\begin{tikzpicture}

	\definecolor{dagfscolor}       {rgb}{.7,0.6,1}
	\definecolor{rumpcolor}       {rgb}{1,0.6,0.6}

	\tikzstyle{treenode} = [component, path fading=flow fade,
	                        minimum width=10ex, minimum height=7ex, align=center,
	                        rounded corners=1]
	\tikzstyle{dagfsnode} = [treenode, bottom color=dagfscolor]


	\tikzstyle{subsystem} = [minimum width=10ex, minimum height=3ex, align=center,
	                         draw=black!80, fill=white, fill opacity=0.6]

	\tikzstyle{treesessionarrow} = [arrow, thick, densely dashed]

	\tikzstyle{treesessionarrow} = [arrow, thick, densely dashed]

	%
	% Components
	%

	% Dagfs components
	\node[dagfsnode,
		minimum width=20ex,
		minimum height=11ex]
		(dagfs_server) {};

	\path (dagfs_server.west) node[right=1ex] {Dagfs};

	\path (dagfs_server.east) node[
		left=2ex, yshift=2ex, subsystem, align=center] (frontends)
		{Frontends};

	\path (dagfs_server.east) node[
		left=2ex, yshift=-2ex, subsystem, align=center] (backends)
		{Backends};


	\node[dagfsnode, below=8ex of dagfs_server]
		(dagfs_fs_store) {Dagfs FS store};

	\node[treenode,
		right=8ex of dagfs_fs_store,
		minimum height=12ex, bottom color=rumpcolor, rounded corners=1]
		(rump) {Rump\\Ext2};

	\node[dagfsnode, above=8ex of dagfs_server, xshift=-16ex] (dagfs_tcp_server) {Dagfs TCP server};
	\node[dagfsnode, above=8ex of dagfs_server, xshift=12ex] (dagfs_fs)         {Dagfs FS};
	\node[dagfsnode, right=2ex of dagfs_fs] (dagfs_rom)        {Dagfs ROM};

	%
	% Linux VM
	%
	\node[treenode, minimum width=24ex, minimum height=22ex, above=8ex of dagfs_tcp_server] (linux) {};
	\path (linux.north) node[below=1ex] {Linux VM};


	%
	% Sessions
	%
	\draw[treesessionarrow] (dagfs_fs_store.90)
		.. controls +(270:-4ex) and +(270:4ex) ..
		node[right, sloped=false] {}
		(backends.270);

	\draw[treesessionarrow] (dagfs_tcp_server.270)
		.. controls +(270:4ex) and +(270:-7ex) ..
		node[right, sloped=false] {}
		(frontends.135);

	\draw[treesessionarrow] (dagfs_fs.270)
		.. controls +(270:4ex) and +(270:-8ex) ..
		node[right, sloped=false] {}
		(frontends.90);

	\draw[treesessionarrow] (dagfs_rom.270)
		.. controls +(270:4ex) and +(270:-7ex) ..
		node[right, sloped=false] {}
		(frontends.45);

	\draw[treesessionarrow] (dagfs_fs_store) --
		node[below, align=center, sloped=false] {File\\system} (rump);

	%
	% TCP
	%

	\node[draw,
		dropshadow, path fading=flow fade, shape=double arrow,
		below=5ex of linux,
		yshift=1ex,
		draw opacity=0.5,
		rotate=90,
		double arrow head extend=1ex,
		inner xsep=2ex, inner ysep=1ex]
		(arrow) {};

	\path (arrow.east) node[yshift=-3ex, right=2ex] {TCP/IP};

\end{tikzpicture}