Image Processing Reference
In-Depth Information
19.16 VNA: Tool Overview
19.16.1 Global Objects
The workflow in VNA ensures that all relevant information about the network is captured. Global
objectsshallbecreatedirst,andthen(re)usedinseveralprojects.heVNAuserworkswithobjects
of types such as signals, nodes, interfaces, etc. hese objects are used to build up the networks used
in a car. Signals are defined by name and type, and can have logical or physical encoding information
attached. Interfaces detailing hardware requirements are defined leading to describe actual nodes
on a network. For each node, receive and transmit signals are defined, and timing requirements are
provided for the signals. This information is intended for “global use,” that is, across car variants,
platforms, etc.
19.16.2 Project or Configuration Related Data (Projects,
Configurations, Releases)
When all global data have been collected, the network will be designed by connecting the interfaces
in a desired configuration. VNA has strong project and variant handling. Different configurations
can selectively use or adapt the global objects, for example, by removing a high-end feature from a
low-end car model. his means that VNA can manage multiple configurations, designs, and releases,
with version and variant handling.
The release handling ensures that all components in a configuration are locked. It is, however, still
possible to reuse the components in unchanged form. his makes it possible to go back to any released
configuration at any point in time.
The database is a central part of the VNA system. In order to ensure highest possible performance,
each instance of VNA accesses a local mirror of the database which is continuously synchronized
with its parent (Figure .).
19.16.3 Database
All data objects, both global and configuration specific, are stored in a common database. he VNA
tool was designed to have one common multiuser database per car OEM. In order to secure highest
possible performance, all complex and time-consuming VNA operations are performed toward a
local RAM mirror of the database. A specially designed database interface ensures consistency in the
local mirror. Operations that are not time critical, such as database management, operate toward the
database.
The built-in multiuser functionality allows multiple users to access all data stored in the database
simultaneously. To ensure that a data object is not modified by more than one user, the object must
be locked before any modification, read access is of course allowed for all users although an object is
locked for modification.
19.16.4 Version and Variant Handling
The VNA database implements functionality for variants and versions handling. Most of the global
data objects, e.g., signals, functions, and nodes, may exist in different versions, but only one version
ofanobjectcanbeusedinaspeciicproject/coniguration.
The node objects can be seen as the main global objects, since hierarchically they include all other
types of global objects. The node objects can exist in different variants but only one object can be
used from a variant folder in a particular project/configuration.
