path, exec_path_len, stack_frame, stack_frame_len,
-		&pc, &newsp, &ps_str, job_m_in.PM_EXECFLAGS);
+		&pc, &newsp, &ps_str, job_m_in.VFS_PM_EXECFLAGS);
 
 	/* Reply status to PM */
-	m_out.m_type = PM_EXEC_REPLY;
-	m_out.PM_PROC = proc_e;
-	m_out.PM_PC = (void *)pc;
-	m_out.PM_STATUS = r;
-	m_out.PM_NEWSP = (void *)newsp;
-	m_out.PM_NEWPS_STR = ps_str;
+	m_out.m_type = VFS_PM_EXEC_REPLY;
+	m_out.VFS_PM_ENDPT = proc_e;
+	m_out.VFS_PM_PC = (void *) pc;
+	m_out.VFS_PM_STATUS = r;
+	m_out.VFS_PM_NEWSP = (void *) newsp;
+	m_out.VFS_PM_NEWPS_STR = ps_str;
 
 	break;
 
-  case PM_EXIT:
-	proc_e = job_m_in.PM_PROC;
+  case VFS_PM_EXIT:
+	proc_e = job_m_in.VFS_PM_ENDPT;
 
 	assert(proc_e == fp->fp_endpoint);
 
 	pm_exit();
 
 	/* Reply dummy status to PM for synchronization */
-	m_out.m_type = PM_EXIT_REPLY;
-	m_out.PM_PROC = proc_e;
+	m_out.m_type = VFS_PM_EXIT_REPLY;
+	m_out.VFS_PM_ENDPT = proc_e;
 
 	break;
 
-  case PM_DUMPCORE:
-	proc_e = job_m_in.PM_PROC;
-	term_signal = job_m_in.PM_TERM_SIG;
-	core_path = (vir_bytes) job_m_in.PM_PATH;
+  case VFS_PM_DUMPCORE:
+	proc_e = job_m_in.VFS_PM_ENDPT;
+	term_signal = job_m_in.VFS_PM_TERM_SIG;
+	core_path = (vir_bytes) job_m_in.VFS_PM_PATH;
 
 	assert(proc_e == fp->fp_endpoint);
 
 	r = pm_dumpcore(term_signal, core_path);
 
 	/* Reply status to PM */
-	m_out.m_type = PM_CORE_REPLY;
-	m_out.PM_PROC = proc_e;
-	m_out.PM_STATUS = r;
+	m_out.m_type = VFS_PM_CORE_REPLY;
+	m_out.VFS_PM_ENDPT = proc_e;
+	m_out.VFS_PM_STATUS = r;
 
 	break;
 
-  case PM_UNPAUSE:
-	proc_e = job_m_in.PM_PROC;
+  case VFS_PM_UNPAUSE:
+	proc_e = job_m_in.VFS_PM_ENDPT;
 
 	assert(proc_e == fp->fp_endpoint);
 
 	unpause();
 
-	m_out.m_type = PM_UNPAUSE_REPLY;
-	m_out.PM_PROC = proc_e;
+	m_out.m_type = VFS_PM_UNPAUSE_REPLY;
+	m_out.VFS_PM_ENDPT = proc_e;
 
 	break;
 
@@ -649,7 +649,7 @@ static void service_pm(void)
 {
 /* Process a request from PM. This function is called from the main thread, and
  * may therefore not block. Any requests that may require blocking the calling
- * thread must be executed in a separate thread. Aside from PM_REBOOT, all
+ * thread must be executed in a separate thread. Aside from VFS_PM_REBOOT, all
  * requests from PM involve another, target process: for example, PM tells VFS
  * that a process is performing a setuid() call. For some requests however,
  * that other process may not be idle, and in that case VFS must serialize the
@@ -665,56 +665,56 @@ static void service_pm(void)
   memset(&m_out, 0, sizeof(m_out));
 
   switch (call_nr) {
-    case PM_SETUID:
+  case VFS_PM_SETUID:
 	{
 		endpoint_t proc_e;
 		uid_t euid, ruid;
 
-		proc_e = m_in.PM_PROC;
-		euid = m_in.PM_EID;
-		ruid = m_in.PM_RID;
+		proc_e = m_in.VFS_PM_ENDPT;
+		euid = m_in.VFS_PM_EID;
+		ruid = m_in.VFS_PM_RID;
 
 		pm_setuid(proc_e, euid, ruid);
 
-		m_out.m_type = PM_SETUID_REPLY;
-		m_out.PM_PROC = proc_e;
+		m_out.m_type = VFS_PM_SETUID_REPLY;
+		m_out.VFS_PM_ENDPT = proc_e;
 	}
 	break;
 
-    case PM_SETGID:
+  case VFS_PM_SETGID:
 	{
 		endpoint_t proc_e;
 		gid_t egid, rgid;
 
-		proc_e = m_in.PM_PROC;
-		egid = m_in.PM_EID;
-		rgid = m_in.PM_RID;
+		proc_e = m_in.VFS_PM_ENDPT;
+		egid = m_in.VFS_PM_EID;
+		rgid = m_in.VFS_PM_RID;
 
 		pm_setgid(proc_e, egid, rgid);
 
