diff --git a/src/app_state.h b/src/app_state.h
index ae2dada..7329e2c 100644
--- a/src/app_state.h
+++ b/src/app_state.h
@@ -5,25 +5,27 @@ struct Delta_Time_Accum {
   u16 start;
 };
 
+struct Inspected_File {
+  FILE *stream;
+  u8   *mem;
+  u64   size;
+
+  const char *name;
+
+	// @Platform: inotify file descriptor
+  int inot;
+};
+
 struct App_State {
   Window_Data win_data;
   User_Input user_input;
   RNTuple_Data rndata;
-  Viewer_Settings vsettings;
-
-  Delta_Time_Accum delta_time_accum;
-
-  FILE       *inspected_file;
-  u8         *inspected_fmem;
-  u64         inspected_file_size;
-  const char *inspected_fname;
-	// @Platform: inotify file descriptor
-	int inot;
+  Viewer viewer;
+  Inspected_File inspected_file;
 
 	const char *ntpl_name;
 
-	// TEMP
-	u64 n_checks;
+  Delta_Time_Accum delta_time_accum;
 
   // Cache the last info node selected for faster lookup of offsets
   const Page_Info_Node *last_pinfo;
diff --git a/src/mainloop.cpp b/src/mainloop.cpp
index 332045a..3af2f85 100644
--- a/src/mainloop.cpp
+++ b/src/mainloop.cpp
@@ -93,9 +93,9 @@ void run_main_loop(GLFWwindow *window, Arena *arena, App_State &app)
 		// Check if the inspected file changed
 		{
 			char buf[sizeof(inotify_event) + NAME_MAX + 1];
-			ssize_t nbytes = read(app.inot, buf, sizeof(buf));
+			ssize_t nbytes = read(app.inspected_file.inot, buf, sizeof(buf));
 			if (nbytes)
-				app.inspected_file_size = file_size(app.inspected_file);
+				app.inspected_file.size = file_size(app.inspected_file.stream);		
 		}
 
 		if (glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS ||
diff --git a/src/platform_linux.h b/src/platform_linux.h
index 00bc934..4f8b429 100644
--- a/src/platform_linux.h
+++ b/src/platform_linux.h
@@ -19,10 +19,10 @@ bool os_open_and_map_file(const char *fname, App_State &app)
   if (!fmem)
     fprintf(stderr, "Failed to open file %s\n", fname);
 
-  app.inspected_fname = fname;
-  app.inspected_file = file;
-  app.inspected_file_size = fsize;
-  app.inspected_fmem = reinterpret_cast<u8*>(fmem);
+  app.inspected_file.name = fname;
+  app.inspected_file.stream = file;
+  app.inspected_file.size = fsize;
+  app.inspected_file.mem = reinterpret_cast<u8*>(fmem);
 
   return true;
 }
@@ -43,14 +43,14 @@ void os_start_file_watch(const char *fname, App_State &app)
   if (inotify_add_watch(inot, fname, IN_MODIFY) == -1)
     fprintf(stderr, "Failed to add inotify watch: %s (%d)\n", strerror(errno), errno);
 
-  app.inot = inot;
+  app.inspected_file.inot = inot;
 }
 
 internal
 void os_stop_file_watch(App_State &app)
 {
-  if (app.inot != -1) close(app.inot);
-  app.inot = -1;
+  if (app.inspected_file.inot != -1) close(app.inspected_file.inot);
+  app.inspected_file.inot = -1;
 }
 
 internal 
diff --git a/src/render.cpp b/src/render.cpp
index fc34845..e27d714 100644
--- a/src/render.cpp
+++ b/src/render.cpp
@@ -39,18 +39,18 @@ u32 mem_edit_bg_color_fn(const u8 *, u64 off, void *user_data)
   const RNTuple_Data &rdata = app->rndata;
   u64 rblob_sz = rdata.rblob_header_size; // @Incomplete
 
-  off += app->vsettings.base_display_addr;
+  off += app->viewer.base_display_addr;
 
