Introduction
As a result of the increased use of technology on the last 20 years, IT and business professionals realized the need of a better understanding of information system organizations in order to align these systems with the business needs. A number of frameworks were created to that organization called enterprise architecture. In this document described briefly the Zachman and TOGAF frameworks.
Zachman framework
In 1987, John A. Zachman published a paper on the IBM System Journal [1]. In this paper, the author analyzed the similarities between an information system implementation and the construction of a building. The architecture discipline is being polished by centuries of successful and failure in the creation of the structures where our civilization lives, and this knowledge could be applied to a younger problem: modern enterprises information systems construction. This article influenced, and was a mayor contribution to the creation of a few enterprise architecture frameworks.
Zanchman framework explains the need of different views for different players to describe the complex information systems that are present in modern enterprises. It recommends a two dimensional matrix as an organization of the different views needed. This matrix reminds me an Indian story called: Blind men and an elephant [2]. In this story, six blind men are asked how and elephant looks like, and each of them described the elephant based on the body part they touch. All their perspectives were right, but none of them along described the elephant properly.
On the Zachman matrix, each row represents a perspective/view of the enterprise system for one player type (Strategists, Executives, Architects, Engineers, Technicians, and works), and every column represent a specific aspect of it responding to the following questions: what, how, where, who, when, and why. Each cell will be very focus on one single aspect for one single player type. Organizing architectural artifacts on this matrix the following benefits can be archived [3]:
- Looking at the matrix the completeness of the information system understanding can be evaluated as “holes” on the matrix will show incorrect level of specification
- Ensures these artifacts are also focus on a single aspect, and a single player view.
- Ensure that the business requirements are mapped to implementation.
TOGAF framework
The first version The Open Group Architecture Framework, TOGAF, was developed in 1965 based on the US Department of Defence Technical Architecture Framework for Information Management (TAFIM). After that version, The Open Group Architecture Forum has developed new versions of the framework being the last one version 9, TOGAF 9, published in January 2009.
TOGAF 9 document is divided on seven parts [4]. The core part is the number two: Architecture Development Method, a step-by-step method for developing enterprise architectures. This framework covers the development of the following architecture domains: Business, Data, Application and Technology. The methods specify nine phases for the enterprise architecture development. These phases, but the first one, are organized on a circle around the business requirements expressing the idea that the process need to be driven by those requires, and also that the enterprise architecture development is an iterative process. By walking this phases, the enterprise will be moved from the current architecture to the target architecture that will support the business requirements. A brief summary of these phases:
- Preliminary phase: In this phase the organization is prepared to start the enterprise architecture initiative.
- Architecture Vision: This phase starts the architecture developing cycle setting up the scope, constraints and expectation for this iteration.
- Business Architecture: A business analysis and modeling is performed to for the iteration scope.
- Information System Architecture: It is composed by the data architecture and the application architecture. Being the first one a definition of the data sources needed on the enterprise, and the second one a definition of the applications needed to process those data and support the business.
- Technology Architecture: It documents the IT systems organization (software, communication and hardware), and develop the target technology architecture.
- Opportunities and Solutions: This phase identify possible alternative to reach the target architecture.
- Migration Planning: It creates the migration plan from the current to the target architecture.
- Implementation Governance: Management and monitoring of the migration plan.
- Architecture Change Management: Ensure that the implementation changes are controlled.
Framework comparison
In my opinion, both frameworks are good for the development of enterprise architectures because they guide the enterprise architecture development by a division of the information system in views. Each view will be associated a view point, and it will represent the concerns of a player/stakeholder. Zachman is more incomplete that TOGAF because it doesn’t provide a step-by-step development method for enterprise architecture, and on the framework, there is no explicit iterative process. On the other hand, on the TOGAF framework, a development method is defined, the concept of iteration is explicit, and the goal is to get from the enterprise state i to the enterprise state i + 1: the sense of movement is always present.
References
1.A framework for information systems architectures, John A. Zanchman, IBM System Journal, Vol 26, NO 3, 1987
2.Blind men and elephant http://en.wikipedia.org/wiki/Blind_men_and_an_elephant
3.A Comparison of the Top Four Enterprise-Architecture Methodologies, Rogers Sessions, ObjectWatch Inc, http://msdn.microsoft.com/en-us/library/bb466232.aspx
4.TOGAF version 9, A Pocket Guide, Published by The Open Group, January, 2009.
