Mission Critical Applications and Web Based UIs?

Jonny Quest asks: "I work for a company with an excellent Client-Server based product. Unfortunately it's not 'Web-Based' (whatever that means). Ours is a 'Line-of-Business' app, i.e. it means that those people who use it absolutely depend on it for making money - if the app is down, they can't process their orders, service their clients & employees, etc. at all - mission critical in other words, and they spend ALL day in the app. What's the best UI that any Slashdotter has seen for a 'Web Based' app? Something with a rich user interface and some decent multiscreen handling (the current app has about 200 screens...)?" 'Web-Based', that's such a loaded buzzword, and like most buzzwords no one is really quite clear on what it means. Does it mean HTML+CGI? Does that allow for Java? Cold-Fusion? Internet operation or just Intranet (if it's mission critical, it better be the latter, and even then...)? Would any of you recommend deploying a mission-critical application over the web? If so, how would you do it? What technologies would you use and what is to be avoided at all costs?

Comments

KISS

[eric2hill]

Keep it simple. Mission-critical applications should be lean applications that do nothing more than their designated task. In the OO model, you need a main collection of objects that perform very specialized tasks relating directly to the business process.
I'm sure you probably have a good idea of what those processes are right now, and as long as you can isolate them, you're home free. Once isolated, you can quickly/easily wrap them in a traditional GUI, web front end with PHP or Perl, and any number of "other" interfaces such as eMail.
Make sure you're core logic is tested well, and put in shareable modules (DLL's on windows), and use that logic many ways. If you ever have performance problems, it's due to the technology you're using. Just switch to another type of interface (different development tool, etc.) and see how that works out.