diff --git a/src/cas/generic/casChannel.cc b/src/cas/generic/casChannel.cc
index e695d4aab..07b77f98a 100644
--- a/src/cas/generic/casChannel.cc
+++ b/src/cas/generic/casChannel.cc
@@ -71,6 +71,25 @@ bool casChannel::confirmationRequested () const
 	return false;
 }
 
+caStatus casChannel::beginTransaction ()
+{
+    return S_casApp_success;
+}
+
+void casChannel::endTransaction ()
+{
+}
+
+caStatus casChannel::read ( const casCtx & ctx, gdd & prototype )
+{
+    return ctx.getPV()->read ( ctx, prototype );
+}
+
+caStatus casChannel::write ( const casCtx & ctx, const gdd & value )
+{
+    return ctx.getPV()->write ( ctx, value );
+}
+
 void casChannel::show ( unsigned level ) const
 {
 	if ( level > 2u ) {
diff --git a/src/cas/generic/casChannelI.cc b/src/cas/generic/casChannelI.cc
index 5b6b262b2..5104ae2a6 100644
--- a/src/cas/generic/casChannelI.cc
+++ b/src/cas/generic/casChannelI.cc
@@ -79,3 +79,24 @@ caStatus casChannelI::cbFunc (
 	return stat;
 }
 
+caStatus casChannelI::read ( const casCtx & ctx, gdd & prototype )
+{
+    caStatus status = this->chan.beginTransaction ();
+    if ( status != S_casApp_success ) {
+        return status;
+    }
+    status = this->chan.read ( ctx, prototype );
+    this->chan.endTransaction ();
+    return status;
+}
+
+caStatus casChannelI::write ( const casCtx & ctx, const gdd & value )
+{
+    caStatus status = this->chan.beginTransaction ();
+    if ( status != S_casApp_success ) {
+        return status;
+    }
+    status = this->chan.write ( ctx, value );
+    this->chan.endTransaction ();
+    return status;
+}
diff --git a/src/cas/generic/casChannelI.h b/src/cas/generic/casChannelI.h
index e06feaca3..8bde7ec48 100644
--- a/src/cas/generic/casChannelI.h
+++ b/src/cas/generic/casChannelI.h
@@ -52,6 +52,8 @@ public:
 	bool readAccess () const;
     bool writeAccess () const;
 	bool confirmationRequested () const;
+    caStatus read ( const casCtx & ctx, gdd & prototype );
+    caStatus write ( const casCtx & ctx, const gdd & value );
 	void show ( unsigned level ) const;
 private:
 	tsDLList < casAsyncIOI > ioList;
diff --git a/src/cas/generic/casStrmClient.cc b/src/cas/generic/casStrmClient.cc
index 467ec4be8..5f1438b8c 100644
--- a/src/cas/generic/casStrmClient.cc
+++ b/src/cas/generic/casStrmClient.cc
@@ -815,7 +815,8 @@ caStatus casStrmClient::monitorResponse (
 		if ( completionStatus == S_cas_noRead ) {
             return monitorFailureResponse ( guard, msg, ECA_NORDACCESS );
 		}
-		else if ( completionStatus == S_cas_noMemory ) {
+		else if ( completionStatus == S_cas_noMemory || 
+            completionStatus == S_casApp_noMemory ) {
             return monitorFailureResponse ( guard, msg, ECA_ALLOCMEM );
 		}
 		else if ( completionStatus == S_cas_badType ) {
@@ -1337,7 +1338,7 @@ caStatus casStrmClient::createChanResponse (
 	    if ( this->userStartedAsyncIO ) {
 		    if ( status != S_casApp_asyncCompletion ) {
 			    fprintf ( stderr, 
-                    "Application returned %d from casPV::read()"
+                    "Application returned %d from casChannel::read()"
                     " - expected S_casApp_asyncCompletion\n", status);
 		    }
 			status = S_cas_success;
@@ -1353,7 +1354,7 @@ caStatus casStrmClient::createChanResponse (
 	    }
         else if ( status == S_casApp_postponeAsyncIO ) {
 		    errlogPrintf ( "The server library does not currently support postponment of " );
-            errlogPrintf ( "string table cache update of casPV::read()." );
+            errlogPrintf ( "string table cache update of casChannel::read()." );
 		    errlogPrintf ( "To postpone this request please postpone the PC attach IO request." );
 		    errlogPrintf ( "String table cache update did not occur." );
             status = enumPostponedCreateChanResponse ( 
@@ -1945,7 +1946,7 @@ caStatus casStrmClient::write()
 	if ( this->userStartedAsyncIO ) {
 		if (status!=S_casApp_asyncCompletion) {
 			fprintf(stderr, 
-"Application returned %d from casPV::write() - expected S_casApp_asyncCompletion\n",
+"Application returned %d from casChannel::write() - expected S_casApp_asyncCompletion\n",
 				status);
 			status = S_casApp_asyncCompletion;
 		}
@@ -1953,7 +1954,7 @@ caStatus casStrmClient::write()
 	else if ( status == S_casApp_asyncCompletion ) {
 		status = S_cas_badParameter;
 		errMessage ( status, 
-		"- expected asynch IO creation from casPV::write()" );
+		"- expected asynch IO creation from casChannel::write()" );
 	}
 
