How to significantly slow/stop computer development from advancing past the early 1990s?
I have a world where both computers and biological technology have matured to serve the needs of my people. Both have numerous people researching and making use of their equipment. For example, biological computers can implement things like logic gates, parallel processing, store massive amounts of data, simulate things like neural nets on a truly massive scale while at the same time simulating things like games, movies or dreams etc. On a more machine-like scale, a biological exoskeleton of sorts exist that people can step into and use. Humans in this world discovered and used biological computers well before the first mechanical computer was even developed. Such biological technology is usually something a human interfaces with and operates with their mind.
Computers in my world also exist but they obviously came later. The major advantage they have over existing bio computers and technology is that they are persistent. A mechanical or digital computer doesn't have to be regrown, they can operate without human input, they can survive certain austere environments better and don't consume resources outside of electricity once built. The major downside is getting the metals and resources for computers requires expeditionary operations to other floating islands that they coast by. However, my floating islanders have been able to construct computers that resemble that of the mid to early 1990s. Especially for military applications.
How can I stop or significantly slow computer development from advancing past the early to mid 1990s?
Year range is 1990-1995 Notes:
1. The primary users of computers are the military, they have the most incentive to push boundaries on computer development. If anyone is to be impacted the most, it is them.
2. 934
All floating islands are moving, though they take time. Smaller islands fall to the surface of the planet eventually. Through a process new islands are essentially lifted back into the sky.
3. There exists two tiers of islands with multiple layers of clouds. Past the first few cloud layers is the first floating island. Radio and wireless communications don't work in this area. Only wired communications work. Past the cloud layer above it, there exists another island. These islands are a bit barren but all forms of radio and wireless communications work, this is also where most combat takes place. Clouds can "poison" both living organisms and non-refined metals when a newly formed island lifts up. The peoples' island in both tiers have been tethered to each other and travel in the same direction.
4. Silicon is the primary semiconductor used and harvested for computers.
5. Setting takes place on planet that is not Earth. Different materials, metals, weather, and particles exist. 1006