【计算机系统导论】5.1 人机交互的发展


Computers have always been good at calculations and data processing. But to evolve from specialized devices to a universal tool required more efficient ways to “talk” to people.

Early computers communicated primarily with coded text. Gradually they learned to use images. The development of graphical interfaces was key to creating powerful hardware and software systems that anyone could use.

People & Machines Communicating: Input and Output

“Human-Computer Interaction” is a two-way street: people talk to computers, and they talk to us. We have been endlessly creative in doing both.

Part of the story is about hardware. But much is about software. Applications and drivers tell devices how to communicate, how to perform the tasks we want. The equation remains, as always: hardware + software = useful tool.

Keyboard “glove”

IBM’s Robert Seibel and Nathaniel Rochester conceived this Cold War device for computer operators flying in “high-acceleration aircraft and missiles,” among other places. They anticipated “wearable computers” by decades.

IBM 2250 graphics station

Part of the System/360 mainframe computer family, this $80,000 graphic terminal displayed vectors starting and ending on points in a 1024-by-1024 grid. If many vectors were displayed, the screen would flicker.

Doug Engelbart’s mouse prototype

The prototype mouse invented at Stanford Research Institute rolled on two sharp wheels facing 90 degrees from each other.

SIG-100 video terminal and mouse

This October 1968 photograph appeared several weeks before Doug Engelbart’s first public demonstration of the SRI mouse. It is unclear whether this “Rollkugel” predates Engelbart’s invention, but it does appear to be the first rolling-ball mouse.

Xerox Alto

Alto I CPU with monitor, mouse, keyboard and 5-key chording keyset

The revolutionary Alto would have been an expensive personal computer if put on sale commercially. Lead engineer Charles Thacker noted that the first one cost Xerox $12,000. As a product, the price tag might have been $40,000.

A mouse. Removable data storage. Networking. A visual user interface. Easy-to-use graphics software. “What You See Is What You Get” (WYSIWYG) printing, with printed documents matching what users saw on screen. E-mail. Alto for the first time combined these and other now-familiar elements in one small computer.

Developed by Xerox as a research system, the Alto marked a radical leap in the evolution of how computers interact with people, leading the way to today’s computers.

By making human-computer communications more intuitive and user friendly, Alto and similar systems opened computing to wide use by non-specialists, including children.

People were able to focus on using the computer as a tool to accomplish a task rather than on learning their computer’s technical details.

Before “Point and Click”

Before the Alto, most people communicated with computers using text. No images, no font choices. Input had to be letter-perfect. With punched cards or paper tape, the lag between input and output ranged from minutes to days.

By the late 1960s, some lucky users communicated through interactive video terminals. Yet terminals were mostly text-based. Graphics was too hard for computers—and computer time was considered too valuable to waste on saving people time. Humans were expected to adapt to their machines.

Computers with graphical interfaces changed the equation, communicating on our terms, not theirs.

A Visual Approach

To make computer use easy, Xerox PARC (Palo Alto Research Center) combined a graphics-based display and mouse with software that presented a rich interface of moveable windows and icons.

The graphics, and Alto’s point-and-click selection method, enabled new approaches to word processing—Bravo’s WYSIWYG printing, and Gypsy’s “cut-and-paste” editing—that have become standard.

Moreover, a graphics-based interface didn’t demand human perfection, freeing users from cumbersome, error-prone text commands. It also made it easy to combine images with varied text fonts and layouts—all on a 600 by 800 pixel monochrome monitor.

Xerox PARC

Xerox PARC

Eager to be known as more than a supplier of office copiers, Xerox created the Palo Alto Research Center (PARC) in 1970. PARC’s modest assignment? Create “the Office of the Future.”

George Pake assembled world-class scientists and engineers—“Architects of Information”—into a hothouse of innovation that flourished for decades. PARC developed laser printing, graphical user interfaces, Ethernet, digital video, word processing, multi-beam solid-state lasers, very large scale integrated circuits (VLSI), and more.

Although many PARC ideas never became successful commercial products, some generated billions of dollars in sales for Xerox.

“The best way to predict the future is to invent it.” - Alan Kay

The Apple Connection

In 1979, Xerox bought a small stake in Apple. Xerox got a stock certificate. Apple got access to Xerox technology.

Apple engineers, and CEO Steve Jobs, visited Xerox PARC in December 1979 to see the Alto’s graphical interface and look “under the hood.” That visit reinforced similar work already underway at Apple for its Lisa and Macintosh.

Computers Talking to Computers: Networking

Ethernet concept sketch

The original Ethernet report observed, “Just as computer networks have grown across continents and oceans to interconnect major computing facilities…they are now growing down corridors and between buildings to interconnect minicomputers in offices and laboratories.” But Ethernet went beyond just “minicomputers.”

