Tornado

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Overview
1.2 Cross-Development with Tornado
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Tornado provides the optimal cross-development environment by ensuring the
smallest possible difference between the target system during development and
after deployment. This is accomplished by segregating the vast majority of the
development facilities on the host system, while providing precise yet minimally
intrusive access to the target. For all practical purposes, the facilities of the runtime
and the development environment are independent of each other, regardless
of the scale of the target application.
With Tornado, you can use the cross-development host to manage project files, to
edit, compile, link, and store real-time code, to configure the VxWorks operating
system, as well as to run and debug real-time code on the target while under hostsystem
control. To understand this environment more clearly, it is useful to outline
the typical development process.
The hardware in a typical development environment includes one or more
networked development host systems and one or more embedded target systems.
A number of alternatives exist for connecting the target system to the host, but
usually the connection is either an Ethernet or serial link. If hardware or hardwarespecific
code is not initially available, the integrated VxWorks target simulator can
be used to begin application development.
A typical host development system is fully equipped with large amounts of RAM
and disk space, backup media, printers, and other peripherals. In contrast, a
typical target system has only the resources required by the real-time application,
and perhaps some small amount of additional resources for testing and
debugging. The target may include no more than a CPU with on-chip RAM and a
serial I/O channel (although connections with higher throughput are generally
desirable).
Application modules in C or C++ are compiled with the cross-compiler provided
as part of Tornado. These application modules can draw on the VxWorks run-time
libraries to accelerate application development. A fundamental advantage of the
Tornado environment is that the application modules do not need to be linked with
the run-time system libraries or even with each other. Instead, Tornado can load
the relocatable object modules directly, using the symbol tables in each object
module to resolve external symbol references dynamically. In Tornado, this symbol
table resolution is done by the target server (which executes on the host).
With Tornado, object-module sizes are considerably smaller during development,
in contrast with other environments. This is because there is no requirement to link
the application fully. This advantage provides important leverage in a crossdevelopment
environment: the less data to be downloaded, the shorter the
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