I'm not trying to be either difficult or confusing. Rather, I asked you for a
sample of a Web Application that has subsecond response.
Instead of providing one, you pointed me to a trivial example which is not a
real world or working example. I have yet to see a web application, despite
your claims, that can support the sub-second response that standard
applications or green screen applications support on a regular basis. I would
be very much tickled to see one, and yes, at that point, I would admit I was
mistaken.
But I would simply have to see one first.
JSP, unless you mean something totally different from what I think you mean,
means Java Server Pages - which is essentially a compiled and running Java
program similar to a servlet that displays a web page. Usually using JavaScript
(a browser based scripting language not at all related to Java the programming
language) to present a more interactive appearance to the user.
I have seen fast JSP applications, but the repsonse speed from these
applications is subject to, and limited by, the client and the network. In
other words, the browser has to render the page and load/interept the
Javascript. That takes a good deal of time to do anything significant.
As for the difference between this and application servers that provide only
display; it should be obvious. The processing horsepower and the network are
all centralized *and controllable*, which means that the processing happens
quickly. The only thing passing between the systems is the display
instructions, which while similar to, are far more optimized than a browser.
The remote display is still rendered by a client, but the client does not have
to content to a large number of different things, such as HTML, StyleSheets,
loading and displaying indicvidual graphics, javascript, ASP, and the legion of
other application protocols. It only deals with display, and the protocol it
understands is designed to do nothing BUT display. Just like X11 by the way.
As for cost, you seem to have not investgated the situation throughly. Do you
know how much WebSphere actually costs to deploy, including the hardware to do
so, database backends and so forth? Hint - it is NOT cheap.
You are pointing at the cost of CALs, so I will assume you are familiar with
Windows. First off, the only *additional* cost is a Terminal Server CAL, which
*replaces* the cost of a standalone Windows workstation license. Typcially, TS
CALS run about $50 (street price.) That is quite a bit cheaper than buying and
supporting Windows on a standalone workstation.
Better yet, take Windows out of the picture and you have a much better economy
of scale. Typically, Windows, with CALS to a server and Office runs between
$1000 and $1400 per desktop/user. (That can vary a little, but it is a pretty
good average, and applies equally well to a system deploying WebSphere
applications or a system deploying full capability applications over a terminal
server interface, or a configuration of a bunch of standalone machines.
Linux gets that cost down to more like $140 per desktop, taking SuSE bundled
pricing for instance. Inlcuding an office suite and the capabilty to run
remotely or locally, with full licensing. WebSphere deployment can and does add
significantly to that cost, as you need WebSphere, databases and the cost of
Rational included in there.
Obviously, should there be web applications (vice applications deployed by the
web to something like an ICA client) that can provide a smooth seamless and
*fast* user experience, then I need to rethink that logic.
Basically, pretend I am from Missouri instead of Texas - show me and I'll
believe.
-Paul
From: Paul Raulerson
What's so hard? Write a simple servlet that updates a counter and
outputs
it to a JSP. Have the JSP show the counter and a button. When the
button
is hit, go back to the servlet.
I rather thought you were talking about a real application, the kinds
that have to hit a backend datasource, perform significant edits on
the data, and redisplay screens fairly quickly. Hopefully doing
things like telling the user what went wrong. You can get subsecond
response out of a Palm M100 with the kind of application you describe.
You are either trying to be difficult, or else we have a serious
communication breakdown. You're complaining about the browser as a UI as
opposed to the Citrix approach, and I'm trying to tell you that the UI
overhead of JSP is almost zero.
Since JSP is only the UI, the back end is pretty much a non-issue, isn't it?
I mean, if the back end processing takes a long time, then the UI won't be
responsive whether it's Citrix or JSP. If the back end doesn't take a long
time, then it's not an issue.
Not that it matters, though. Since I use RPG as my back end and the JSP is
purely used for data conversion and presentation (as it should be), the
overhead due to the application is indeed negligible. The applications I'm
talking about are web-enabled ERP applications, about the most complex thing
you have ever seen.
Certainly more complex from a business perspective than, say, a word
processor.
I have not seen a real heavy duty transaction processing application
on the web with the kinds of response time you indicate you get -
especially on applications distributed over the WAN to multiple
remote geographic locations.
I'm telling you flat out that we get sub-second or near-subsecond response
time on a WAN for traditional ERP applications. That's about as heavy
transaction processing as it gets. You don't believe me? Then we don't
have much more to discuss, Paul. My clients believe me, that's all I care
about.
And now you're bringing up a WAN and multiple remote geographics, which
means lots and lots of CALs for Citrix. Or else NoMachine, which costs
thousands of dollars, even on a Linux box.
The browser is zero cost.
I do this with my PSC product. I web-enable subfiles and even over
a WAN we get sub-second response time.
That I would really like to see - especially with some rather complex
screens that require updating based upon processing of entered data.
And will you then get on the mailing list and explain to everyone that
you're completely wrong? Of course, my clients might not want to talk to
you; they LIKE the idea of their competition using expensive, cumbersome
options like Citrix.
Joe
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