The origins of ubiquitous computing research at PARC in the late 1980s by M. Weiser R. Gold † J. S. Brown ‡ Ubiquitous computing began in the Electronics At the same time, the anthropologists of the Work and Imaging Laboratory of the Xerox Palo Alto Practices and Technology area within PARC, led by Research Center. This essay tells the inside story of its evolution from “computer walls” to “calm Lucy Suchman, were observing the way people re- computing.” ally used technology, not just the way they claimed to use technology. To some of the technologists at PARC, myself included, their observations led toward thinking less about particular features of a comput- er—such as random access memory and number of pixels or megahertz—and much more about the de- n late 1987, Bob Sprague, Richard Bruce, and tailed situational use of the technology. In partic- other members of the Xerox Palo Alto Research I ular, how were computers embedded within the com- Center (PARC) Electronics and Imaging Laboratory plex social framework of daily activity, and how did (EIL) proposed fabricating large, wall-sized, flat- they interplay with the rest of our densely woven panel computer displays from large-area amorphous physical environment (also known as “the real silicon sheets. It was thought at the time that this world”)? technology might also permit these displays to func- tion as input devices for electronic pens and also for From these converging forces (“from atoms to cul- the scanning of images (by placing documents di- ture,” as we like to say of PARC) emerged the Ubiq- rectly against the displays). Quickly, members of uitous Computing program in the Computer Science other labs were willingly drawn into designing both Laboratory (CSL) in early 1988. The program was at the hardware and software for this new kind of com- first envisioned only as a radical answer to what was puter system—one that seemed to honor the trans- wrong with the personal computer: too complex and parent ease of use of a traditional whiteboard while hard to use; too demanding of attention; too isolat- extending its power computationally, particularly ing from other people and activities; and too dom- when networked with other such devices. The re- inating as it colonized our desktops and our lives. search vision these “computer walls” inspired was far different from the then-current “one person–one desktop computer” paradigm and opened up to re- ௠Copyright 1999 by International Business Machines Corpora- searchers at PARC the idea of spreading computers tion. Copying in printed form for private use is permitted with- out payment of royalty provided that (1) each reproduction is done ubiquitously, but invisibly, throughout the environ- without alteration and (2) the Journal reference and IBM copy- ment. right notice are included on the first page. The title and abstract, but no other portions, of this paper may be copied or distributed royalty free without further permission by computer-based and †Supplied posthumous revisions other information-service systems. Permission to republish any ‡Contributed epilogue other portion of this paper must be obtained from the Editor. IBM SYSTEMS JOURNAL, VOL 38, NO 4, 1999 0018-8670/99/$5.00 © 1999 IBM WEISER, GOLD, AND BROWN 693 We wanted to put computing back in its place, to ing, user interface, and work studies research. The reposition it into the environmental background, to pad’s operating system and hardware design have concentrate on human-to-human interfaces and less proved their robustness and are still in use in new on human-to-computer ones. By 1992, when our first projects at PARC today. The pad is also the clear pre- experimental “ubi-comp” system was being imple- cursor to the Personal Document Reader** (PDR) mented, we came to realize that we were, in fact, ac- to be released by Xerox in 2000. tually redefining the entire relationship of humans, work, and technology for the post-PC era. The ParcTab, designed by Roy Want and his team, was unique in its ability to be used with one hand Starting in late 1988, there emerged three inter- and its integration—using a location-sensitive, agent- twined major building efforts at PARC within the based, enterprise-wide infrared network—with ap- Ubiquitous Computing program. The large wall-dis- plications on workstations, LiveBoards, and with play program, now known as the LiveBoard**, con- other devices, including the now famous CSL coffee- tinued to be spearheaded from EIL, but migrated maker. 