The Helsinki declaration: observation 2（Toon Koppelaars, March 12, 2009）

Thursday, March 12, 2009

The Helsinki declaration: observation 2

To illustrate the second observation, let's take a look at thefollowing quadrant. It maps character-mode / GUI-mode applicationsagainst stateless / statefull underlying protocol.


Atthe end of the eighties the bottom-left square, is were we were.Database applications were provided to endusers who were sitting behinda dumb character-mode terminal, 25 by 40 characters, maybe 25 by 80.Thebackend mainframe or mini computer would spit out a form to theterminal. The enduser could tab through fields, change data, and thenhit the infamous SEND key (the only worn down key that didn't showanymore what it was for). While tabbing through the fields nocommunication with the backend server was possible. The SEND wouldsubmit the whole form back to the server, process it, and generate anew form back to the enduser. Those were the eighties.

Enter the early nineties, the dawn of the client-server era.


Theuser now has a PC on the desk. I.e. a machine with a local CPU. We'restill in character mode. But, big but, the user is not looking at astatic form, but at the screen output generated by a "client"program.There is now code that actually runs on the CPU of the users' PC. Andthis program has a dedicated connection to the server, open to be usedat all times. So while the user is tabbing through fields the programcan communicate to the server, typically to validate user input in aearly stage. The uses was experiencing a very responsive application.The program might change the user interface on-the-fly without goingback and forth to the server. When the user is done changing the data,he/she presses a Commit key (which would ussually be mapped to one ofthe function keys F1-F10). This would then cause the client program tocompose and submit a transaction to the server.

During the nineties the only thing that really changed, is that the user interface went from character mode to graphical mode.


The dominant client operating system MS-DOS was replaced by Windows 3.11, NT, Win 95, etc.
Theinternet now became available. Browser wars were going on. And at thedawn of the new millenium browsers became the platform of choice todeliver database applications to end users. In terms of our quadrantthis meant a shift to the bottom right square.


Beware:a browser brought us back to a stateless protocol (http). It is inessence a device that can display a graphical form. As opposed to thedumb terminal at the end of the eighties that was displaying acharacter form. This also caused lots of complaints from our endusers,who had gotten used to responsive (client/server) databaseapplications. This was countered by introducing Javascript runninginside the browser. In the early stages a bit unstructured, later on(nowadays) by using techniques such as Ajax, partial page refresh,dynamic html, etc. So we countered the loss of responsiveness byintroducing more complexity inside the browser.


Rich(responsive) internet applications (RIA) are the buzzword now. Enterthe third dimension. I sometimes refer to it as "complexity".Complexity not only on the client, but also between the client and theserver. We still have the database server way at the end, but inbetween we now also have webservers and application servers.

Sowe are still delivering UFI's (User Friendly Interfaces) to our enduser, but in ways that are much more complex than they have ever been.KISS is out, MICS (make it complex stupid) is hot.

Which leads us to the third observation. To follow soon.