Introduction
This section describes the key concepts of the system model and the
system definition file.
The system definition file is an XML file which contains the system model
architecture and build information. The System Model Manager (SMM) uses the
file to generate the system model diagram. Licensees can modify the file to
reflect their changes in the system model.
Key concepts
- System model
-
The system model is a hierarchical representation of the Symbian
platform architecture. It is a hierarchy of Symbian platform architectural
levels, layers, blocks, sub-blocks, collections and components.
- System definition file
-
The system definition file is an XML file, which describes the
layers, blocks, sub-blocks, collections, and components that constitute the
system model. It provides information about the Symbian platform architecture
which is used to build the system and generate a system model diagram.
- Module
-
The term module is used to refer to a block or a sub-block. If a
block has sub-blocks, the sub-blocks are modules. If a block does not have
sub-blocks, the block is a module.
- CBR
-
CBR stands for Component Based Release. The CBR mechanism packages
and delivers Symbian platform in a modular way. Licensees and partners can use
this modularity to integrate and build components on the platform.
How the system model maps to the system definition
file
The system definition file describes the Symbian platform system model.
The following screenshot is a scaled down view of a system model diagram for
Symbian OS v9.5.
The following table summarises the mapping information between the
system model and the system definition file. For more information about the
elements in the system definition file, refer to
System Definition File Elements.
System Model
|
System definition File
|
Definition
|
Examples in Symbian platform
|
layer
|
<layer>
|
The highest level and a fundamental representation of Symbian
platform.
A layer contains blocks or collections.
|
Kernel Services and OS Servicesare layers.
|
block (optional)
|
<block> (optional)
|
Represents a different technology division within a particular
Symbian platform layer.
A block contains sub-blocks or collections.
|
PIM and Messagingare modules of the Application Services layer.
|
sub-block (optional)
|
<subblock>(optional)
|
Represents a tightly coupled subdivision with a technology.
A sub-block contains collections.
|
Communications Framework and Cellular Baseband Services are the
sub-blocks of the Comms Services block. The Comms Services block belongs to the
OS Services layer.
|
collection
|
<collection>
|
Represents a logical group of components, coupled by function,
for example, a client/server, or coupled by usage, for example, a family of
plug-ins.
A collection contains components.
|
PIM Protocol and PIM Application Services are collections within
the PIM module.
|
component
|
<component>
|
The smallest architectural unit that appears in the System Model.
It maps to a single bld.inf file or a CBR package.
Note:A system definition file with no components
cannot be used by the SMM to draw the system model diagram.
|
Calendar and Contacts Model are components of the PIM Application
Services collection.
|
unit
|
<unit>
|
The build details of a component. The build details comprise an
MRP file and/or a bld.inf file. A number of alternative units may be listed for
each component.
Note: Unit elements are not used by the SMM.
|
For the Calendar component, the build directory is
common/generic/app-engines/calendar/group, and the MRP file is
common/generic/app-engines/calendar/group/app-engines_calendar.mrp .
|