Ted Leung on the air
Ted Leung on the air: Open Source, Java, Python, and ...
Sun, 07 Sep 2003
Web services: contracts and coupling
I'm working through a backlog of interesting posts. Sometimes that produces interesting juxtapositions, like this old post by Bill de Hora on component and service models and this new article by Rich Salz on Typeless Schemas and Services.

Both are talking about contracts, both deal with contracts as an XML level thing. Bill says contracts are best described as an ordered exchange of documents -- a protocol. Rich says that contracts are about the shape of the XML (tree) but not about the types of the values (stuff at the leaves) In his coverage of Tim Ewald's MSDN article, Rich does discuss document flows, but this time in terms of validation, that successively finer validation occurs at various points in the document flow.

Bill's point about interface changes propagating to clients is a good one. It is going to happen in all models designed around a static or explicit type system. The type system itself creates tight coupling between services and clients, so if the goal is loose coupling, then one way to do that is to get rid of the types. You can argue that this is what you are doing if you either use highly generic methods (you turn types into argument data) or a dictionary interface (same thing).

Food for thought.

[00:42] | [computers/internet] | # | TB | F | G | 0 Comments | Other blogs commenting on this post
DRM destroys value - it destroys the customer relationship
I'm not sure that I completely agree with Kevin Marks when he says that all DRM is readily circumvented, because the methods of circumvention can lead to degradation of quality, which is important. I do think that the effect of companies vigorously enforcing DRM is counterproductive. But then again, so much of how business get's done in America is counterproductive -- just look at telemarketing. I fully agree with Kevin that it's time to
create a marketplace that reflects people's desires and trust.
The companies that figure out how to do that will have my business and recommendation for a long time to come.
[00:22] | [computers] | # | TB | F | G | 3 Comments | Other blogs commenting on this post
Alan Green was reminiscing about the olden days, and started thinking. That thinking led to a table comparing a Commodore 64 to his current hardware. If you stop for a minute and look at the multipliers in the right hand column (crude though they be), you have to marvel at the wonders that the hardware engineers have been doing. And no offense to Alan, but his system is isn't that current. You could multiply CPU clock by 2, RAM by 2 and disk by 2 or 3.

Of course, if you think some more, you start wondering what the software multipliers would be if you had corresponding ones...

[00:17] | [computers/hardware] | # | TB | F | G | 0 Comments | Other blogs commenting on this post

twl JPG


Ted Leung FOAF Explorer

I work at the Open Source Applications Foundation (OSAF).
The opinions expressed here are entirely my own, not those of my employer.

Creative Commons License
This work is licensed under a Creative Commons License.

Now available!
Professional XML Development with Apache Tools : Xerces, Xalan, FOP, Cocoon, Axis, Xindice
Technorati Profile
PGP Key Fingerprint
My del.icio.us Bookmarks
My Flickr Photos

RSS 2.0 xml GIF
Comments (RSS 2.0) xml GIF
Atom 0.3 feed
Feedburner'ed RSS feed

< September 2003 >
  1 2 3 4 5 6
7 8 910111213


Macintosh Tips and Tricks

Blogs nearby
geourl PNG

/ (1567)
  books/ (33)
  computers/ (62)
    hardware/ (15)
    internet/ (58)
      mail/ (11)
      microcontent/ (58)
      weblogs/ (174)
        pyblosxom/ (36)
      www/ (25)
    open_source/ (145)
      asf/ (53)
      osaf/ (32)
        chandler/ (35)
        cosmo/ (1)
    operating_systems/ (16)
      linux/ (9)
        debian/ (15)
        ubuntu/ (2)
      macosx/ (101)
        tips/ (25)
      windows_xp/ (4)
    programming/ (156)
      clr/ (1)
      dotnet/ (13)
      java/ (71)
        eclipse/ (22)
      lisp/ (34)
      python/ (86)
      smalltalk/ (4)
      xml/ (18)
    research/ (1)
    security/ (4)
    wireless/ (1)
  culture/ (10)
    film/ (8)
    music/ (6)
  education/ (13)
  family/ (17)
  gadgets/ (24)
  misc/ (47)
  people/ (18)
  photography/ (25)
    pictures/ (12)
  places/ (3)
    us/ (0)
      wa/ (2)
        bainbridge_island/ (17)
        seattle/ (13)
  skating/ (6)
  society/ (20)

[Valid RSS]

del.icio.us linkblog



Listed on BlogShares

Locations of visitors to this page
Where are visitors to this page?

pyblosxom GIF