RE: VM images and working in the VM image

Assume the server crashes for some reason: what happens to those patches?
Does "loading the patch" imply that the on-disk image is modified?

Ted Neward
Java, .NET, XML Services
Consulting, Teaching, Speaking, Writing
http://www.tedneward.com

> -----Original Message-----
> From: [email protected] [mailto:strongtalk-
> [email protected]] On Behalf Of James Robertson
> Sent: Saturday, May 12, 2007 7:52 PM
> To: [email protected]
> Subject: RE: VM images and working in the VM image
> 
> 
> I'm talking about Cincom Smalltalk (VisualWorks specifically, but
> most of what I said applies to Squeak as well).  When I change class
> definitions, existing objects change shape as well - even as methods
> are running.  I've not worried about that, because it's not been an issue.
> 
> As to how I persist those changes, I do things like this:
> 
> 1) Export the changes code from my test server as a Smalltalk file-out
> 
> 2) Export the new versions of all the packages changed
> 
> 3) Upload the patch and the new packages to the server
> 
> 4) Put the new packages into the directory used when the image
> starts, and put the patch into the patch directory
> 
> 5) Kick the server (via a web console) to load the patch (and then delete
> it)
> 
> I patch in place, and also make sure to have all the most current
> startup packages in place in case the server needs a restart.
> 
> I would also argue that most of the "high end" Java app servers you
> speak of could be done quite easily in Smalltalk.  We have plenty of
> customers with complex applications.
> 
> 
> >(*) No argument on the dynamic nature of the image vs. the static nature
> of
> >the Java app server (though, in theory, the app server doesn't need to go
> >down just to change code, either--all that is handled through
> ClassLoaders
> >in the JVM, which are far more dynamic than you might expect). This may
> be
> >more complicated than what we can approach in this email, but... When you
> >change the shape of objects in memory, though, how does the ST image
> handle
> >that? Do existing objects receive the change? And what happens if methods
> >are invoked in the middle of the reload?
> >
> >(BTW, you and I, I think we've had this discussion on the usefulness of
> the
> >ST image before, over blogs--I'm not arguing against the idea, just
> trying
> >to understand it better.)
> >
> >(*) You're referring to your Cincomm Smalltalk flavor, correct?
> VisualWorks?
> >Not Strongtalk?
> >
> >(*) How do you persist those changes to the image so that if the machine
> >crashes, the image doesn't lose all those changes? Do you periodically
> have
> >to flush the image to disk? And is that transactional somehow?
> >
> >(*) Hopefully you'll also allow me to assert that running a blog engine
> >isn't exactly the high-scale requirement environment that some of the
> Java
> >(and .NET) app servers are asked to handle. :-) What I'd *really* love,
> >though, in order to move this particular point out of the realm of the
> >abstract, is to know *exactly* what the runtime footprint of your "app
> >server image" takes up, so as to hopefully compare/contrast it against
> the
> >runtime footprint of a Java app server stack. (I'd much rather argue
> facts
> >than assertions, and numbers against "belief".)
> >
> >Heck, for that matter, I'm not trying to "argue" at all. Just learn. :-)
> >
> >Ted Neward
> >Java, .NET, XML Services
> >Consulting, Teaching, Speaking, Writing
> >http://www.tedneward.com
> >
> > > -----Original Message-----
> > > From: [email protected] [mailto:strongtalk-
> > > [email protected]] On Behalf Of James Robertson
> > > Sent: Saturday, May 12, 2007 7:19 PM
> > > To: [email protected]
> > > Subject: RE: VM images and working in the VM image
> > >
> > >
> > > Oh?  My blog: http://www.cincomsmalltalk.com/blog
> > >
> > > runs on an image, as do all the others hosted there:
> > >
> > > http://www.cincomsmalltalk.com/userblogs
> > >
> > > Any arbitrary application server for Java you pick is going to chew
> > > resources as well; claiming that the image is some kind of resource
> > > hog is just silly.  Running a Smalltalk image w/o the GUI is fairly
> > > easy to do (at least using the flavor I use) - and having the
> > > compiler present allows me to add patches (including ones that change
> > > the shape of objects in memory) as the image runs - I don't have to
