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?
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AIt was primarily a non-interactive batch plotting tool with punch cards.
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BIt 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.
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CIt was a text-only interface without graphical input devices.
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DIt was a consumer-grade system designed for low-cost home use.
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ENone of the above
Answer
Correct 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.
Explanation
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:
1) Match platform: SKETCHPAD ran on the TX-2 and drove a CRT oscilloscope for vector display.2) Confirm interactivity: users could draw, apply constraints, and edit geometric entities in real time.3) Evaluate cost and sophistication: capabilities were novel and required substantial compute and specialized hardware, implying high expense.4) Select the option that combines all three factual elements.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.