1 The tab came with a complete suite of real- from amorphous silicon to rear screen projection. time networked utilities including e-mail, memo, cal- CSL initiated two programs to create smaller com- endar, sketch pad, address book, pager, and remote puters: the book-sized ParcPad** (later called the drawing tool (which drew on LiveBoards). The tab’s MPad**) and the palm-sized ParcTab**; both were alphanumeric input was via a patented Unistroke** supported, in part, by a three-year DARPA grant. Aug- system, while selections were activated by the touch menting these devices was the Active Badge** sys- screen and three ergonomically placed buttons. The tem, developed originally for Olivetti by Roy Want tab’s simple design philosophy was later extended (who had joined PARC). These programs: the board, into other CSL projects to create, among other things, the pad, the tab, and the badge, together with a flex- a keychain computer. ible, computational infrastructure that recognized not just device name, but the location, situation, usage, The Ubiquitous Computing project at PARC resulted connectivity, and ownership of each device, staked in many fundamental patents and papers, in a wide out a new conception of what computers could be range of what had been at the time considered in- and feel like. By 1994 these ubi-comp building pro- dependent areas of computer science, including grams had produced a working infrastructure for ev- physical transport, network protocols, operating sys- eryday use at PARC. tems, window systems, file systems, user interfaces, energy management, and input design. In the end, The LiveBoard, designed primarily by Scott Elrod ubi-comp created a new field of computer science, and Richard Bruce, was commercialized by Xerox one that speculated on a physical world richly and in a subsidiary called LiveWorks. Besides the hard- invisibly interwoven with sensors, actuators, displays, ware, the LiveBoard came with a collaborative draw- and computational elements, embedded seamlessly ing system, spearheaded by Tom Moran, that pio- in the everyday objects of our lives and connected neered shoulder-to-shoulder computing, remote through a continuous network. What is truly star- drawing collaboration, casual interfaces, and first- tling is how quickly we are finding this new form of class annotation systems. LiveWorks sold hundreds computation manifesting itself around us. of units (including units sold to high schools who found that the LiveBoards augmented, rather than Like all great research, the Ubiquitous Computing replaced, the teachers) before being closed down in project gave us more questions than answers. Once 1998. the infrastructure was up and running we clearly saw the vast potential of such a system for augmenting While the LiveBoard more traditionally plugged into and improving work practices and knowledge shar- the network, the ParcPad maintained constant net- ing, by essentially getting the computers out of the work connectivity by using a unique “near-field ra- way while amplifying human-to-human communica- dio” system designed by Ed Richley. The pad itself tion. But simultaneously we came across an unex- was based on hardware designed by Bob Krivacic, pected problem, often blared in newspaper headlines a window-and-pen interface system designed by as: “Big Brother Comes to the Office.” The prob- Chris Kantarjiev, an operating system by Al Dem- lem, while often couched in terms of privacy, is re- ers, as well as other components created by a wide ally one of control. If the computational system is range of PARC researchers. The pad proved an im- invisible as well as extensive, it becomes hard to know portant platform for radio, protocol, mobile network- what is controlling what, what is connected to what, 694 WEISER, GOLD, AND BROWN IBM SYSTEMS JOURNAL, VOL 38, NO 4, 1999 where information is flowing, how it is being used, Computer Science Laboratory Technical Report CSL-95-1 what is broken (vs what is working correctly, but not (March 1995). helpfully), and what are the consequences of any M. Weiser, “The Computer for the 21st Century,” Scientific Amer- given action (including simply walking into a room). ican 265, No. 3, 94–104 (September 1991). Maintaining simplicity and control simultaneously M. Weiser, “Some Computer Science Problems in Ubiquitous Computing,” Communications of the ACM 36, No. 7, 74–83 (July is still one of the major open questions facing ubiq- 1993). uitous computing research. M. Weiser and J. S. Brown, “The Coming Age of Calm Tech- nology,” Beyond Calculation: The Next Fifty Years of Computing. In the last several years a few of us at PARC have P. Denning and R. Metcalfe, Editors, Springer-Verlag, Inc., New begun to speak of calm computing as the goal, de- York (1997). scribing the desired state of mind of the user, as op- posed to the hardware configuration of the computer. Accepted for publication May 11, 1999. Just as a good, well-balanced hammer “disappears” in the hands of a carpenter and allows him or her Epilogue to concentrate on the big picture, we hope that com- On April 27, 1999, Mark Weiser passed away fol- puters can participate in a similar magic disappear- lowing a sudden encounter with cancer. Young as ing act. But it is not so simple. Besides the daunting he was, he leaves behind many great legacies, ubiq- computational and infrastructural problems, we must uitous computing being the one most known to the also find the balance between control and simplic- world.