Central Working Surface

Examples:

A universal remote control, for a set of stereo or TV components
A Web browser window, with its assorted preferences dialogs, Find dialogs, etc.
A complex Web site's home page
Someone's desk, office, or workshop

Bad Examples:

Some Motif applications, designed to have an "application window" with practically nothing useful in it except a menu bar and a status area [did anyone actually like these?]

Context: The artifact is composed of multiple working surfaces, and is centered on one particular activity. This could happen in any genre.

Problem: How should the artifact's working surfaces be organized?

Forces:

The user should have one predictable place where most of their work with the artifact gets done.
If the artifact is complex, the user may get disoriented as they interact with its various working surfaces; they may then want a familiar "home base" to go to.
The user needs to know where to find the basic operations of the artifact, such as the existential or state-changing commands (see Convenient Environment Actions) or starting points for navigation; they shouldn't have to hunt for them across many working surfaces.

Solution: Create one working surface where the artifact's major functions are collected together; if most of the work can actually be done there, so much the better. Secondary functionality may be placed on secondary working surfaces, which can be easily reached from the central one and which allow the user to easily get back to the central one. Place the Convenient Environment Actions on this surface.

If you are revising the design of an artifact, find out if users spend a lot of their time going back and forth between two or three different surfaces instead of just one. If that's the case, consider consolidating these most-frequently-used areas into one working surface, or into Tiled Working Surfaces, or at least into a Stack of Working Surfaces; the idea is to minimize the amount of unnecessary back-and-forth the user has to do. (But don't do this if it ends up inhibiting their work, obviously.)

Resulting Context: The Central Working Surface could be the first thing the user sees upon starting to use the artifact, but not necessarily -- this may be better done by some other working surface, whose express purpose is to orient the new user and direct them towards one subpart or the other. This would be especially true with an artifact which supports multiple activities, which may even require multiple Central Working Surfaces to properly support those activities (and may thus give the impression of being two or more separate artifacts). Consider a multimedia reference book, in which one may either browse casually or do a directed search for certain information. Such an artifact may have two different "home bases" where work gets done -- one for browsing, one for searching.

Notes: This pattern is more analogous to an architectural space than most others in this language. It's meant to be like a workshop, an office, or a living room, and not so much a lobby or reception room -- you do stuff there, it's within easy reach of other places you want to go, etc.

The pattern relates to the concept of a "strong center" as formulated by Christopher Alexander in his upcoming work, The Nature of Order. The idea is that a strong center, surrounded and supported by a set of smaller centers (e.g. the secondary working surfaces), is a fundamental organizing principle that the human mind can easily grasp. Central Working Surface evokes this principle both in terms of transition states and visual representation.

Comments to: jtidwell@alum.mit.edu
Last modified May 17, 1999