\subsubsection{Address space}
\label{address_space}

An \addressspace is specified by the following 
definitions \cite{Adr1} \cite{Adr2}:\\

(1) It is the range of virtual addresses that the operating 
system assigns to a user or separately running program.\\ 

(2) The range of addresses which a \processor or process can access, 
or at which a device can be accessed. \\ 

(3) It refers to either physical address or virtual address.\\

(4) An \addressspace may be associated to an address protection mechanism.\\

(5) An \addressspace defines a range of discrete addresses, 
each of which may correspond to a network host, peripheral device, 
disk sector, a memory cell or other logical or physical entity.\\

(6) It allows to model a logical unit of memory.\\

\begin{center}
Standard attributes
\end{center}

$Name$ : it is the unique name of the \addressspace.\\

$Cpu_-name$: It is the name of \processor which contain \addressspace.\\

$Text_{-}Memory_{-}Size$: It is the size of text segment. 
A text segment contains the executable image of the program.

It is used to perform a global memory analysis.\\

$Stack_{-}Memory_{-}Size$: It is the size of stack segment. 
A stack segment contains the function-call stack. 

This segment is extended automatically as needed.\\

$Data_{-}Memory_{-}Size$: It is the size of data segment. 
A data segment contains the \textit{heap} of dynamically allocated data space.\\

$Heap_{-}Memory_{-}Size$: It is the size of logical memory reserved for the heap.\\

$Scheduling$: It defines all parameters of scheduling. 

It is the type of $Scheduling_{-}Parameters$ (see Annexes for 
definitions of $Scheduling_{-}Parameters$). \\

$mils_{-}confidentiality_{-}level$ : It defines the level of confidentiality
 of an address space. $mils_{-}confidentiality_{-}level$ can be UnClassified, 
or $Classified$, or $Secret$, or $Top_{-}Secret$ \\

$mils_{-}integrity_{-}level$ : It defines the level of integrity of an
 address space. $mils_{-}integrity_level$ can be $Low$, or $Medium$, or $High$ \\

$mils_{-}component$ :  It defines the type of an address space according 
to the classification of components in MILS architecture. It can have the
 $SLS$ value for
 Single Level Secure component, or $MLS$ for Multi-Level Secure component, or
 $MSLS$ for Multi Single-Level Secure component.\\

$mils_{-}partition$ : It defines the kind of MILS component modeled by the address space. 
It can have either the $Device$ value or the $Application$ value.\\
$mils_{-}compliant$ : It is a boolean that specifies if an address
 space models a component of MILS or not.\\


\begin{center}
Legality rules
\end{center}

(L1) The \addressspace name must not be empty.\\

(L2) The \addressspace name must be valid identifier.\\

(L3) An \addressspace must be linked to a \processor.\\

(L4) The $Text_{-}Memory_{-}Size$ must be greater than or equal to 0.\\

(L5) The $Stack_{-}Memory_{-}Size$ must be greater than or equal to 0.\\

(L6) The $Data_{-}Memory_{-}Size$ must be greater than or equal to 0.\\

(L7) The $Heap_{-}Memory_{-}Size$ must be greater than or equal to 0.\\

 
\begin{center}
Annexes
\end{center}

(A1) See Annexes of $Dynamic_-Deployment$ for attributes of $Scheduling_{-}Parameters$.\\

\begin{center}
Implementation
\end{center}

The figure \ref{dtd_addr} gives the DTD of entity \addressspace.


\begin{figure}{}
\begin{lstlisting}{}
<!ELEMENT address_spaces (address_space)+>
<!ELEMENT address_space (object_type | name 
  | cpu_name | text_memory_size | stack_memory_size 
  | data_memory_size | heap_memory_size 
  | scheduling | mils_confidentiality_level | mils_integrity_level 
  | mils_component | mils_partition | mils_compliant)*>
<!ATTLIST address_space id ID #REQUIRED>
\end{lstlisting}
	\caption{The DTD of entity $Address$\_$Space$}
	\label{dtd_addr}
\end{figure}



\begin{center}
Example
\end{center}

The figure \ref{example_adr} gives an example of \addressspace.

This \addressspace, named $addr1$ is based on \processor $processor1$. 
The others parameters are fixed on $0$, and the scheduling parameters 
have a $quantum$ equal to $0$, and is the type $PREEMPTIVE$.

\begin{figure}[H]{}
\begin{lstlisting}{}

<address_space id=" 18" >
 <object_type>ADDRESS_SPACE_OBJECT_TYPE</object_type>
 <name>addr1</name>
 <cpu_name>processor1</cpu_name>
 <text_memory_size>0</text_memory_size>
 <stack_memory_size>0</stack_memory_size>
 <data_memory_size>0</data_memory_size>
 <heap_memory_size>0</heap_memory_size>
 <scheduling><scheduling_parameters>
  <scheduler_type>NO_SCHEDULING_PROTOCOL</scheduler_type>
  <quantum>0</quantum>
  <preemptive_type>PREEMPTIVE</preemptive_type>
  <capacity>0</capacity>
  <period>0</period>
  <priority>0</priority>
  <start_time>0</start_time>
  </scheduling_parameters>
 </scheduling>
 <mils_confidentiality_level>TOP_SECRET</mils_confidentiality_level>
 <mils_integrity_level>HIGH</mils_integrity_level>
 <mils_component>SLS</mils_component>
 <mils_partition>DEVICE</mils_partition>
 <mils_compliant>TRUE</mils_compliant>
</address_space>

\end{lstlisting}
\caption{An Example of entity \addressspace described using Cheddar ADL}
\label{example_adr}
\end{figure}