On Jan 28, 2008, at 4:45 PM, Martin Klingensmith wrote:

> What made wire-wrapping necessary on something required to be so  
> highly
> reliable? Yes, I know wirewrapping can be reliable but it seems as
> though through-hole PCBs are about the most reliable construction  
> method.

Wirewrap used to be really popular for backplanes, back before buses  
became standardized and popular.  We had a couple people who would  
spend time debugging DecSystem-20s (late 1970s era computer) by  
figuring out which wire was wrapped too tightly around a nearby pin,  
eventually causing the insulation to "creep" and short the signal.   
(This in the late 1980s, well beyond 'expected lifetime' of such a  
computer.)

BillW

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