The personal computer has changed so much since the early days of the computer. The earliest true computer, the ENIAC was a massive machine that took up a warehouse. This massive machine used vacuum tubes to perform calculations instead of the modern silicon chips that the computers of today use. There were many computers and electronic calculators available in the 1960`s that used the vacuum tube technology to perform computing tasks, but they were prone to failure. Still, a computer running with this technology could still be a worthwhile ally when cracking enemy codes or calculating artillery trajectories. The first ever computer bug was an actual bug; a moth trapped in a computer that caused a malfunction in the circuitry. The work of Grace Hopper is explained in more detail on this web page. Her work was done in the days of punched cards that allowed users to simply insert a punched card into a machine and the data would be read in. Of course you would need to do this for a whole set to get enough data input into the computer. Here is a picture of a punched card. Read more about the workings of the cards on this page.
Later on with the advent of the solid state circuitry, computers could be built smaller than the vacuum tube equivalents. The first ever microchip, an ugly blob of material would end up being the basis for our modern technological society. In 1968 there was a demonstration of video conferencing and use of a computer mouse for the first time as well as collaboratively editing a document with someone over a network. This was an amazing accomplishment for 1968. It would be a long time before this sort of technology would be seen again. There is a video of this momentous demonstration at this address: http://www.youtube.com/watch?v=JfIgzSoTMOs. watch this and be amazed at what we could achieve one year before the moon landing where the massive Saturn 5 rocket blasted the first astronauts to the moon. The Xerox Star computer system from 1981 also had a computer mouse as well as icons on a desktop and a screen that would show documents onscreen just the same way that they appeared on the printed page. This would have been an awesome computer system to use. And then we went backwards with the release of the Windows 3.11 operating system that had an ugly clunky interface that was not the most attractive interface for a computer after seeing what the Xerox Star system offered.
What would computers have looked like if they had continued evolving from the Star computer system until today; if Xerox had continued the computer system and became a massive computing company that had their own Xerox operating system and hardware. Sort of like Apple, but they would not be using x86 Intel chips; rather their own computer chips that were powerful and an operating system geared towards productivity and with an attractive and functional interface that would attract all computer users. With no flashy Unity interface and no Metro in sight. Just a computer for productivity with a stable and reliable interface that would not get in the way of the user. That is what we need, the current fad of tablet computing might pass and then we could go back to the desktop computer form factor. Or we might be wearing computers on our wrists like in the Blue Mars and Green Mars novels. That could happen, something like Google Glasses would just make you look like a massive douche, but something useful like a flexible wrist mounted computer screen the size of a slightly larger iPhone 5 would be something useful. Worn in the place of a wristwatch it would be useful for keeping track of time and your appointments as well.
The Apple IIe was a commonplace sight in many schools in the 1990`s, this machine was usable, but modern general purpose computers like the Dell desktops and Lenovos are more common sights now. Macintosh computers are a rarer sight, mostly the single screen with the computer and disk drive built in. But these are still workable computers. Still an open source operating system like Linux or OpenBSD offers more freedom if that is what you desire in a computer system. Hopefully in the future we will still have computer systems that offer openness and freedom and they are not locked down with UEFI and closed source operating systems. Still the Douglas Englebart demo that showcased future technologies before their time is quite an astounding feat.