 |
Reprinted from Interactions, issue 1/1997, pp. 40-53.
Copying by permission of the Association for Computing Machinery.
 |  Figure 1. The Lisa Desktop (January 1983) |
Today’s familiar Macintosh user interface is a direct descendant of
the interface first developed and used on Apple’s Lisa computer.
Instead of a text-based system that presented the user with a blank
screen and blinking cursor, the Lisa displayed an electronic desktop,
a picture that the user manipulated directly to tell the computer
what to do. The electronic desktop, with its windows, menu bar,
and icons was not part of the original design; rather, it was the
result of a 4-year-long process of refining goals and developing,
testing, and synthesizing many alternative ideas. In fact, the iconic
desktop was first tried in 1980 and discarded! The final result (Figure
1) not only made computers easier to use, it made them fun.
The authors were members of the software team that designed and implemented Lisa’s system
software and applications. Rod Perkins joined the team in early 1979, shortly after the
start of the project, to work on applications and
prototypes of the early ideas about the appearance and workings of windows, dialogue boxes,
and menus. Dan Keller and Frank Ludolph began working on Lisa in late 1980 and were
responsible for what eventually became the Desktop Manager with folders and icons.
Goals and guiding principles
The new machine, first proposed in late 1978, was to be designed for general office use
– a high-quality, easy-to-use computer for secretaries, managers, and
professionals that would give the individual more independence performing
multiple tasks without disrupting the office. The ease-of-use goal evolved during 1979
as the software team tried many ideas. Requirements, developed jointly by marketing
and engineering, enumerated the following goals [4]:
 |  |  | Lisa must be fun to use. It will not be a system that is used by someone “because it is
part of the job” or “because the boss told them
to.” For this reason, special attention must be paid to the friendliness of
the user interaction and the subtleties that make using Lisa rewarding and job enriching.
|
| | | Lisa will be designed to require extremely minimal user training and “hand
holding.” The system will provide one standard method of interacting with
a user in handling text, numbers, and graphics...
|
| | | The system will adhere to the concept of “gradual learning”... A user
must be able to do some important tasks easily and with minimal instruction
or preparation... The more sophisticated features will be unobtrusive until they are needed.
|
| | | Errors will be handled consistently in as friendly a manner as possible, and the user
will be protected from obvious errors...
|
| | | ...A “Set-up” program will allow the user to customize several system attributes in order
to “personalize” interaction with the system... in order to make the
system uniquely personal for the user without interfering with the
interface standards...
|
| | | (It should allow) a user to put whatever he/she is doing on “hold” in order to answer
the phone, look up an address, or respond to an asynchronous interrupt (time for a meeting,
mail received on the network, etc.)...
|
| | | In addition, the use of graphics in general user interaction will set Lisa apart from its
competitors and will go a long way toward making the system friendly, easy and enjoyable
to use. “Intuitive icons” can be designed to indicate certain messages to the user...
|
|  |
During the same period the engineering team developed several principles that would
be used to achieve these goals. The interface would be “intuitive,” modeled on documents
and other office-based objects instead of traditional and unfamiliar computer concepts.
Like the office, this electronic desktop would not be limited to showing only one thing at a
time. Commands would be visible on the screen, consistent across applications, and
modeless. When possible, commands would be replaced by direct actions using the mouse.
Data were to be moved easily between documents and displayed on the screen in a style
known as WYSIWYG (“what you see is what
you get”) – that is, the screen and printed output should look the same.
Some of these ideas came from team members with strongly held convictions, some
came from other projects within Apple; and other ideas originated outside the company.
Whatever the source, it took time for these goals and principles to develop and be
assimilated by the Lisa team.
