Defence and environment monitoring tools
APC company announced a new generation of defence and monitoring of NetBotz environment tools. The main improvements were: advanced camera support; optimized cable connection; Power over Ethernet technology support; and new design. NetBotz - is a family of network solutions to identify a human presence and alarm in those cases when human activity can harm a network infrastructure. Module structre of this system allows to scale it from small networks to big data-centers, and apply flexible camera configuration.
NetBotz offers the following facilities:
- improved camera supporting. NetBotz allows to integrate Pelco ip-cameras.
- improved connection system. NetBotz uses cables of 5 and 6 categories to decrease a time of connection.
- Power over Ethernet technology.
- compact design.
Netbotz products will go on sale in April 2009.
Introduction to Distributed Systems
A distributed system is a collection of independent computers that appears to its users as a single coherent system.
There are two aspects to such a system: hardware and software. The hardware machines must be autonomous and the software must be organized in such a way as to make the users think that they are dealing with a single system. Expanding on these fundamentals, distributed systems typically have the following characteristics; they should:
- be capable of dealing with heterogeneous devices, i.e., various vendors, software stacks and operating systems should be able to interoperate
- be easy to expand and scale
- be permanently available (even though parts of it may not be)
- hide communication from the users.
In order for a distributed system to support a collection of heterogeneous computers and networks while offering a single system view, the software stack is often divided into two layers. At the higher layers, there are applications (and users) and at the lower layer there is middleware, which interacts with the underlying networks and computer systems to give applications and users the transparency they need.
Middleware abstracts the underlying mechanisms and protocols from the application developer and provides a collection of high-level capabilities to make it easier for programmers to develop and deploy their applications. For example, within the middleware layer, there may be simple abstract communication calls that do not specify which underlying mechanisms they actually use, e.g., TCP/IP, UDP, Bluetooth, etc. Such concrete deployment bindings are often decided at run time through configuration files or dynamically, thereby being dependent on the particular deployment environment.
Middleware therefore provides the virtual overlay across the distributed resources to enable transparent deployment across the underlying infrastructures.