diff --git a/src/nt/ntfield.cpp b/src/nt/ntfield.cpp
index 434fbd1..9455156 100644
--- a/src/nt/ntfield.cpp
+++ b/src/nt/ntfield.cpp
@@ -64,7 +64,7 @@ bool NTField::isTimeStamp(FieldConstPtr const & field)
    ScalarConstPtr s = static_pointer_cast<const Scalar>(f);
    if(s->getScalarType()!=pvLong) return false;
    f = fields[1];
-   if(names[1].compare("nanoSeconds")!=0) return false;
+   if(names[1].compare("nanoseconds")!=0) return false;
    if(f->getType()!=scalar) return false;
    s = static_pointer_cast<const Scalar>(f);
    if(s->getScalarType()!=pvInt) return false;
@@ -184,7 +184,7 @@ bool NTField::isAlarmLimit(FieldConstPtr const & field)
    s = static_pointer_cast<const Scalar>(f);
    if(s->getScalarType()!=pvInt) return false;
    f = fields[9];
-   if(names[9].compare("hystersis")!=0) return false;
+   if(names[9].compare("hysteresis")!=0) return false;
    if(f->getType()!=scalar) return false;
    return true;
 }
diff --git a/src/nt/ntfield.h b/src/nt/ntfield.h
index e7fc73f..3314051 100644
--- a/src/nt/ntfield.h
+++ b/src/nt/ntfield.h
@@ -15,6 +15,7 @@
 #include <pv/pvAlarm.h>
 #include <pv/timeStamp.h>
 #include <pv/pvTimeStamp.h>
+#include <pv/sharedVector.h>
 
 namespace epics { namespace pvData { 
 /**
@@ -23,8 +24,6 @@ namespace epics { namespace pvData {
  * 
  */
 
-typedef std::tr1::shared_ptr<epics::pvData::StringArray> StringArrayPtr;
-
 class NTField;
 typedef std::tr1::shared_ptr<NTField> NTFieldPtr;
 
diff --git a/src/nt/nttable.cpp b/src/nt/nttable.cpp
index 308990b..7e14e3c 100644
--- a/src/nt/nttable.cpp
+++ b/src/nt/nttable.cpp
@@ -44,7 +44,7 @@ bool NTTable::isNTTable(PVStructurePtr const & pvStructure)
 
 NTTablePtr NTTable::create(
     bool hasFunction,bool hasTimeStamp, bool hasAlarm,
-    StringArray const & valueNames,
+    shared_vector<std::string> const & valueNames,
     FieldConstPtrArray const &valueFields)
 {
     StandardFieldPtr standardField = getStandardField();
@@ -55,10 +55,8 @@ NTTablePtr NTTable::create(
     nfields += valueFields.size();
     FieldCreatePtr fieldCreate = getFieldCreate();
     PVDataCreatePtr pvDataCreate = getPVDataCreate();
-    FieldConstPtrArray fields;
-    StringArray names;
-    fields.resize(nfields);
-    names.resize(nfields);
+    FieldConstPtrArray fields(nfields);
+    StringArray names(nfields);
     size_t ind = 0;
     if(hasFunction) {
         names[ind] = "function";
@@ -83,7 +81,10 @@ NTTablePtr NTTable::create(
     PVStructurePtr pvStructure = pvDataCreate->createPVStructure(st);
     PVStringArrayPtr pvLabel = static_pointer_cast<PVStringArray>
         (pvStructure->getScalarArrayField("label",pvString));
-    pvLabel->put(0,numberValues,valueNames,0);
+    shared_vector<std::string> xxx(numberValues);
+    for(size_t i=0; i<numberValues; ++i) xxx[i] = valueNames[i];
+    shared_vector<const std::string> data(freeze(xxx));
+    pvLabel->replace(data);
     return NTTablePtr(new NTTable(pvStructure));
 }
 
diff --git a/src/nt/nttable.h b/src/nt/nttable.h
index 683463d..44e3e1e 100644
--- a/src/nt/nttable.h
+++ b/src/nt/nttable.h
@@ -41,7 +41,7 @@ public:
      */
     static NTTablePtr create(
         bool hasFunction,bool hasTimeStamp, bool hasAlarm,
-        StringArray const & valueNames,
+        shared_vector<std::string> const & valueNames,
         FieldConstPtrArray const &valueFields);
     static NTTablePtr clone(PVStructurePtr const &);
     /**
diff --git a/test/nt/ntfieldTest.cpp b/test/nt/ntfieldTest.cpp
index 1c9e150..71aee93 100644
--- a/test/nt/ntfieldTest.cpp
+++ b/test/nt/ntfieldTest.cpp
@@ -14,16 +14,18 @@
 #include <cstdlib>
 #include <cstddef>
 #include <string>
-#include <cstring>
-#include <cstdio>
 #include <ctime>
 #include <list>
+#include <iostream>
 
