[¤2] The Open Group Architectural Framework
[¤4] The US Department of Defense Technical Architecture Framework for Information Management was developed from the IEEE POSIX.0 architectural framework, and was used as the basis of TOGAF. As a result there is a strong resemblance between the three. TAFIM, POSIX.0 and TOGAF share the same Generic Technical Reference Model diagram:
[¤7] Unlike POSIX, TAFIM includes a breakdown of the Application Software, Application Platform and External Environment entities into service categories:
[¤10] The TAFIM breakdown is complex, and differs from TOGAF in a number of significant ways:
[¤18] The TAFIM approach is very similar to that of TOGAF, but the TAFIM detailed technical reference model makes some assumptions about the structure of the final architecture. In particular, TAFIM places the Operating System service category between all the other categories and the External Environment Interface. While this is conceivable as an implementation strategy, it does rule out some possible architectures which would otherwise be perfectly valid.
[¤19] TAFIM also divides the Application Software Entity into Mission Area and Support applications. TOGAF takes the view that a support application is actually part of the application platform, and the fact that it is a utility program rather than a module of the operating system is merely an implementation detail.
[¤21] TAFIM and TOGAF are very closely related, so a detailed listing of TAFIM contents would largely repeat the statement of the TOGAF technical reference model.
[¤22] TOGAF and TAFIM identify the same set of services with some minor differences in the way they are grouped into categories. TAFIM does not pull out transaction processing and object services into separate categories, but instead covers transaction processing as a Data Mangement service and includes object services as a Distributed Computing service.
[¤23] The main exception to the equivalence of TAFIM and TOGAF is Security services. TAFIM is aimed at meeting the needs of the US Department of Defense and so focuses on military needs. TOGAF is the product of a civilian organization. The result is that the two architectural frameworks list different sets of services. For instance, TAFIM does not have a separate category for Encryption services, or for System Entry Control, but includes Availability and Security Labeling services. In fact, detailed consideration of the TAFIM and TOGAF security services reveals that they both cover much the same ground, but under different headings.
[¤25] TAFIM is the parent of TOGAF, and the US Defense Information Systems Agency has contributed extensively to the development of TOGAF, with the result that the two architectural frameworks have much in common, both in their goals and their content. The TOGAF technical reference model and architecture development method have been largely derived from the TAFIM. The differences between them reflect the differing needs of the civil and defense communities, and to some extent the development history of The Open Group's architecture prior to production of TOGAF.
[¤27] Copyright © The Open Group, 1997