diff --git a/Aux/EventBuilder.cpp b/Aux/EventBuilder.cpp
index 604dc74..79e1624 100644
--- a/Aux/EventBuilder.cpp
+++ b/Aux/EventBuilder.cpp
@@ -8,42 +8,7 @@
 #include "TFile.h"
 #include "TTree.h"
 
-#define MAX_MULTI  100
-
-#define ORDERSHIFT 100000
-
-struct FileInfo {
-  std::string fileName;
-  unsigned int fileSize;
-  unsigned int SN;
-  unsigned long hitCount;
-  unsigned short DPPType;
-  unsigned short tick2ns;
-  unsigned short order;
-  unsigned short readerID;
-
-  unsigned long long t0;
-
-  unsigned long ID; // sn + 100000 * order
-
-  void CalOrder(){ ID = ORDERSHIFT * SN + order; }
-
-  void Print(){
-    printf(" %10lu | %3d | %50s | %2d | %6lu | %10u Bytes = %.2f MB\n", 
-            ID, DPPType, fileName.c_str(), tick2ns, hitCount, fileSize, fileSize/1024./1024.);  
-  }
-};
-
-struct GroupInfo{
-
-  std::vector<unsigned short> fileIDList;
-  uInt sn;
-  unsigned short currentID ; // the ID of the readerIDList;
-  ulong hitCount ; // this is the hitCount for the currentID;
-  uInt usedHitCount ;
-  bool finished;
-
-};
+#define MAX_MULTI  1000
 
 //^#############################################################
 //^#############################################################
@@ -71,14 +36,6 @@ int main(int argc, char **argv) {
 
   uInt runStartTime = get_time_us();
 
-  /// File format must be YYY...Y_runXXX_AAA_BBB_TT_CCC.fsu
-  /// YYY...Y  = prefix
-  /// XXX = runID, 3 digits
-  /// AAA = board Serial Number, 3 digits
-  /// BBB = DPPtype, 3 digits
-  ///  TT = tick2ns, any digits
-  /// CCC = over size index, 3 digits
-  
   ///============= read input
   unsigned int  timeWindow = atoi(argv[1]);
   bool traceOn = atoi(argv[2]);
@@ -173,8 +130,17 @@ int main(int argc, char **argv) {
       printf("Processing %s (%d/%d) ..... \n", inFileName[i].Data(), i+1, nFile);
       reader[i] = new FSUTSReader(inFileName[i].Data(), false);
 
+      if( !reader[i]->isOpen() ){
+        printf("------- cannot open file.\n");
+        continue;
+      }
       reader[i]->ScanFile(0); 
-  
+
+      if( reader[i]->GetNumHit() == 0 ){
+        printf("------- file has no data.\n");
+        continue;
+      }
+
       FileInfo tempInfo;
       tempInfo.fileName = inFileName[i].Data();
       tempInfo.readerID = i;
@@ -279,9 +245,7 @@ int main(int argc, char **argv) {
   for( int i = 0; i < nGroup; i++){
     std::string fileName = fileInfo[group[i].fileIDList[0]].fileName;
     tsReader[i] = new FSUTSReader(fileName);
-
-    tsReader[i]->ScanFile(1);
-
+    tsReader[i]->ScanFile(0);
     group[i].usedHitCount = 0;
   }
 
@@ -307,9 +271,6 @@ int main(int argc, char **argv) {
   } 
 
   if( debug ) printf("First timestamp is %llu, group : %u\n", t0, gp0);
-
-  unsigned int maxUInt = -1;
-
   do{
 
     if( debug ) printf("################################ ev build %llu \n", evID);
@@ -317,14 +278,11 @@ int main(int argc, char **argv) {
     ///===================== check if the file is finished.
     for( int i = 0; i < nGroup; i++){
       uShort gpID = (i + gp0) % nGroup;
-
       if( group[gpID].finished ) continue;
-
       short endCount = 0;
-
       do{
 
-        if( group[gpID].usedHitCount > tsReader[gpID]->GetHitID() || tsReader[gpID]->GetHitID() == maxUInt){
+        if( group[gpID].usedHitCount > tsReader[gpID]->GetHitID() || tsReader[gpID]->GetFilePos() <= 4){
           if( tsReader[gpID]->ReadNextHit(traceOn, 0) == 0 ){ 
             hitProcessed ++;
             if( debug ){ printf("............ Get Data | "); tsReader[gpID]->GetHit()->Print();}
@@ -363,6 +321,10 @@ int main(int argc, char **argv) {
             if( debug ){ printf("..Get Data after fill | "); tsReader[gpID]->GetHit()->Print();}
           }
 
