diff --git a/src/rt/RcontribSimulManager.cpp b/src/rt/RcontribSimulManager.cpp
index 5a85f645..a361a464 100644
--- a/src/rt/RcontribSimulManager.cpp
+++ b/src/rt/RcontribSimulManager.cpp
@@ -1,5 +1,5 @@
 #ifndef lint
-static const char RCSid[] = "$Id: RcontribSimulManager.cpp,v 2.2 2024/10/29 19:47:19 greg Exp $";
+static const char RCSid[] = "$Id: RcontribSimulManager.cpp,v 2.3 2024/10/30 01:38:21 greg Exp $";
 #endif
 /*
  *  RcontribSimulManager.cpp
@@ -443,7 +443,8 @@ RcontribOutput::CheckHeader(const RcontribSimulManager *rcp)
 		return -1;
 	}
 						// check format
-	if (!(cp = findArgs(hdr, FMTSTR, begData)) || strcmp(cp, formstr(etyp))) {
+	if (!(cp = findArgs(hdr, FMTSTR, begData)) ||
+				strncmp(cp, formstr(etyp), strlen(formstr(etyp)))) {
 		sprintf(errmsg, "expected %s%s in '%s'", FMTSTR, formstr(etyp), GetName());
 		error(USER, errmsg);
 		return -1;
@@ -632,7 +633,8 @@ RcontribSimulManager::GetChild(bool forceWait)
 				FD_ISSET(kid[n].w, &writeset) |
 				FD_ISSET(kid[n].w, &errset)) {
 						// update output row counts
-			UpdateRowsDone(kidRow[n]);
+			if (!FD_ISSET(kid[n].w, &errset))
+				UpdateRowsDone(kidRow[n]);
 			kidRow[n] = -1;		// flag it available
 			pn = n;
 		}
@@ -716,7 +718,6 @@ RcontribSimulManager::StartKids(int n2go)
 				close(kid[nkids].w);
 			free(kid); free(kidRow);
 			kid = NULL; kidRow = NULL;
-			rowsDone.NewBitMap(0);
 			RunChild();		// should never return
 			_exit(1);
 		}
diff --git a/src/rt/RcontribSimulManager.h b/src/rt/RcontribSimulManager.h
index cd3d705e..9c030807 100644
--- a/src/rt/RcontribSimulManager.h
+++ b/src/rt/RcontribSimulManager.h
@@ -1,4 +1,4 @@
-/* RCSid $Id: RcontribSimulManager.h,v 2.2 2024/10/29 19:47:19 greg Exp $ */
+/* RCSid $Id: RcontribSimulManager.h,v 2.3 2024/10/30 01:38:21 greg Exp $ */
 /*
  *  RcontribSimulManager.h
  *
@@ -154,7 +154,7 @@ extern lut_free_t	FreeRcMod;
  */
 
 /// Output channel opening options: new/exclusive, overwrite if exists, or recover data
-enum RCOutputOp {RCOnew, RCOforce, RCOrecover};
+enum RCOutputOp {RCOnew=0, RCOforce, RCOrecover};
 
 /// Converts above to RdataShare open flags (may be adjusted by calling program)
 extern int	RSDOflags[];
diff --git a/src/rt/RdataShareFile.cpp b/src/rt/RdataShareFile.cpp
index a5294e67..4ace3bd1 100644
--- a/src/rt/RdataShareFile.cpp
+++ b/src/rt/RdataShareFile.cpp
@@ -1,5 +1,5 @@
 #ifndef lint
-static const char RCSid[] = "$Id: RdataShareFile.cpp,v 2.1 2024/10/29 00:36:54 greg Exp $";
+static const char RCSid[] = "$Id: RdataShareFile.cpp,v 2.2 2024/10/30 01:38:21 greg Exp $";
 #endif
 /*
  *  RdataShareFile.cpp
@@ -84,16 +84,16 @@ RdataShareFile::RdataShareFile(const char *name, int flags, size_t siz)
 	int	oflags = O_CLOEXEC;
 	switch (flags & (RDSread|RDSwrite)) {
 	case RDSread|RDSwrite:
-		oflags |= O_RDWR;
+		oflags |= O_RDWR|O_CREAT;
+		break;
+	case RDSwrite:
+		oflags |= O_WRONLY|O_CREAT;
 		break;
 	case RDSread:
 		oflags |= O_RDONLY;
 		break;
-	case RDSwrite:
-		oflags |= O_WRONLY;
-		break;
 	}
-	if (flags & RDSexcl) oflags |= O_CREAT|O_EXCL;
+	if (flags & RDSexcl) oflags |= O_EXCL;
 	else if (flags & RDSextend && !siz) oflags |= O_TRUNC;
 	fd = open(name, oflags, 0666);
 	if (fd < 0) {
diff --git a/src/rt/RdataShareMap.cpp b/src/rt/RdataShareMap.cpp
index d13d5414..d120aaf4 100644
--- a/src/rt/RdataShareMap.cpp
+++ b/src/rt/RdataShareMap.cpp
@@ -1,5 +1,5 @@
 #ifndef lint
-static const char RCSid[] = "$Id: RdataShareMap.cpp,v 2.1 2024/10/29 00:36:54 greg Exp $";
+static const char RCSid[] = "$Id: RdataShareMap.cpp,v 2.2 2024/10/30 01:38:21 greg Exp $";
 #endif
 /*
  *  RdataShareMap.cpp
@@ -36,25 +36,24 @@ RdataShareMap::RdataShareMap(const char *name, int flags, size_t siz)
 		error(CONSISTENCY, "bad RDSextend in RdataShareMap()");
 		return;
 	}
-	int	mmprot = PROT_NONE;
-	int	oflags = 0;
+	int	oflags, mmprot;
 	switch (flags & (RDSread|RDSwrite)) {
 	case RDSread|RDSwrite:
-		mmprot |= PROT_READ|PROT_WRITE;
-		oflags |= O_RDWR;
-		break;
-	case RDSread:
-		mmprot |= PROT_READ;
-		oflags |= O_RDONLY;
+		mmprot = PROT_READ|PROT_WRITE;
+		oflags = O_RDWR|O_CREAT;
 		break;
 	case RDSwrite:
-		mmprot |= PROT_WRITE;
-		oflags |= O_WRONLY;
+		mmprot = PROT_WRITE;
+		oflags = O_RDWR|O_CREAT;	// XXX system limitation
+		break;
+	case RDSread:
+		mmprot = PROT_READ;
+		oflags = O_RDONLY;
 		break;
 	}
 	int	fd = -1;
 	if (name) {			// opening a shared file
-		if (flags & RDSexcl) oflags |= O_CREAT|O_EXCL;
+		if (flags & RDSexcl) oflags |= O_EXCL;
 		else if (flags & RDSextend && !siz) oflags |= O_TRUNC;
 		fd = open(name, oflags, 0666);
 		if (fd < 0) {