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Products > Technological choices
Embedded software platform
> Linux operating system
The Linux operating system is now universally acclaimed.
Strengths:
- reliability and stability,
- low cost,
- security,
- separation of execution zones between kernel and applications,
- support and reactivity of the community,
- high availability of software in source code,
- community spirit…
Weaknesses:
KERLINK has chosen a Linux operating system for all its qualities with the desire to able the whole community to benefit from its experience and improvements made to the kernel.
The real time behaviour necessary for the WIRMA calculator is included in the communication and data acquisition modules. This means that the central operating system does not require real time operation, enabling applications to benefit from all its services, particularly network services, available with Linux.
In conclusion the memory foot print is relatively small (2.5Mo) and the number of application services available easily justifies the increased cost of memory extensions.
Communication technologies
> GPRS
GPRS was chosen for long distance data transfer because it is currently the only wireless technology proposing virtually continuous coverage for all of France and neighbouring countries.
In addition, this means of communication is totally compatible with IP technologies, thus simplifying the integration of a communications solution into networks.
It has the following limitations: relatively low and asymmetric bandwidth (20Kbps upstream and 40Kbps downstream maximum), high cost of use (around 0.002 € per ko), no quality-of-service guarantee (best effort type network) and a network architecture which prevents a mobile object from being reached from a fixed application.
One of the advantages of KERLINK's WANESY offer is minimises these limitations by increasing the quality of service with guaranteed delivery and transfer methods with recovery. Compression and on-the-fly data encryption methods increase the volume of useful data transferred, thus reducing the relative cost of transfer. In addition, its centralised peer-to-peer architecture solves the problem of mobile accessibility.
> WLAN
The Wireless LAN network, using 802.11b/g technology, provides a solution for the low bandwith of the GPRS network, with bandwidth of up to 54Mbps (version g). In addition, its running costs are low, as there is no need for a network operator. Its limitations are: limited coverage (around 120m outside), an infrastructure (access point) which must be installed and maintained and the complexity of the embedded application for managing the choice of means of transfer (WLAN/GPRS).
KERLINK's WANESY offer enables the application to be freed from the management of the transfer link by providing an automatic switching mechanism according to criteria (geographical and/or quality of service) detectable by the application. The network development time is greatly reduced.
> M2M Services: KMS with XML/TCP/IP
XML (eXtend Mark up Language) is a representation standard formalising methods for structuring data. One of the specificities of XML is its modularity enabling tags and data to be added very quickly, making applications very adaptable. Since these formats are very widespread on the web, high-performance parsers are available on all software platforms.
The socket interface chosen for access to WIRMA M2M resources renders software compatibility due to embedded libraries unnecessary. The development interface no longer includes software to be linked to the application, thus limiting problems of compilation and integration. Application of whatever language requires only the opening of a TCP/IP socket and messages to be sent and received in XML format.
This interface is also accessible via a TCP/IP network, in particular LAN, which means it can be used to develop an embedded application on a remote station, integrating all the development and debugging tools for validation before loading it onto WIRMA.
For more technical information, please visit our developers' page.
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