 #include <epicsAssert.h>
 
 #include <pv/nt.h>
 
 using namespace epics::pvData;
+using std::string;
+using std::cout;
+using std::endl;
 
 static FieldCreatePtr fieldCreate = getFieldCreate();
 static PVDataCreatePtr pvDataCreate = getPVDataCreate();
@@ -31,61 +33,42 @@ static StandardFieldPtr standardField = getStandardField();
 static StandardPVFieldPtr standardPVField = getStandardPVField();
 static NTFieldPtr ntField = NTField::get();
 static PVNTFieldPtr pvntField = PVNTField::get();
-static String builder;
 
 static void testNTField(FILE * fd)
 {
     StructureConstPtr structureConstPtr = ntField->createEnumerated();
-    builder.clear();
-    structureConstPtr->toString(&builder);
-    fprintf(fd,"%s\n",builder.c_str());
+    cout << *structureConstPtr << endl;
     assert(ntField->isEnumerated(structureConstPtr));
 
     structureConstPtr = ntField->createTimeStamp();
-    builder.clear();
-    structureConstPtr->toString(&builder);
-    fprintf(fd,"%s\n",builder.c_str());
+    cout << *structureConstPtr << endl;
     assert(ntField->isTimeStamp(structureConstPtr));
 
     structureConstPtr = ntField->createAlarm();
-    builder.clear();
-    structureConstPtr->toString(&builder);
-    fprintf(fd,"%s\n",builder.c_str());
+    cout << *structureConstPtr << endl;
     assert(ntField->isAlarm(structureConstPtr));
 
     structureConstPtr = ntField->createDisplay();
-    builder.clear();
-    structureConstPtr->toString(&builder);
-    fprintf(fd,"%s\n",builder.c_str());
+    cout << *structureConstPtr << endl;
     assert(ntField->isDisplay(structureConstPtr));
 
     structureConstPtr = ntField->createAlarmLimit();
-    builder.clear();
-    structureConstPtr->toString(&builder);
-    fprintf(fd,"%s\n",builder.c_str());
+    cout << *structureConstPtr << endl;
     assert(ntField->isAlarmLimit(structureConstPtr));
 
     structureConstPtr = ntField->createControl();
-    builder.clear();
-    structureConstPtr->toString(&builder);
-    fprintf(fd,"%s\n",builder.c_str());
+    cout << *structureConstPtr << endl;
     assert(ntField->isControl(structureConstPtr));
 
     StructureArrayConstPtr structureArrayConstPtr
         = ntField->createEnumeratedArray();
-    builder.clear();
-    structureArrayConstPtr->toString(&builder);
-    fprintf(fd,"%s\n",builder.c_str());
+    cout << *structureConstPtr << endl;
 
     structureArrayConstPtr = ntField->createTimeStampArray();
-    builder.clear();
-    structureArrayConstPtr->toString(&builder);
-    fprintf(fd,"%s\n",builder.c_str());
+    cout << *structureConstPtr << endl;
 
     structureArrayConstPtr = ntField->createAlarmArray();
-    builder.clear();
-    structureArrayConstPtr->toString(&builder);
-    fprintf(fd,"%s\n",builder.c_str());
+    cout << *structureConstPtr << endl;
 }
 
 static void testPVNTField(FILE * fd)
@@ -97,61 +80,39 @@ static void testPVNTField(FILE * fd)
     choices[2] = "three";
     PVStructurePtr pvStructure = PVStructurePtr(
         pvntField->createEnumerated(choices));
-    builder.clear();
-    pvStructure->toString(&builder);
-    fprintf(fd,"%s\n",builder.c_str());
+    cout << *pvStructure << endl;
     assert(ntField->isEnumerated(pvStructure->getStructure()));
 
     pvStructure = PVStructurePtr(pvntField->createTimeStamp());
-    builder.clear();
-    pvStructure->toString(&builder);
-    fprintf(fd,"%s\n",builder.c_str());
+    cout << *pvStructure << endl;
     assert(ntField->isTimeStamp(pvStructure->getStructure()));
 