 	return status;
@@ -2010,7 +2011,7 @@ caStatus casStrmClient::writeScalarData ()
 	    //
 	    // call the server tool's virtual function
 	    //
-	    status = this->ctx.getPV()->write ( this->ctx, *pDD );
+	    status = this->ctx.getChannel()->write ( this->ctx, *pDD );
     }
 
 	//
@@ -2099,7 +2100,7 @@ caStatus casStrmClient::writeArrayData()
 	    //
 	    // call the server tool's virtual function
 	    //
-	    status = this->ctx.getPV()->write ( this->ctx, *pDD );
+	    status = this->ctx.getChannel()->write ( this->ctx, *pDD );
     }
     else {
         status = S_cas_noConvert;
@@ -2134,7 +2135,7 @@ caStatus casStrmClient::read ( const gdd * & pDescRet )
 	//
 	// call the server tool's virtual function
 	//
-	status = this->ctx.getPV()->read ( this->ctx, * pDD );
+	status = this->ctx.getChannel()->read ( this->ctx, * pDD );
 
 	//
 	// prevent problems when they initiate
@@ -2144,7 +2145,7 @@ caStatus casStrmClient::read ( const gdd * & pDescRet )
 	if ( this->userStartedAsyncIO ) {
 		if ( status != S_casApp_asyncCompletion ) {
 			fprintf(stderr, 
-"Application returned %d from casPV::read() - expected S_casApp_asyncCompletion\n",
+"Application returned %d from casChannel::read() - expected S_casApp_asyncCompletion\n",
 				status);
 			status = S_casApp_asyncCompletion;
 		}
@@ -2152,7 +2153,7 @@ caStatus casStrmClient::read ( const gdd * & pDescRet )
 	else if ( status == S_casApp_asyncCompletion ) {
 		status = S_cas_badParameter;
 		errMessage(status, 
-			"- expected asynch IO creation from casPV::read()");
+			"- expected asynch IO creation from casChannel::read()");
 	}
 
 	if ( status == S_casApp_success ) {
diff --git a/src/cas/generic/casdef.h b/src/cas/generic/casdef.h
index 96ae491cc..f93279aab 100644
--- a/src/cas/generic/casdef.h
+++ b/src/cas/generic/casdef.h
@@ -571,6 +571,34 @@ public:
 	// for confirmation prior writing to this PV
 	epicsShareFunc virtual bool confirmationRequested () const;
 
+    //
+    // If this function is not provided in the derived class then casPV::beginTransaction()
+    // is called - see casPV::beginTransaction() for additional comments.
+    //
+    epicsShareFunc virtual caStatus beginTransaction ();
+    
+    //
+    // If this function is not provided in the derived class then casPV::endTransaction()
+    // is called - see casPV::endTransaction() for additional comments.
+    //
+    epicsShareFunc virtual void endTransaction ();
+
+    //
+    // read
+    //
+    // If this function is not provided in the derived class then casPV::read()
+    // is called - see casPV::read() for additional comments.
+    //
+    epicsShareFunc virtual caStatus read (const casCtx &ctx, gdd &prototype);
+    
+    //
+    // write 
+    //
+    // If this function is not provided in the derived class then casPV::write()
+    // is called - see casPV::write() for additional comments.
+    //
+    epicsShareFunc virtual caStatus write (const casCtx &ctx, const gdd &value);
+
 	//
 	// This is called for each channel in the server if
 	// caServer::show() is called and the level is high