Designing the Star The Star user interface adheres rigorously to a small set of principles designed to make the system seem friendly by simplifying the human-machine interface.

Dr. , Charles Irby, Ralph Kimball, and Bill Verplank Corporation 3333 Coyote Hill Rd. Palo Nto, CA 94304

Eric Harslem Xerox Corporation El Segundo, CA 90245

In April 1981, Xerox announced the work station's network, or on a behind those features and illustrate the 8010 Star Information System, a file server on a different network. the principles with examples. This new designed for Mailing permits users of work sta- discussion is addressed to the offices. Consisting of a processor, a tions to communicate with one designers of other computer pro- large display, a keyboard, and a another. Printing utilizes laserdriven grams and systems-large and small. cursor-control device (see photo I), it raster printers capable of printing is intended for business professionals both text and graphics. Star Architecture who handle information. As Jonathan Seybold has written, Before describing Star's user inter- Star is a multifunction system com- 'This is a very different product: Dif- face, several essential aspects of the bining document creation, data pro- ferent because it truly bridges word Star architecture should be pointed cessing, and electronic filing, mailing, processing and functions; out. Without these elements, it would and printing. Document creation in- different because it has a broader have been impossible to design an cludes text editing and formatting, range of capabilities than anything interface anything like the present graphics editing, mathematical for- which has preceded it; and different one. mula editing, and page layout. Data because it introduces to the commer- The Star hardware was modeled processing deals with homogeneous, cial market radically new concepts in after the experimental relational databases that can be human engineering." (See reference computer (see reference 19). Like sorted, filtered, and formatted under 15.) Alto, Star consists of a Xerox- user control. Filing is an example of a The Star user interface adheres developed, high-bandwidth, MSI network service utilizing the rigorously to a small set of design (medium-scale integration) processor; local-area network (see references 9 principles. These principles make the local disk storage; a -mapped and 13). Files may be stored on a system seem familiar and friendly, display screen having a 72dots-per- work station's disk, on a file server on simplify the human-machine interac- inch, resolution; a pointing device tion, unify the nearly two dozen func- called the "mouse"; and a connection About the Authors tional areas of Star, and allow user to the Ethernet network. Stars are These five Xerox employees have worked on experience in one area to apply in higher-performance machines than the Star user interface project for the past five others. In reference 17, we presented Altos, being about three times as fast, years. Their academic backgrounds are in com- an overview of the features in Star. having 512K bytes of main memory puter science and psychology. Here, we describe the principles (versus 256K bytes on most Altos), 10

242 A~rill982O BYTE Publications lnc Circle 26 on inquiry card.

MODELIII WITH 2DISK DRIVES (UK RAM)...... S17U.06

DRIVE0 INTERNAL

Photo 1: A Star work station showing the processor, display, keyboard, and mouse. ' '

DRIVE 2 DRIVE 3 EXTERNAL EXTERNAL 4OTraL sn9.95 .SS.m

Photo 2: The Star keyboard and mouse. Note the two buttons on top of thi mouse.

or 29 megabytes of disk memory (ver- the user interface is the bit-mapped sus 2.5 megabytes), a 10%- by display screen. Both Star and Alto 13%-inch display screen (versus 10?h devote a portion of main memory to by 8 inches), and a 10-megabits-per- the screen: 100K bytes in Star, 50K second Ethernet (versus 3 megabits). bytes (usually) in Alto. Every screen Typically, Stars, like Altos, are dot can be individually turned on or linked via to each other and off by setting or resetting the cor- to shared file, mail, and print servers. responding bit in memory. It should Communication servers connect be obvious that this gives both com- Ethernets to one another either direct- puters an excellent ability to portray ly or over telephone lines, enabling visual images. We believe that all im- internetwork communication. (For a pressive office systems of the future _, detailed description of the Xerox Alto will have bit-mapped displays.,

computer, see the September 1981 Memory cost will soon be insignifi- -8 BYTE article 'The Xerox Alto Com- cant enough that they will be feasible I + puter" by Thomas A. Wadlow on even in home computers. Visual com- 4 ! page 58.) munication is effective, and it can't be ,!, The most important ingredient of exploited without graphics flexibility. Tiwe must be a way k change network or what anyone else is da- do% on the screen quickly. Star has a ing. Larger programs can be written, high memory bandwidth, about 90 using the disk for swapping. megahertz (MHz).The entire Star The Ethernet lets both ,Stars and screen is repainted from memory 39 Altos have a distributed architecture. times per second, about a 50-MHz Each hachine is connected to an data rate between memory and the Ethernet. Other machines on the screen. This would swamp most com- Ethernet are dedicated as puter memories. However, since "serversn-machines that are at- Star's memory is double-ported, tached to a resource and provide ac- refreshing the display does not ap- cess to that resource. preciably slow down processor memory access. Star also has separate Star Design Methodology logic devoted solely to refreshing the We have learned from Star the im display. Finally, special portance of formulating the fun has been written to assist in changing damental concepts (the user's concep the contents of memory. quickly, per- tual model) before software is writ- mitting a variety of screen processing ten, rather than tacking on a user in- : that would not otherwise be practical terface afterward. Xerox devoted II (see reference 8). about thirty work-years to the design People need a way to quickly point of the Star user interface. It was to items on the screen. Cursor step designed before the functionality of keys are too slow; nor are they the system was fully decided. It was suitable for graphics. Both Star and even designed before the computer Alto use a pointing device called the hardware was built. We worked for mouse (see photo 2). First developed two years before we wrote a single at Stanford Research Institute (see line of actual product software. reference 06), Xerox's version has a Jonathan Seybold put it this way, ball on the bottom that turns as the ''Most system design efforts start with mouse slides over a flat surface such hardware specifications, follow this SITTING as a table. Electrobics sense the ball with a set of functional specifications rotation and guide a cursor on the for the software, then try to fii screen in corresponding motions. The out a logical user interface and com-

mouse possesses several important mand structure. The Star project ' PRETTY attribute% started the other way around: the You can use just about any desk for a paramount coniern was to define a stand. But with *It is a ''Fitts's law" device, That is, conceptqal model of how the user CF&A, yoli're sitting pretty. Our full rangeaf desks, , and ter- after some practice you can point would relate to the system. Hardware ' mine1 stands are designed to accom- with a mouse as quickly and easily as and software followed from this." modate a variety of computer equip you can with the tip of your finger. (See reference 15.') ment. Choose from our Classic Series The limitations on pointing speed are In fact, before we even began desks, DR Series desks and enclo- those inherent in the human nervous designing the model, we developed a sures, specialtyitems like our Apple11 . desk, or a univeisal piinter stand. system (see references 3 and 7). methodology by which we would do You'll be sitting pretty with attractive .It stays where it was left when you the design. Our methodology report color selections, durable construc- are not touching it. It doesn't have to (see reference 10) stated: tion, versatile configurations, useful be picked up like a light pen or stylus. options, competitive prices, qulczk .It has buttons on top that can be One of the most troublesome and delivery, and personal service. It's our least understood aspects of interactive ,way of doing business. sensed under program control. The buttons let you point to and interact systems is the user interface. In the design of user interfaces, we are con- with objects on the screen in a variety cerned with several issues: the provi- of ways. sion of languages by which users can express their commands to the com- puter; the design of display representa- tions that show the state of the system Computer Furniture and Every Star and Alto has its own Accessories, Inc. hard disk for local storage of pro- to the user; and other more abstract issuesthat affect the user's understand- 1441 West 13-d Street grams and data. This enhances their ing of the system's behavior. Many of Qardena, CA 90249 personal name, providing consistent these issues are highly subjective and (213) 327-7710 accws' to information raardless of are therefore often addressed in an ad how'ntmy.other:ma~bi~esare on the hoc fashion. We believe, however,