Beginnings of the Lisa
When the Lisa project was started in late 1978 the goal was to build a computer that would
propel Apple into the business market of the 1980s. The original plan was to build a custom
microprocessor that would be more powerful than the established Apple II computer
and could provide greater flexibility for future machines. The Lisa hardware would have an
Apple II-style bitmap screen and graphics support for creating simple line drawings
using Logo™-style instructions. The hardware would also scroll the screen one line
at a time to give a smooth scrolling effect. “Soft”
function keys (soft keys) and cursor keys appeared on the keyboard to be used by the
applications. The Lisa hardware was to be competitive with the specialized business
equipment that existed in 1978, but with the added distinction of being a general-purpose
computer.
 | | Figure 2. The Lisa display as seen on an Apple II screen (July 1979) |
The early hardware limited the user interface that the Lisa applications would have.
The video capabilities of the hardware could not display high-resolution graphics. Fortunately,
it was envisioned that word processing and databases would be the first applications,
neither of which would rely heavily on graphics. Each application was to be distinctive in
its use of the soft keys and cursor keys, thereby providing an easier interface to the user.
Early prototypes of the Lisa applications were written on the Apple II until the new hardware
could be used.
Early user interface
The first Lisa application, a data Forms Editor,
was started during Summer 1979. Forms
Editor created the data entry forms for the
database engine that would drive the Lisa software.
Additionally, the Forms Editor could
create simple line drawings such as a business
organization chart. Even in this early application,
the following familiar Lisa user interface
concepts could be seen (Figure 2):
| | | Easy to Manipulate. The user could create text, lines, boxes, and data fields; move
them on the screen; and go back and edit them, all by using the cursor keys and a
special selection key. The user would constantly receive visual feedback as things
were drawn, which we felt would increase their feeling of control.
|
| | | Intuitive. The soft keys displayed the options currently available. The user simply
pointed to the option desired instead of typing a command. There was no need
for the user to remember complicated command sequences. Likewise, there were
no hidden commands because all choices were clearly displayed on the screen. An
arrow displayed what cursor movements were appropriate at a given moment. This
display was useful for drawing and while filling in a form.
|
| | | Friendly. The Lisa would prompt with messages instead of just waiting
for a command to be typed. The prompts could be answered by typing in a special message
area or by selecting from the choices listed in the soft key display. Errors would be
reported in a status panel or in the message area using clear, friendly English, not
computer jargon. Users were prevented from making common errors by visibly
indicating inappropriate commands.
|
| |
Although the first Lisa interface was consistent with the appearance of business equipment
of 1979, it was not very exciting to use. It showed that Apple was serious about being
businesslike, but the Lisa interface did not generate the same enthusiasm created by the
emerging, highly graphic-oriented video game industry and programs found on the Apple II
platform. The progress on the first interface established the correct goals, but left most of
us dissatisfied with our hardware and soft key approach. Many people shared feelings that
Apple could get better leverage from the Lisa hardware, especially from its bitmap display.
Outside influences
In late 1979, two major events occurred that helped to change
the thinking behind the design of the Lisa hardware and software: the
announcement of the release of the Motorola 68000 microprocessor and visits by a small
group of Apple engineers to Xerox Corporation’s Palo Alto Research Center (PARC).
The Motorola 68000 microprocessor had the performance to support both a higher resolution
bitmap display and a highly interactive user interface. This made the 68000 a natural
replacement for the custom microprocessor designed for the Lisa and broadened the vision
of what people thought possible with Lisa hardware. Lisa software could make use of this
powerful new platform to expand on its user interface concepts. The team thought that
with this processor the Lisa would be so fast that it would be waiting on the user most of
the time! The idle time could then be used to drive a more elaborate user interface.
In the summer of 1979, Apple was still a private company and sought additional venture
capital through a private offering of stock [14]. Xerox Corporation bought 100,000
shares and agreed not to buy more than 5 percent of Apple. According to Mike Scott, the
president of Apple at the time, the deal helped Apple gain access to Xerox’s research laboratory
while limiting their access to Apple’s advance products.
