โ Scribed by Michael Leesley
No coin nor oath required. For personal study only.
Computer-aided design has become so much a part of our industrial world during the last 20 years that we already take it for granted. We live with buzzwords: 'mainframe CAD', 'host-based CAD', 'workstation CAD', 'PC CAD', 'high-end CAD', 'low-end CAD' and others. Sometimes, all the jargon obscures the real distinctions and developments that have taken place and are taking place in CAD.
Those who were involved in CAD during the early 1980s may remember those creative individuals, frequently entrepreneurs, who proposed the use of personal computers for CAD, and were laughed to scorn. PCs were 'toys' then. A quick backward look at the 'ancient' history of CAD (which is really quite recent), and a snapshot of some of the functionality available now in PC CAD (which is really quite impressive) shows that the early PC-CAD pioneers were correct, and all the indications are that, in a few years, mainframe CAD will be rare.
To cut through the 'buzzword jungle' related to mainframe computers, minicomputers, superminicomputers, workstation computers, and personal computers, we'll use the term 'mainframe' for everything that does not specifically refer to personal computers.
The work at the Massachusetts Institute of Technology, USA, that developed the SAGE computer system in the 1950s produced the tools which made CAD possible and economically feasible: the computer-driven cathode-ray tube display and the time-sharing computer system 1. Sketchpad, also developed at MIT, and first demonstrated in 1963, used a cathode-ray tube driven by a Lincoln TX2 computer to display graphical information drawn on the screen with a device called a lightpen 2. This was the first 'CAD system'.
Because of extremely high costs, only well endowed universities and large automotive and aerospace corporations could afford to invest in the development of CAD through the mid1960s. They did so primarily for their own internal use. Thus, General Motors' UNISURF, Ford Motor Company's PDGS, Lockheed's CADAM, McDonnell Douglas' Unigraphics, and Dassault Aerospace's CATIA began to bring a return.
The first CAD systems specifically developed as commercial products soon began to appear:
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