An observation
State - The definition of state is interesting. I like the
definition in UML – “A condition or situation during the life of an
object [during] which it satisfies some condition, performs some do[sic]
activity, or waits for some event.” [The UML Ref Manual, 2nd ed
by Rumbaugh, Jacobson and Booch]. It says to me that the attributes that
define state are those that allow one to determine the whether some condition
is satisfied, what activity is being undertaken or what event is being waited
upon.
Within the RM-WG we have split attributes into configuration
attributes and state attributes. Configuration attributes to some degree define
behavior, defining or constraining the set of allowed states, as well as the possible
values of state attributes and allowed transitions between states. Clearly configuration
attributes are “interesting”, and thus according to the definition
below they would be considered part of the state. I’m not sure that this
is the case.
Regards
Paul
From: ogsa-wg-bounces@ogf.org
[mailto:ogsa-wg-bounces@ogf.org] On Behalf Of
Treadwell, Jem
Sent: Thursday, April 12, 2007
11:06 AM
To: ogsa-wg
Subject: Re: [ogsa-wg] Glossary
terms for Thursday's call
Hi,
Thanks to all those who joined today’s call for the
glossary segment – we had an excellent discussion that resulted in
agreement on definitions for state, resource and service.
The agreed-upon definitions (with some minor post-meeting
wordsmithing) are below – please take a look, and let me know if you have
any comments. I’ll move them into the draft document if there are
no objections by Monday — after that you can still comment at any time,
and there will, of course, be a review period for the full document later.
Thanks!
-
Jem
-
State: An entity’s state
is the combined values of its “interesting” attributes. Interesting
attributes are those for which external observers may see changes over
time. Examples include the position of a switch, the price of a stock, or
the amount of memory allocated to a process.
Since
not all attributes may be available or interesting to all possible observers,
different observers may have different views of the state of an entity at a
given time.
A
change in state is an event.
Resource: A resource is a physical or
logical entity that supports use or
operation of a computing application or environment.
In a
Grid context the term encompasses entities that provide a capability or
capacity (e.g., servers, networks, disks, memory, applications, databases, IP
addresses, and software licenses). Dynamic entities such as processes,
print jobs, database query results and virtual
organizations may also be represented and handled as resources.
Service: A service in the most general sense is an entity, usually composed of one or more
software components, that provides
functionality in response to client
requests.
A
service is often a part of a service-oriented
architecture, and participates in realizing one or more capabilities.
For
example, an electronic bookstore application is a service, and its database component
provides a database service to the bookstore. Thus high-level services
may be decomposed into lower-level constituent services. In general, a
service and all of its decomposable sub-services are considered to be components.
Jem Treadwell
Software Engineer
HP Software
856.638.6021 office | 856.638.6190 fax | jem.treadwell@hp.com
www.hp.com/go/software
From: ogsa-wg-bounces@ogf.org
[mailto:ogsa-wg-bounces@ogf.org] On Behalf Of
Treadwell, Jem
Sent: Wednesday, April 11, 2007
11:50 AM
To: ogsa-wg
Subject: [ogsa-wg] Glossary terms
for Thursday's call
HI,
I’ve
uploaded version 4 of the glossary – this version includes the changes
for deployment and provisioning, as agreed at the last discussion.
You’ll find it at http://tinyurl.com/2mo6r3.
For
Thursday’s call I propose to discuss the following terms, as time permits
o
State. We had discussed
this, and Jay has an action to improve the current proposal. So far I
haven’t had a proposal from Jay, but we need to put this one to bed, so
we’ll have a brief discussion and if we don’t have a better
proposal at the meeting I’ll go with what we have. There will be an
opportunity to improve this or any term in the final review.
o
Resource, Grid component, and
Service. We had definitions for Resource and Service in both the OGSA and
the EGA glossaries, so we need to produce a consolidated definition. Grid
component comes from the EGA glossary. I’ve condensed it from the
original, but (hopefully) haven’t changed its meaning.
Rather than reproduce these
terms here please take a look at the working/discussion document, which
you’ll find at http://tinyurl.com/23a6zd.
These are the first four terms listed, and the text you’ll find is a
starting point for discussion. If you have comments and you’re not going
to make tomorrow’s meeting, please pass them on to me; otherwise
I’ll follow up after the meeting with revised text for review.
Thanks!
- Jem
Jem Treadwell
Software Engineer
HP Software
856.638.6021 office | 856.638.6190 fax | jem.treadwell@hp.com
www.hp.com/go/software