 #define COL(c) (ImColor((c)[0], (c)[1], (c)[2]))
   // TFile start
-  if (off <= rdata.root_file_header_size) return COL(app->vsettings.col_tfile);
+  if (off <= rdata.root_file_header_size) return COL(app->viewer.col_tfile);
 
   // Handle pages
   // fast case: `off` is in the same page info as previous `off`.
   if (app->last_pinfo->range.start < off && off < app->last_pinfo->range.end()) {
     if (off >= app->last_pinfo->range.end() - app->last_pinfo->checksum_size())
-      return COL(app->vsettings.col_checksum);
-    return COL(app->vsettings.col_page);
+      return COL(app->viewer.col_checksum);
+    return COL(app->viewer.col_page);
   }
 
   // still fast case: `off is in the next page info as the previous.
@@ -59,25 +59,35 @@ u32 mem_edit_bg_color_fn(const u8 *, u64 off, void *user_data)
 
   if (app->last_pinfo && app->last_pinfo->range.start <= off && off < app->last_pinfo->range.end()) {
     if (off == app->last_pinfo->range.start)
-      return COL(app->vsettings.col_page_start);
+      return COL(app->viewer.col_page_start);
     if (off >= app->last_pinfo->range.end() - app->last_pinfo->checksum_size())
-      return COL(app->vsettings.col_checksum);
-    return COL(app->vsettings.col_page);
+      return COL(app->viewer.col_checksum);
+    return COL(app->viewer.col_page);
   }
 
-  if (rdata.rng_anchor_key.start <= off && off < rdata.rng_anchor_key.end()) return COL(app->vsettings.col_key);
-  if (rdata.rng_header.start - rblob_sz <= off && off < rdata.rng_header.start) return COL(app->vsettings.col_key);
-  if (rdata.rng_footer.start - rblob_sz <= off && off < rdata.rng_footer.start) return COL(app->vsettings.col_key);
-  if (rdata.rng_anchor.start <= off && off < rdata.rng_anchor.end() - 8) return COL(app->vsettings.col_anchor);
-  if (rdata.rng_anchor.end() - 8 <= off && off < rdata.rng_anchor.end()) return COL(app->vsettings.col_checksum);
-  if (rdata.rng_header.start <= off && off < rdata.rng_header.end() - 8) return COL(app->vsettings.col_header);
-  if (rdata.rng_header.end() - 8 <= off && off < rdata.rng_header.end()) return COL(app->vsettings.col_checksum);
-  if (rdata.rng_footer.start <= off && off < rdata.rng_footer.end() - 8) return COL(app->vsettings.col_footer);
-  if (rdata.rng_footer.end() - 8 <= off && off < rdata.rng_footer.end()) return COL(app->vsettings.col_checksum);
+  if (rdata.rng_anchor_key.start <= off && off < rdata.rng_anchor_key.end()) return COL(app->viewer.col_key);
+  if (rdata.rng_anchor.start <= off && off < rdata.rng_anchor.end() - 8)     return COL(app->viewer.col_anchor);
+  if (rdata.rng_anchor.end() - 8 <= off && off < rdata.rng_anchor.end())     return COL(app->viewer.col_checksum);
+
+  if (rdata.rng_header.start - rblob_sz <= off && off < rdata.rng_header.start) return COL(app->viewer.col_key);
+  if (rdata.rng_header.start <= off && off < rdata.rng_header.end() - 8)        return COL(app->viewer.col_header);
+  if (rdata.rng_header.end() - 8 <= off && off < rdata.rng_header.end())        return COL(app->viewer.col_checksum);
+
+  if (rdata.rng_footer.start - rblob_sz <= off && off < rdata.rng_footer.start) return COL(app->viewer.col_key);
+  if (rdata.rng_footer.start <= off && off < rdata.rng_footer.end() - 8)        return COL(app->viewer.col_footer);
+  if (rdata.rng_footer.end() - 8 <= off && off < rdata.rng_footer.end())        return COL(app->viewer.col_checksum);
+
+  // @Speed
+  for (u64 cg_idx = 0; cg_idx < rdata.n_cluster_groups; ++cg_idx) {
+    Cluster_Group_Info &cg_info = rdata.cluster_groups[cg_idx];
+    if (cg_info.rng_page_list.start -rblob_sz <= off && off < cg_info.rng_page_list.start) return COL(app->viewer.col_page_list);
+    if (cg_info.rng_page_list.start <= off && off < cg_info.rng_page_list.end() - 8)       return COL(app->viewer.col_page_list);
+    if (cg_info.rng_page_list.end() - 8 <= off && off < cg_info.rng_page_list.end())       return COL(app->viewer.col_checksum);
+  }
 