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246 Ap " -32 0 BYTE Publications Inc that more rigorous approaches ta user The idea behind this phase of design is largest prototyping effort ever. interface design can be developed. . . . to build up a new task environment for Dozens of experimental programs the user, in which he can work to ac- coniplish the same goals as before, sur- were written for the Alto by members These design methodologies are all of the Xerox Palo Alto Research unsatisfactory for the same basic rounded now by a different set of ob- reasoli: they all omit an essential step jects, and employing new methods. Center. Without the creative ideas of that must precede the design of any the authors of those systems, Star in successful user interface, namely task Prototyping is another crucial ele- its present form would have been im- analysis. By this we mean the analysis ment of the design process. System possible. In addition, we ourselves of the task performed by the user, or designers should be prepared to im- programmed various aspects of the users, prior to introducing the pro- posed computer system. Task analysis plement the new or difficult concepts Star design on Alto, but all of it was involves establishing who the users and then to throw away that code "throwaway" code. Alto, with its bit- are, what their goals are in performing when doing the actual implementa- mapped display screen, was powerful the task, what information they use in tion. As Frederick Brooks says, the enough to implement and test OUI performing it, what information they question "is not whether to build a ideas on visual interaction. generate, and what methods they employ. The descriptions of input and pilot system and throw it away. You Some types of concepts are in- output information should include an will do that. The only question is herently difficult for people to grasp. analysis of the various objects, or in- whether to plan in advance to build a Without being too formal about it, dividual types of information entity, throwaway, or to promise to deliver our experience before and during the employed by the user. . . . the throwaway to customers. . . . Star design led us to the following The purpose of task analysis is to Hence plan to throw one away; you classification: simplify the remaining stages in user will, anyhow. " (See reference 2.) The interface design. The current task Alto sewed as a valuable prototype Easy Hard description, with its breakdown of the for Star. Over a thousand Altos were information objects and methods eventually built. Alto users have had concrete abstract presently employed, offers a starting point for the definition of a corre- several thousand work-years of ex- visible invisible sponding set of objects and methods to perience with them over a period of copying creating be provided by the computer system. eight years, making Alto perhaps the choosing filling in recognizing generating editing programming interactive batch

The characteristics on the left were in- corporated into the Star user's con- ceptual model. The characteristics on 7 working day RUSH service the right we attempted to avoid. FREE demo samples Principles Used Quality design The following main goals were pur- Very COMPETITIVE PRICES sued in designing the Star user inter- Personalized assistance face : FREE shipping - in continental U.S. COMPLIMENTARY quotes on familiar user's conceptual model custom forms *seeing and pointing versus remem- 1 bering and typing *what you see is what you get CHECKS A Currently providing forms support A L for: *universal commands Systems Plus Vector TCS Alpha Micro consistency Radio Shack Insoft IMS Continental DIBS simplicity Libra Structured Systems Group Peachtree Anchor Accounting Plus BPI Designer MCI modeless interaction Graham Dorian MCBA Durango Dynabyte user tailorability ICall NOW for FREE sample forms packet. Your customer service We will discuss each of these in turn. representative is waiting to assist you with your continuous forms Familiar User's Conceptual Model Ineeds! 1 A user's conceptual model is the set . . .a any other continuous of concepts a person gradually ac- Checks 8384 Hercules St. quires to explain the behavior of a forln YOU may need! (@ To-Go La Mesa, CA 92041 - system, whether it be a computer system, a physical system, or a analogies and metaphors or to in- they would also be represented by hypothetical system. It is the model troduce entirely new functions requir- pictures on the display screen. They developed in the mind of the user that ing new approaches. Each option has would be selected by pointing to them enables that person to understand advantages and disadvantages. We with the mouse and clicking one of and interact with the system. The first decided to create electronic counter- the buttons. Once selected, they task for a system designer is to decide parts to the physical objects in an of- would be moved, copied, or deleted what model is preferable for users of fice: paper, folders, file cabinets, mail by pushing the appropriate key. the system. This extremely important boxes, and so on-an electronic Moving a document became the elec- step is often neglected or done poor- metaphor for the office. We hoped tronic equivalent of picking up a ly. The Star designers devoted several this would make the electronic piece of paper and walking work-years at the outset of the proj- "world" seem more familiar, less somewhere with it. To file a docu- ect discussing and evolving what we alien, and require less training. (Our ment, you would move it to a picture considered an appropriate model for initial experiences with users have of a file drawer, just as you take a an office information system: the confirmed this.) We further decided physical piece of papqr to a physical , --'1 *A file cabinet. metaphor of a physical office. to make the electronic analogues be 1 P ir ;- The designer of a computer system concrete objects. Documents would The reason that the user's concep- can choose to pursue familiar be more than file names on a disk; tual model should be decided first

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+ 'r . t52 April 1982 0 BYTE Publicatiom mc ' , -. \' ' . 1 - , . when designing a system is that the approach adopted changes the func- tionality of the system. An example is electronic mail. Most electronic-mail systems draw a distinction between messages and files to be sent to other people. Typically, one program sends messages and a different program handles file transfers, each with its own interface. But we observed that offices make no such distinction. 1: Figure In-basket and out-basket icons. The in-basket contains an envelope indicating Everything arrives through the mail, that mail has been received. (This figure was taken directly from the Star screen. from one-page memos to books and Therefore, the text appears at screen resolution.) I reports, from intraoffice mail to inter- national mail. Therefore, this became part of Star's physical-office metaphor. Star users mail documents of any size, from one page to many pages. Messages are short documents, just as in the real world. User actions are the same whether the recipients are in the next office or in another country. A physical metaphor can simplify and clarify a system. In addition to eliminating the artificial distinctions of traditional computers, it can eliminate commands by taking ad- vantage of more general concepts. '1ke DSUO 'Ierminal Controller makes your LA36 For example, since moving a docu- perform like a DECwritera III, ment on the screen is the equivalent The Datasouth DS1U) gives your DECwritermI1 the hi speed printing of picking up a piece of paper and and versatile performance features of the DECwriteraDeI1 at only a frac- walking somewhere with it, there is tion of the cost. The DS120 is a plug compatible replacement for your no "send mail" command. You sim- LA36 logic board which can be installed in minutes. Standard features include: ply move it to a picture of an out- 165 cps bidirectional printing RS232 interface basket. Nor is there a "receive mail" Horizontal & Vertical Tabs 20 rnA Current Loop interface command. New mail appears in the Page Length Selection Top of Form in-basket as it is received. When new 11O-4800 baud operation Adjustable Margins mail is waiting, an envelope appears 1000 character print buffer Double wide characters X-on, X-off protocol Parity selection in the picture of the in-basket (see Self Test Optional APL character set figure 1).This is a simple, familiar, Over 5,000 DS120 units are now being used by customers ranging from nontechnical approach to computer the Fortune 500 to personal computing enthusiasts. In numerous instal- mail. And it's easy once the physical- lations, entire networks of terminals have been upgraded to take advan- office metaphor is adopted! tage of today's higher speed data communications &rvic&. LSI While we want an analogy with the C microprocessor electronics physical world for familiarity, we and stirict quality control en- - don't want to limit ourselves to its sure dependable performance capabilities. One of the raisons d'Ctre for years to come. When ser- for Star is that physical objects do not vice is required, we will respond promptly and effec- provide people with enough power to tively. Best of all, we can de- manage the increasing complexity of liver immediately through the "information age." For example, our nationwide network of we can take advantage of the corn-. distributors. Just give us a puter's ability to search rapidly by call for all the details. providing a search function for its electronic file drawers, thus helping 0 computer torpor- 4740 Dwight Evans Road Charlotte, North Carolina 28210 7041523-8500 to solve the long-standing problem of - lost files.