+          if( multi > MAX_MULTI) {
+            printf("  !!!!!! multi > %d\n", MAX_MULTI);
+          }
+
         }else{
           break;
         }
diff --git a/Aux/EventBuilderNoTrace.cpp b/Aux/EventBuilderNoTrace.cpp
index b655130..e26864e 100644
--- a/Aux/EventBuilderNoTrace.cpp
+++ b/Aux/EventBuilderNoTrace.cpp
@@ -7,40 +7,7 @@
 #include "TFile.h"
 #include "TTree.h"
 
-#define MAX_MULTI  10000
-
-#define ORDERSHIFT 100000
-
-struct FileInfo {
-  TString fileName;
-  unsigned int fileSize;
-  unsigned int SN;
-  unsigned long hitCount;
-  unsigned short DPPType;
-  unsigned short tick2ns;
-  unsigned short order;
-  unsigned short readerID;
-
-  unsigned long ID; // sn + 100000 * order
-
-  void CalOrder(){ ID = ORDERSHIFT * SN + order; }
-
-  void Print(){
-    printf(" %10lu | %3d | %50s | %2d | %6lu | %10u Bytes = %.2f MB\n", 
-            ID, DPPType, fileName.Data(), tick2ns, hitCount, fileSize, fileSize/1024./1024.);  
-  }
-};
-
-struct GroupInfo{
-
-  std::vector<unsigned short> readerIDList;
-  uInt sn;
-  unsigned short currentID ; // the ID of the readerIDList;
-  ulong hitCount ; // this is the hitCount for the currentID;
-  ulong hitID ; // this is the ID for the reader->GetHit(hitID);
-  bool finished;
-
-};
+#define MAX_MULTI  1000
 
 //^#############################################################
 //^#############################################################
@@ -64,14 +31,6 @@ int main(int argc, char **argv) {
   }
 
   uInt runStartTime = get_time_us();
-
-  /// File format must be YYY...Y_runXXX_AAA_BBB_TT_CCC.fsu
-  /// YYY...Y  = prefix
-  /// XXX = runID, 3 digits
-  /// AAA = board Serial Number, 3 digits
-  /// BBB = DPPtype, 3 digits
-  ///  TT = tick2ns, any digits
-  /// CCC = over size index, 3 digits
   
   ///============= read input
   unsigned int  timeWindow = atoi(argv[1]);
@@ -180,7 +139,6 @@ int main(int argc, char **argv) {
   unsigned long long                evID = 0;
   unsigned int                     multi = 0;
   unsigned short           sn[MAX_MULTI] = {0}; /// board SN
-  //unsigned short           bd[MAX_MULTI] = {0}; /// boardID
   unsigned short           ch[MAX_MULTI] = {0}; /// chID
   unsigned short            e[MAX_MULTI] = {0}; /// 15 bit
   unsigned short           e2[MAX_MULTI] = {0}; /// 15 bit
@@ -190,7 +148,6 @@ int main(int argc, char **argv) {
   tree->Branch("evID",           &evID, "event_ID/l"); 
   tree->Branch("multi",         &multi, "multi/i"); 
   tree->Branch("sn",                sn, "sn[multi]/s");
-  //tree->Branch("bd",                bd, "bd[multi]/s");
   tree->Branch("ch",                ch, "ch[multi]/s");
   tree->Branch("e",                  e, "e[multi]/s");
   tree->Branch("e2",                e2, "e2[multi]/s");
@@ -208,7 +165,6 @@ int main(int argc, char **argv) {
     // arrayTrace->BypassStreamer();
   // }
 
-
   //*====================================== build events
   printf("================= Building events....\n");
 
@@ -247,7 +203,7 @@ int main(int argc, char **argv) {
           group[gpID].hitID = 0;
           uShort rID = group[gpID].readerIDList[group[gpID].currentID];
           group[gpID].hitCount = reader[rID]->GetHitCount();
-          printf("-----> go to the next file, %s \n", fileInfo[rID].fileName.Data() );
+          printf("-----> go to the next file, %s \n", fileInfo[rID].fileName.c_str() );
         }
       }
 