   // Slow page group lookup, ideally only done once per render when last_pinfo is invalid.
   for (Page_Info_Chunk *chunk = rdata.page_chunks; chunk; chunk = chunk->next) {
-    if (chunk->range.start - rblob_sz <= off && off < chunk->range.start) return COL(app->vsettings.col_key);
+    if (chunk->range.start - rblob_sz <= off && off < chunk->range.start) return COL(app->viewer.col_key);
     if (chunk->range.start <= off && off < chunk->range.end()) {
       for (u64 group_idx = chunk->first_group; group_idx < rdata.n_page_groups; ++group_idx) {
         const Page_Info_Group &group = rdata.page_groups[group_idx];
@@ -87,9 +97,9 @@ u32 mem_edit_bg_color_fn(const u8 *, u64 off, void *user_data)
         for (Page_Info_Node *pinfo = group.first; pinfo; pinfo = pinfo->next) {
           if (pinfo->range.start <= off && off < pinfo->range.end()) {
             app->last_pinfo = pinfo;
-            if (pinfo->range.start == off) return COL(app->vsettings.col_page_start);
-            if (off >= pinfo->range.end() - pinfo->checksum_size()) return COL(app->vsettings.col_checksum);
-            return COL(app->vsettings.col_page);
+            if (pinfo->range.start == off)                          return COL(app->viewer.col_page_start);
+            if (off >= pinfo->range.end() - pinfo->checksum_size()) return COL(app->viewer.col_checksum);
+            return COL(app->viewer.col_page);
           }
         }
       }
@@ -117,10 +127,12 @@ MemoryEditor make_memory_editor(App_State &app)
 }
 
 internal
-Viewer_Settings make_viewer_settings()
+void make_viewer(App_State &app)
 {
-  Viewer_Settings settings {};
-#define COL(c, r, g, b) settings.c[0] = r/255.0, settings.c[1] = g/255.0, settings.c[2] = b/255.0
+  Viewer viewer {};
+  viewer.mem_edit = make_memory_editor(app);
+
+#define COL(c, r, g, b) viewer.c[0] = r/255.0, viewer.c[1] = g/255.0, viewer.c[2] = b/255.0
   COL(col_anchor, 150, 150, 0);
   COL(col_header, 150, 0, 50);
   COL(col_footer, 50, 0, 150);
@@ -129,12 +141,21 @@ Viewer_Settings make_viewer_settings()
   COL(col_page,   125, 0, 125);
   COL(col_page_start, 200, 0, 200);
   COL(col_checksum, 134, 65, 25);
+  COL(col_page_list, 60, 110, 120);
 #undef COL
-  return settings;
+
+  app.viewer = viewer;
 }
 
 internal
-void jump_to_page(App_State &app, u64 page_idx)
+void viewer_jump_to(Viewer &viewer, u64 addr)
+{
+  viewer.base_display_addr = addr;
+  viewer.mem_edit.GotoAddr = 0;
+}
+
+internal
+void viewer_jump_to_page(App_State &app, u64 page_idx)
 {
   assert(app.rndata.n_pages > 0);
   page_idx = (page_idx + app.rndata.n_pages) % app.rndata.n_pages;
@@ -146,8 +167,8 @@ void jump_to_page(App_State &app, u64 page_idx)
     assert(page);
   }
 
