[ Cloud Computing ] Re: Front Ends to Cloud Hosted Applications

I've been lurking and reading for a while, and am still struggling
with the google interface, but I'd like to make a few comments based
on recent posts. First up for transparency, I used to be a
Distinguished Engineer at IBM, I'm taking a break now between jobs. I
was part of the On demand architecture and Design team from 2002-2005
and first started pushing utility computing into the corporate
strategy back in 1999.

Bruce comments on mainframe applications and clouds. In order to move
a mainframe application (including the infrastructure) into a cloud
type environment you really need to understand the application
transactional requirements. If what you have is a purely batch
application, ie one that is triggered by schedule or event and it only
requires I/O to/from disk including network files/data, then that
should be perfectly possible.

Once you switch to looking at online systems, especially those needing
CICS and IMS subsystems, then you really do need to understand the
requirements for transactional integrity. Many of these applications
will use LU 6.2 or LU 2 type connectivity. Both these protocols
guarantee transactional integrity from point to point. That is for
example, when the user presses enter or clicks submit at the end user
terminal/browser etc. There are many components involved in this and
just moving the processing will require significant network
cooperation, and may break the integrity. You need to evaluate the
break points and decide if these are acceptable. Mostly these days m/f
customers have done away with dedicated ACF/VTAM networks in favor of
IP networks.

My prior assignment at IBM was looking at 10gb ethernet and converged
network adapters. I can tell you that while the latency and contention
management of 10gb ethernet is impressive, that alone isn't good
enough to simple convert LU 6.2 apps. You need switches that can
process data at wire speed and support no drop, to allow these
synchronous apps to work in that environment.

If what you have are a bunch of CICS and IMS transactions that are
isolated at the point of invocation, ie not part of a network then
indeed you could move them into a variable compute pool. Think of
building CICS and IMS regions in the same way you create vmware images
today. Theres no reason why you can't allocate n-virtual regions
across n-physical processors, and have the system create these regions
on the fly, use them and then destroy them when no longer needed. Of
course, this would have to be on mainframe engines, and the mainframe
aka z/OS has ways of doing this already. Moving workloads and
provisioning regions across a pool of physical mainframes is not so
difficult, until of course you get back to transactions. Thats when/
why we invented parallel sysplex although you could largely replace
this today if you used a transactional message/queuing system where
you can ensure a message is processed once and only once irrespective
of which server processed it.

Moving outside of mainframe architecture processors becomes much more
complicated, although not impossible. As noted, microfocus have
technology, mainframe architecture emulation is also possible ala
hercules, it will also be interesting to see what IBM does with its
PSI acquisition.

Now, what context did you want to discuss physical/virtualized
processors?

++Mark.
(a knight of VM :-) )
Blog: http://cathcam.wordpress.com

On Dec 15, 10:22 pm, bstanle...@bellsouth.net wrote:
>
> The reason I ask is that the mainframe world consisted of "workloads" which for all current purposes and definintions is a VM in today's verbiage. These workloads represented a CICS region or a IMS database process or backups. This same technology is what a VM represents today.

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