diff --git a/documentation/pvDataCpp.html b/documentation/pvDataCpp.html
index 06f8e72..48945d3 100644
--- a/documentation/pvDataCpp.html
+++ b/documentation/pvDataCpp.html
@@ -1691,6 +1691,8 @@ public:
     virtual ~PVStructureArray();
     virtual StructureArrayConstPtr getStructureArray() = 0;
     virtual void setCapacity(int capacity) = 0;
+    virtual int append(int number) = 0;
+    virtual bool remove(int offset,int number) = 0;
     virtual int get(int offset, int length,
         StructureArrayData *data) = 0;
     virtual int put(int offset,int length,
@@ -1712,6 +1714,14 @@ private:
 <dl>
   <dt style="font-family: courier;">getStructureArray</dt>
     <dd>Get the introspection interface shared by each element.</dd>
+  <dt style="font-family: courier;">append</dt>
+     <dd>Create new elements and append them to the end of the array.
+     It returns the index of the first new element.</dd>
+  <dt style="font-family: courier;">remove</dt>
+     <dd>Remove the specfied set of elements. It returns (false,true)
+     if the elements (were not, were) removed.
+     It will not removed any elements unless all requested elements
+     exist or are null.</dd>
 </dl>
 
 <p>The other methods are similar to the methods for other array types.</p>
diff --git a/pvDataApp/factory/BasePVStructureArray.h b/pvDataApp/factory/BasePVStructureArray.h
index fd503b2..c487a8b 100644
--- a/pvDataApp/factory/BasePVStructureArray.h
+++ b/pvDataApp/factory/BasePVStructureArray.h
@@ -29,6 +29,8 @@ namespace epics { namespace pvData {
              StructureArrayConstPtr structureArray);
         virtual ~BasePVStructureArray();
         virtual StructureArrayConstPtr getStructureArray();
+        virtual int append(int number);
+        virtual bool remove(int offset,int number);
         virtual void setCapacity(int capacity);
         virtual int get(int offset, int length,
             StructureArrayData *data);
@@ -62,8 +64,8 @@ namespace epics { namespace pvData {
     BasePVStructureArray::~BasePVStructureArray()
     {
         delete structureArrayData;
-        int length = getLength();
-        for(int i=0; i<length; i++) {
+        int number = getCapacity();
+        for(int i=0; i<number; i++) {
            if(value[i]!=0) {
                 delete value[i];
            }
@@ -71,6 +73,38 @@ namespace epics { namespace pvData {
         delete[] value;
     }
 
+    int BasePVStructureArray::append(int number)
+    {
+        int currentLength = getCapacity();
+        int newLength = currentLength + number;
+        setCapacity(newLength);
+        StructureConstPtr structure = structureArray->getStructure();
+        for(int i=currentLength; i<newLength; i++) {
+            structure->incReferenceCount();
+            value[i] =  getPVDataCreate()->createPVStructure(0,structure);
+        }
+        return newLength;
+    }
+
+    bool BasePVStructureArray::remove(int offset,int number)
+    {
+        int length = getCapacity();
+        if(offset+number>length) return false;
+        for(int i=offset;i<offset+number;i++) {
+           if(value[i]!=0) {
+                delete value[i];
+                value[i] = 0;
+           }
+        }
+        // move any at end up
+        int nToMove = length - (offset+number);
+        for(int i=0; i<nToMove; i++) {
+            value[i+offset] = value[i+length];
+            value[i+length] = 0;
+        }
+        return true;
+    }
+
     void BasePVStructureArray::setCapacity(int capacity) {
         if(getCapacity()==capacity) return;
         if(!isCapacityMutable()) {
@@ -78,7 +112,9 @@ namespace epics { namespace pvData {
             PVField::message(message, errorMessage);
             return;
         }
-        int length = PVArray::getLength();
+        int length = getCapacity();