-  app.vsettings.base_display_addr = page->range.start;
-  app.vsettings.latest_page_gone_to = page_idx;
+  app.viewer.latest_page_gone_to = page_idx;
+  viewer_jump_to(app.viewer, page->range.start);
 }
 
 internal
@@ -161,20 +182,11 @@ void update_and_render(Arena *arena, App_State &app, f32 delta_time_ms)
   Temp scratch = temp_begin(arena);
   defer { temp_end(scratch); };
 
-  const u64 inspected_max_size = 2048;
-  u64 text_buf_size = min(app.inspected_file_size * 2, inspected_max_size);
-  char *text_buf = arena_push_array_nozero<char>(scratch.arena, text_buf_size + 1);
-  // Convert file content to human readable
-  // @Speed: maybe do this only when the file changes
-  for (u64 i = 0; i < text_buf_size / 2; ++i)
-    sprintf(&text_buf[2 * i], "%02X", app.inspected_fmem[i]);
-  text_buf[text_buf_size] = 0;
-  
   const auto main_win_flags = ImGuiWindowFlags_NoResize | ImGuiWindowFlags_NoTitleBar | ImGuiWindowFlags_NoDecoration;
   if (ImGui::Begin("main", nullptr, main_win_flags)) {
         
     String8 ntpl_desc = rntuple_description(scratch.arena, app.rndata);
-    ImGui::Text("RNTuple '%s' (%s) from file \"%s\"", app.ntpl_name, ntpl_desc.c(), app.inspected_fname);
+    ImGui::Text("RNTuple '%s' (%s) from file \"%s\"", app.ntpl_name, ntpl_desc.c(), app.inspected_file.name);
 
     // Draw stats
     {
@@ -199,59 +211,74 @@ void update_and_render(Arena *arena, App_State &app, f32 delta_time_ms)
 
     // Draw main content
     {
-      static MemoryEditor mem_edit = make_memory_editor(app);
       ImGui::BeginTable("Hex View", 2, ImGuiTableFlags_Resizable);
 
       ImGui::TableNextColumn();
 
-      assert(app.vsettings.base_display_addr < app.inspected_file_size);
-      void *content = app.inspected_fmem + app.vsettings.base_display_addr;
-      u64 content_size = app.inspected_file_size - app.vsettings.base_display_addr;
+      assert(app.viewer.base_display_addr < app.inspected_file.size);
+      void *content = app.inspected_file.mem + app.viewer.base_display_addr;
+      u64 content_size = app.inspected_file.size - app.viewer.base_display_addr;
       app.last_pinfo = &invalid_pinfo;
-      mem_edit.DrawContents(content, content_size, app.vsettings.base_display_addr);
+      app.viewer.mem_edit.DrawContents(content, content_size, app.viewer.base_display_addr);
 
       ImGui::TableNextColumn();
       ImGuiColorEditFlags flags =  ImGuiColorEditFlags_NoInputs|ImGuiColorEditFlags_NoLabel;
 
-      ImGui::ColorEdit3("_TFile",          app.vsettings.col_tfile,  flags);
+      ImGui::ColorEdit3("_TFile",          app.viewer.col_tfile,  flags);
       ImGui::SameLine(); 
-      if (ImGui::Button("TFile")) app.vsettings.base_display_addr = 0;
+      if (ImGui::Button("TFile"))          viewer_jump_to(app.viewer, 0);
 
-      ImGui::ColorEdit3("_RNTuple Anchor", app.vsettings.col_anchor, flags);
+      ImGui::ColorEdit3("_RNTuple Anchor", app.viewer.col_anchor, flags);
       ImGui::SameLine(); 
-      if (ImGui::Button("RNTuple Anchor")) app.vsettings.base_display_addr = app.rndata.rng_anchor.start;
-
-      ImGui::ColorEdit3("_RNTuple Header", app.vsettings.col_header, flags);
+      if (ImGui::Button("RNTuple Anchor")) viewer_jump_to(app.viewer, app.rndata.rng_anchor.start);
       ImGui::SameLine(); 
-      if (ImGui::Button("RNTuple Header")) app.vsettings.base_display_addr = app.rndata.rng_header.start;
+      ImGui::Text("%s", to_pretty_size(scratch.arena, app.rndata.rng_anchor.len).c());
 