     pvStructure = PVStructurePtr(pvntField->createAlarm());
-    builder.clear();
-    pvStructure->toString(&builder);
-    fprintf(fd,"%s\n",builder.c_str());
+    cout << *pvStructure << endl;
     assert(ntField->isAlarm(pvStructure->getStructure()));
 
     pvStructure = PVStructurePtr(pvntField->createDisplay());
-    builder.clear();
-    pvStructure->toString(&builder);
-    fprintf(fd,"%s\n",builder.c_str());
+    cout << *pvStructure << endl;
     assert(ntField->isDisplay(pvStructure->getStructure()));
 
     pvStructure = PVStructurePtr(pvntField->createAlarmLimit());
-    builder.clear();
-    pvStructure->toString(&builder);
-    fprintf(fd,"%s\n",builder.c_str());
+    cout << *pvStructure << endl;
     assert(ntField->isAlarmLimit(pvStructure->getStructure()));
 
     PVStructureArrayPtr pvStructureArray = PVStructureArrayPtr(
         pvntField->createEnumeratedArray());
-    builder.clear();
-    pvStructureArray->toString(&builder);
-    fprintf(fd,"\n%s\n",builder.c_str());
-    builder.clear();
-    pvStructureArray->getStructureArray()->getStructure()->toString(&builder);
-    fprintf(fd,"%s\n",builder.c_str());
+    cout << *pvStructure << endl;
+    cout << *pvStructureArray->getStructureArray()->getStructure();
 
     pvStructureArray = PVStructureArrayPtr(
         pvntField->createTimeStampArray());
-    builder.clear();
-    pvStructureArray->toString(&builder);
-    fprintf(fd,"\n%s\n",builder.c_str());
-    builder.clear();
-    pvStructureArray->getStructureArray()->getStructure()->toString(&builder);
-    fprintf(fd,"%s\n",builder.c_str());
+    cout << *pvStructure << endl;
+    cout << *pvStructureArray->getStructureArray()->getStructure();
 
     pvStructureArray = PVStructureArrayPtr(
         pvntField->createAlarmArray());
-    builder.clear();
-    pvStructureArray->toString(&builder);
-    fprintf(fd,"\n%s\n",builder.c_str());
-    builder.clear();
-    pvStructureArray->getStructureArray()->getStructure()->toString(&builder);
-    fprintf(fd,"%s\n",builder.c_str());
+    cout << *pvStructure << endl;
+    cout << *pvStructureArray->getStructureArray()->getStructure();
 }
 
 int main(int argc,char *argv[])
diff --git a/test/nt/ntnameValueTest.cpp b/test/nt/ntnameValueTest.cpp
index 05904f0..accad8a 100644
--- a/test/nt/ntnameValueTest.cpp
+++ b/test/nt/ntnameValueTest.cpp
@@ -14,45 +14,41 @@
 #include <cstdlib>
 #include <cstddef>
 #include <string>
-#include <cstring>
-#include <cstdio>
 #include <ctime>
 #include <list>
+#include <iostream>
 
 #include <epicsAssert.h>
 
 #include <pv/nt.h>
+#include <pv/sharedVector.h>
 
 using namespace epics::pvData;
+using std::string;
+using std::cout;
+using std::endl;
 
 static PVDataCreatePtr pvDataCreate = getPVDataCreate();
 static NTFieldPtr ntField = NTField::get();
 static PVNTFieldPtr pvntField = PVNTField::get();
-static String builder;
 
 static void test(FILE * fd)
 {
     NTNameValuePtr ntNameValue = NTNameValue::create(true,true,true);
     PVStructurePtr pvStructure = ntNameValue->getPVStructure();
-    builder.clear();
-    pvStructure->toString(&builder);
-    fprintf(fd,"%s\n",builder.c_str());
-    builder.clear();
-    pvStructure->getStructure()->toString(&builder);
-    fprintf(fd,"%s\n",builder.c_str());
+    cout << *pvStructure << endl;
+    cout << *pvStructure->getStructure() << endl;
     PVStringArrayPtr names = ntNameValue->getNames();
     PVStringArrayPtr values = ntNameValue->getValues();
     size_t n = 2;
-    StringArray name;
-    StringArray value;
-    name.resize(n);
-    value.resize(n);
+    shared_vector<string> name(n);
+    shared_vector<string> value(n);
     name[0] = "name 0";
     name[1] = "name 1";
     value[0] = "value 0";
     value[1] = "value 1";
-    names->put(0,n,name,0);
-    values->put(0,n,value,0);
+    names->replace(freeze(name));
+    values->replace(freeze(value));
     PVStringPtr function = ntNameValue->getFunction();
     function->put("test");
     PVAlarm pvAlarm;
@@ -66,9 +62,7 @@ static void test(FILE * fd)
     ntNameValue->attachTimeStamp(pvTimeStamp);
     TimeStamp timeStamp(1000,1000,10);
     pvTimeStamp.set(timeStamp);
-    builder.clear();
-    pvStructure->toString(&builder);
-    fprintf(fd,"%s\n",builder.c_str());
+    cout << *pvStructure << endl;
     assert(NTNameValue::isNTNameValue(pvStructure));
 }
 