The visits to Xerox were prompted after a number of people at Apple read papers published
by Xerox about their Smalltalk™ environment [3]. Smalltalk made extensive use of
a mouse rather than a keyboard to control the cursor. A high-resolution bitmapped display
allowed Smalltalk to prominently use graphics to enhance what the user viewed on the
screen. It was a friendly yet powerful environment that used the concept of modeless commands,
which were reported to be less confusing for the user.
The Apple group made two visits to Xerox. The purpose of the first visit, in December
1979, was originally to see demonstrations of programs under development at Xerox – but
not Smalltalk specifically. However, during that trip, the Apple group was given an
impromptu Smalltalk demonstration. During the second visit there were additional demonstrations
and another look at Smalltalk. The Apple team was very excited by the Xerox visits
and sought to make the Lisa as exciting. Enthusiasm from that visit caused us to further
rethink the Lisa’s user interface.
A shift in thinking
 | | Figure 3a. The Lisa display with a simple window, as seen on Lisa prototype hardware (February 1980) |
After the Xerox visits, the user interface became more dynamic as our new hardware became
available. We began experimenting with the mouse and changed our interface to include
windows (Figures 3a and 3b) similar to those we saw in Smalltalk. The soft key display
was kept from the earlier interface, but it was now
attached to the window. Using the soft keys retained
the keyboard control that was thought to be important
for a business-oriented machine. The mouse
was introduced into the interface as an alternative
to using the keyboard. We began to allow things
to be drawn with either the mouse or the cursor keys.
Likewise, the user could select an option either from the
keyboard or by pointing with the mouse. The decision to become completely
mouse oriented was still hotly debated. A number of us felt that radical changes
could not be made to the user interface because the Lisa was scheduled to be
announced later in the year at the National Computer Conference of 1980.
 | | Figure 3b. The Lisa display with a simple window and dialogue box (March 1980) |
The interface was moving toward a standard
that was called the Lisa “look and feel.” All the
applications would be similar in their appearance
and use commands that would be common to each of them. This consistency
reinforced our previously defined interface concepts
because the user would interact with all the Lisa applications in
the same manner. This also made writing the applications
easier because the software to create the user interface
could be shared by all the applications.
The first Lisa hardware using the 68000
began to appear in Spring 1980. Numerous software prototypes of
our user interface ideas were written and subsequently
incorporated into Forms Editor. For the first time
we could see how the user interface looked as well as how it felt.
Desktop metaphor
 | | Figure 4. The Lisa display with dialogue box (August 1980) |
We had developed a model to describe the typical Lisa user. This user was a business person
whose day was constantly interrupted with immediate requests to do other things.
From that user model it was decided that the Lisa had to
offer an environment that safely allowed several applications
to be used simultaneously and would permit any of the user’s
work to be put on hold. The job of the user interface was to
portray this multitasked environment in a manner that would make sense to the user
(Figure 4).
After numerous experiments, a new interface was developed that became known as the
Lisa desktop metaphor. The interface had multiple windows on the screen to display the
different types of work conducted by the user. We called he work performed within the windows
“documents” – to use a concept already familiar to the user. We
decided that the user should not have to worry about which application
went with which document. Instead, users would select the document they wanted
and the Lisa would determine which application
was needed. Switching between different documents was as obvious as pointing at the
window containing the desired work. The window appearance was spruced up to look
more like a file folder as we sought to create an
electronic equivalent of the user’s real desktop. The Lisa desktop would have objects already
familiar from a real desktop such as documents, folders, calculator, and other handy
tools; everything short of an electronic paperclip to mangle.
Role of user testing
Controversy surrounded a number of decisions that were made on the user interface, the
introduction of the mouse being a good example. We were concerned that our target users
would not accept using the mouse. We had investigated alternatives, such as the soft keys
and even a light pen, but none proved to be as efficient. Our own experience with the mouse
agreed with the research conducted by Douglas Engelbart [2],
who created the mouse while at SRI International, and with that by
Xerox [1], which discussed the virtues of the mouse. We knew that users would benefit by
using the mouse, but we had to make using it as easy as possible. We felt that
the number of buttons affected how easy it was to use. Factions
developed to promote their choice for the “correct” number
of mouse buttons. What ensued became known as the
“button wars” – one of many wars that developed over interface issues.