-      ImGui::ColorEdit3("_RNTuple Footer", app.vsettings.col_footer, flags);
+      ImGui::ColorEdit3("_RNTuple Header", app.viewer.col_header, flags);
       ImGui::SameLine(); 
-      if (ImGui::Button("RNTuple Footer")) app.vsettings.base_display_addr = app.rndata.rng_footer.start;
+      if (ImGui::Button("RNTuple Header")) viewer_jump_to(app.viewer, app.rndata.rng_header.start);
+      ImGui::SameLine(); 
+      ImGui::Text("%s", to_pretty_size(scratch.arena, app.rndata.rng_header.len).c());
 
-      ImGui::ColorEdit3("_TKey Header",    app.vsettings.col_key,    flags);
+      ImGui::ColorEdit3("_RNTuple Footer", app.viewer.col_footer, flags);
+      ImGui::SameLine(); 
+      if (ImGui::Button("RNTuple Footer")) viewer_jump_to(app.viewer, app.rndata.rng_footer.start);
+      ImGui::SameLine(); 
+      ImGui::Text("%s", to_pretty_size(scratch.arena, app.rndata.rng_footer.len).c());
+
+      ImGui::ColorEdit3("_TKey Header",    app.viewer.col_key,    flags);
       ImGui::SameLine(); 
       if (ImGui::Button("TKey Header"))    {} // TODO jump to next key
 
-      ImGui::ColorEdit3("_Page Start", app.vsettings.col_page_start, flags);
+      ImGui::ColorEdit3("_Page Start", app.viewer.col_page_start, flags);
       ImGui::SameLine(); 
-      if (ImGui::Button("Page Start"))     jump_to_page(app, 0);
+      if (ImGui::Button("Page Start"))     viewer_jump_to_page(app, 0);
 
-      ImGui::ColorEdit3("Page", app.vsettings.col_page, ImGuiColorEditFlags_NoInputs);
+      ImGui::ColorEdit3("_Page", app.viewer.col_page, flags);
+      ImGui::SameLine();
+      if (ImGui::Button("Page"))           viewer_jump_to_page(app, app.viewer.latest_page_gone_to);
       ImGui::SameLine();
       {
         // TODO: support u64
-        i32 page_to_go_to = static_cast<i32>(app.vsettings.latest_page_gone_to);
+        i32 page_to_go_to = static_cast<i32>(app.viewer.latest_page_gone_to);
         ImGui::PushItemWidth(100.f);
         if (ImGui::InputInt("##page_viewed", &page_to_go_to))
-          jump_to_page(app, page_to_go_to);
+          viewer_jump_to_page(app, page_to_go_to);
         ImGui::PopItemWidth();
       }
+      ImGui::SameLine();
+      ImGui::Text("%s", to_pretty_size(scratch.arena, app.rndata.tot_page_size).c());
 
-      ImGui::ColorEdit3("_Checksum", app.vsettings.col_checksum, flags);
+      ImGui::ColorEdit3("_Checksum", app.viewer.col_checksum, flags);
       ImGui::SameLine(); 
       if (ImGui::Button("Checksum")) {} // TODO jump to next checksum
 
