Mike McGrady wrote:
Thank you.
My desire was not to force you to talk any particular way. My desire
was to find out what you neantt. I suspected from my own experience
that once you gave your statements a fleshing out that they would not
hang together.
The more important thong in my thinking is my work with very large and
complicated systems and my resultant need to separate things into
cohesive units matching a sensible architecture.
My present work involves connecting the global information grid (GIG)
with the FAA NAS through FAA SWIM with a pluggable architecture that
will work with other ATC agencies like SESAR. I am using KARMA and
AUM to OSGify GigaSpaces.
So you can see I am very much atti ed to what you want to do but just
think you might be misapprehending OSGi by not fully grasping it's
notion of services. I would suggest a close read of Richard Hall's
MEAP book on ISGi.
Ok, thanks for the tip, I'll look it up, I'm very open to good reference
material and learning ; )
Cheers,
Peter.
Mike
Sent from my iPhone
On Nov 9, 2009, at 12:15 AM, Peter Firmstone <[email protected]> wrote:
Mike,
You come from a background of Standard setting? Well that explains
your wish to have a discussion using "correct terminology". For a
layman like myself (at least in Computing), I use loose terms to
describe what I'm talking about. I guess this means there's a gulf
between us when making attempts to communicate using computing
terms. To the layman, me, a Service appears to be a software design
pattern. Yes I'm also guilty of calling MVC a design pattern.
On the other hand, something that you can take away from our
conversation, that might serve you well in future endeavors, is that
you need tolerance, patience and understanding when dealing with
people who are of different cultural or work backgrounds, the average
programmer is not at your level of detail and would most likely take
offense.
I'm a Mechanical Engineer, so I understand the importance of accurate
terms in Engineering, the only difference between my field and yours,
is that Mechanical Engineers are legally liable and suffer heavy
penalties, or gaol terms for mistakes, hence strict adherence to
terminology, so it is surprising to see it in computing.
If I were to discuss with you, a Power Station, or Structural Stress,
you would be the layman.
I decided to respond in an aggressive manner, as your post had the
tell tale signs of a protracted heated argument brewing and this
Subject has been touchy in the past. I was cutting you off at the
pass and battening down the hatches.
You have my apologies, I didn't show you the courtesy of tolerance,
patience and understanding either. I take back what I said.
If you'd like to try again, you can tell me that my terminology isn't
right and I'll try to find another way of explaining it, without
getting frustrated or offended. But you must also understand, that
just because people like myself don't use proper terminology doesn't
mean we don't have an understanding, you might have a better
understanding, but do try not to get frustrated, that is detectable
and comes across poorly.
Regards,
Peter Firmstone.
Peter Firmstone wrote:
Good luck with your endeavours too Mike.
Perhaps you might try a less aggressive approach next time, look for
the common ground first, I don't know anybody that likes being told
they don't know what they're talking about, perhaps my ego isn't the
only one that got in the way?
I hope your friends found it amusing. Do you still have the iPhone?
Peter.
Mike McGrady wrote:
I am presently the author of a framework called "Karma" (Kolona
Automated Resource Management Architecture) that is open source
with a management app under another open source framework AUM
(Automated Universal Middleware).
UM (Universal Middleware) is a more current name for OSGi.
We could have called it DUM (Distributed Universal Middleware)
instead of AUM but thought better.
Too bad we did not get on better when I asked you what you meant by
"Service Pattern". (I still have no idea what you mean.) Anyway,
this does all you want to do and we have a plan to have it set as a
standard with IEEE, where I am a member of the standards
committee. If you check there in a few months, you can see what I
was hoping to talk to you about before your ego got in the way.
Good luck with your endeavors.
Mike
On Nov 8, 2009, at 5:06 PM, Peter Firmstone wrote:
Yes that's the beauty of Services, they provide opportunity for
pluggable replacement implementations. That's the "Service
Pattern" As we have seen it is possible to use the Service
Pattern to solve a number of different problems. Eg Netbean
Plugins, SPI, OSGi, Jini.