I- -pril1982 0 BYE Publications Inc Circle 139 on inquiry card. The "Desktop" 'lirger form called a "window," which The Desktop is the principal Sta~ Every user's initial view of Star is displays the icon's contents. Win- technique for realizing the physical *'kr,; . the 'Desktop," which resembles the dows are the principal mechanism for office metaphor. The icons on it are q,; ., top of an office desk, together with displaying and manipulating infor- visible, concrete embodiments of the 8. surrounding furniture and equip- mation. corresponding physical objects. Star fi' ment. It represents your working en- The Desktop "surface" is displayed users are encouraged to think of the h.,! vironment-where your current proj- as a distinctive gray pattern. This objects on the Desktop in physical >-f ects and accessible resources reside. restful design makes the icons and terms. Therefore, you can move the On the screen are displayed pictures windows on it stand out crisply, icons around to arrange your of familiar office objects, such as minimizing eyestrain. The surface is Desktop as you wish. (Messy documents, folders, file drawers, in- organized as an array of one-inch Desktops are certainly possible, just baskets, and out-baskets. These ob- squares, 14 wide by 11 high. An icon as in real life.) Two icons cannot oc- jects are displayed as small pictures or can be placed in any square, giving a cupy the same space (a basic law of kikj, #,. b .-,'. icons," as shown in figure 2. maximum of 154 icons. Star centers physics). Although moving a docu- p:' YOU can "open" an icon to deal an icon in its square, making it easy ment to a Desktop resource such as a ,,a ,,a A. ._.I ', . with what it represents. This enables to line up icons neatly. The Desktop printer involves transferring the h::,;,... you to read documents, inspect the always occupies the entire display document icon to the same square as ,. . gi; ; contents of folders and file drawers, screen; even when windows appear the printer icon, the printer im- see what mail you have received, etc. on the screen, the ~esktopcontinues mediately "absorbs" the document, k.;. ' queuing it for printing. You can leave B. .': When opened, an icon expands into a to exist ."beneath - them. ,A,-.. '. f a;

XEROX STAR User-Interfaces

DOCUMENT OBJECTS

Documtnt Record File

paragraph "-.,.. File Drawer In- and 8:lut-Bajketr

Footnote

Select Adjust UNIVERSAL COMMANDS

:how Prspotie; Copy Propertie:

. .

Figure 2: A Desktop as it appears on the Stur screen. Several commonly used icons appear across the top of the screen, including documents foseme as "fom-pd" sources for letters, memos and hlank waver. An open window displaying a document containing an illustration is also shown,

t56 Apd 1982 O BYEPublications lnc

I . . P-, 3 documents on your Desktop in- We Were Here Yeeterday... definitely, just as on a real desk, or you can file them away in folders or IWe Will Be Here Tomorrow file drawers. Our intention and hope is that users will intuit things to do (With Support & Service For You!J with icons, and that those things will indeed be part of the system. This will happen if:

(a) Star models the real world ac- curately enough. Its similarity with the office environment preserves your familiar way of working and your ex- isting concepts and knowledge. (b) sufficient uniformity is in the system. Star's principles and "generic" commands (discussed below) are applied throughout the LlST 64k QD ~4195 system, allowing lessons learned in $3275 one area to apply to others. - ''g~~~~131-- 25 The model of a physical office pro- vides a simple base from which learn- PRINTERS ing can proceed in an incremental HARD DISKS I cow-- - 11 ...... n9s fashion. You are not exposed to 5mb for IBM, Superbrain, S-100,) EPSON MX80 ~aralle~...... $479 entirely new concepts all at once. Zenith, TRS-80 .II & Ill, Xerox, EPSON ~~100...... $ Much of your existing knowledge is Apple. Clt0h F10 40 cps parallel * ...... $I embedded in the base. $2 NEC 7710, 7730 * ...... In a functionally rich system, it is NEC 3510 rs232 * ...... $1 DATA SOUTH 180 cps...... $1 probably not possible to represent OKIOATA 82A...... S everything in terms of a single model. MPI 886 120 cps...... S There may need to be more than one MPI 99G L.C. dscenders ...... $ model. For example, Star's records- CORVUS +Tractors Available...... $ processing facility cannot use the Call For Prices physical-office model because * I SOFTWARE physical offices have no "records pro- C Basic 11...... DISKETTES M Basic 80...... I276 cessing" worthy of the name. MT Pascal...... I430 Therefore, we invented a different TANDON S/S O/O DYSAN Fortran 80...... '460 model, a record file as a collection of IBM COMPATIBLE...... '225 5'/4" S/S, O/D Cobol 80...... 'bbO M Basic Compiler. ..'328 fields. A record can be displayed as a TANOON 01s 010...... '350 ACCT. Plus...... '386 row in a table or as filled-in fields in a TANOON 100-4 80 track. ...'a00 Word Star...... '306 form. Querying is accamplished by BOX OF 10 Supercalc ...... '261 0-Base 11...... '600 filling in a blank example of a record SUPERBRAIN ADD-ON * with predicates describing the desired S/S, 0/0 w/power supply, cable, case. values, which is philosophically software, one drive. SUPERBRAIN 6RAPHlGS t S-100 Bus Adapter similar to Zloof's "Query-by- For SUPERBRAIN LIST $595 '476 Graphics Board. ... Example" (see reference 21). Symbol Generator. . .I200 LlST $90 Of course, the number of different SUPERBRAIN Graphics Plotter. ....I200 Parallel Port $76 3-0 Graphics...... I400 user models in a system must be kept Surface Plotter...... I460 TERMINALS I LlST $205 to a minimum. And they should not Many brands available. Graphics Terminal overlap; a new model should be in- Call for ~rices. SBE Prom 5155 Emulator ...... '460 I troduced only when an existing one Toll-Free Ordrrine 1-800-426-2662 does not cover the situation. For Information CaI (206) 453-8159 Mall and telephone orders only. Mastercharge, VISA add 3%. COD Certified check under Seeing and Pointing 51000. All Dricss FOB origin. Send lor cataloa. Mall all correspondence to P.O. Box 3952, A well-designed system makes Bellevue, WA 98009 everything relevant to a task visible on the screen. It doesn't hide things PACIFIC------rn"VTER------BROKERS P.O. Box 3952, Belkvue, WA 98009 under CODE + key combinations or

258 April 1982 O BYTE Publications Inc Circle 318 on inquiry card. force you to remember conventions. short-term memory by acting as a sort understood in terms of their effects on That burdens your memory. During of "visual cache." Thinking becomes the screen. This lets users conduct ex- conscious thought, the brain utilizes easier.and more productive. A well- periments to test, verify, and expand several levels of memory, the most designed computer system can actual- their understanding-the essence, of important being the "short-term ly improve the quality of your think- experimental science. memory." Marly studies have ana- ing (see reference 16). In addition, In Star, we have tried to make the lyzed the short-term memory and its visual communication is often more objects and actions in the system visi- role in thinking. Two conclusions efficient than linear communication; ble. Everything to be dealt with and stand out: (1)conscious thought deals a picture is worth a thousand words. all commands and effects have a visi- with concepts ' in the short-term A subtle thing happens when 6ie representation on the display memory (see reference 1) and (2) everything is ' visible: the display screen pr on the keyboard. You never the capacity of the short-term becomes reality. The user model have to remember that, for example, memory is limited (see reference 14). becomes identical with what is qn the CODE+Q does something in one When everything being dealt with in screen. Objects can be understood context and something different in a computer system is visible, the purely in terms of their visible another context. In fact, our desire to display screen relieves the load on the characteristics. Actions can bi eliminate this possibility led us to

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/ 6 CALIFORNIA COMPUTER SYSTEMS ;:;: . -- - Sl00 ?$ Font cla~;icl= ~itanlsoldIlctter~othicl5cientific 15cientific~hin :::: IX~I la2 32K STATIC RAM A & T; 200 NSEC .....$629.00 .I.- I06 64K DYNAMIC RAM A & T...... $548.95 $$ ,.,. Size 100 S-100 MAIN FRAM A 8 T ...... $379.95 ,:.: 81101C8[113118 231 & 122 FLOPPY DISC WITH CP/M 2.2'" ...... $329.95 I..' 1101 280 CPU A & T...... $249.95 .:( Fa- I I '101 4 SERIAL 110 A & T...... $291.95 'I8A 2 SERIAL 2 PARALLEL A 8 T...... $305.95 '20A 4 PARALLEL A 8 T...... $214.95 lOT0 BOAR08 WW ...... $39.95 LE PROOUCTS 14A 12K ROMlPROM...... $68.50 144A CALENOAW.CLOCK, ...... $106.95 1401 PROGRAMMABLE TIMER...... $98.50 l70A A TO 0 CONVERTER ...... $105.95 llOA GPlB (IE 488) INTERFACE...... $265.95 '101 ASYNC SERIAL...... $125.95 'ItA SYNC SERIAL...... $153.95 '2OA PARALLEL STANDARD...... $98.95 'LOB PARALLEL CENTRONICS.. ...: ...... $98.95 11 11 ARITHMETIC PROCESSOR WIDISC. ....$342.95 ll lC ARITHMETIC PROCESSOR WIROM . . $342.95 iOOA WW BOARD...... $22.95 ilOA SOLDERTAIL BOARD...... $23.95 Figure 3: The property sheet for text characters.