-		m_out.m_type = PM_SETGID_REPLY;
-		m_out.PM_PROC = proc_e;
+		m_out.m_type = VFS_PM_SETGID_REPLY;
+		m_out.VFS_PM_ENDPT = proc_e;
 	}
 	break;
 
-    case PM_SETSID:
+  case VFS_PM_SETSID:
 	{
 		endpoint_t proc_e;
 
-		proc_e = m_in.PM_PROC;
+		proc_e = m_in.VFS_PM_ENDPT;
 		pm_setsid(proc_e);
 
-		m_out.m_type = PM_SETSID_REPLY;
-		m_out.PM_PROC = proc_e;
+		m_out.m_type = VFS_PM_SETSID_REPLY;
+		m_out.VFS_PM_ENDPT = proc_e;
 	}
 	break;
 
-    case PM_EXEC:
-    case PM_EXIT:
-    case PM_DUMPCORE:
-    case PM_UNPAUSE:
+  case VFS_PM_EXEC:
+  case VFS_PM_EXIT:
+  case VFS_PM_DUMPCORE:
+  case VFS_PM_UNPAUSE:
 	{
-		endpoint_t proc_e = m_in.PM_PROC;
+		endpoint_t proc_e = m_in.VFS_PM_ENDPT;
 
 		if(isokendpt(proc_e, &slot) != OK) {
 			printf("VFS: proc ep %d not ok\n", proc_e);
@@ -731,56 +731,56 @@ static void service_pm(void)
 
 		return;
 	}
-    case PM_FORK:
-    case PM_SRV_FORK:
+  case VFS_PM_FORK:
+  case VFS_PM_SRV_FORK:
 	{
 		endpoint_t pproc_e, proc_e;
 		pid_t child_pid;
 		uid_t reuid;
 		gid_t regid;
 
-		pproc_e = m_in.PM_PPROC;
-		proc_e = m_in.PM_PROC;
-		child_pid = m_in.PM_CPID;
-		reuid = m_in.PM_REUID;
-		regid = m_in.PM_REGID;
+		pproc_e = m_in.VFS_PM_PENDPT;
+		proc_e = m_in.VFS_PM_ENDPT;
+		child_pid = m_in.VFS_PM_CPID;
+		reuid = m_in.VFS_PM_REUID;
+		regid = m_in.VFS_PM_REGID;
 
 		pm_fork(pproc_e, proc_e, child_pid);
-		m_out.m_type = PM_FORK_REPLY;
+		m_out.m_type = VFS_PM_FORK_REPLY;
 
-		if (call_nr == PM_SRV_FORK) {
-			m_out.m_type = PM_SRV_FORK_REPLY;
+		if (call_nr == VFS_PM_SRV_FORK) {
+			m_out.m_type = VFS_PM_SRV_FORK_REPLY;
 			pm_setuid(proc_e, reuid, reuid);
 			pm_setgid(proc_e, regid, regid);
 		}
 
-		m_out.PM_PROC = proc_e;
+		m_out.VFS_PM_ENDPT = proc_e;
 	}
 	break;
-    case PM_SETGROUPS:
+  case VFS_PM_SETGROUPS:
 	{
 		endpoint_t proc_e;
 		int group_no;
 		gid_t *group_addr;
 
-		proc_e = m_in.PM_PROC;
-		group_no = m_in.PM_GROUP_NO;
-		group_addr = (gid_t *) m_in.PM_GROUP_ADDR;
+		proc_e = m_in.VFS_PM_ENDPT;
+		group_no = m_in.VFS_PM_GROUP_NO;
+		group_addr = (gid_t *) m_in.VFS_PM_GROUP_ADDR;
 
 		pm_setgroups(proc_e, group_no, group_addr);
 
-		m_out.m_type = PM_SETGROUPS_REPLY;
-		m_out.PM_PROC = proc_e;
+		m_out.m_type = VFS_PM_SETGROUPS_REPLY;
+		m_out.VFS_PM_ENDPT = proc_e;
 	}
 	break;
 
-    case PM_REBOOT:
+  case VFS_PM_REBOOT:
 	/* Reboot requests are not considered postponed PM work and are instead
 	 * handled from a separate worker thread that is associated with PM's
 	 * process. PM makes no regular VFS calls, and thus, from VFS's
 	 * perspective, PM is always idle. Therefore, we can safely do this.
-	 * We do assume that PM sends us only one PM_REBOOT message at once,
-	 * or ever for that matter. :)
+	 * We do assume that PM sends us only one VFS_PM_REBOOT message at
+	 * once, or ever for that matter. :)
 	 */
 	worker_start(fproc_addr(PM_PROC_NR), pm_reboot, &m_in,
 		FALSE /*use_spare*/);
diff --git a/servers/vfs/misc.c b/servers/vfs/misc.c
index 058abb324..57ecaf6e2 100644
--- a/servers/vfs/misc.c
+++ b/servers/vfs/misc.c
@@ -531,7 +531,7 @@ void pm_reboot()
   /* Reply to PM for synchronization */
   memset(&m_out, 0, sizeof(m_out));
 
-  m_out.m_type = PM_REBOOT_REPLY;
+  m_out.m_type = VFS_PM_REBOOT_REPLY;
 
   if ((r = send(PM_PROC_NR, &m_out)) != OK)
 	panic("pm_reboot: send failed: %d", r);