Normally, the user interface wars would end in a stalemate of opinions. We found it
best during these times to test our opinions on the users for which we were designing. We
would use as test subjects new Apple employees who had no previous computer experience.
The first tests were conducted during Summer 1980 by Larry Tesler, the applications
software manager, and were observed by psychologists as well as ourselves. Many of the
observations were recorded for later review and served as a form of d‚tente between the
warring factions.
Some of the engineers resisted taking time to make improvements derived from the user
testing or from recommendations made by users themselves. A system was established
whereby a troika, led by Larry Tesler with representatives from engineering and marketing
groups, ruled on controversial issues.
User testing continued throughout the Lisa’s development for each application, the
desktop manager, and new Lisa concepts such as pull-down menus, the location of scroll bars,
and alert boxes. More than a year before first shipment, a special room was built to give a
sneak preview of the Lisa to potential corporate customers. These
“sneaks,” as they were called, generated positive feedback when participants
were challenged to learn the user interface and be productive within 30 minutes of use.
Recommendations from the sneaks helped generate changes that fine-tuned the interface
design. In some cases, the recommendations were misguided and were either rolled back or,
more often, led to some other approach being taken. Many of the high priority changes were
made before the final product shipped. The team felt this was an innovative approach for
the personal computer industry because the user interface was being designed from the
user’s perspective using their direct feedback.
In the case of the mouse button, it was discovered that with our user interface
the three-button mouse used in Smalltalk had a slight,
but not significant, advantage for the experienced users. Similar results were observed for
the two-button mouse. For beginners, the extra buttons were confusing as the users
sought to remember which button to press. The extra buttons also hindered learning the
Lisa user interface quickly. The one button mouse was chosen to make the user interface
easier for the first-time user.
Arriving at an interface
By the end of Summer 1980 the design of the Lisa user interface culminated in the release of
the Lisa User Interface Standards document [5]. The document served as a guideline
for what should and should not be done in the user interface. The document
also began to involve the hardware as part of the overall user interface.
The scope of the user interface now included items such as the keyboard layout, how the
machine was turned on and off, how the machine would be serviced-even whether
there should be a door on the disk drive. These issues became part of shaping users’
perceptions of the entire machine and defining what would entice them to use it.
 | | Figure 5. The Lisa display as seen in the Lisa User Interface Standards Document (October 1980) |
The interface would continue to evolve, but the release of this document signaled the birth
of what eventually became the Lisa and Macintosh user interfaces (Figure 5). Only after
the user interface standards were resolved did serious work begin on the applications. Work
on Forms Editor and other prototypes became the basis for the other Lisa applications.
Early days of the Desktop Manager
With the basics of the interface defined, work began on filling out the rest of the user model
of the system. In late 1980, we began designing the interface for the filing functions of
the Lisa system. The questions we were trying to answer included
| | | How are documents created or destroyed?
|
| | | How are they located?
|
| | | How are they returned to their filing homes?
|
| | | How should their attributes be displayed?
|
| |
In considering each of these questions, we were guided by the desire for consistency,
ease of use, and efficiency.
Desktop icons rejected!
One of the first models we considered used desktop icons for performing the basic filing
functions. Our interface to this point had only folder title tabs as document and folder
icons. The title tabs could be moved into and out of filing folders by nesting. Destroying an
object was accomplished by moving it into a wastebasket icon. Diskettes were to appear on
the screen as desk drawers that could be opened to reveal folder tabs.
