Information Architecture

WHY??? I THOUGHT THIS WAS A COURSE IN OPERATIONS MANAGEMENT Information architecture underlies the entire enterprise computing platform and determines its characteristics This is design at the highest level and a bad design here can cost a firm billions, making it totally ineffective

Components of any Software Application

Components in brief

Mainframe Architecture (circa 1993)

Problems with Mainframe Architecture Absence of data integration, resulting in little enterprise visibility The applications are maintainable only by the centralized MIS shop, which is overloaded, resulting in 36 month lead times to get revisions effected Every application had to be built from scratch, line-by-line, resulting in large cost and long lead times to create new applications

More problems with Mainframe Architecture No reuse was possible These mainframe apps were accessed on networked PC’s via IBM 3278 terminal emulation software that was completely incompatible with the windows GUI applications—meaning no cut and paste Mainframes were computational bottlenecks Desktop PCs sat idle 99% of the time

First solution: Client/server architecture Server (DM) Clients (PM, BL) Database

These were known as thick clients Because they contained both the presentation management (PM) and the business logic (BL) components of the application Notice how the application is distributed across the network, residing in two computing boxes—the client or desktop and the server

Advantages of Client/server architecture Data are all accessible behind the Server which runs the data management portion of the application—usually an Oracle Database engine Now the marketing guy can see where his customer’s job is, and whether the customer is current with his payments, among other ‘things’

Advantages of client/sever architecture The IT professional could sit shoulder-to-shoulder with the end-user and develop applications as well as make changes to existing software rapidly, without a 36 month backlog There are huge reuse opportunities—in particular, the IT professional does not have to create a DM component—the Oracle engine can be reused Reuse enables some code to not have to be created from scratch, resulting in huge savings of money and time.

Problems with Client/server It wasn’t Internet compatible It required an IT professional to install software on the end-user’s personal computer (the client) It required an IT professional to work closely with the non-IT professional This meant sitting in the adjacent carrel in the marketing department or finance department, etc.

Modern solution of today: N-TIER DISTRIBUTED This is a distributed architecture like client/server, but now the application is distributed across three or more computing boxes on the network

N-Tier distributed Architecture Data Server (DM) Thin Clients (1/2PM) Database ApplicationServer 1 ApplicationServer 2

Comments on N-Tier Distributed Architecture Clients are called ‘thin’ because the only thing running on them is the Internet Browser (MS Internet Explorer or Netscape Navigator) The IT professional doesn’t have to install anything on the client More re-use is possible—specifically that browser

Advantages of N-Tier Distributed Architecture Like Client/server, it accommodates enterprise visibility because the data are integrated Applications can be built rapidly because there are abundant reuse opportunities The DM module is reused Half of the PM component is reused There are reuse opportunities within the rest of the PM component and the BL component as well

More advantages of N-Tier Distributed Architecture IT Professional no longer has to be decentralized and a part of some non-IT group that doesn’t have a career path for him Now, IT can be centralized where there is a career path for the IT professional and where (s)he can effect changes to software from a centralized location. {Today, its possible for that IT professional to install things on your remote desktop computer, even to see what you are doing on your desktop, etc., from a remote location.}

Application Servers do Two things They serve out web pages upon request They do all of the business logic processing.