Friday, May 10, 2002

Capstone. It's only fitting to put a capstone on my previous entries about architecture. I have a few loose ends in the form of documents and links that complete the picture of what constitutes architecture, and a tie-in to component-based software engineering, which is a close cousin.

The quick and dirty list:

Also related are two documents from IBM: Business Rules for Electronic Commerce and Multi-Dimensional Separation of Concerns Using Hyperspaces (see also: previous entries about separation of concerns).

Thursday, May 09, 2002

Architectures Redeux. I've been discussing architecture within the context of web services, which is but one facet of the topic. First, I want to get a pet peeve out of the way: architect is a noun, not a verb. You can be a software architect, but you don't architect software. This atrocious misuse of the English language was introduced by Steve Jobs many years ago, and has unfortunately become a permanent part of the IT lexicon.

What is the essence of architecture? One of the best descriptions of software architecture is provided by Bredemeyer Consulting's Software Architecture Page. Despite the use of the dreaded word, architecting, the definitions provided capture the essence. My personal view is to consider architecture in its traditional form, which is the development of a high level design - the big picture. That is what those folks who design buildings for a living do. However, there are some marked differences between the original architects and software architects, which can be summarized in these three comparisons:

  1. Those who design buildings are have stringent education requirements and are licensed. There are legal definitions as to who can proclaim themself to be an architect. In software anyone can claim that he or she is an architect - and they frequently do just that. No credentials other than a proclamation and, perhaps, some references that will support the claim that they actually functioned as a software architect.
  2. Architects who design buildings are held to legal and engineering standards to which their designs must comply. Software architects can do pretty much anything they can get away with without legal or professional oversight.
  3. Building architects blend design with engineering constraints. They use both creativity and a good deal of science and math. Software architects may or may not employ either - and they are not compelled to do so in order to claim to be an architect.
However, my objective is not to bemoan the misuse of English or the sorry state of software architecture, but to provide reference material that I hope will be used to get one thinking about the essence of software architecture and advance our profession through knowledge sharing. The resources that I am providing portray many different ways to approach architecture, and some are better than others. Moreover, some of the resources conflict with one another, but what they have in common is the fact that the approach is based on methodology and quantification. Each provides an opportunity to learn.

Resources that I recommend include:

Architectures also define the building materials and techniques needed to execute the design developed by the architect. This is true regardless of whether the architect is a licensed professional or a software architect. Both the building and the software architect need to understand the characteristics of the materials and techniques. To that end I am including miscellaneous references to materials and techniques that a software architect will find interesting:My next entry will depart from the architecture theme, and will focus on M-Commerce and related topics.
No Surprises Here. According to an 8 May eWeek article titled Error in MS Protocol Could Compromise Security, "Microsoft Corp. has already identified at least one protocol and two APIs that it plans to withhold from public disclosure under a security exemption in the federal antitrust settlement proposal agreed to in November, according to Jim Allchin, Microsoft's group vice president for Platforms, who testified in the antitrust case in court Tuesday."

Plans to withold from public disclosure? Yeah, and we need to destroy this villiage in order to save it, right?

Wednesday, May 08, 2002

Availability. Linda and I are now available for consulting assignments, either as a team or individually. Marcia Hopkins will be available in early June. A summary of our experience and qualifications is available on the TEAM Zarate-Tarrani page.
Dimming Light. Kate Hartshorn has taken an indefinite leave of absence from contributing her insights and thoughts here. Her time and efforts have been redirected towards a difficult, but surmountable, challenge. Until her return this weblog and its Postcards from the Revolution sister will be bereft of rare points of view and a touch of humor and class that is missing from most technical resources. When she does return it will be on a permanent basis.

Shedding Light. What are web services, and why is there so much debate about a definition? I subscribe to a large number of news services and this question arises, debate ensues, issues become murky and the process repeats itself. I go with the definition that is set forth in the W3C Web Services Architecture Requirements that states:

A Web service is a software application identified by a URI, whose interfaces and binding are capable of being defined, described and discovered by XML artifacts and supports direct interactions with other software applications using XML based messages via internet-based protocols.
That wasn't too difficult. We have a definition that is sanctioned by an internationally respected body, and until a better definition comes along why not go with it? It certainly cuts through the hype spewing forth from Microsoft, Sun and the industry experts.

If you're interested in web services architecture the following resources are essential reading:

I've by no means exhausted my thoughts on this topic, and you can be sure that it will resurface again in the near future.

Bright Light. When Kate does return I promise that I'll make sure she stays around, and her place will never be filled until that time.

Tuesday, May 07, 2002

Correction. In my last entry I left out one of the true Oracle gems off the beaten path on the web: Thomas B. Cox's home page. This little known page contains some of the most impressive whitepapers I've found, including a DBA capability maturity model, DBA checklist and Oracle security information that you won't find elsewhere.

XML Update. One of the themes I've started this month has been web services, with a focus on some of the common building blocks such as VoiceXML, and specifications such as the Web Services Flow Language. I'm going to provide a few updated links on ebXML, which is in a constant state of change and is emerging as an important standard.

Technical specifications, white papers and reference materials are available at's specification page. This is a primary source of up-to-date information, work in progress documents and deliverables related to ebXML. If you're unclear about what ebXML is and why you should be paying attention to it, the site's FAQ will answer any basic question and provide the business and technical reasons for ebXML.

Another source of information is Sun's online whitepaper titled Overview of ebXML Specifications. This paper sorts our the specifications and their relationships to one another.

Monday, May 06, 2002

Off the Beaten Path in Search of an Oracle. Actually, I am not seeking a source of wisdom - I'm updating my primary Oracle links and want to share the lesser known ones and some of my frequently visited favorites:
More on Web Services. Two documents that neatly tie up my last entry on web services flow language are Web Services Architecture Directions and Web Services Flow Language Specification 1.0. Both files are in PowerPoint format.

Loose Ends. A few other documents and presentations tie any loose ends left from last week's entries. My descriptions are terse, but each is interesting and worth downloading and reading:

Enjoy, and have a wonderful workweek.

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