The development of the microprocessor in the 1970's initiated the personal computer. Now a computer that was nearly as powerful as the earlier mainframes was small enough, cheap enough, and reliable enough to be on many people's desks and in their homes. Each computer could do the work in its own processor, so there was little need for mainframes in many situations.Mainframes continued to be used, (and they are still very much with us) but the popular image of a computer changed to the individual machine on each person's desk.
This change brought about some interesting side effects. Individuals were empowered by having their own machine, but the communications capabilities of the mainframes were lost. The "paperless office" has long been touted as a potential benefit of computing, but anyone who works in an office knows better: Computers started generating more paperwork than ever, because it was so easy to do so. Paper remained the transfer medium of choice, although trading disks became an option. The solution to this predicament was the Local Area Network (LAN). This innovation was a combination of programs and hardware designed to connect a series of personal computers so they could communicate electronically. Once a LAN was set up in an office, it became much easier to send documents across the LAN to other computers on the network. People still had the power of individual computers, and now they had regained some of the communications abilities of the mainframe days.
LAN's, however, had some problems of their own. It became much easier to communicate electronically within an organization tied together with a LAN, but that organization became an "information island". Transferring information beyond the LAN involved the same old problems of transfer to paper or disk. Connectivity created a larger problem. As we shall see, different types of computers have different ways of storing information. In the mid-1980's, there were as many as 10 different types of computers popular within the home market. None of these machines could speak directly with each other. As the market settled down, there became far fewer popular operating systems, but the problem still persisted. If you create a document on a Macintosh at work, your IBM at home will not recognize it without some special modifications. There was not a uniform way to describe and transfer information across computing platforms.