diff --git a/test/nt/nttableTest.cpp b/test/nt/nttableTest.cpp
index 8df9cd4..78326dc 100644
--- a/test/nt/nttableTest.cpp
+++ b/test/nt/nttableTest.cpp
@@ -14,29 +14,29 @@
 #include <cstdlib>
 #include <cstddef>
 #include <string>
-#include <cstring>
-#include <cstdio>
 #include <ctime>
 #include <list>
-
+#include <iostream>
 #include <epicsAssert.h>
 
 #include <pv/nt.h>
 
 using namespace epics::pvData;
 using std::tr1::static_pointer_cast;
+using std::string;
+using std::cout;
+using std::endl;
 
 static FieldCreatePtr fieldCreate = getFieldCreate();
 static PVDataCreatePtr pvDataCreate = getPVDataCreate();
 static NTFieldPtr ntField = NTField::get();
 static PVNTFieldPtr pvntField = PVNTField::get();
-static String builder;
 
 static void test(FILE * fd)
 {
     size_t n = 2;
     FieldConstPtrArray fields(n);
-    StringArray names(n);
+    shared_vector<string> names(n);
     names[0] = "position";
     names[1] = "alarms";
     fields[0] = fieldCreate->createScalarArray(pvDouble);
@@ -44,23 +44,19 @@ static void test(FILE * fd)
     NTTablePtr ntTable = NTTable::create(
         true,true,true,names,fields);
     PVStructurePtr pvStructure = ntTable->getPVStructure();
-    builder.clear();
-    pvStructure->toString(&builder);
-    fprintf(fd,"%s\n",builder.c_str());
-    builder.clear();
-    pvStructure->getStructure()->toString(&builder);
-    fprintf(fd,"%s\n",builder.c_str());
+    cout << *pvStructure << endl;
+    cout << *pvStructure->getStructure() << endl;
     PVDoubleArrayPtr pvPositions
         = static_pointer_cast<PVDoubleArray>(ntTable->getPVField(0));
-    DoubleArray positions(2);
+    shared_vector<double> positions(2);
     positions[0] = 1.0;
     positions[1] = 2.0;
-    pvPositions->put(0,2,positions,0);
+    pvPositions->replace(freeze(positions));
     PVStructureArrayPtr pvAlarms
         = static_pointer_cast<PVStructureArray>(ntTable->getPVField(1));
     PVAlarm pvAlarm;
     Alarm alarm;
-    PVStructurePtrArray palarms(n);
+    shared_vector<PVStructurePtr> palarms(n);
     for(size_t i=0; i<n; i++) {
         palarms[i] = pvntField->createAlarm();
         pvAlarm.attach(palarms[i]);
@@ -69,12 +65,12 @@ static void test(FILE * fd)
         alarm.setStatus(clientStatus);
         pvAlarm.set(alarm);
     }
-    pvAlarms->put(0,n,palarms,0);
-    StringArray labels(n);
+    pvAlarms->replace(freeze(palarms));
+    shared_vector<string> labels(n);
     labels[0] = pvPositions->getFieldName();
     labels[1] = pvAlarms->getFieldName();
     PVStringArrayPtr label = ntTable->getLabel();
-    label->put(0,n,labels,0);
+    label->replace(freeze(labels));
     PVStringPtr function = ntTable->getFunction();
     function->put("test");
     ntTable->attachAlarm(pvAlarm);
@@ -86,9 +82,7 @@ static void test(FILE * fd)
     ntTable->attachTimeStamp(pvTimeStamp);
     TimeStamp timeStamp(1000,1000,10);
     pvTimeStamp.set(timeStamp);
-    builder.clear();
-    pvStructure->toString(&builder);
-    fprintf(fd,"%s\n",builder.c_str());
+    cout << *pvStructure << endl;
     assert(NTTable::isNTTable(pvStructure));
 }