A number of objections were raised early in the discussion of the icon
model. The Lisa had only a 12-inch-diagonal display, and some thought that
it was too small to display full-width documents and desktop icons
simultaneously. There was concern that simple tasks, such as deleting
a document by dragging it to a wastebasket, would be too cumbersome if the
user tried to locate the wastebasket buried under open documents. Locating
documents in nested folders was also considered too unwieldy. The scenario
of opening a series of nested folders, accumulating more and more desk
clutter along the way while searching for a document, seemed to be less
efficient than a real-world paper filing system. Some suggested that people
would spend an inordinate amount of time positioning icons and moving
or resizing windows.
Others argued that mimicking the office filing system would simply give
people an electronic version of a system that already had many problems.
In particular, we thought that most paper filing systems had serious
difficulties in both filing and retrieval. With all these things
considered, but without producing a more detailed mock-up, we rejected the
iconic filing interface as too inefficient and set out to design something
superior.
A document browser
Our initial attempts at producing a more efficient human interface centered
on something resembling the Smalltalk browser. The browser was used
to locate and display objects in the Smalltalk system. It had a window with
a top portion containing four lists of categories, allowing the
hierarchical selection of an object, and an area below in which the
selected object was displayed.
 | | Figure 6. Desktop Manager – The Document Browser (December 1980) |
We were interested in avoiding a strictly hierarchical filing system (Figure 6). We wanted to free users from having to decide the correct place
to file a document and then the converse problem of trying to find where
the document was filed. The upper area of our document browser contained
various attributes that could be selected to narrow the choice
of documents. As attributes were selected, documents with those attributes
were displayed in the lower area. In this model, documents could be quickly
located by type of document, keyword, author, and so on.
Our paper prototype seemed to work well for selecting a document but became
awkward when trying to perform other operations such as moving, copying,
or creating something new. It also lacked a certain approachability. Its
operation was not at all obvious when first encountered, and other team
members felt that it was too abstract for office users.
Twenty Questions Filer
 | | Figure 7. The Twenty Questions Filer (July 1981) |
In an attempt to make the system easier for the first-time user we tried
a hierarchical browser with more prompting, which became known as the
“Twenty Questions Filer” (Figure 7). Selecting Documents
from the Desktop menu brought up a dialog window that prompted the user
to select a disk, folder, and document, with statements such as “Choose
a document from the list below.” After the user made a selection, an Action
menu would appear with items such as Pull, Refile, Cross-file, and Discard.
Selecting one of these menu items would apply the action to the selected
document. This system was fast and a bit easier to understand than the
previous version but still somewhat abstract. We were running out of time
on the project schedule and decided that despite its problems this was to
be our filing interface.
The system was fairly efficient because the filing dialogue could
be brought up easily from a menu, and only a few mouse clicks were needed.
However, after many months of implementation, and some early user testing,
a few of us were not satisfied with the interface. Some users were confused
about the relationship of the selections in the upper area to the list
below. They did not always notice the appearance of the Action menu after
a selection was made and would not know how to continue from there. The
constant prompting made users feel that they were playing a game of Twenty
Questions. It also failed to achieve one of Lisa’s major goals
– it wasn’t fun!
“Son of Dataland”
In a clandestine effort, some of us decided to further investigate the
problem on our own and asked Bill Atkinson, who defined many aspects of the
global human interface, for help. Bill recalled a trip to the M.I.T. Media
Lab in which he saw a futuristic data navigation system called the
“Spatial Data Management System” [7]. In this system, a person
sat in a chair with two hand controls and faced a large screen, referred
to as Dataland. The controls allowed you to “fly” over some data space
projected on a large screen in front of you, in this case the Boston area,
and then to zoom in to very fine levels of detail, or zoom out to see
a huge geographical area.
Bill adapted this idea to the filing problem by creating an enormous
virtual desktop, perhaps a mile square, and then providing methods for very
quickly moving around and zooming in or out. Documents were represented
as small icons that could be organized spatially, with related documents
placed near each other. The idea was incredibly simple but placed quite
a burden on the user’s memory when the number of documents became large.
