The 1st personal computers were home-built by physics hobbyists.

When Apple, IBM and others began merchandising ready-made systems to "normal" folk, most buyers ne er considered opening the case, even as to look, more less do changes.

That was roughly 25 years ago - one human generation, but more than a dozen generations for computers.

By the second decade of the personal computer age, computer stores were merchandising hard drives, memory upgrades, sound and video cards and another components to an progressively large segment of the house computer market who wanted to do their PC "more" than what the manufacturer oversubscribed them.

Today, such parts can be found in any office supply or general merchandise store - even as several supermarkets and drug st