booo... resorting to wikipedia on ya
I can tell you all about these better than wikipedia cause I was there. The 1980's was a huge decade for computers.
At the start of the 1980's, there wasn't a whole lot of computers for regular people. People didn't really use computers for much besides keeping records or doing their taxes. Mostly they were used by scientists and professional computer nerds who had big mainframes at the local tech institute. But by the end of the '70's there was a consumer-friendly and mainly useless computer for households sold by Radio Shack, called the TRS-80.
The trs-80 wasn't the first regular-people computer, but it was the first one sold retail as opposed to being a kit. It had a whole 4kb of RAM, its operating system was programmable on the spot in basic and you could use any tape recorder as a tape drive.
It was never a very serious computer, though, the big players soon got into the game in the early '80's. The biggest ones were Apple, with the fairly useful apple 2, and IBM which released the amazingly successful, big and heavy IBM pc. It was IBM that coined the phrase "personal computer," the other makers were calling theirs "home computers." That reflected differences in their business model, as IBM's product was meant to be useful both for enterprise use and use at home. It took a lot of space to put the bulky PC into your house, but people did that and it spawned a new generation of do-it-yourself tech nerds.
That was the wave of computers for adults, and it was those two companies, apple and ibm, that were at the top of the chain all the way into the '90's. Then something really huge happened that I'll mention later.
Meanwhile in the early '80's one of the greatest uses for computers ever was being discovered: the video game! At first, manufacturers simply made consoles that would play roms, generally copies of arcade games. But then a minor company called Commodore decided to try combining the idea of console and computer. Their first 2 products, the pet and the vic-20, were barely any better than a trs-80. But then they released the cheap, versatile and easy-to-use Commodre 64. This was the first real computer to be used seriously as a video game platform. IBM's were still using monochrome monitors at the time. The C64 could play games as well as or better than the reigning consoles of the time, the Ataris, Intellivisions, Colecovisions, and so forth. Better yet, the C64's games were on floppy disk and could be easily hacked and copied. Millions of kids around the world became hackers in the 1980's, learning the nuts and bolts of computers just so they could steal their favorite video games. In the movie Wargames, Matthew Broderick is stealing video game secrets with an IBM, but in reality the thing to have was C64, then Amiga. IBM and Apple sucked for games.
Around the mid to late 1980's Apple saw it was losing out to IBM because apple's product was a "home" computer while ibm's was a more versatile "personal" computer. So apple decided to borrow the C64's appeal of being a little do-anything computer, and one-upped it, releasing the Macintosh. The original Mac was a tiny little box, shaped like a power droid from star wars but much smaller. Maybe a foot high. And the monitor was included! The cpu and monitor being in the same box meant they could include the entire system with just that one little box and a small keyboard. Soon they invented the mouse and a visual operating system too. You probably use a descendant of apple's invention right now. Until then, all computing was done by command line and terminal, or menu systems.
These Macintosh's were marketed as "idiot-proof" computers and as such they were very popular. By the early '90's, Macs were outselling pc's overall in the US and worldwide. The development of the Video Graphics Array (VGA) card and the x286 and x386 cpu's made pc's much faster at the same time, so that video games began migrating to them and away from Commodore, whose Amiga was last of its line.
Now for what happened in the early '90's, it is computer legend: Apple was beating IBM and thus Microsoft. More people used Apple's OS. Microsoft responded by copying Apple's visual-based OS, calling it "Windows." Apple sued, on the grounds that Windows was practically a carbon copy of its OS. Somehow, the courts ruled in favor of Microsoft. Having successfully stolen Apple's main selling point, Microsoft would go on to achieve the monopoly status. The computing world is still trying to emerge from the shadow of their giant monopoly.