It also did not work well when multiple disks were online, representing
several flat filing spaces.
Office model
We were drawn to the simplicity of M.I.T.’s Dataland but thought that
we needed something more familiar to the office worker. Our newly formed
Macintosh group was also experimenting with icons for its Finder. Slowly,
we were migrating back to icons for the
sake of simplicity and approachability.
While searching the literature for information on other iconic systems,
we uncovered an IBM research proposal for a graphical office system called
Pictureworld [8]. In the concept paper, a large screen presented small
icons for file cabinets, a desk pad, in/out trays, a wastebasket, and other
objects. Touching a file cabinet caused a prompting file folder to appear
with a form for specifying search parameters. After the user filled out the
form and pressed the “Do” button, a list of matches appeared.
Selecting one of these documents caused the list to go away and the desk
pad icon to become large in the center of the screen with the full-sized
document placed on it. If another document was opened, the current document
was reduced to an icon and was shown in the “Pending” box on
the desk pad. Documents and other objects were moved by touching arrows
that automatically appeared on the screen, indicating valid transfer
possibilities. The authors of the proposal perhaps underestimated the power
of such an interface by the interesting statement, “We have not
implemented a Pictureworld system and we make no claims for it as
a potential product.”
At about this time, the Xerox Star [10, 12], another office system with
an iconic interface, was announced. The Star, however, was an actual
implementation. It had a very large screen that easily accommodated the
icons and full-sized documents, a luxury we didn’t have. Their use of
icons though, seemed to give further validity to this approach.
In considering these models, we created several mock-ups that presented two
levels of detail to the user. The first view was a look at the office as
a whole. Here you could see the desk, filing cabinets, wastebasket, and
other office objects. To view a document it was necessary to remove
a document icon from the drawer and place it on the desk. The view would
then change to one looking down on the desktop with documents at full size.
After experimenting with this model for some time we realized that having
the two different views (or “world swaps,” as they became
known) was both confusing and inefficient.
Final desktop model
Eliminating the dual-view model brought us very close to the final design.
We quickly implemented a working prototype, which presented a single
desktop on which both small icons and full-sized documents were kept.
Design discussions with a few others helped to refine some of the ideas and
prompted additional cute and useful features such as windows zooming open
and closed from their icons. We were pleased with how easily the remaining
details of the interface fell into place.
Revealing the new interface to the rest of the team drew mixed reactions.
Some were thrilled with the new look and simplicity, and others were
concerned about the lateness of the schedule. The new design was subjected
to the same user testing philosophy that had guided development of the
Lisa. It was found that key areas such as speed of learning, speed of task
completion, level of comprehension, and error rate were all
indistinguishable between the new iconic design and the Twenty Questions
Filer. However, no user preferred the Twenty Questions design, and some
preferred the iconic Filer because it was more interesting and fun!
Wayne Rosing, the engineering manager at the time, gave the go-ahead, and
we raced to catch up with the rest of the Lisa team. After more than a year
of looking for something highly efficient, we had come full circle, back
to the more approachable, iconic, direct manipulation interface!
In retrospect
 | | Apple Lisa 1 |
As we look back at our experiences on the Lisa project, there are a few
points and lessons that stand out as critical to the success of the user
interface. Foremost is that from the very first proposal in 1978, the focus
was on the user. This approach affected not only the interface but also the
underlying software and hardware. A second critical factor was that the
interface was developed through experience, and was not just some
programmer’s idea of what should work. This experience was gained
by extensive testing on representative users and the implementation
of several applications. The variety of the applications stressed the
interface in unanticipated ways, highlighting weaknesses in the original
design. Finally, management’s commitment to ease of use in spite of tight
schedules, and strong centralized control of the user interface, encouraged
the engineers to make improvements that worked within the metaphor.
The iconic desktop taught us something about the importance of efficiency.
