CS789, Spring 2005, Lecture notes, Week 11

>CS789, Spring 2005

Lecture notes, Week 11

Scalable Interfaces

What happens when we look outside at the same set of objects

The same set of objects, different views
Perception problems solved in different ways

What happens when we want to call somebody back

The same goal, different affordances
Action problems solved in different ways

What happens when we want to find where a meeting is

Ideally we see the meeting, not the device
It's the same meeting seen through different views

How do we do this? Obvious answers.

How do we deal with differing input and output capabilities? Not so obvious answers


Documentation is an extrememly important part of the user interface, usually the first part of the interface with which the user interacts, and if the user gives up on a program it is often the last thing with which he or she interacted.

Documentation comes in four types:

  1. Tutorial,
  2. Integrated assistance,
  3. Error message, and
  4. Reference.

In what follows we will notice that rules and principles are very different from each of them. For example, who reads it?

  1. Tutorial: a user who has little or no operational experience with the interface, but who may have extensive experience with programs of similar type, and may not, of course.
  2. Integrated assistance: a user who may or may not want it,
  3. Error message: a user who has over-stepped his or her assumed expertise, but may just have typed incorrectly.
  4. Reference: a user who has some level of operational experience with the interface, but may still be inexperienced with similar programs, or even with the computer in general.

And how are problems like this usually solved:

  1. Tutorial. There are actually two tutorials, an implicit one in the "quick start" installations, and a real one that is expected to be done after the user has gone through the naive installation. How is this peculiar? Quick start is usually designed for the knowledgeable user who wants to get right down to work; the real tutorial can only be started once an installation has been performed. Who do you have to be in order to do the non-quick installation?
  2. Error message. These are optional reading. How do we make them so? Two levels: signs, and sentences. These tend to be shaded into reference.
  3. Reference. We try to provide lots of re-entry to the tutorial for users who have gotten beyond their expertise. This stuff, of course, also allows the user to measure his or her expertise, and the confidence provided by seeing a pointer and knowing "I don't have to follow that one." is worth something. But not if it's unjustified by actual knowledge. And it can go the other way. You don't want a user thinking "What kind of an idiot do they think I am?"

Remember. Almost all documentation was written to describe an obsolete version of the program!

1. How is documentation read?

Different documentation is read different amounts.

Which requires its subject to be slowly evolving? Which can tolerate fast evolution?

You can expect that different users will read differently. Urgency is bound to be an issue here.

2. When is documentation read?

How do users find what they need?

3. How does documentation refer?

Types of reference:

How does the medium of documentation affect its referential qualities?

How does the type of the interface affect the referential qualities of documentation? For example, in a form "type in the traveller's name" clearly refers to something abstract, the name, of which a representation is being created in the form. Whether the user thinks that the representation is letters on a screen, letters on a keyboard, pixels on a display, bytes in a memory, doesn't matter much. But when documentation says "Drag the icon to the shredder", the concreteness of the reference is unpredictable. And the whole idea of the interface design is that different users can do the right thing even while thinking very different things about what they are doing.

4. How are we going to handle the cost of documentation?

What's the problem?

What are the solutions?

Do illustrations help? Illustrations are very expensive. Manufacturing cost will become unimportant as we go increasingly on-line. But preparation cost won't change. It may even get worse. Reference is the problem. We don't notice that there are very many different levels of abstraction. Which bird book makes bird identification easier for the novice

What is the most easily recognizable hand?

5. What is the most common substitute for documentation?

Models of technology spread.

6. Can interfaces be self-revealing?

"Self-revealing" is a buzz-word for self-documenting.

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