+        int numRemove = length - capacity;
+        if(numRemove>0) remove(length,numRemove);
         PVStructurePtrArray  newValue = new PVStructurePtr[capacity];
         int limit = length;
         if(length>capacity) limit = capacity;
diff --git a/pvDataApp/pv/pvData.h b/pvDataApp/pv/pvData.h
index ea61d25..acef197 100644
--- a/pvDataApp/pv/pvData.h
+++ b/pvDataApp/pv/pvData.h
@@ -162,6 +162,8 @@ class PVStructureArray : public PVArray {
 public:
     virtual ~PVStructureArray();
     virtual StructureArrayConstPtr getStructureArray() = 0;
+    virtual int append(int number) = 0;
+    virtual bool remove(int offset,int number) = 0;
     virtual void setCapacity(int capacity) = 0;
     virtual int get(int offset, int length,
         StructureArrayData *data) = 0;
diff --git a/test/testPVStructureArray b/test/testPVStructureArray
index b84d060..9b3ed89 100644
--- a/test/testPVStructureArray
+++ b/test/testPVStructureArray
@@ -54,62 +54,6 @@ structure powerSupply
     timeStamp timeStamp
         long secondsPastEpoch 0
         int nanoSeconds 0
- reference counts powerSupply referenceCount 1
-    value referenceCount 1
-    alarm referenceCount 14
-        severity referenceCount 14
-        message referenceCount 14
-    timeStamp referenceCount 2
-        secondsPastEpoch referenceCount 2
-        nanoSeconds referenceCount 2
-before incReferenceCount reference counts powerSupply referenceCount 4
-    voltage referenceCount 4
-        value referenceCount 4
-        alarm referenceCount 14
-            severity referenceCount 14
-            message referenceCount 14
-    power referenceCount 4
-        value referenceCount 4
-        alarm referenceCount 14
-            severity referenceCount 14
-            message referenceCount 14
-    current referenceCount 4
-        value referenceCount 4
-        alarm referenceCount 14
-            severity referenceCount 14
-            message referenceCount 14
-after incReferenceCount reference counts powerSupply referenceCount 5
-    voltage referenceCount 5
-        value referenceCount 5
-        alarm referenceCount 17
-            severity referenceCount 17
-            message referenceCount 17
-    power referenceCount 5
-        value referenceCount 5
-        alarm referenceCount 17
-            severity referenceCount 17
-            message referenceCount 17
-    current referenceCount 5
-        value referenceCount 5
-        alarm referenceCount 17
-            severity referenceCount 17
-            message referenceCount 17
-after decReferenceCount reference counts powerSupply referenceCount 4
-    voltage referenceCount 4
-        value referenceCount 4
-        alarm referenceCount 14
-            severity referenceCount 14
-            message referenceCount 14
-    power referenceCount 4
-        value referenceCount 4
-        alarm referenceCount 14
-            severity referenceCount 14
-            message referenceCount 14
-    current referenceCount 4
-        value referenceCount 4
-        alarm referenceCount 14
-            severity referenceCount 14
-            message referenceCount 14
 field:  totalConstruct 102 totalDestruct 102
 pvField:  totalConstruct 56 totalDestruct 56
 linkedListNode:  totalConstruct 5 totalDestruct 5
diff --git a/test/testPVStructureArrayDiff b/test/testPVStructureArrayDiff
index e69de29..5557c62 100644
--- a/test/testPVStructureArrayDiff
+++ b/test/testPVStructureArrayDiff
@@ -0,0 +1,57 @@
+56a57,112
+>  reference counts powerSupply referenceCount 1
+>     value referenceCount 1
+>     alarm referenceCount 14
+>         severity referenceCount 14
+>         message referenceCount 14
+>     timeStamp referenceCount 2
+>         secondsPastEpoch referenceCount 2
+>         nanoSeconds referenceCount 2