IS100 PROOUCTS CB-2 280 PROCESSOR BOARD. abolish the CODE key. (We have yet text selection and push the PROPER- I KIT ...... $1 98.95. A 8 T ...... : $269.95 VBlC 64 x 16 VIDEO. PCBO...... $32.95 to see a computer system with a TIES key. It contains such properties KIT ...... ,8153.95, A8T ...... $I9995 CODE key that doesn't violate the as type font and size; bold, italic, YES 80 CHARACTER VIDEO 4MHZ. principle of visibility ) You never in- underline, and strikeout face; and KIT ...... $345.95, A 8 T ...... $425.95 . voke a command or push a key and superscript/subscript positioning. In- 104 2 PARALLEL 2 SERIAL PCBD ...... $32.95 KIT ...... $155.95. A 8 T ...... $194.95 have nothing visible happen. At the stead of having to remember the PB-1 2708.2716 PROGRAMMER BOARD. very least, a message is posted ex- properties of characters, the current KIT ...... $135.95. A 8 T ...... S185.95 plaining that the command doesn't settings of those properties, and, APPLE PROOUCTS AIO SERIAUPARALLEL INTERFACE. work in this context, or it is not im- worst of all, how to change those KIT...... $125.95. A 8 T ...... S155.95 plemented, or there is an error. It is properties, property sheets simply AS10 SERIAL 110 disastrous to the user's model when show everything on the screen. All I KIT . . $87.95, AdT ...... S97.95 APIO PARALLEL 10 W/O CABLES you invoke an action and the system the options are presented. To change I KIT...... $67.95 A 8 T...... $87.95 does nothing in response. We have one, you point to it with the mouse seen people push a key several times and push a button. Properties in ef- BOAROS WlTH HlKO8 PARTS in one system or another trying to get fect are displayed in reverse video. MEI-3 32K STATIC RAM. PCBD...... $36.95 a response. They are not sure whether This mechanism is used for all KIT LESS RAM...... $95.95. A 8 T...... $135.95 the system has 'heard" them or not. properties of all objects in the system. CPU-2 Z80 PROCESSOR. PCBO...... $32.95 KIT LESS ROM...... $109.95. A 8 T...... $149.95 Sometimes the system is simply Star contains a couple of hundred Ell-2 16K132K EPROM. PCBO...... $32.95 throwing away their keystrokes. properties. To keep you from being KIT LESS ROM...... $65.95, A 8 T...... $99.95 Sometimes it is just slow and is queu- overwhelmed with information, FPE-1FRONT PANEL PCBD ...... $48.50 ing the keystrokes; you can imagine property sheets display only the KIT ...... $144.95, A 8 T ...... $184.95 the unpredictable behavior that is properties relevant to the type of ob- OMB-12 13 SLOT MOTHER BOARD. PCBO...... $39.95 KIT...... $95.95. A8 T...... ,. ..$135.95 possible. ject currently selected (e.g., ...... We have already mentioned icons character, paragraph, page, graphic and windows as mechanisms for line, formula element, frame, docu- making the concepts in Star visible. ment, or folder). This is an example MONDAY-FRIDAY.~OKO~ 8:W TO 12:W. 1 :00 TO 530 Other such mechanisms are Star's of "progressive disclosure": hiding THURSDAYS. 8:00 TO 9:~P.M. (415) 728-9121 property and option sheets. Most ob- complexity until it is needed. It is also P.O. BOX 955 EL GRANADA, CA 94018 jects in Star have properties. A prop- one of the clearest examples of how PLEASE SEN0 FOR IC XiSTOR AND COMPUTER PARTS LlSl VISA u MASTERCHARGE Send amount Mlbn. mledra* number. erty sheet is a two-dimensional, form- an emphasis on visibility can reduce exporatm date and s~pnyar or& Wax postape wll be &&a like environment that displays those the amount of remembering and typ- mt a I- custom, plskca use chaw, &sks mhor.p~ta~ maay or& Omsmiw Umml be a wwwLWay lor mksto properties, Figure 3 shows the ing required. deaf. CaW rasldanls add 6% tu Uonv back 30-day ouarantee We canm~amp1 r~uw lC's that have bwnwadto mces~t10 character property sheet. It appears Property sheets may be thought of chaw wlhart mllce $20.00 BIIIDIBoh $2 00 unb chqrlr on Ir*n Itu Yu ItO.00. on the screen whenever you make a as an alternate representation for ob- Circle 56 on inquiry ca

:N TIRE DOCL

200 cps bidirectional printing 50 cps proportional mode Enhanced/ emphasized print Dot-addressable graphics Tractor/friction feed up to 16" Program-selectable character size Microline Printers

NEC Printers Figure 4: The option sheet for the Find command showing both the Search and NEC PC-8023A-C ...... ,... uw Substitute options. The last two lines of options appear only when CHANGE IT is Epson Prinfers turned on. MX-80 ~/GRAFTRAX...... $474= UX-80/F-T...... $56988 jects. ~h~ screen shows you the ,,isi- WYSIWYG is a simplifying tech- MX-80/F-T ~/GRAFTRAX...... $619= MX-lOO ...... ; 9719m ble characteristics of objects, such as nique for documentcreation systems. GRA~...... $8~ the type font of text characters or the All composition is done on the names of icons. Property sheets show screen. It eliminates the iterations Centronics Prinks you the underlying structure of ob- that plague users of document com- jects as they 'make this structure visi- pilers. You can examine the ap- CENTRONICS739 (Parallel) ...... $53F ble and accessible. pearance of a page on the screen and CENTRONICS739 (RS-232-C) ...... $Wm 2-Color Adapter...... $6988 Invisibility also plagues the com- make changes until it looks right. The mands in some systems. Commands printed page will look the same (see C./to h Printers often have several arguments and op- figure 5). Anyone who has used a tions that you must remember with document compiler or post-processor C.lToH I ...... 5284a no assistance from the system. Star knows how valuable WYSIWYG is. CATOHPRO WRITER w/3K buffer addresses this problem with option The first powerful WYSIWYG editor . (parallel and serial) ...... $63F C.ITOHF-10 DNSYWHEEL sheets (see figure 4), a twodimen- was , an experimental editor (40cps)...... $1564= sional, form-like environment that developed for Alto at the Xerox Palo cables and interfacesavailable for displays the arguments to commands. Alto Research Center (see reference Apple, Atari, CBM/PET, and TRS-80 It serves the same function for com- 12). The text-editor aspects of Star microcomputers mand arguments that property sheets were derived from Bravo. Orders & Information: do for object properties. Trade-offs are involved in WYSIWYG editors, chiefly having to CALL (603)-673-8857 What You See Is What You Get do with the lower resolution of Orders Only: CALL (800)-343-0726 'What you see is what you get" (or display screens. It is never possible to , I WYSIWYG) refers to the situation in get., an exact representation of a We Occept surcharge credit which the display screen portrays an printed page on the screen since most cards-No charge for UPS shipping Stock shipments next day-All equip- accurate rendition of the printed screens have only 50 to 100 dots per ment factory fresh w/MFG warranty page. In systems having such inch (72 in Star), while most printers

MCW rvbied M &go capabilities as multiple fonts and have higher resolution. 'Completely HIGH TECHNOLOGYAT AFFORDABLE PRICES variable line spacing, WYSIWYG re- accurate character positioning is not quires a bit-mapped display because possible. Nor is it usually possible to HE BOTTOM only that has sufficient graphic power represent shape differences for fonts I to render those characteristics ac- smaller than eight points in size since 12 Johnson Street, Milford WH a055 cur at el^. there are too few dots per character to i 8010 Star Information System 1 IS 0 User-Interf ace Design To niake it easy to compose text and graphics, to do electronic filing. printing, arid mailing . 311 at the same wurkst.3tion, require? a rel.rolutionary n;:e r-inte dace de;:ign, 50

