RemoCast InternalsRemoCast has been designed following a layered structure that helps adding components and features as required. New motherboards with much more horsepower and/or memory can be easily incorporated. Custom interfaces such as CAN bus adapters, multi-port I/O cards are typically assembled on request. The following image shows a RemoCast appliance and depicts its functional pieces which may be identified by their own colour. Please leave the mouse over a components to see its name or click on it in order to get further information.
You may also click on any of the following links:
Standard RemocastRemoCast CoreBase hardware
RemoCast hardware core is built around upgraded COTS (Commercial Off-The-Shelf) motherboards. Their CPU and memory provide the system with enough resources to run all required software modules, processes and services. Components to control all expansion elements are also integrated into the motherboard. Permanent storage, network access, serial ports, PCI socket and GPIO are some interface examples. Permanent Storage
RemoCast includes permanent storage not only to save the OS (Operating System) and all application modules but to keep user configuration, multicast binaries and custom commands. Storage is divided into physical partitions and into logical spaces. Regular operations implicitly access some of these spaces. Access to others depend on operator privileges. System Abstraction Layer
SAL (System Abstraction Layer) is a thick stack of layers that encompass the OS (Operating System) kernel, device drivers and system modules. A layer on top of them encapsulates all differences among the various types of hardware and operating systems. It exhibits a URAM (Uniform Resource Access Method) which covers system control, service management, file management, I/O functions, inter-process communication and a unified user command set. All variants of RemoCast (simulated, embedded, distributed or stand-alone) share the source tree above SAL. RemoCast ModulesUnit Control Module
This module is responsible for general configuration, system control and monitoring of the RemoCast unit itself. It takes care of network interface, system services and user configuration. STB Control and Status Module
This module deals with Set-Top Box identification, software versions, custom commands, additional features and optional components. User Application Module
This is actually a storage space where operators can save any kind of file. A restricted HTTP daemon may serve them as from any other web space. That allows system integrators to use RemoCast as a complete solution. STB may get their initial home page from RemoCast and then go to a different expansion server, if required. Some canned applications and EPG (Electronic Program Guide) generators are available on request. I/O InterfacesConsole Port
This interface is designed to allow low level access. Its main purpose is first time configuration. Control Network
Operators that use web interface access RemoCast via this network interface. It is usually connected to the office network and, from there, to the Internet. System configuration, STB type definition, binary signature, command customization, user management and similar actions have to be executed via this interface. STB/Multicast Network
A complete network interface has been created for multicast transmission. Multicast traffic is routed via this path by means of internally hard-coded rules. Office and corporate networks don't get invaded by unwanted packets. All Set-Top Boxes are connected to this network. ExpansionsExpansion ModulesExpansion Module
Certain applications require additional hardware to be connected to and controlled by RemoCast. Those pieces of hardware are called expansion modules. They are usually placed inside RemoCast housing. Sometimes the expansion module is just an adapter card. Expansion modules and their control are installed from the factory on customer request. Expansion Module Control
Almost all expansion modules require either driver and/or a software component. Those elements are known as module control. Drivers are embedded into the OS (Operating System) and their functionality gets exposed via SAL (System Abstraction Layer) primitives. The software component usually extends standard SAL interface. Expansion modules and their control are installed from the factory on customer request. Expansion Module Connector
Despite of their structure all expansion modules exchange information with the outside world by a physical connection. The actual characteristics depend on the expansion module. The connector is usually part of the expansion module. Expansion modules are installed from the factory on customer request. PCI Connection
The RemoCast motherboard includes a PCI connector that is used to plug most of the extension modules. Serial Connection
An additional serial port is available. Depending on the model, a male DB9 connector is mounted on the front plate. Some special expansion modules are connected via serial interface. GPIOThe motherboard includes a GPIO (General Purpose I/O) interface. Temperature, pressure sensors and some other types of transducers use this interface. |