Technical Design Report Super Fragment Separator

DRAFT
source tier are split in two logical layers: equipment control, which implements the device connection
and real-time equipment handling, and device presentation which models the equipment
and implements the network access. Both functional layers can be physically implemented on the
same hardware platform.
Devices are implemented as objects in the object-oriented software terminology. They provide
access by services and applications via the controls network and will be modeled by similar patterns
for all devices. This allows access through identical mechanisms for all devices. Devices are
set, read or controlled by properties via the controls middleware.
Devices will support several beams at a given time (time multiplexing). The setting and configuration
data for all beams reside in the equipment controllers. Because of this, no download from
higher layers of the control system is needed between accelerator cycles, except for changes. Thus
several sets of reference and actual data can be handled simultaneously, one for each of the beams
configured in the accelerator facility. Switching the components settings to fit to the actual beam
parameters is done in the equipment control sub layer, according to information which is distributed
by the timing system.
2.4.A2.7 Controls Middleware
The controls middleware is an ensemble of protocols, Application Programming Interfaces (API)
and software frameworks, which allows seamless communication between the software entities of
the ACS. Two conceptual models are supported: the device access model and the messaging model.
The device access model is mainly used in the communication between the resource and business/presentation
tier while the messaging model is mainly used within the business tier or between
the business tier and applications running in the presentation tier.
The devices access model is implemented by using the CORBA protocol which provides a high
level of abstraction. Complementary, the messaging model is based on the Java Message Service
(JMS) as the messaging solution for Java based control applications.
2.4.A2.8 Services and Application Software Architecture
Applications controlling the GSI/FAIR accelerator chain must handle a great variety of tasks such
as visualization of data and significant computation, together with database and equipment access.
These applications rely on several services such as security, transactions, and remote access and
resource management. These requirements dictate a modular and distributed architecture with a
clear separation between the user interfaces (GUI), the control core or service, the model, and the
devices that are controlled.
In the general system architecture, the consoles of the presentation tier are responsible for GUI
applications and translate the operator’s actions into commands invocation in the business tier. The
business tier, through its centralized shared processing power is in charge for providing services,
coordination of the client applications, and accessing databases. It also ensures coherence of operator
actions and enforces separation between presentation and application logic.
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