Originally rejected for reasons of inefficiency, we later resurrected the
iconic desktop to replace the “more efficient” Twenty Questions design.
Why? Because it grabbed the attention of new users and enticed them
to explore using it. We believe that by adding direct manipulation to an
attractive graphical representation of the familiar desktop, the icons and
controls shown on the screen became, in some sense, real and the interface
began to disappear.
 | | Illustration by David Goldin |
We also learned something about the implementation of metaphors. As
a general rule they should, of course, be implemented as faithfully
as possible; otherwise, the user may be confused when things don’t work
as expected. However there are valid reasons for occasionally breaking out
of the metaphor. The physical limitations of the computer, such as the
display screen’s being smaller than a piece of paper, can force some
changes. Sometimes the computer removes limitations of the metaphor-a desk
does not “know” what is on it, but because a computer can keep track
of what is on its screen the Lisa had a menu that listed everything on the
desktop for quick access. No matter what the reasons, we worked to keep the
total number of differences small because each one burdens the user with
another thing to remember.
By combining a clear, concise presentation and an intuitive, smoothly
operating set of controls with a distinctive style, the Lisa and Macintosh
user interfaces popularized a new way of working with computers. (See [6,
9, 11, 13] for additional viewpoints and details and [12] for discussion
of a similar project.)
In these few pages, we could neither record and analyze all the important
events in the development of the Lisa interface nor individually credit all
the people that contributed significantly to the appearance and operation
of the final interface. We hope we have managed to convey a sense of the
design process and trade-offs involved.
Roderick Perkins, Dan Smith Keller, Frank Ludolph
References
[1] Card, Stuart K., English, William K., and Burr, Betty. Evaluation
of mouse, rate-controlled isometric joystick, step keys, and text keys for
text selection on a CRT. Ergonomics 21 (1978): 601-613.
[2] English, W.K., Englebart, D.C., and Berman, M.L. Display-selection
Techniques for Text Manipulation. Transactions on Human Factors
in Electronics, HFE-8, 1, March 5-15, 1967.
[3] Ingalls, Daniel H. H. The Smalltalk-76 Programming System Design and
Implementation. Conference Record of the 5th Annual ACM Symposium
on Principles of Programming Languages, Tucson, Arizona, January 1978.
[4] Lisa Marketing Requirements Document. Internal company document. Apple
Computer, Inc., April 1980.
[5] Lisa User Interface
Standards. Internal company document. Apple
Computer, Inc., October 1980.
[6] Morgan, Chris, Lenmons, Phil, and Williams, Gregg.
An interview with
Wayne Rosing, Bruce Daniels, and Larry Tesler. Byte 8,2 (February 1983):
90-114.
[7] Negroponte, Nicholas. Spatial Data Management. DARPA Order
MDA903-77-C-0037, Massachusetts Institute of Technology, Cambridge, 1979.
[8] Schild, W., Power, L., and Karnaugh, M. PICTUREWORLD: A Concept for
Future Office Systems, IBM Research Report RC-8384, July 30, 1980.
[9] Schmuker, Kurt J. The Complete Book of Lisa. Harper & Row, New York,
1984.
[10] Seybold, Jonathan. Xerox’s “Star.” The Seybold Report 10,16 (April 27,
1982). Seybold Publications, Inc., Box 644, Media, Pa. 19063.
[11] Seybold, Jonathan. Apple’s Lisa, a personal office system. The
Seybold Report (Jan. 28 1983). Seybold Publications, Inc., Box 644, Media,
Pa. 19063.
[12] Smith, D.C., Irby, C., Kimball, R., Verplank, B., and Harslem,
E. Designing the Star
user interface. Byte 7, 4 (April 1982): 242-282.
[13] Williams, Gregg. The Lisa computer system. Byte 8, 2 (February 1983):
33-55.
[14] Moritz, Michael. The Little Kingdom. William Morrow and Company, Inc.,
New York, 1984.
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