prometeu-runtime/discussion/lessons/DSC-0001-runtime-learn-legacy-import/LSN-0014-mental-model-portability-and-cross-platform.md

id	ticket	title	created	tags
LSN-0014	legacy-runtime-learn-import	Portability and Cross-Platform Execution	2026-03-27	migration tech-debt

Portability and Cross-Platform Execution

Status: pedagogical Companion spec: ../specs/11-portability-and-cross-platform-execution.md

PROMETEU treats portability as an architectural property of the machine, not as an after-the-fact adaptation.

Core Idea

The main point is simple:

• the machine defines the semantics;
• the host performs presentation and physical integration;
• the cartridge does not negotiate behavior with the operating system.

That avoids the common notion that each platform has "its own version" of game logic.

Why This Matters

When time, memory, input, audio, and graphics are defined by the machine, the following become easier:

• deterministic replay;
• reproducible certification;
• execution on desktop, mobile, and DIY hardware;
• clean separation between semantics and adaptation.

Practical Separation

A useful way to think about it is:

• the cartridge carries program and assets;
• the VM/runtime executes the logic;
• the host shows pixels, delivers audio, and collects physical input;
• the host does not redefine the game's rules.

What Portability Does Not Mean

PROMETEU does not promise:

• the same physical latency;
• the same power consumption;
• the same raw host throughput.

It promises logical consistency. That is what matters to the machine's identity.

Teaching Value

This model helps teach:

• the difference between logic and presentation;
• why modern engines often lose determinism;
• how to design portable software without relying on luck.