+      ImGui::ColorEdit3("_Page List", app.viewer.col_page_list, flags);
+      ImGui::SameLine(); 
+      if (ImGui::Button("Page List")) {} // TODO jump to next page list
+      ImGui::SameLine(); 
+      ImGui::Text("%s", to_pretty_size(scratch.arena, app.rndata.tot_page_list_size).c());
+
       ImGui::Separator();
       ImGui::Text("Num pages: %lu", app.rndata.n_pages);
       ImGui::Text("Num elements: %lu", app.rndata.n_elems);
diff --git a/src/render.h b/src/render.h
index acac666..664e2e6 100644
--- a/src/render.h
+++ b/src/render.h
@@ -1,4 +1,6 @@
-struct Viewer_Settings {
+struct Viewer {
+  MemoryEditor mem_edit;
+  
   f32 col_anchor[3];
   f32 col_header[3];
   f32 col_footer[3];
@@ -7,6 +9,7 @@ struct Viewer_Settings {
   f32 col_page[3];
   f32 col_page_start[3];
   f32 col_checksum[3];
+  f32 col_page_list[3];
 
   u64 base_display_addr;
   u64 latest_page_gone_to;
@@ -14,6 +17,6 @@ struct Viewer_Settings {
 
 struct Edit_Bg_Color_Data {
   RNTuple_Data *rndata;
-  Viewer_Settings vsettings;
+  Viewer viewer;
 };
 
diff --git a/src/rntuple.cpp b/src/rntuple.cpp
index 3498176..adc3f45 100644
--- a/src/rntuple.cpp
+++ b/src/rntuple.cpp
@@ -69,18 +69,46 @@ void gather_metadata(Arena *arena, RMicroFileReader &reader, const RNTuple_File_
   using namespace ROOT::Experimental::Internal;
 
   RNTupleDescriptor descriptor = create_descriptor(arena, reader, info);
-  u64 n_pages = 0;
-  u64 n_elems = 0;
-  Page_Info_Node *pinfo_head = nullptr, *pinfo_tail = nullptr;
-  Page_Info_Node *last_inserted_pinfo = nullptr;
-  
+
+  // gather cluster groups metadata
+  Cluster_Group_Info *cluster_groups = arena_push_array_nozero<Cluster_Group_Info>(arena, descriptor.GetNClusterGroups());
+  u64 tot_page_list_size = 0;
+  u64 cg_idx = 0;
+  for (const RClusterGroupDescriptor &cg_desc : descriptor.GetClusterGroupIterable()) {
+    Cluster_Group_Info &cg_info = cluster_groups[cg_idx++];
+
+    // Page list locator
+    RNTupleLocator plist_locator =  cg_desc.GetPageListLocator();
+    cg_info.rng_page_list.start = plist_locator.GetPosition<u64>();
+    cg_info.rng_page_list.len = plist_locator.fBytesOnStorage;
+    tot_page_list_size += plist_locator.fBytesOnStorage;
+  }
+
   fprintf(stderr, "Loading pages...\n");
   
+  u64 n_pages = 0;
+  u64 n_elems = 0;
+  u64 tot_page_size = 0;
+  Page_Info_Node *pinfo_head = nullptr, *pinfo_tail = nullptr;
+  Page_Info_Node *last_inserted_pinfo = nullptr;
+
+  Cluster_Info_Node *clinfo_head = nullptr, *clinfo_tail = nullptr;
+  u64 n_clusters = 0;
+      
   chr::time_point start_t = chr::high_resolution_clock::now();
   u64 n_slow = 0;
-  
-  // for all clusters, gather page metadata
+
+  // gather clusters and pages metadata
   for (const RClusterDescriptor &cluster_desc : descriptor.GetClusterIterable()) {
+    if (!clinfo_head) {
+      clinfo_head = clinfo_tail = arena_push<Cluster_Info_Node>(arena);
+    } else {
+      Cluster_Info_Node *clinfo = arena_push<Cluster_Info_Node>(arena);
+      clinfo_tail->next = clinfo;
+      clinfo_tail = clinfo;
+    }
+    ++n_clusters;
+
     // for (const RClusterDescriptor::RColumnRange &col_range : cluster_desc.GetColumnRangeIterable()) {
     for (auto col_id : cluster_desc.GetColumnIds()) {
       const auto &col_range = cluster_desc.GetColumnRange(col_id);
@@ -122,6 +150,7 @@ void gather_metadata(Arena *arena, RMicroFileReader &reader, const RNTuple_File_
         last_inserted_pinfo = pinfo;
 
