The personal computer is one of the most important inventions in the past century. They became possible due to major innovations in electronics, computing, storage, and software that made computers smaller, cheaper, and easier for people to use. Before personal computers, most computers were huge machines used only by governments, militaries, universities, and large corporations. This was partly due to their large size, with most early computers requiring multiple rooms of equipment to operate. These early computers relied on vacuum tubes, making them big, expensive, hot, and unreliable. A significant breakthrough came with the invention of the transistor in 1947 by the researchers in the Nokia Bell Labs. Transistors replaced vacuum tubes for the logic within a computer and allowed electronic devices to become smaller, faster, and more dependable.
Another important advance was the integrated circuit, developed in the late 1950s by Texas Instruments and Fairchild Semiconductor. Instead of building computers with many separate components wired together, engineers could place multiple electronic parts onto a single chip. This greatly reduced size and cost, while improving speed and reliability.
The most crucial innovation came in the early 1970s with the microprocessor. A microprocessor combined all of the previous innovations into one. However, it also fundamentally changed how computers were built from that point on. Intel's 4004 microprocessor was able to be programmed at the software level instead of the hardware level. This allowed any company to take the 4004 and program it to suit their needs. Instead of having an expensive, custom chip designed specifically for one use case.
These hardware changes inspired hobbyists and engineers to experiment. In 1975, the Altair 8800 became one of the first successful microcomputers sold to the public at just $400. It was not user-friendly by today’s standards, as there was no screen, just a set of blinking lights to show output. The Altair 8800 is famous for Altair BASIC, an operating system developed by Bill Gates and Paul Allen, which directly lead to the founding of Microsoft. At the same time, innovators Steve Jobs and Steve Wozniak created the Apple I and, shortly after, the Apple II. The Apple II was particularly important because it came as a complete machine, supporting a keyboard, display, and software.
Software innovations were equally important as hardware. Early machines were hard to program, but higher-level programming languages and operating systems made computers easier to use. In the late 1970s and early 1980s, spreadsheet programs like VisiCalc gave businesses a strong reason to buy computers as they greatly increased the efficiency of their operations. Later, word processors and database programs expanded their usefulness. In 1981, IBM released the IBM PC, which became very influential because its design helped create a widely adopted standard. This allowed other companies to make compatible hardware and software, leading to quick growth in the PC market.
Another key innovation was the graphical user interface (GUI), which replaced typed commands with windows, icons, and menus. Popularized by Apple’s Macintosh in 1984, the graphical interface and mouse made computers much easier for non-experts to use as they no longer had to learn how to code to operate a computer. All they had to do now was click on icons and links.
Over time, advances in processors, hard drives, networking, and the internet continued to improve personal computers. Altogether, the personal computer became possible because of a series of innovations that transformed computing from a specialized tool into a common device that can be held in your pocket.