10. From Desktops to Handhelds
EN: This book was published in 2002, so the information about mobile computing is very dated, and as mobile technology has evolved and continued to evolve, specific details may not be applicable.
The author acknowledges the limited capabilities of the mobile computing device (PDA and mobile phone), but suggests it will continue to grow and mature, and predicts that demand for mobile access to certain information and capabilities will increase.
Notably, he indicates that much of the Web is not usable, given the limitations of the device, and because the demand for portability will necessitate a small screen, it is doubtful mobile computing will ever be as usable as desktop computing - but there are a certain subset of activities that may be feasible or useful to provision to the mobile platform.
10.1 The Technology of Wireless Devices
EN: I expect there's little value in too close an examination of the technology at the time this book was written, so I'll elide some details and focus on what is still relevant.
Constraints of mobile devices (compared to desktop or notebook computers) include low computing power, limited software functionality, limited input capabilities, low memory, short battery life, and miniscule screen size.
Some of these problems may be overcome, to various degrees, by advances in technology, but others will remain. For example, small screen size cannot be overcome if the device is to remain portable (handheld).
Research into usability is in its infancy. Because of the lack of standards, each product works differently, so it's not possible to derive many general guidelines or standard practices.
10.2 The Usability of Wireless Devices
Usability of a wireless device is generally geared toward the primary function of that device (if it's a phone, it is first and foremost designed to be a phone, with Web browser being a secondary feature).
Research demonstrates that users consider it as such, and do not feel that the phone is a substitute for a desktop computer, and do not have the expectation that they will be able to do the same things with their cell phone as they can with a standard computer.
Moreover, the ability to do specific tasks are generally perceived as individual and isolated functions of the device (the ability to "check the weather on my phone") - specifically, the user doesn't consider the device to be a method of accessing he internet to perform various tasks.
10.3 The Role of Context
Context (the physical location from which the user accesses a Web site) is the most significant difference between mobile and fixed-location computing. Simply stated, a cell phone can be feasible used in more locations than even a notebook. There are a handful of specific concerns the author addreses:
Infrastructure Context: At the time of authoring, disconnection failures (dropped calls) were very common for mobile devices, and there was no way for the Web browser to preserve session data when a connection was dropped.
Application Context: The Web "browser" on a cell phone is extremely limited, in terms of capabilities, compared to the standard computer-based browser.
Location Context: Location will vary greatly with a mobile device, and there is greater demand for information that is pertinent to the location of the user (typical uses are finding a nearby ATM or restaurant, checking weather, checking traffic, and other data that is dependent on the user's present physical location)
Physical Context: A cell phone is used in a variety of environmental conditions. The lighting will vary, there may be background noise, beign inside a vehicle may make it difficult to type, etc.
10.4 Small-Size Effects
Small screens are the most significant problem with mobile computing. The author describes three key effects of small screen size:
10.4.1 Screen context effect
The amount of information shown affects how the viewer of the information interprets it. Simply stated, the user can't be presented much information on a small screen, and views it in small pieces, so items are seldom seen in the proper context. Even when designing specifically for the mobile platform, it is often impossible to place enough content on screen to control the context, and it may be impossible to put enough content on screen to be meaningful or usable at all.
10.4.2 Constructive Synthesis Effect
Breaking down data into chunks small enough to present on a small screen require the user to learn information in pieces and organize it in their head. This is no small feat, cognitively speaking, and given that a mobile user may be in an environment with many distractions, it may not be feasible for a user to hold even a small amount of information in memory.
There are also instances (for example, a large illustration or a graph) where viewing pieces out of context renders them meaningless, and it is simply not feasible to present them in "chunks" and expect the user to see the big picture.
10.4.3 Partial Content Effect
There are instances where showing partial content can be misleading - even when all of the parts have been viewed, their meaning depends on the user viewing them in a specific spatial relationship to one another.
10.5 Effective Functionality and Task Preferences
The conclusion is that it is not possible to provide the same functionality on a mobile device as is possible on a standard computer - but how does one decide which functions to make available for the mobile user?
The author suggests that the first concern is whether a given function can feasibly be performed on a mobile device, given the limitations of the technology, as well as the user, given the limitations of human perception and cognition and the distractions of the mobile environment.
Beyond that, the author suggests asking the standard questions (who/what/when/where/why) of each function a site provide to define scenarios in which it would be beneficial for a user to have access from a mobile environment.
10.6 Information Presentation
The author looks into various solutions for presenting information in the context of a handheld device ... though it seems to be that the burden is on the device manufacturer, rather than the site designer, to implement these solutions. The designer can exploit these capabilities (when and if they become available, and are standardized across platforms), but is largely unable to implement these solutions.
10.7 Interaction and Navigation
More talk about what a user "should be" able to do on a mobile device, but is not presently, due to device design rather than Web design factors.
10.8 Designer's Palette: Guidelines for Hand Web Design
The author goes off on another one of his long lists of random nuggets of advice without any supporting information, only made worse because the limitations of the mobile device make it impossible to satisfy these constraints.
EN: I'll skip them - there are probably more reliable, qualified, and up-to-date resources about designing for the mobile platform.