Bit-mctp di..~n~x.y- E:adi of the 827,3!32 dn ts 1111 the scree11is rn:arll:lect to a bit in meritor::; thus, arbitrarily complb:.: im:ages be diq11:q;eti. STAR displq!:s all f~~ritsarid gr:aphics as tiley t rill .bprinted, In :ad~:iitiori,familiar office obje~::ts such as do~::uments, f alders, file 0 drwx-ers and in-baskets are portrayed as rel::og~izzil:~leim:ages, Frle rrt.ows - A unicjue pointing del.rice that: shorterpror~,lction nUes allo\x*.s the user to quickly select aryj text, - * IS pr:.3~1:lhicIS or office 1:1]1j!jel:ltor1 ~lediq11~!{, . E:,~erience :at Kero:.: with protot;,q~e work- stratio 11s &I:I--~.~~ sli13rte r productin n tim as See and Point :allti 1~1wer cc~sts, me fl:~llo.~x~-irigeqnatio n All Star functi~:~-nsare 1.risible to ~leuser on e:.qIresses tklis,$ the keyb~:~ardor on tkle sc.reen, ?he user does filing and retriel~al k!; ~1e"irig tk~em\xv*ith #XI&<: I C a die mouse and tou&ing tlie ,.~OVE,, CQPY, c',y'lI '. ...' - 11:13 .4;cy DELETE or FPr:rPERTIE5 c~~mrnaridkeys, Text + n and graphics are edited yvitli the same keys, :LT J i= 1 Star users :are likely to do more 13f their ow11 composition :and layout, controlling the entire process including printing and distrik~ution. Text and Graphics

11f off ice objects TI] replace t;,yese tting, Star offers :a I:J~I:I~I::E: t;,qje f~:~ntsand sizes, from 8 pl:~irlt to 24 point,

H+_rr is i sent+n-~c.f8y:ht t&. H-MY :1:. '-.. 4 ...Ielt~e:c l:,f 10 -pl&t text.,

,MOUSE: select Here is :x zerlte~lceof 12-point te:.:t. obiects- menus Heye i.3 a senter-18::e ~::,f 14-1:,oint te:.!:t.

ICWBQ411D. -c Here is a sentence of 18-point myccw text.

lgure 5: A Star document showing multicolumn text, graphics, and formulas. This is the way the document appears on the screen. It also the way it will print (at higher resolution, of course).

266 AprU 1982 0 BYTE F'ubUcatiom lnc Circle 140 on Inquiry card. be recognizable. Even 10-point ("nor- (HELP and UNDO don't use a selec- pie, clear theories, progress in the mal" size) fonts may be uncomfort- tion.) Each generic command has a usability of computers is coming to ably small on the screen, necessitating key devoted to it on the keyboard. depend on simple, clear user inter- a magnified mode for viewing text. These commands are far more faces. WYSIWYG requires very careful basic than the commands in other MOVE is the most powerful com- design of the screen fonts in order to computer systems. They strip away mand in the system. It is used during keep text on the screen readable and the extraneous application-specific text editing to rearrange letters in a attractive. Nevertheless, the increase semantics to get at the underlying word, words in a sentence, sentences in productivity made possible by principles. Star's generic commands in a paragraph, and paragraphs in a WYSIWYG editors more than derive from fundamental computer- document. It is used during graphics

a outweighs these difficulties. science concepts because they also editing to move picture elements, underlie operations in programming such as lines and rectangles, around Universal Commands languages. For example, much pro- in an illustration. It is used during Star has a few commands that can gram manipulation of data structures formula editing to move mathemati- be used throughout the system: involves moving or copying values cal structures, such as summations MOVE, COPY, DELETE, SHOW from one data structure to another. and integrals, around in an equation. PROPERTIES, COPY PROPERTIES, Since Star's generic commands em- It replaces the conventional "store AGAIN, UNDO, and HELP. Each body fundamental underlying con- file" and "retrieve file" commands; performs the same way regardless of cepts, they are widely applicable. you simply move an icon into or out the type of object selected. Thus, we Each command fills a variety of of a file drawer or folder. It eliminates call them "universal" or "generic" needs, meaning fewer commands are the "send mail" and "receive mail" commands. For example, you follow required. This simplicity is desirable commands; you move an icon to an the same set of actions to move text in in itself, but it has another subtle ad- out-basket or from an in-basket. It a document and to move a line in an vantage: it makes it easy for users to replaces the ''print" command; you . illustration or a document in a folder: form a model of the system. People move an icon to a printer. And so select the object, push the MOVE can use what they understand. Just as on. MOVE strips away much of the key, and indicate a destination. progress in science derives from sim- historical clutter of computer com- mands. It is more fundamental than the myriad of commands it replaces. It is simultaneously more powerful BYTEWRITER and simpler. Much simplification comes from DAISY WHEEL PRINTER Star's object-oriented interface. The LETTER QUALITY PRINTER AND TYPEWRITER action of setting properties also re- IN ONE PACKAGE places a myriad of commands. For ex- The BYTEWRITER is a new Olivetti Praxis 30 electronic typewriter with a micro-processorcontrolled driver added internally. ample, changing paragraph margins is a command in many systems. In Star, you do it by selecting a paragraph object and setting its L MARGINS property. (For more in- formation on object-oriented lan- A I guages, see the August 1981 BYTE.) $795 Consistency plus shipping Consistency asserts that mecha- Dealer nisms should be used in the same way Inquiries Invited wherever they occur. For example, if FEATURES the left is used to select Underlining 10, 12, or 15 characters per inch switch selectable 2nd keyboard with foreign grammar symbols switch selectable Changeable type daisy wheel a character, the same button should Centronics-compatible parallel input operates with TRS-80, Ap le, Osborne, IBM be used to select a graphic line or an and others Cartrid e rlbbon Typewriter operation with not&ng to disconnect Service from any 0fivetti dealer Self test program built in. icon. Everyone agrees that consisten- cy is an admirable goal. However, it is perhaps the single hardest BYTEWRITER characteristic of all to achieve in a 1 25 NORTHVIEW RD.. ITHACA, N.Y. 14850 computer system. In fact, in systems (607)272- 1 132 of even moderate' complexity, con- Praxis .70 Is a tmdemark of Ollvettl Corp TRS-80 is a tmdemark of Tandy Corp. sistency may not be well defined. BYTEWRITER is a trademark ofWilliams Laboratories A question that has defied consen-

mr Apd 1982 O BY232 Publiutio~lnc Clrcle 70 on inquiry card. Clrcle 294 on inquiry card. ' - t p.4; . -. r,, I t. ., r i I2 T ' .. sus in Star is what should happen to a are supposed to behave similarly to a document, gets it just right, prints document after it has been printed. their physical counterparts. It makes it, and finds that it has disappeared, Recall that a user prints a document sense that icons are deleted after they that person is going to become very by selecting its icon, invoking are mailed because after you put a nervous, not to mention angry. We MOVE, and designating a printer piece of paper in a physical out- also decided to put it back where it icon. The printer absorbs the docu- basket and the mailperson picks it up, came from (2a instead of 2b or 2c) for ment, queuing it for printing. What it is gone. However, the physical the pragmatic reason that this in- happens to that document icon after analogue for printers is the office volves slightly less wqrk on the user's printing is completed? The two copier, and there is no notion of part. plausible alternatives are: deleting a piece of paper when you 3. Seriousness-When you file or make a copy of it. Function icons mail an icon, it is not deleted entirely 1. The system deletes the icon. should behave consistently with their from the system. It still exists in the 2. The system does not delete the physical counterparts. file drawer or in the recipients' in-bas- icon, which leads to several further There is no one right answer here. kets. If you want it back, you can alternatives: Both arguments emphasize a dimen- move it back out of the file drawer or 2a. The system puts the icon back sion of consistency. In this case, the send a message to one of the recip- where it came from (i.e., where it dimensions happen ta overlap. We ients asking to have a copy sent back. was before MOVE was invoked). eventually chose alternative 2a for Deleting after printing, however, is 2b. The system puts the icon at an the following reasons: final; if you move a document to a arbitrary spot on the Desktop. printer and the printer deletes it, that 2c. The system leaves the icon in 1. Model dominance-The physi- document is gone for good. the printer. You must move it out cal metaphor is the stronger model at One way to get consistency into a of the printer explicitly. the Desktop level. Analogy with system is to adhere to paradigms for physical counterparts does form the operations. By applying a successful The consistency argument for the basis for people's understanding of way of working in one area to other first alternative goes as follows: when what icons are and how they behave. areas, a system acquires a unity that you move an icon to an out-basket, Argument 1 advocates an implicit is both apparent and real. Paradigms the system mails it and then deletes it model that must be learned; argu- that Star uses are: from your Desktop. When you move ment 2 advocates an explicit model an icon to a file drawer, the system that people already have when they @Editing-Much of what you do in files it and then deletes it from your are introduced to the system. Since Star can be thought of as editing, In Desktop. Therefore, when you move people do use their existing knowl- addition to the conventional text, an icon to a printer, the system edge when confronted with new sit- graphics, and formula editing, you should print it and then delete it from uations, the design of the system manage your files by editing filing your Desktop. Function icons should should be based on that knowledge. windows. You arrange your working behave consistently with one This is especially important if people environment by editing your Desk- another. are to be able to intuit new uses for top. You alter properties by editing The consistency argument for the the features they have learned. property sheets. Even programming second alternative is: the user's con- 2. Pragmatics-It is dangerous to can be thought of as editing data ceptual model at the Desktop level is delete things when users don't expect structures (see reference 16). the physical-office metaphor. Icons it. The first time a person labors over .Information retrieval-A lot of

