Before any application can be executed, we need to know:
- how it can be run (e.g., path to the executable, parameters)
- where the application runs (e.g., machine, queues)
- what it needs to run (data files, their format, type, names)
- what it produces (files -- format and type, logs, stdout, etc.)
The structure which keeps this information is a called
Abstract Application Descriptor
(AAD) -- an XML file and the corresponding DTD.
Once we are about
to execute the application, we need to convert some of the generic requirements
into actual run-time parameters (e.g., actual file names, actual queue, etc.)
and we get Application Descriptor
(AD). The details can still be found at
the original NPAC site: http://www.npac.syr.edu/users/haupt/WebFlow/MODULES/AAD.html
or locally here.
The applications have to be combined together to form a computational
session. Relation between individual applications, which are combined to
form the session, is described by
Abstract Task
Descriptor (
ATD). This is again an XML file
and lists pointers to Application Descriptors or other tasks (i.e., the
groups of applications working together). For the description, ATD's DTD,
and examples check
http://www.npac.syr.edu/users/haupt/WebFlow/MODULES/ATD.html
or see the local copy
here. Their format and role is also discussed in
http://www.npac.syr.edu/users/haupt/WebFlow/XML/model.html
or its local copy:
here.