Build a Business Out of Fixed Massproduced Game Data the Cartridge Rom

# Build a Business Out of Fixed, Mass-Produced Game Data: the Cartridge ROM

## 1. Sell a Mask ROM as the Product Itself

A game cartridge put a mask-programmed ROM holding a complete game's program and data inside a plastic shell with an edge connector, sold as a standalone retail product that plugged into a shared console the buyer already owned. This inverted the usual mask-ROM economics described in Steps 5–7: instead of one company designing a mask set once for a product it manufactured itself, a console maker built the reusable hardware (the "common CPU" idea from `microprocessor_1971_step06`, extended to a whole consumer console rather than a single calculator) and licensed or sold blank cartridge capacity to game publishers, each of whom committed to the full mask design-and-fabrication lead time for their own game's bit pattern, separately, on their own schedule.

## 2. Recognize the Business Model This Enabled

Because a mask ROM's per-unit cost drops sharply at high volume once its one-time mask-set cost is paid (exactly the cost structure already named in `eprom_eeprom_history_step08`'s plastic-package-at-volume comparison, referenced here rather than re-derived), a publisher who could forecast a hit game's sales volume accurately could mass-produce its cartridge ROM very cheaply per unit, while a publisher who misjudged demand was stuck holding either too few units (lost sales, no fast way to make more without repeating Step 5's full lead time) or too many (unsold inventory of a now-committed mask pattern that could not be repurposed for any other game). This volume-forecasting risk, baked directly into the fixed-at-fabrication nature of the ROM inside every cartridge, became a defining commercial feature of the entire games-publishing business built on this technology.

Step 11 names specific early cartridge-based systems that actually shipped this way.