diff --git a/apps/nexus/borderserver.cpp b/apps/nexus/borderserver.cpp
new file mode 100644
index 00000000..239c285f
--- /dev/null
+++ b/apps/nexus/borderserver.cpp
@@ -0,0 +1,61 @@
+#include "borderserver.h"
+#include <iostream>
+
+using namespace std;
+using namespace nxs;
+
+void BorderServer::AddBorder(unsigned short nbord, unsigned int used) {
+  BorderEntry entry;
+  entry.border_start = Size();
+  entry.border_size = nbord;
+  entry.border_used = used;
+  borders.push_back(entry);
+  Resize(entry.border_start + nbord);
+}
+
+Border BorderServer::GetBorder(unsigned int border, bool flush) {
+  assert(border < borders.size());
+  BorderEntry &entry = borders[border];
+  Link *start = GetRegion(entry.border_start, entry.border_size, flush);
+  return Border(start, entry.border_used, entry.border_size);
+}
+
+bool BorderServer::ResizeBorder(unsigned int border, unsigned int nbord) {
+
+  assert(border < borders.size());
+  BorderEntry &entry = borders[border];
+  if(nbord > entry.border_size) {
+    unsigned int capacity = nbord;
+    if(capacity < entry.border_size*2) 
+      capacity = entry.border_size * 2;
+    unsigned int newstart = Size(); 
+    Resize(newstart + capacity);
+
+    Link *src = GetRegion(entry.border_start, entry.border_size);
+    Link *dst = GetRegion(newstart, capacity, false);
+    memcpy(dst, src, entry.border_used * sizeof(Link));
+    entry.border_start = newstart;
+    entry.border_size = capacity;
+    entry.border_used = nbord;
+    return true;
+  }
+  entry.border_used = nbord;
+  return false;
+}
+
+bool BorderServer::ReadEntries(FILE *fp) {
+  unsigned int n;
+  fread(&n, 1, sizeof(int), fp);
+  borders.resize(n);
+  fread(&*borders.begin(), n, sizeof(BorderEntry), fp);
+  return true;
+}
+
+bool BorderServer::WriteEntries(FILE *fp) {
+  unsigned int n = borders.size();
+  fwrite(&n, 1, sizeof(int), fp);
+  fwrite(&*borders.begin(), n, sizeof(BorderEntry), fp);
+  return true;
+}
+
+  
diff --git a/apps/nexus/borderserver.h b/apps/nexus/borderserver.h
new file mode 100644
index 00000000..36faabb1
--- /dev/null
+++ b/apps/nexus/borderserver.h
@@ -0,0 +1,42 @@
+#ifndef NXS_BORDERSERVER_H
+#define NXS_BORDERSERVER_H
+
+#include "vfile.h"
+#include "border.h"
+#include <vector>
+
+namespace nxs {
+
+struct BorderEntry {
+  unsigned int border_start; //granuralita' Link
+  unsigned short border_size; //in Links
+  unsigned short border_used; //in Links
+};
+
+class BorderServer: public VFile<Link> {
+ public:
+  void AddBorder(unsigned short nbord, unsigned int used = 0);
+  Border GetBorder(unsigned int border, bool flush = true);
+  //return true if you need to reread border as it changed location
+  bool ResizeBorder(unsigned int border, unsigned int nbord);
+
+  bool ReadEntries(FILE *fp);
+  bool WriteEntries(FILE *fp);
+
+  unsigned int BorderSize(unsigned int i) { 
+    return borders[i].border_used; 
+  }
+  unsigned int BorderCapacity(unsigned int i) { 
+    return borders[i].border_size; 
+  }
+  
+  
+
+  
+  std::vector<BorderEntry> borders;
+
+};
+
+}
+
+#endif
diff --git a/apps/nexus/patchserver.cpp b/apps/nexus/patchserver.cpp
new file mode 100644
index 00000000..0d0341ad
--- /dev/null
+++ b/apps/nexus/patchserver.cpp
@@ -0,0 +1,162 @@
+#include "patchserver.h"
+
+#include <iostream>
+
+using namespace std;
+using namespace nxs;
+
+//TODO support compression!