I I The HOMEBRAINTMis a ded- WE HOME BRA1NTM 1s EVALUATETHEHOMEBRAIN"" icated microcomputer system in a Order NOW BY CaMng TOM-~mr stand-alone package. HOME- the First Total Home i.eoe22a.202e EXT. 332 BRAIN'S'" 110 potential exceeds Control Computer Lines Open 8 AM TO 6 PM C.S.T. 300 channels. Communicate w~th Me HOMEBRAIN " Just give us your Name, Shipping. Address uslng ywr personal computer RS232 Inter- and Visa or Mastercard number and we face will charge the $750.00 purchase prlce, ACHIEVE TOTAL HOMEBRAIN " controls your home using plus $20.00 shlpp~ng(N.J. residents add nu232 your define lcglc sequences 5% sales tax to your account. Or, SEND* HOME CONTROL your qHHECd* or MONEY ORDER* to. A - 32 Channels Log~cd~agrams. tlmers, counters, alarm Buffered Input clocks, calendars, are directly implemented HYPERTEK, INC Energy Management B -8 Relay Output by the HOMEBRAIN microprocessor 30-4 FARM ROAD Home Security C -Un~nterruptable HOMEBRAIN rn logs controlled operating SOMERVILLE, NEW JERSEY 08876 Lighting Control Power Supply tlmes for the month -CPU,tlOnss Cornrnun'ca-256 Channel The HOMEBRAlNn operates totally ~nde- ^Send~ngyour chack wll qual~fyyou for an Safety Monitoring pendent of your personal com uter Crashlng lNTRODUCTORY REBATE of AC Wireless con- prcomputer w~notcrash H~MEBRAINm Appliance Control trot eaving your home defenseles~ Allow 6.8 weeks for delivery

270 April 1982 O BYEPublications Inc Figure 6: The keyboard-interpretation window serves as the source of characters that may be entered from the keyboard. The character set shown here contains a variety of office symbols.

power can be gained by applying in- ous domains of star, you create by Graphics are created by copying formatipn-retrieval techniques to in- copying. Creating something out of existing graphic images and modify- formation wherever it exists in a sys- nothing is a difficult task. Everyone ing them. In a sense, you can even tem. Star broadens the definition of has observed that it is easier to type characters in Star's 216-character "database." In addition to the tradi- modify an e~istjngdocument or pro- set by "copying" them from keyboard tional notion as represented by its gram than to write it originally. windows (see figure 6). record files, Star views file drawers as Picasso once said, 'The most awful databases of documents, in-baskets as thing for a painter is the white can- These paradigms change the very databases of mail, etc. This teaches' vas . . . To copy others is nec- way you think. They lead to new users to think of information retrieval essary." (See reference 20.) Star habits and models of behavior that as a general tool applicable through- makes a serious attempt to alleyiate are more powerful and productive. out the system. the problem of the "white canvas" by They can lead to a human-machine copying-star elevates the concept making copying a practical aid to synergism. of "copying" to a high level: that of a creation. For example, you create Star obtains additional consistency paradigm for creating. In all the vari- new icons by copying existing ones. by using the class and subclass no-

BASF-DPS

DATA TRAC C-10 G20 BLANK COMPUTER CASSETTES UNIVERSAL INDUSTRY ACCEPTANCE MONEY BACK GUARANTEE LENGTH 1 DOZEN 2 DOZEN s-4s----- 5rn---153-~Q, C-20 10.00 18.00 Shipping: 1 doz. $2. 2doz. $3.50 addt'l. doz.. $1 Calif residents add 6% sales tax

Circk$444 on i&ry card. C~rcle238 on lnqulry card. Circle 80 on inquiry card.

AdlM 5 BnEPuBHcat~ons lnc tions of Simula (see reference 4) and distinctions that occur in some sys- with than intricate ones. I %Iff:..--.*. (see reference 11). The tems. Another way to achieve simplicity clearest example of this is classifying is to minimize the redundancy b a icons at a higher level into data icons Simplicity system. Having two or more ways to and function icons. Data icons repre- Simplicity is another principle with do something increases the complexi- sent objects on which actions are per- which no one can disagree. Obvious- ty without increasing the capabilities. formed. Currently, the three types ly, a simple system is better than a The ideal system would have a mini- (i.e., subclasses) of data icons are complicated one if they have the same mum of powerful commands that ob- documents, folders, and record files. capabilities. Unfortunately, the world tained all the desired functionality Function icons represent objects that is never as simple as that. Typically, a and that did not overlap. That was perform actions. Function icons are trade-off exists between easy novice the motivation for Star's "generic" of many types, with more being use and efficient expert use. The two commands. But again the world is not added as the system evolves: file goals are not always compatible. In so simple. General mechanisms are drawers, in- and out-baskets, Star, we have tried to follow Alan often inconvenient for high-frequen- printers, floppy-disk drives, calcula- Kay's maxim: "simple things should cy actions. For example, the SHOW r tors, terminal emulators, etc. be simple; complex things should be PROPERTIES command is Star's gen- In general, anything that can be possible." To do this, it was some- eral mechanism for changing prop- b,, done to one data icon can be done to times necessary to make common erties, but it is too much of an inter- 9 all, regardless of its type, size, or things simple at the expense of un- ruption during typing. Therefore, we location. All data icons can be common things being harder. Sim- added keys to optimize the changing 'a moved, copied, deleted, filed, mailed, plicity, like consistency, is not a of certain character properties: (ji printed, opened, closed, and a variety clear-cut principle. BOLD, ITALICS, UNDERLINE, P of other operations applied. Most One way to make a system appear SUPERSCRIPT, SUBSCRIPT, C function icons will accept any data simple is to make it uniform and con- LARGER/SMALLER (font), . I ., icon; for example, you can move any sistent, as we discussed earlier. CENTER (paragraph). These signifi- data icon to an out-basket. This use Adhering to those principles leads to cantly speed up typing, but they don't iJot; the class concept in the user-inter- a simple user's model. Simple models add any new functionality. In this fa'ce design reduces the artificial are easier to understand and work case, wq felt the trade-off was worth

