In the history of interactive computer graphics, what best characterizes the SKETCHPAD system developed on the Lincoln TX-2 with a cathode-ray oscilloscope display?

Introduction / Context:
SKETCHPAD, created by Ivan Sutherland in the early 1960s, is widely regarded as a foundational milestone in interactive computer graphics and human–computer interaction. The question asks you to recognize the defining characteristics of that system's architecture and capabilities.

Given Data / Assumptions:

• Hardware platform: Lincoln TX-2 computer.
• Display device: cathode-ray oscilloscope.
• Interaction model: direct manipulation with input devices enabling constraints and hierarchical drawings.
• Era: research lab system with significant hardware costs.

Concept / Approach:
Identify which statement captures multiple core facts: the TX-2 host, oscilloscope display, interactivity, and high cost/resource intensity typical of cutting-edge research machines of the time.

Step-by-Step Solution:

Verification / Alternative check:
Historical accounts consistently cite SKETCHPAD's interactive constraint-based drawing and its use of light pen input on a CRT, running on the TX-2, validating the comprehensive description.

Why Other Options Are Wrong:

• Non-interactive batch tool: contradicts SKETCHPAD's real-time interactivity.
• Text-only interface: incorrect; it was graphical with light pen interaction.
• Consumer-grade low-cost: historically inaccurate; it was a research system.
• None of the above: incorrect because one option precisely matches the facts.

Common Pitfalls:
Confusing SKETCHPAD with later CAD packages or assuming it used raster displays; it was vector-based on a CRT oscilloscope.

Final Answer:
It consisted of a cathode-ray oscilloscope driven by the Lincoln TX-2, supported interactive graphics, and was expensive due to its sophistication and resource demands.