I'm looking at OSGi to wire up services inside the JVM as you
say. When I say package, I mean a java package residing in the
local JVM it may or may not be part of a Jini service, it may be a
purely local JVM package, eg a library dependency or local domain
package. For example, I have package X, version 1 loaded in my
local JVM, I need to have package X version 2 loaded as version 1
isn't compatible with the new Objects (domain data) I'm recieving
in serialized form. I need to share this information locally with
Package Y that currently has references to objects in Package X
version 1. The Objects in Package X version 1 that Package Y
references need to have their class files upgraded. Without OSGi
I can do this by persisting state, stopping the JVM, restarting
and loading package X version 2.
I'm not looking at distributed OSGi, but I can see a use case for
utilising a Jini Service, when a local OSGi bundle that performs
some task that could be done optimally if the processing can be
moved to where the data resides, this is just an example there are
probably 10 other ways of doing this:
A local application bundle that provides an OSGi service locally
queries a remote database using JDBC and performs a considerable
amount of manipulation to that data prior to returning a subset.
The query and its result are sent over the network using a
database JDBC connection.
The processing for that data, if shifted to the machine that has
the database data, would consume significantly less network
resources. EG the data transferred over the network is reduced by
a factor of 100 by processing the data on the database machine
after querying. A bundle that provides a "local JVM application"
an "OSGi service" could utilise a "Jini Service" to request the
data be processed at the Database machine in a particular manner
before receiving the result. This function could be locally
available as an OSGi service to some other local application, that
application doesn't need to know about Jini, it is an
implementation detail that is abstracted.
My objectives are all based around codebase services (objects
aren't locked to their http codebase origin), in combination with
OSGi or something like it, to ensure compatible classes and
packages are loaded among separate JVM instances. Yes Newton does
something similar, however it is AGPLv3 licensed.
I envision a distributed environment where nodes can have the
majority of their packages downloaded and upgraded via codebase
servcies. Providing an evolving cluster, that upgrades it's
bundles incrementally, while maintaining the maximum level of
class and package compatibility. Think Agile Cluster Running
System component upgrades.
People, who are jumping in now because I've mentioned OSGi, are
making assumptions and haven't been following the discussions I've
posted previously about Versioned Classes, Classloader trees,
Static Analysis and Codebase Services, this is frustrating as I
was hoping for some participation. It seems I can only get
attention when I mention a controversial subject. What I want is
attention to solving the problems that will make River better.
In my note below when I'm referring to the "Service Pattern", I
mean the service pattern that OSGi implements, enables bundles to
be upgraded by loading the replacement bundle in a new
classloader, The service is a common interface, the new upgraded
service is discovered after it is started. The alternative is to
use delegates to update references between objects when the
Classloader changes as per some of the other patches I've uploaded.
Jini also utilises a "Service Pattern", but to solve a different
problem.
I knew this was going to be a difficult topic to present.
What we need are separate lists, where people who want to
participate in constructive development to solve problems can do
so and another list where people can pontificate about software
ideals and have disrespectful arguments with each other without
holding up development. While we're developing we can keep an eye
on the argument list without getting embroiled.
Anyway I've said enough, I'm going back to doing the things I need
to do, if someone who has been following my posts to date has
implementation ideas, but are afraid to mention it, please feel
free to contact me directly to discuss, I do need some input to
gain confidence that I'm approaching these problems in the right
manner.
Peter.
Dennis Reedy wrote:
On Nov 8, 2009, at 1251AM, Peter Firmstone wrote:
I had avoided OSGi purely due to the controversy it generates on
this list, however without the Service Pattern one cannot
upgrade a package without first persisting everything and
shutting down the entire JVM, then restarting. At least OSGi
allows you to stop a bundle and any dependents, persist what you
need to then start with a later bundle version if desired,
without having to persist or shut down the entire JVM.
If thats all you want you dont need OSGi. Service lifecycles are
supported with a variety of container approaches, from JEE,
Spring to Rio. You also do not need to shutdown the JVM to load
new service classes.
Adopting OSGi as a micro-kernel architecture for wiring up
services inside the JVM is a different thing. Looking at
distributed OSGi is a totally different thing on top of that.
IMO, if you want to consider OSGi for River, you focus on the
former, not the latter.
Mike McGrady
Principal Investigator AF081-028 AFRL SBIR
Senior Engineer
Topia Technology, Inc.
1.253.720.3365
[email protected]
