Start pulling over the block store code from Roxanne, kind of.

src/main.adb

@@ -1,8 +1,12 @@
 with Alog.Logger;
 
+with Sting.Blockstore;
+
 procedure Main is
     Log : Alog.Logger.Instance (Init => True);
 begin
+    Sting.Blockstore.Bitmap_Store.Initialize_Bitmap_File;
+
     Log.Log_Message (Level => Alog.Info,
                      Msg => "Starting stingd..");
 end Main;

src/sting-blockstore.adb

@@ -0,0 +1,40 @@
+with POSIX.Memory_Mapping,
+     POSIX.Permissions;
+
+package body Sting.Blockstore is
+
+    protected body Bitmap_Store is
+
+        procedure Initialize_Bitmap_File is
+        begin
+            Data.Initialize (Block_Bitmap_File);
+        end Initialize_Bitmap_File;
+
+    end Bitmap_Store;
+
+
+    procedure Initialize (Bitmap    : in out Bitmap_Type;
+                          File_Path : in String) is
+
+        use POSIX,
+            POSIX.Memory_Mapping;
+    begin
+        Bitmap.File_Handle := POSIX.IO.Open_Or_Create
+                                  (Name        => POSIX.To_POSIX_String (File_Path),
+                                   Mode        => POSIX.IO.Read_Only,
+                                   Permissions => POSIX.Permissions.Access_Permission_Set);
+
+
+        Bitmap.Mapped_Address := POSIX.Memory_Mapping.Map_Memory
+                                     (First => System.Null_Address,
+                                      Length     => Block_Bitmap_Bytes,
+                                      Protection => Allow_Read,
+                                      Mapping    => Map_Shared,
+                                      Location   => Exact_Address,
+                                      File       => Bitmap.File_Handle,
+                                      Offset     => 0);
+
+    end Initialize;
+
+
+end Sting.Blockstore;

src/sting-blockstore.ads

@@ -0,0 +1,56 @@
+with POSIX.IO,
+     System,
+     System.Storage_Elements;
+
+
+package Sting.Blockstore is
+
+    --- constant: Storage_Root
+    ---
+    --- Root directory for all Sting storage to go
+    Storage_Root : constant String := "/tmp/sting";
+
+    --- constant: Block_Bitmap_File
+    ---
+    --- Full path to the block bitmap file on disk
+    Block_Bitmap_File : constant String := Storage_Root & "/block_bitmap";
+
+    --- constant: Block_Bitmap_Bytes
+    ---
+    --- Size of the block bitmap file to mmap(2) onto disk
+    Block_Bitmap_Bytes : constant System.Storage_Elements.Storage_Offset := 134217728;
+
+
+    --- type: Bitmap_Type
+    ---
+    --- This type is merely a container for the file handle to a Sting block
+    --- bitmap file
+    type Bitmap_Type is tagged record
+        File_Handle : POSIX.IO.File_Descriptor;
+        Mapped_Address : System.Address;
+    end record;
+
+    --- function: Initialize
+    ---
+    --- Initialize the given <Bitmap_Type> with the given file path
+    procedure Initialize (Bitmap : in out Bitmap_Type; File_Path : in String);
+
+
+    --- class: Bitmap_Store
+    ---
+    --- The Bitmap_Store is a "singleton" protected object which will
+    --- synchronize access to the underlying <Bitmap_Type>
+    ---
+    protected Bitmap_Store is
+
+        --- function: Initialize_Bitmap_File
+        ---
+        --- This procedure will open/create the Sting block bitmap file for mapping
+        --- which blocks in the DB are free/used.
+        procedure Initialize_Bitmap_File;
+
+    private
+        Data : Bitmap_Type;
+    end Bitmap_Store;
+
+end Sting.Blockstore;

src/sting-store.ads

@@ -1,4 +1,5 @@
-with Ada.Containers.Hashed_Maps;
+with Ada.Containers.Hashed_Maps,
+     GNATcoll.Mmap;
 
 package Sting.Store is
     type Engine is tagged private;

sting.gpr

@@ -1,4 +1,6 @@
 with "aunit";
+with "gnatcoll";
+with "florist";
 
 project Sting is
     -- Only two ways to build sting, as a debug build or a release build
@@ -9,20 +11,8 @@ project Sting is
 
     for Object_Dir use "obj/" & Mode;
     for Exec_Dir use "bin";
-
-
-    case Mode is
-        when "debug" | "release" =>
-            for Main use ("main.adb");
-            for Source_Dirs use ("src",
-                                "contrib/alog/src",
-                                "contrib/anet/src");
-        when "test" =>
-            for Main use ("test_runner.adb");
-            for Source_Dirs use ("src",
-                                "test/cases",
-                                "test");
-    end case;
+    for Main use ("main.adb", "test_runner.adb");
+    for Source_Dirs use ("src", "test/**", "contrib/alog/src/**");
 
 
     package Builder is