+
+
+bool PatchServer::Create(const std::string &filename, 
+			 Signature sig, 
+			 unsigned int csize,
+			 unsigned int rsize) {
+  signature = sig;
+  chunk_size = csize;
+  ram_size = rsize;
+  ram_used = 0;
+  lru.clear();
+  return File::Create(filename);
+}
+
+bool PatchServer::Load(const std::string &filename, Signature sig, 
+		       unsigned int csize, bool readonly, 
+		       unsigned int rsize) {
+  signature = sig;
+  chunk_size = csize;
+  ram_size = rsize;
+  ram_used = 0;
+  lru.clear();
+  return File::Load(filename, readonly);
+}
+
+void PatchServer::Close() {
+  cerr << "Closing!" << endl;
+  FlushAll();
+  File::Close();
+}
+
+//TODO add error checking.
+bool PatchServer::ReadEntries(FILE *fp) {
+  unsigned int n;
+  fread(&n, 1, sizeof(int), fp);
+  patches.resize(n);
+  for(unsigned int i = 0; i < n; i++) {
+    patches[i].patch = NULL;
+    fread(&(patches[i].patch_start), 1, sizeof(unsigned int), fp);
+    fread(&(patches[i].patch_size),  1, sizeof(unsigned short), fp);
+    fread(&(patches[i].ram_used),    1, sizeof(unsigned short), fp);
+    patches[i].lru_pos = 0xffffffff;
+  }
+  return true;
+}
+
+bool PatchServer::WriteEntries(FILE *fp) {
+  unsigned int n = patches.size();
+  fwrite(&n, 1, sizeof(int), fp);
+  for(unsigned int i = 0; i < patches.size(); i++) {
+    fwrite(&(patches[i].patch_start), 1, sizeof(unsigned int), fp);
+    fwrite(&(patches[i].patch_size),  1, sizeof(unsigned short), fp);
+    fwrite(&(patches[i].ram_used),    1, sizeof(unsigned short), fp);
+  }
+  return true;
+}
+
+void PatchServer::AddPatch(unsigned short nvert, unsigned short nface) {
+  PatchEntry entry;
+  entry.patch = NULL;
+  entry.patch_start = Length()/chunk_size;
+  entry.patch_size = Patch::ChunkSize(signature, nvert, nface, chunk_size);
+  entry.ram_used = entry.patch_size;
+  entry.lru_pos = 0xffffffff;
+  patches.push_back(entry);
+
+  Redim(Length() + entry.patch_size * chunk_size);
+}
+
+Patch &PatchServer::GetPatch(unsigned int idx, 
+			     unsigned short nvert, unsigned short nface,
+			     bool flush) {
+
+  assert(idx < patches.size());
+  PatchEntry &entry = patches[idx];
+
+  if(entry.patch) { 
+    assert(entry.lru_pos < lru.size());
+    assert(lru[entry.lru_pos].patch == idx);
+    lru[entry.lru_pos].frame = frame++;
+  } else {
+    SetPosition(entry.patch_start * chunk_size);
+    
+    assert(entry.patch_size != 0);
+    char *start = new char[entry.patch_size * chunk_size];
+    ReadBuffer(start, entry.patch_size * chunk_size);
+   
+    entry.patch = new Patch(signature, start, nvert, nface);
+    entry.lru_pos = lru.size();
+    lru.push_back(PTime(idx, frame++));
+    ram_used += entry.ram_used;
+  }
+
+  //avoid frame overflow!
