• Subject: RE: What About Price vs. Performance?
  • From: "Joe Pluta" <joepluta@xxxxxxxxxxxxxxxxx>
  • Date: Wed, 4 Apr 2001 18:58:14 -0500
  • Importance: Normal

The true moral of the story is that a markup language like HTML takes more
than a straight buffer-based protocol such as 5250.  But you realized that,
right?  There's currently no way you can get around the fact that perhaps
2/3 or more of the data passed across the line in HTML is never displayed,
whereas in a good 5250 design, 90% or more of the data is actually seen by
the user.

Now, there is something called an IFRAME that may allow us to remove some of
that, but it's going to take me a few months to get that entirely worked
out, and even so it may be a little iffy.  Even IFRAMEs tend to be
client-driven rather than host-driven.  This is one of the reasons a captive
display device such as the 5250 can be so finely tuned.  And in the days of
1200-baud dialups (you remember the old 5251 with a synchronous modem?),
those bytes were needed.

Today, the speed of the transmission line is such that we can afford the
extra bytes, so we don't begrudge them.  The true measures now are speed and
ease of use.  Especially for web storefronts, where a badly designed site
can actually cost you real dollars.  So we look for subsecond response time
matched to a pleasing and intuitive interface.  And that's what I'm trying
to design, without making you rewrite all of your existing green screens.

Joe


> -----Original Message-----
> From: owner-midrange-l@midrange.com
> [mailto:owner-midrange-l@midrange.com]On Behalf Of James W. Kilgore
> Sent: Wednesday, April 04, 2001 5:33 PM
> To: MIDRANGE-L@midrange.com
> Subject: Re: What About Price vs. Performance?
>
>
> Joe Pluta wrote:
> >
> <<snip>>
> > "A well written web application can serve up a 3KB dynamically
> generated web
> > page in about 100msec [of CPU time], as opposed to a green screen
> > application outputting 1920 characters (or less) in about 20msec."
> >
> > About a 3-1 KB/sec ratio (or less).
>
> Hmmmm, must be the new math.  100 vs 20 looks like 5:1 ratio to this old
> bird. ;-)
>
> All kidding aside, one of the benefits of the 5250 controller (dates
> back to the S/38) is that with a text based panel, AFAIK, the controller
> only sends the changed characters not the entire screen.
>
> So although you have the capability of having 1920 characters on a
> screen, your data stream may be much smaller.  So let's say you put up a
> panel with a clear instruction followed by 700 bytes of data and text.
> The user presses ENTER and you want to highlight a field.  It is my
> understanding that the twinax controller will only send the necessary
> code to cause the highlighting and _not_ resend the entire 700 bytes.
> I'm not sure if the TN5250 emulators receive the same benefit.
>
> So I guess that the requirements for a 3k page to perform as well, one
> would need a processor 5 times as fast and 3 times the data transmission
> speed.
>
> Now the data transmission speed is no problem.  Even the enhanced 5250
> twinax, I think, runs at 2mb, so even a simple 10mb Ethernet can beat
> that.  Even with collision recovery.
>
> IBM's strides in processor enhancements take of of the processor
> requirements.
>
> The moral of the story is, you get a faster machine, a faster network,
> then you change the interactive paradigm to try get the performance you
> had to begin with.
>
> Looking good doesn't come cheap or easy!
>
> Ducking and running ;-)
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