Changes between Version 23 and Version 24 of PHAL-OE_Concept

Timestamp:

11/13/08 22:56:43 (16 years ago)

Author:

ismael (IP: 62.57.188.40)

Comment:

--

PHAL-OE_Concept

@@ -51 +51 @@
 In previous figure, a representation of the abstraction layers involved in PHAL-OE is drawn. On the top we see the connection graph of the object pieces building the radio application, this is the Abstract Application Layer. On the next level, objects are mapped into real Processing Elements (PE), they physically need a place to be executed or located on. The PHAL-OE Layer is the abstraction layer found between the real application processes and the Hardware Layer. An overall P-HAL Platform is represented although three PE (each of them enabling the PHAL-OE functionalities) are under it.  
 
+= The P-HAL Architecture = 
+
+3.5. P-HAL Architecture
+In order to join multiple platforms providing support to the application with the previ-ously seen set of functions, P-HAL has defined an underlying structure for both, inter-operability of independently developed P-HAL software and portability of P-HAL rou-tines from one platform to another. 
+
+In this section, the different layers inside P-HAL and their functions are focused. First of all, it is necessary to identify the roles and players within a P-HAL context. Applica-tion modules are well known and benefit from the described API to exchange informa-tion. But under the modules there are a set of tasks and functions that must implement the requests from the first.
+
+In order to achieve the purpose of P-HAL, it is possible to identify a large number of tasks that do not change from platform to platform, while there are other tasks that are platform dependant. Larger is the number of functions that can be included in the first set, easier is the portability of P-HAL from one platform to the other. Conversely, larger is the platform dependant part, lower is the flexibility to adapt the services to a new platform. This is because the offered services become more complex when with increas-ing software sizes. Then, the P-HAL platform dependant part will define elemental ser-vices that can potentially be implemented with a low cost and software depth.
 
 
+[[Image(PHALOEH4.gif)]] 
+
+
+
+In previous figure, we can find a schematic view of the different P-HAL components and librar-ies. At the top-left level of the stack there is application software represented here by a single P-HAL application object, which only uses P-HAL functions to interact with its environments. These P-HAL functions are called inside the different objects in the ap-plication and their implementation is found within the P-HAL Software Library, which is a platform independent library. These interactions with the environment and the rest of the operations done by the framework are executed by the P-HAL Software Daemons (on the top-right of the stack). These are a set of stand-alone entities each of them in charge of a few operations (see section 3.5.2 for a short summary). 
+
+Until here, all the implementations of such functionalities are platform dependant. To interact with the hardware, these software pieces use the platform-dependant P-HAL Hardware Library (accessed through the Hardware Library API). This enables the pre-viously stated portability of P-HAL functions. The implementation of the Hardware Library may require, in some platforms, the use of an underlying Operating System (OS) or may access directly to the platform Hardware if, although an OS is present, no support for certain device is provided. 
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