+  if(frame > (1<<30)) {
+    cerr << "oVERFLOW!" << endl;;
+    for(unsigned int i = 0; i < lru.size(); i++) {
+      if(lru[i].frame < (1<<29)) lru[i].frame = 0;
+      else lru[i].frame -= (1<<29);
+    }
+    make_heap(lru.begin(), lru.end());
+    for(unsigned int i = 0; i < lru.size(); i++)
+      patches[lru[i].patch].lru_pos = i;
+  }
+
+  if(flush && ram_used > ram_size * 1.1)
+    Flush();
+
+  return *(entry.patch); 
+}
+
+void PatchServer::Flush() {
+  cerr << "FLUSHING\n\n\n n";
+  cerr << "ram_size: " << ram_size << endl;
+  cerr << "ram_used: " << ram_used << endl;
+  make_heap(lru.begin(), lru.end());
+  while(ram_used > ram_size) {
+    pop_heap(lru.begin(), lru.end());
+    PTime &ptime = lru.back();
+
+    Flush(ptime.patch);
+
+    lru.pop_back();
+  }
+  make_heap(lru.begin(), lru.end());
+  for(unsigned int i = 0; i < lru.size(); i++)
+    patches[lru[i].patch].lru_pos = i;
+}
+
+void PatchServer::FlushAll() {
+  for(unsigned int i = 0; i < lru.size(); i++) {
+    PTime &ptime = lru[i];
+    Flush(ptime.patch);
+  }
+  assert(ram_used == 0);
+  lru.clear();
+}
+
+
+void PatchServer::Flush(unsigned int patch) {
+
+  PatchEntry &entry = patches[patch];
+  assert(entry.patch);
+
+  if(!readonly) { //write back patch
+    SetPosition(entry.patch_start * chunk_size);
+    WriteBuffer(entry.patch->start, entry.patch_size * chunk_size);
+  }
+  delete [](entry.patch->start);
+  delete entry.patch;
+  entry.patch = NULL;
+  entry.lru_pos = 0xffffffff;
+  ram_used -= entry.ram_used;
+}
diff --git a/apps/nexus/patchserver.h b/apps/nexus/patchserver.h
new file mode 100644
index 00000000..dd2125bb
--- /dev/null
+++ b/apps/nexus/patchserver.h
@@ -0,0 +1,64 @@
+#ifndef NXS_PATCH_SERVER_H
+#define NXS_PATCH_SERVER_H
+
+#include "patch.h"
+#include "file.h"
+
+#include <vector>
+
+namespace nxs {
+
+struct PatchEntry { 
+  Patch *patch;
+  unsigned int patch_start;  //granularita' Chunk
+  unsigned short patch_size;  //in chunks
+  unsigned short ram_used;  // in chunks (used when compressed)
+  unsigned int lru_pos;
+};
+
+class PatchServer: public File {
+ public:
+  struct PTime {
+    unsigned int patch;
+    unsigned int frame;
+
+    PTime(unsigned int p = 0xffffffff, unsigned int f = 0xffffffff):
+	 patch(p), frame(f) {}
+
+    bool operator<(const PTime &p) const { return frame < p.frame; }
+  };
+
+
+  Signature signature;
+  unsigned int chunk_size;
+  unsigned int ram_size;
+  unsigned int ram_used;
+  unsigned int frame;
+    
+
+  bool Create(const std::string &filename, Signature signature, 
+	      unsigned int chunk_size, unsigned int ram_size = 128000);
+  bool Load(const std::string &filename, Signature sig, 
+	    unsigned int chunk_size, bool readonly, 
+	    unsigned int ram_size = 128000);
+
+  void Close();
+
+  bool ReadEntries(FILE *fp);
+  bool WriteEntries(FILE *fp);
+
+  void AddPatch(unsigned short nvert, unsigned short nface);
+  Patch &GetPatch(unsigned int patch, unsigned short nvert, unsigned short nface,
+		  bool flush = true);
+
+  void Flush();
+  void FlushAll();
+  void Flush(unsigned int patch);
+
+  std::vector<PatchEntry> patches;
+  std::vector<PTime> lru;
+};
+
+}
+
+#endif