Agreed. I *really* don't like Dave Linthicum's definition of a
metaservice. That's just plain stupid. If we follow his logic,
Meta means "data about", so metadata = "data" about data, and metaservice = data
about service, and metafruitflies = data about fruitflies, and an encyclopedia
is really a metatheworld.
Joe's
definition is at least reasonable, but I still don't think it adds any value,
and I agree with Ken that such a definition makes service composition very ugly
(can lead to meta-meta-meta services, etc.).
I typically cause physical damage to people who say metadata is about
data. (OK, not really.) That is a circular definition that tells you
nothing. In our context, metadata is a subset of information related to
an entity, including parts of the entity, that are needed for a particular
purpose. That means metadata can also be descriptive information about a
service. The early SOA-RM drafts (I think 07 and before) had an appendix
on metadata
As far as metaservice, the description of
service supports a hierarchy or combination of services, including services
working with and on other services. To have metaservice as a useful
concept, you would need a base level SERVICE and then things acting on
it. The identification of SERVICE will be use dependent and the source
of endless, fruitless arguments.
Ken
On Feb 10, 2006, at 8:34 AM, Chiusano Joseph wrote:
This may
potentially be pertinent for our Reference Architecture
work:
In a recent
entry[1] in his blog called "Focus on Repositories", David Linthicum
mentions the term "metaservice". Quote (see end of [1]):
"Since data
about data is called metadata, I call data about services metaservices. A
term we may be hearing more about in the future, and what will exist in
these repositories."
I differ with
Dave on this, and see "metaservice" as being something different. Here's my
comment on his blog:
<Comment>
On the
following: "Since data about data is called metadata, I call data about
services metaservices":
Since metadata is "data about data", I wonder
if a metaservice should really be considered a "service about services"? If
so, what would that really mean? Perhaps it's a service that "sits above" a
number of other services and provides, well, services about (or for?) those
services that, upon invocation, returns various details about those
services, or perhaps performs services upon the services themselves (such as
aggregating them at design time).
Just thinking out loud
here... </Comment>
Comments on my comment?
Joe
Joseph Chiusano
Associate
Booz Allen Hamilton
700 13th St. NW, Suite 1100
Washington, DC 20005
O: 202-508-6514
C: 202-251-0731
---
Ken Laskey
MITRE Corporation, M/S H305 phone:
703-983-7934
7515 Colshire Drive
fax:
703-983-1379
McLean VA 22102-7508
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