SJTAG in Distributed Systems

[Ian McIntosh]

The subject of "distributed systems" has been coming up with increasing frequency. We've long recognised that "system" may be a reference to more than a single box, but greater use of loose coupling methods such as Bluetooth this raises a number of questions from an SJTAG perspective, including:

• Should these be considered as a single system or a hierarchical arrangement - a system of systems?
• If the connection between major items is only by a "mission bus" like ethernet, wireless, etc., then how relevant is SJTAG? Is SJTAG a set of slave operations under the control of a functional test? Is there a relevance for testing of the network or interconnections between items?
• Do such distributed architectures need to be considered within a base SJTAG standard, or does it seem more appropriate as an extension?
• Is SJTAG only applicable where the costituent parts are described by some specific design description or can ad hoc arrangements be accomodated?

The above are just some sampler issues to kick off discussions: What are your views? How significant are such distributed systems to your industry sector?

[Heiko Ehrenberg]

I think "system of systems" describes Distributed Systems very well and would be a good way to approach this topic from the SJTAG perspective. We should start solving problems for Systems, before looking at even more complicated arrangements such as Distributes Systems. Once we solve test problems related to "normal" systems, we should be able to extend these solutions to "distributed" systems as well.
The first release of an SJTAG standard (SJTAG.1) should concentrate on self-contained systems, I would think.