@@ -259,7 +215,7 @@ int main(int argc, char **argv) {
         group0 = gpID;
       }
     }
-    if (debug ) printf("the eariliest time is %llu at Group : %u, hitID : %lu, %s\n", t0, group0, group[group0].hitID, fileInfo[group[group0].currentID].fileName.Data());
+    if (debug ) printf("the eariliest time is %llu at Group : %u, hitID : %lu, %s\n", t0, group0, group[group0].hitID, fileInfo[group[group0].currentID].fileName.c_str());
 
     printf("hit Porcessed %u/%u....%.2f%%\n\033[A\r", hitProcessed, totHitCount,  hitProcessed*100./totHitCount);
     
diff --git a/Aux/fsuReader.h b/Aux/fsuReader.h
index d5dc155..9b0b505 100644
--- a/Aux/fsuReader.h
+++ b/Aux/fsuReader.h
@@ -3,6 +3,47 @@
 #include <algorithm>
 #include <filesystem>
 
+#define ORDERSHIFT 100000
+
+struct FileInfo {
+  std::string fileName;
+  unsigned int fileSize;
+  unsigned int SN;
+  unsigned long hitCount;
+  unsigned short DPPType;
+  unsigned short tick2ns;
+  unsigned short order;
+  unsigned short readerID;
+
+  unsigned long long t0;
+
+  unsigned long ID; // sn + 100000 * order
+
+  void CalOrder(){ ID = ORDERSHIFT * SN + order; }
+
+  void Print(){
+    printf(" %10lu | %3d | %50s | %2d | %6lu | %10u Bytes = %.2f MB\n", 
+            ID, DPPType, fileName.c_str(), tick2ns, hitCount, fileSize, fileSize/1024./1024.);  
+  }
+};
+
+struct GroupInfo{
+
+  std::vector<unsigned short> fileIDList;
+  uInt usedHitCount ;
+
+  std::vector<unsigned short> readerIDList;
+  ulong hitID ; // this is the ID for the reader->GetHit(hitID);
+
+  unsigned short currentID ; // the ID of the readerIDList;
+  ulong hitCount ; // this is the hitCount for the currentID;
+  uInt sn;
+  bool finished;
+
+  unsigned long long timeShift; 
+
+};
+
 class FSUReader{
 
   public:
@@ -107,6 +148,14 @@ inline FSUReader::FSUReader(std::string fileName, uShort dataSize, int verbose){
 
 inline void FSUReader::OpenFile(std::string fileName, uShort dataSize, int verbose){
 
+  /// File format must be YYY...Y_runXXX_AAA_BBB_TT_CCC.fsu
+  /// YYY...Y  = prefix
+  /// XXX = runID, 3 digits
+  /// AAA = board Serial Number, 3 digits
+  /// BBB = DPPtype, 3 digits
+  ///  TT = tick2ns, any digits
+  /// CCC = over size index, 3 digits
+
   inFile = fopen(fileName.c_str(), "r");
 
   if( inFile == NULL ){
diff --git a/Aux/fsutsReader.h b/Aux/fsutsReader.h
index 11e5391..ec57531 100644
--- a/Aux/fsutsReader.h
+++ b/Aux/fsutsReader.h
@@ -30,6 +30,7 @@ class FSUTSReader{
 
     std::string   GetFileName()     const {return fileName;}
     unsigned long GetFileByteSize() const {return inFileSize;}
+    unsigned int  GetFilePos()      const {return filePos;}
     int           GetFileOrder()    const {return order;}  
     uShort        GetSN()           const {return sn;}
     ullong        GetT0()           const {return t0;}
@@ -110,7 +111,7 @@ inline void FSUTSReader::OpenFile(std::string fileName, int verbose){
 
   fseek(inFile, 0L, SEEK_END);
   inFileSize = ftell(inFile);
-  if(verbose) printf("###### %s | file size : %ld Byte = %.2f MB\n", fileName.c_str() , inFileSize, inFileSize/1024./1024.);
+  if(verbose) printf("###### %50s | %11ld Byte = %.2f MB\n", fileName.c_str() , inFileSize, inFileSize/1024./1024.);
   fseek(inFile, 0L, SEEK_SET);
   filePos = 0;