         ++n_pages;
+        tot_page_size += pinfo->range.len;
         n_elems += page_info.fNElements;
       }
     }
@@ -136,7 +165,7 @@ void gather_metadata(Arena *arena, RMicroFileReader &reader, const RNTuple_File_
   // Each page group is a grouping of GROUP_SIZE page infos whose range is equal to the combined ranges
   // of its components. It is an acceleration structure used to more quickly find the correct page info
   // that an offset belongs to.
-  // A page chunk is a grouping of adjacent page groups, used to quickly determine if an offset is part
+  // A page chunk is a grouping of adjacent pages, used to quickly determine if an offset is part
   // of a page or not.
   assert(pinfo_head);
   const u64 GROUP_SIZE = 500;
@@ -185,6 +214,7 @@ void gather_metadata(Arena *arena, RMicroFileReader &reader, const RNTuple_File_
 
   assert(!chunks_tail->next);
   assert(!pinfo_tail->next);
+  assert(!clinfo_tail->next);
 
   rndata.pages = pinfo_head;
   rndata.page_groups = groups;
@@ -193,6 +223,12 @@ void gather_metadata(Arena *arena, RMicroFileReader &reader, const RNTuple_File_
   rndata.n_page_chunks = n_chunks;
   rndata.n_pages = n_pages;
   rndata.n_elems = n_elems;
+  rndata.tot_page_size = tot_page_size;
+  rndata.cluster_groups = cluster_groups;
+  rndata.n_cluster_groups = cg_idx;
+  rndata.tot_page_list_size = tot_page_list_size;
+  rndata.clusters = clinfo_head;
+  rndata.n_clusters = n_clusters;
 }
 
 internal
diff --git a/src/rntuple.h b/src/rntuple.h
index c59cefd..5c4dce6 100644
--- a/src/rntuple.h
+++ b/src/rntuple.h
@@ -29,6 +29,14 @@ struct Page_Info_Chunk {
   u32 first_group;
 };
 
+struct Cluster_Info_Node {
+  Cluster_Info_Node *next;
+};
+
+struct Cluster_Group_Info {
+  Byte_Range rng_page_list;
+};
+
 struct RNTuple_Data {
   struct {
     u16 epoch, major, minor, patch;
@@ -45,6 +53,14 @@ struct RNTuple_Data {
   u64 n_pages;
   // total number of elements of all pages
   u64 n_elems;
+  u64 tot_page_size;
+
+  Cluster_Group_Info *cluster_groups;
+  u64 n_cluster_groups;
+  u64 tot_page_list_size;
+
+  Cluster_Info_Node *clusters;
+  u64 n_clusters;
 
   Page_Info_Group *page_groups;
   u64 n_page_groups;
diff --git a/src/rntviewer.cpp b/src/rntviewer.cpp
index 142e4f8..fafb385 100644
--- a/src/rntviewer.cpp
+++ b/src/rntviewer.cpp
@@ -70,8 +70,8 @@ internal
 void app_cleanup(App_State &app)
 {
   os_stop_file_watch(app);
-  os_unmap_file(app.inspected_fmem, app.inspected_file_size);
-  if (app.inspected_file) fclose(app.inspected_file); 
+  os_unmap_file(app.inspected_file.mem, app.inspected_file.size);
+  if (app.inspected_file.stream) fclose(app.inspected_file.stream); 
 }
 
 int main(int argc, char **argv)
@@ -121,7 +121,7 @@ int main(int argc, char **argv)
 
   app.ntpl_name = ntpl_name;
   app.rndata = get_rntuple_data(arena, fname, ntpl_name);
-  app.vsettings = make_viewer_settings();
+  make_viewer(app);
   
   // Start main loop
   run_main_loop(window, arena, app);