f \ DlSCOU NT TRS-80@ Computers We have the Largest Inventory in the Central United States. Discount prices on all software and accessories for 'your TRS-80 computer needs. I Model II BUY DIRECT Toll Free Order: * No out of state Taxes 1-800-835-9056 * Immediate Shipment Severcil Payment Methods Kansas Residents: * 1-800-362-9091 * ~irectBuying I 8 Megabyte Hard- Disk (Primary) Jimscot, Inc. 26-4 150. WRITE TODAY FOR YOUR P.O. Box 607 - 1023 N. Kansas FREE CATALOG! '39940° Liberal, Ks. 67901 TRS-80 is a Registered Trademark of Tandy Corporation it because typing is a frequent activi- In fact, we prototyped and tested six Bravo. In Bravo, the main typing ty. 'Minimum redundancy" is a good different semantics for the mouse but- keys are normally interpreted as com- but not absolute guideline. tons: one one-button, four two- mands. The "i" key invokes the Insert In general, it is better to introduce button, and a three-button design. command, which puts the system in new general mechanisms by which We were chagrined to'find that while "insert mode." In insert mode, Bravo "experts" can obtain accelerators some were better than others, none of interprets keystrgkes as letters. he rather than add a lot of special one- them was completely easy to use, story goes that a person intendec! to purpose-only features. Star's mecha- even thsugh, a priori, it seemed like type the word "edit" into his docu- nisms are discussed below under all of them would work! We then ment, but he forgot to enter insert 'User Tailorability." took the most successful features of mode first. Bravq' interpreted "edit" Another way to have the system as two of the two-button designs anh as the following commands: a whole appear simple is to make prototyped and tested them as a each of its parts simple. In particular, seventh design. To our relief, it not E(verything) select everything in the system should avoid overloading only tested better than any of the the document the semantics of the parts. Each part other six, everyone found it simple D(e1ete) delete it should be kept conceptually clean. and trouble-free ts use. I (nsert) enter insert mode Sometimes, this may involve a major This story has a couple of morals: t type a "t" redesign of the user interface. An ex- ample from Star is the mouse, which .The intuition of designers is error- The entire contents of the document has been used on the Alto for eight prone, no matter how good or bad were replaced $y the letter "t." This years. Before that, it was qsed on the they are. makes the point, perhaps too strong- NLS system at Stanford Research Inr .The critical parts of a system should ly, that modes should be introduced stitute (see reference 5). All of those be tested on representative users, into a user interface with caution, if mice have three buttons on top. Star preferably of the "lowest common at all. has only two. qydid we depart denominator" type. Commands in Star take the foqn of from "tradition"? We observed that owhat is simplest along any one noun-verb. You specify the object sf the dozens of Alto programs all had dimension (e.g., number of buttons) interest (the noun) and then invoke a different semantics for the mouse but- is not necessarily conceptually command to manipulate it (the verb). tons. Some used them one way, some simplest for users; in particular, Specifying an object is called "making another. There was no consistency minimizing the number of keystrokes a selection." Star provides powerful between systems. Sometimes, there may not make a system easier to use. selection mechanisms that reduce the was not even consistency within a number and complexity of commands system. For example, Bravo uses the Modeless Interaction in the system. Typically, you will ex- mouse , buttonss for selecting text, defines a mode as ercise more dexterity and judgment in scrolling windows, and creating and follows: making a selection than in invoking a deleting windows, depending on command. The object (noun) is where the cursor is when you push a A mode of an interactive computer almost always specified before: the ac- mouse button. Each of the three but- system is a state of the user interface tion (verb) to be performed. This tons has its own meaning in eqch of that lasts for a period of time, is not helps make the command interface the different regions. It is difficult to associated with any particular object, modeless; you can change your mind remember which button dies what and has no role other than to place an as to which object to affect simply by interpretation on operator input. where. (See reference 18.) making a new selection before invok- Thus, we decided to simplify the ing the command. No "accept" func- mouse for Star. Since it is apparently Many computer systems use modes tion is needed to terminate or confirm quite a temptation to ~verlgadthe because there are too few keys on the commands since invoking the com- semantics 'of the buttoqa, we keyboard to represent all the avail- mand is the last step. Inserting text eliminated temptation by eliminating able commands. Therefore, the inter- does not even require a command; buttons. Well then, khy didn't we use pretation of the keys depends on the you simply make a selection and a one-button mouse? Here the plot mode or state the system is in. Modes begin typing. The text is placed after thickens. We did consider and pro- can and do cause trouble by making the end of the selection. totype a one-button mouge interface. habitual actions cause unexpected The noun-verb command form One button is sufficient (with a little results. If you do not notice what does not by itself imply that a com- cleverness) to provide all the func- mode the system is in, you may find mand interface is modeless. Bravo tionality needed in a pouse. But yourself invoking a sequence of com- also uses the noun-verb form; yet, it when we tested the interfacg on naive mands quite different from what you is a highly modal editor (although the users, as we did with 9 variety of had intended. latest version of Bravo has drastically featpres, we found that they had a lot Our favorite story about modes, reduced its modalness). The dif- of trouble making selectiqns with it. probably apocryphal, involves ference is that Bravo tries to make Actual Size ft$$+?+

Double Size f 828 Normal Move COPY Copy Properties Menu Illegal Graphics mode mode mode selecting dest~nation Ei Figure I: Some of the cursor shapes wed by the Star to indicate the state of the system. The cursor is a 16- by 16-bit map that can be changed under program control.

one mechanism (the main typing the cursor as an additional indication. another with it being 12-point keys) serve more than one function You can always tell the state of the Modern italic. The documents need (entering letters and invoking com- system by inspection (see figure 7). not be blank; they may contain fixed mands). This inevitably leads to con- Second, the allowable actions are text and graphics, and fields for vari- fusion. Star avoids the problem by constrained during modes. The only able fill-in. A typical form might be a having special keys on the keyboard action that is allowed-except for ac- business-letter form with address, ad- devoted solely to invoking functions. tions directly related to the mode-is dressee, salutation, and body fields, The main typing keys only enter scrolling to another part of the docu- each field with its own default text characters. (This is another example ment. This constraint makes it even style. Or it might be an accounting of the simplicity principle: avoid more apparent that the system is in an form with lines and tables. Or it overloading mechanisms with mean- unusual state. might be a mail form with To, From, ings. ) and Subject fields, and a heading Modes are not necessarily bad. User Tailorability tailored to each individual. Whatever Some modes can be helpful by simpli- No matter how general or powerful the form or document, you can put it fying the specification of extended a system is, it will never satisfy all its on your Desktop and make new in- commands. For example, Star uses a potential users. People always want stances of it by selecting it and invok- "field fill-in order specification ways to speed up often-performed ing COPY. Thus, each form can act mode." In this mode, you can specify operations. Yet, everyone is different. like a "pad of paper" from which new the order in which the NEXT key will The only solution is to design the sys- sheets can be "torn off." step through the fields in the docu- tem with provisions for user extensi- Interesting documents to set up are ment. Invoking the SET FILL-IN bility built in. The following mecha- "transfer sheets," documents contain- ORDER command puts the system in nisms are provided by Star: ing a variety of graphics symbols the mode. Each field you now select is tailored to different applications. For added to the fill-in order. You ter- *You can tailor the appearance of example, you might have a transfer minate the mode by pushing the your system in a variety of ways. The sheet containing buildings in different STOP key. Star also utilizes tem- simplest is to choose the icons you sizes and shapes, or one devoted to porary modes as part of the MOVE, want on your Desktop, thus tailoring furniture, animals, geometric shapes, COPY, and COPY PROPERTIES your working environment. At a flowchart symbols, circuit com- commands. For example, to move an more sophisticated level, a work sta- ponents, logos, or a hundred other object, you select it, push the MOVE tion can be purchased with or with- possibilities. Each sheet would make key that puts the system in "move out certain functions. For example, it easier to create a certain type of il- mode," and then select the destina- not everyone may want the equation lustration. Graphics experts could tion. These modes work for two rea- facility. Xerox calls this "product fac- even construct the symbols on the sons. First, they are visible. Star posts toring." sheets, so that users could create a message in ,the Message Area at the *You can set up blank documents high-quality illustrations without top of the screen indicating that a with text, paragraph, and page layout needing as much skill. mode is in effect. The message re- defaults. For example, you might set @Youcan tailor your filing system by mains there for the duration of the up one document with the normal changing the sort order in file drawers mode. Star also changes the shape of text font being 10-point Classic and and folders. You can also control the Circle 6 on inquiry car

filing hierarchy by putting folders in- side folders inside folders, to any desired level. I I *You can tailor your record files by defining any. number of "views" on them. Each view consists of a filter, a sort order, and a formatting docu- I I ment. A filter is a set of predicates that produces a subset of the record file. A formatting document is any locument that contains fields whose lames correspond to those in the ,ecord file. Records are always dis- )layed through some formatting locument; they have no inherent ex- ernal representation. Thus, you can et up- your- own individual subset(s) and appearance(s) for a record file, 3 1 even if the record file is shared by several users. You can define "meta operations" by writing programs in the Customer CUSP. For example, you can further tailor your forms by assigning computation rules expressed in CUSP to fields. Even- tually, you will be able to define your own commands by placing CUSP '%uttons" into documents. .You can define abbreviations for f commonly used terms by means of The Birth of UNJX"for CP/Mm! the abbreviation definitiodexpan- sion facility. For example, you might define "sdd as an abbreviation for "Xerox Systems Development De- The ... partment." The expansion can be an .,,,, ,u, ,, entire paragraph, or even multiple aPOPULARITY OF paragraphs. This is handy if you create documents out of predefined Available for adoption by: CP/M SOFTWARE DEVELOPERS "boilerplate" paragraphs, as the legal CP/M SOFTWARE USERS I I profession does. The expansion can even be an illustration or mathe- matical formula. .Every user has a unique name used for identification to the system, usually the user's full name. How- ever, you can define one or more aliases by which you are willing to be known, such as your last name only, a shortened form of your name, or a nickname. This lets you personalize your identification to the rest of the network.