A personal computer is nice. But it’s even nicer when you can exchange files and e-mail, or share access to printers. Xerox designers agreed, connecting Altos into networks.

Inspired by other networks, such as Alohanet, they invented a “local area network” called Ethernet, first described by Bob Metcalfe in 1973.

Video Displays

Pictures are worth a thousand words—and most people more readily “look” than read. Video displays satisfy that instinct. They also let us see and act on information as soon as the computer generates it.

Analog radar displays date from World War II. Video displays for digital computers were developed in the early 1950s for MIT’s Whirlwind computer and for Ferranti Canada’s DATAR multi-ship naval defense computer.

Initially, video was expensive, both in dollars and computing power. For years, only research and the military, where power and cost were secondary concerns, used video.


With so many new elements to create, computer designers were happy not to re-invent text-based input and output. They used existing teletypes and automatic typewriters—including the established QWERTY keyboard.

Contrary to urban legend, QWERTY was designed to speed, not slow, typing. Patented in 1878, it limited interference between keys commonly struck in sequence.

QWERTY keyboard

Despite its ergonomic shortcomings, and claims that a well-trained typist can work faster with other layouts, the QWERTY keyboard remains the most widespread for users of Roman

Cabinet of Keyboard Curiosities

Designers have been creative, brilliant, playful, and sometimes misguided in devising ways for computers and humans to communicate with computers.

Some devices, such as mice, illustrate the evolution of solutions common today. Some represent technological or marketing dead ends. Others are niche devices for specific needs.

Do some look weird? What we use today may look equally quaint 100 years from now.

The Mouse

Prototype Engelbart mouse (replica)

SRI engineer Bill English built the first Engelbart mouse prototype, which used knife-edge wheels and had space for only one button.

Trackballs, light pens, and other clever pointing devices were widespread. Then the mouse was invented. Twice. (Well, at least twice.)

Doug Engelbart reportedly conceived the mouse during a conference lecture in 1961. His first design, in 1963, used rolling wheels inspired by mechanical area-measuring devices called planimeters invented in the 1800s.

Engineers at Germany’s Telefunken also invented a mouse in the mid-1960s. First described in 1968, their version used a rolling ball—essentially a small, upside-down trackball—which became the standard for decades.

Who Named the Mouse?

When asked who named his most famous invention, Doug Engelbart recalled, “No one can remember. It just looked like a mouse with a tail, and we all called it that.” The wire “tail” originally came out under the user’s wrist.

A Menagerie of Mice

The basic idea of the mouse is simple, but there are many variations on the theme. Engineers have experimented with different shapes, numbers of buttons, internal mechanisms, and aesthetics – as well as with the part of the human body that activates it.

Laser Printers

Dover laser printer

The Dover was a prototype for Xerox’s first commercial laser printer, the 9700, which printed 120 pages per minute on standard paper.

Xerox physicist Gary Starkweather realized in 1967 that exposing a copy machine’s light-sensitive drum to a paper original wasn’t the only way to create an image. A computer could “write” it with a laser instead.

Xerox wasn’t interested. So in 1971, Starkweather transferred to Xerox PARC, away from corporate oversight. Within a year, he had built the world’s first laser printer, launched a new era in computer printing…and earning billions for Xerox.

Unlike the company’s Xerography process, however, Xerox had to share the laser printer market. IBM and Canon soon developed competing products.

Input Devices: Sometimes Clever, Sometimes Strange

Input Cabinet of Curiosities

Designers have been playfully creative in finding ways for humans to talk to machines. They’ve given us keyboards, mice, trackballs, joysticks, tablets, switches, gloves, light pens, microphones, cameras, and more. Each is best for a particular application.

It is still an active area for innovation, so watch for even more creative ideas in the future. Brain wave analysis, maybe?

Tablet, Stylus, Eye-tracking, trackball, Joystick, scanner, vr gloves

The Diversity of Output Devices

The Sword of Damocles: Early head-mounted display

Harvard computer science professor Ivan Sutherland created this virtual reality head-mounted display, jokingly referred to as “The Sword of Damocles” because of the large overhead beam required to support its weight. His student Bob Sproull assisted with the design. An early application showed a three-dimensional wire-frame virtual room that users like this man could explore by moving their heads.

Whether with a realtime display or a permanent printed record, many computers need to communicate visually with humans to be useful. Hundreds of mostly clever – but sometimes silly – devices have been invented to do that.

The cycle of innovation and competition is fierce. Even popular mainstays like the daisy-wheel printer quickly become museum pieces as they are displaced by the next great idea.

3d display, print chain, glasses