1. Handicraft, small master craftsman with a few journeymen and apprentices, where each laborer produces a complete application.

2. Manufacture, where greater numbers of developers, grouped in one large establishment, produce the complete application on the principle of division of labor, each workman performing only one partial operation, so that the product is complete only after having passed successively through the hands of all.

3. Modern industry, where the product is produced by datacenters driven by power, and where the work of the developer is limited to superintending and correcting the performance of the mechanical agent.

(From Engels' Socialism: Utopian and Scientific, replacing "industry" with "software".)