+> before incReferenceCount reference counts powerSupply referenceCount 4
+>     voltage referenceCount 4
+>         value referenceCount 4
+>         alarm referenceCount 14
+>             severity referenceCount 14
+>             message referenceCount 14
+>     power referenceCount 4
+>         value referenceCount 4
+>         alarm referenceCount 14
+>             severity referenceCount 14
+>             message referenceCount 14
+>     current referenceCount 4
+>         value referenceCount 4
+>         alarm referenceCount 14
+>             severity referenceCount 14
+>             message referenceCount 14
+> after incReferenceCount reference counts powerSupply referenceCount 5
+>     voltage referenceCount 5
+>         value referenceCount 5
+>         alarm referenceCount 17
+>             severity referenceCount 17
+>             message referenceCount 17
+>     power referenceCount 5
+>         value referenceCount 5
+>         alarm referenceCount 17
+>             severity referenceCount 17
+>             message referenceCount 17
+>     current referenceCount 5
+>         value referenceCount 5
+>         alarm referenceCount 17
+>             severity referenceCount 17
+>             message referenceCount 17
+> after decReferenceCount reference counts powerSupply referenceCount 4
+>     voltage referenceCount 4
+>         value referenceCount 4
+>         alarm referenceCount 14
+>             severity referenceCount 14
+>             message referenceCount 14
+>     power referenceCount 4
+>         value referenceCount 4
+>         alarm referenceCount 14
+>             severity referenceCount 14
+>             message referenceCount 14
+>     current referenceCount 4
+>         value referenceCount 4
+>         alarm referenceCount 14
+>             severity referenceCount 14
+>             message referenceCount 14
diff --git a/testApp/pv/testPVStructureArray.cpp b/testApp/pv/testPVStructureArray.cpp
index 03049c4..bbd54b1 100644
--- a/testApp/pv/testPVStructureArray.cpp
+++ b/testApp/pv/testPVStructureArray.cpp
@@ -49,33 +49,13 @@ void testPowerSupplyArray(FILE * fd) {
     PVStructureArray * powerSupplyArray =
         powerSupplyArrayStruct->getStructureArrayField(String("value"));
     assert(powerSupplyArray!=0);
-    PVStructurePtrArray structureArray = new PVStructurePtr[3];
-    StructureConstPtr structure =
-        powerSupplyArray->getStructureArray()->getStructure();
-    structure->incReferenceCount();
-    structureArray[0] = pvDataCreate->createPVStructure(0,structure);
-    structure->incReferenceCount();
-    structureArray[1] = pvDataCreate->createPVStructure(0,structure);
-    structure->incReferenceCount();
-    structureArray[2] = pvDataCreate->createPVStructure(0,structure);
-    powerSupplyArray->put(0,3,structureArray,0);
+    int offset = powerSupplyArray->append(3);
+    powerSupplyArray->setLength(offset);
     buffer.clear();
     powerSupplyArrayStruct->toString(&buffer);
     fprintf(fd,"%s\n",buffer.c_str());
-    buffer.clear();
-    powerSupplyArrayStruct->getField()->dumpReferenceCount(&buffer,0);
-    fprintf(fd," reference counts %s\n",buffer.c_str());
-    buffer.clear();
-    structure->dumpReferenceCount(&buffer,0);
-    fprintf(fd,"before incReferenceCount reference counts %s\n",buffer.c_str());
-    structure->incReferenceCount();
-    buffer.clear();
-    structure->dumpReferenceCount(&buffer,0);
-    fprintf(fd,"after incReferenceCount reference counts %s\n",buffer.c_str());
-    structure->decReferenceCount();
-    buffer.clear();
-    structure->dumpReferenceCount(&buffer,0);
-    fprintf(fd,"after decReferenceCount reference counts %s\n",buffer.c_str());
+    StructureConstPtr structure = 
+         powerSupplyArray->getStructureArray()->getStructure();
     delete powerSupplyArrayStruct;
 }