> > > play the "take it down, update, bring it up" game.
> > >
> > > To build my runtime I start with a base image, and start with a
> > > command line like this:
> > >
> > > visual baseImage.im -filein startupScript.st - nogui
> > >
> > > Where startupScript.st has Smalltalk code that loads in the
> > > components I need to run, and configures the system for runtime.
> > >
> > > >Case in point: ST's notion of the IDE-in-the-image is pretty lame
> when
> > > >looking to deploy an image within a "headless" environment. Is there
> > > another
> > > >approach when trying to build a server? Surely when running Seaside,
> for
> > > >example, I don't want or need the overhead of the IDE hanging
> around....
> > > It
> > > >might be useful in certain scenarios, but most of the time, it's just
> > > going
> > > >to be useless overhead....
> > > >
> > > >I recognize that it's probably impossible to summarize the ST
> philosophy
> > > >down into a single email of reasonable proportions, and of course
> it's up
> > > to
> > > >Richard to go read more about the ST philosophy if he wants to "get"
> ST
> > > in
> > > >any reasonable sense. But it's not too much to ask, I don't think, to
> > > answer
> > > >in single-sentence form the specific issues being raised--plus, that
> way,
> > > >it's in the archives for others to discover later when they come to
> ST
> > > with
> > > >their own questions.
> > > >
> > > >Ted Neward
> > > >Java, .NET, XML Services
> > > >Consulting, Teaching, Speaking, Writing
> > > >http://www.tedneward.com
> > > >
> > > > > -----Original Message-----
> > > > > From: [email protected] [mailto:strongtalk-
> > > > > [email protected]] On Behalf Of tim Rowledge
> > > > > Sent: Saturday, May 12, 2007 2:50 PM
> > > > > To: [email protected]
> > > > > Subject: Re: VM images and working in the VM image
> > > > >
> > > > >
> > > > >
> > > > > On 12-May-07, at 2:24 PM, Richard wrote:
> > > > >
> > > > > >
> > > > > > Coming from a background of C++, Ruby and Java I'm used the idea
> > > that
> > > > > > you program in an IDE and then you output a Jar
> > > > > That imply isn't the way Smalltalk works Richard. It sounds as if
> you
> > > > > would gain a lot by reading up on how Smalltalk works and how it
> is
> > > > > very different to old ways of doing things.
> > > > >
> > > > > Try  Smalltalk Central (http://www.smalltalk-central.com/
> > > > > showDocument.ssp?section=Articles&name=Documentation), http://
> > > > > www.iam.unibe.ch/~ducasse/FreeBooks.html etc.
> > > > >
> > > > > Basically we just don't do dead code. As one wag put it "source
> code
> > > > > in files? How quaint."
> > > > >
> > > > >
> > > > > tim
> > > > > --
> > > > > tim Rowledge; [email protected]; http://www.rowledge.org/tim
> > > > > There can never be a computer language in which you cannot write a
> > > > > bad program.
> > > > >
> > > > >
> > > > >
> > > > > >
> > > > > No virus found in this incoming message.
> > > > > Checked by AVG Free Edition.
> > > > > Version: 7.5.467 / Virus Database: 269.6.8/800 - Release Date:
> > > 5/11/2007
> > > > > 7:34 PM
> > > > >
> > > >
> > > >No virus found in this outgoing message.
> > > >Checked by AVG Free Edition.
> > > >Version: 7.5.467 / Virus Database: 269.6.8/800 - Release Date:
> 5/11/2007
> > > >7:34 PM
> > > >
> > > >
> > > >
> > > >
> > > <Talk Small and Carry a Big Class Library>
> > > James Robertson, Product Manager, Cincom Smalltalk
> > > http://www.cincomsmalltalk.com/blog/blogView
> > >
> > >
> > > >
> > > No virus found in this incoming message.
> > > Checked by AVG Free Edition.
> > > Version: 7.5.467 / Virus Database: 269.6.8/800 - Release Date:
> 5/11/2007
> > > 7:34 PM
> > >
> >
> >No virus found in this outgoing message.
> >Checked by AVG Free Edition.
> >Version: 7.5.467 / Virus Database: 269.6.8/800 - Release Date: 5/11/2007
> >7:34 PM
> >
> >
> >
> >
> <Talk Small and Carry a Big Class Library>
> James Robertson, Product Manager, Cincom Smalltalk
> http://www.cincomsmalltalk.com/blog/blogView
> 
> 
> > 
> No virus found in this incoming message.
> Checked by AVG Free Edition.
> Version: 7.5.467 / Virus Database: 269.6.8/800 - Release Date: 5/11/2007
> 7:34 PM
> 

No virus found in this outgoing message.
Checked by AVG Free Edition. 
Version: 7.5.467 / Virus Database: 269.6.8/800 - Release Date: 5/11/2007
7:34 PM
 


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