Back in the 1990s, software was delivered in a static way—using a physical floppy disk or CD-ROM. The SDLC always took years per cycle, because it wasn't easy to (re)deliver applications to the market.

At that time, one of the major software development methodologies was the waterfall model. This is made up of various phases, as shown in the following diagram:

Once one phase was started, it was hard go back to the previous phase. For example, after starting the Implementation phase, we wouldn't be able to go back to the Design phase to fix a technical expandability issue, for example, because any changes would impact the overall schedule and cost. Everything was hard to change, so new designs would be relegated to the next release cycle.

The waterfall method had to coordinate precisely with every department, including development, logistics, marketing, and distributors. The waterfall model and static delivery sometimes took several years and required tremendous effort.