Historically, when computers first began to control production machinery (early numerical control), which recording medium was commonly used to feed instructions to the machines?

Introduction / Context:
Early numerical control (NC) systems in manufacturing needed a way to encode and deliver sequences of machine instructions. Before modern digital interfaces, simple, durable media were required on the shop floor. This question targets the historically accurate medium first used to control production machines via computers or controllers.

Given Data / Assumptions:

• The era predates widespread magnetic storage in industrial settings.
• Instructions had to be durable, easy to duplicate, and readable by simple electromechanical readers.
• Media were handled in harsh environments and had to be low cost.

Concept / Approach:

Punched paper tape—with holes representing coded instructions—became the early standard for NC machining. The tape reader would step through the tape, translating hole patterns into control signals. While punched cards and magnetic tape existed, paper tape was favored for continuous, linear feeds and ease of splicing/repair for long instruction streams typical of CNC/NC jobs.

Step-by-Step Solution:

Verification / Alternative check:

Manufacturing histories and CNC retrospectives consistently cite punched paper tape as the initial widespread method for driving machine tool operations.

Why Other Options Are Wrong:

Punched cards: Common in offices, less practical for long continuous feeds in NC.

Magnetic tape/cards: Became more common later; early NC relied on simpler readers.

None of the above: Incorrect because punched paper tape was indeed used.

Common Pitfalls:

Assuming office data storage norms applied unchanged to industrial control before ruggedized magnetic systems matured.

Final Answer:

punched paper tape