CP~Y22132~ w,tn 80801w&lZBOCPU RHlu#raa Mall or Phone Adoption Requests to' Summary *ADOPTION FEE: $150.00 NEW 2153 Golf Course Drive In the 1980s, the most important Manual Only: $ 25.00 Reston. VA 22091 (VA residents add 4% aales tax) (703)47&9143 factors affecting how prevalent com-

VISA, MC, Check or Money Order SYSTEMS* inc* CPIM - TM 01 ~4911.1 R-I* ~orp puter usage becomes will be reduced UNlX - TM 018.11 TehehOm Labs

280 ~pd1982 0 BYTE Publications lnc Clrcie 299 on Inquiry card. cost, increased functionality, im- 8. Ingalls, Daniel. in he Smalltalk Graphics Uew proved availability and servicing, Kernel." BYTE, August 1981, pp. and, perhaps most important of all, 168-194. 9. Intel, Digital Equipment, and Xerox Cor- progress in user-interface design. The porations. The Ethernet, A Local Area first three alone are necessary, but Network: Data Link Layer and Physical not sufficient for widespread use. Re- Layer Specifications. Version 1.O, 1980. duced cost will allow people to buy 10. lrby, Charles, Linda Bergsteinsson, computers, but improved user inter- Thomas Moran. William Newman, and Larry Tesler. A Methodology for User In- Mordlndex llTM$195 faces will allow people to use com- terface Design. Systems Development utomatic generation of subject index puters. In this article, we have pre- Division, Xerox Corporation, January nd tables of contents, figures, etc. sented some principles and techniques 1977. Wordlndex commands placed in any docu- that we hope will lead to better user 11. Kay, Alan and the Learning Research ment produced by wordstarTM automati- Group. Personal Dynamic Media. Xerox cally number chapters and L? levels of sec- interfaces. tions; create tables of contents, figures, and Palo Alto Research Center Technical tables, and a sorted subject index with User-interface design is still an art, Report SSL-76-1, 1976. (A condensed page references. not a science. Many times during the version is in IEEE Computer, March

Star design we were amazed at % the 1977, pp. 31-41.) depth and subtlety of user-interface 12. Lampson, Butler. "Bravo Manual." Alto Multiple files. Wordlndex II supports the issues, even such supposedly straight- User's Handbook, Xerox Palo Alto Re- search Center, 1976 and 1978. (Much of wordStarTM .f1 dot command: forward issues as consistency and Free choice of page number format. the design of all the implementation of Multiple choice of layout of all tables. simplicity. Often there is no one Bravo was done by and No limit on size of subject index. "right" answer. Much of the time the skilled programmers in his "software Automatic generation of headings and there is no scientific evidence to sup- factory.") footings. port one alternative over another, 13. Metcalfe, Robert and . Alternating page offset for even and odd "Ethernet:. Distributed Packet Switching pages slmplif~esprinting procedures. just intuition. Almost always there for Local Computer Networks." Com- SWM.QFaeR for owners of all previous are trade-offs. Perhaps by the end of munications of the ACM, vol. 19, no. 7, versions of Wordlndex. return your original 1976, pp. 395-404. Wordlndex diskette dlrectly to us and re- the decade, user-interface design wjll celve Wordlndex II at a nominal cost of $50. be a more rigorous process. We hope 14. Miller, George. "The Magical Number that we have contributed to that pro- Seven, Plus or Minus Two: Some Limits on Our Capacity for Processing Informa- gress. m tion." In The Psychology of Communica- tion, by G. Miller, New York: Basic Books, I Previously available on minls and main- 1967. (An earlier version appeared in frames only. I References Psychology Review, vol. 63, no. 2, 1956, Supplled with the original ~ektronix~~ 1. Arnheim, Rudolf. Visual Thinking. pp. 81.97. documentation, MicroPlot fully mplements Berkeley: University of California Press, 15:Seybold, Jonathan. "Xerox's 'Star'." In the entire Tektronlx Terminal Control Sys- tem on your 80801280 based microcompu- 1971. The Seybold Report, Media, PA: Seybold ter at a fractlon of the or~glnalcod 2. Brooks, Frederick. The Mythical Man- Publications, vol. 10, no. 16. 1981. This package enables you to run even Month. Reading, MA: Addison-Wesley, 16. Smith, David Canfield. Pygmalion, A mainframe-developed software for the 1975. Computer Program to Model and Stimu- Plot-10 TCS on your microcomputer using 3. Card, Stuart, William English, and Betty late Creative Thought. Basel, Switzer- Tektronix compatible peripherals. Burr. "Evaluation of Mouse, Rate- land: Birkhauser Verlag, 1977. Microplot is supplled as ~icrosoft~~.RE1 files to be used with ~ortran-'80TM. Controlled Isometric Joystick, Step Keys, 17. Smith, David Canfield, Charles Irby, and Text Keys for Text Selection on a Ralph Kimball, and Eric Harslem. "The CRT." Ergonomics, vol. 21, no. 8, 1978, Star User Interface: An Overview." Sub- - MenuMaslerm $95 pp. 601 -613. mitted to the AFlPS 1982 National COm- Stoo messina around with CP/M ' commands. fienu~astermakes all 4. Dahl, Ole-Johan and Kristen Nygaard. puter Conference. your software~menudriven. "SIMULA-An Algol-Based Simulation 18. Tesler, Larry. Private communication; but Slmply create your own menus directly Language." Communications of the also see his excellent discussion of on-screen using any text editor. The menu ACM, vol. 9, no. 9, 1966, pp. 671-678. modes in "The Smalltalk Environment." dispenses of long and hard-to-remember 5. Engelbart, Douglas and Willlam English. BYTE, August 1981, pp. 90-147. CP/M~"commands. The user may simply select programs from the menu using sim- "A Research Center for Augmenting 19. Thacker, C. P., E. M. McCreight, B. W. ple commands of his own choice. Human Intellect." Proceedings of the Lampson, R. F. Sproull, and D. R. Boggs. AFlPS 1968 Fall Joint Computer Con- "Alto: A Personal Computer." In Com- Order your copy today directly from us by phone, telex, or mail. Please send cashier's ference, vol. 33. 1968, pp. 395-410. puter Structures: Principles and Ex- check or state Visa or Master Charge ac- 6. English, William, Douglas Engelhaft, and amples, edited by D. Siewiorek, C. G. count no. M. L. Berman. "Display-Select~onTech- Bell, and A. Newell, New York: McGraw- Detailed descriptlons may be requested at niques for Text Manipulation." IEEE Hill, 1982. no cost. Just circle reader service. Dealers Transactions on Human Factors in Elec- 20. Wertenbaker, Lael. The World of, may apply for free demo-vers~onsof all programs. tronics, vol. HFE-8, no. 1, 1967, pp. Picasso. New York: Time-Life Books. 21-31. 1967. 7. Fitts, P. M. "The Information capacity of 21. Zloof, M. M. "Query-by-Example." Pro- the Human Motor System in Controlling ceedings of the AFlPS 1975 National Dun Laoghaire Amplitude of Movement." Journal of Ex- Computer Conference, vol. 44, 1975, p~ Dublin. ReDuhlic of Ireland perimental Psycholonv vol. 47, 1954, pp. 431-438. Phone 1802514. Telex 25105 GSOP 381-391. ATTN. BORLAND J<, t.::- ;