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Human Interface Guidelines/Design Fundamentals/Key Design Principles (view source)
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<noinclude>{{Translations}}</noinclude>{{hig-subnav-inter|p_link=Design Fundamentals/Know Your Audience|p_label=Know Your Audience|c_section=Design Fundamentals|c_page=Key Design Principles|n_link=The Laptop Experience/Introduction|n_label=The Laptop Experience}}
===Key Design Principles===
''Low floor, no ceiling:'' this mantra should guide your development efforts for OLPC. All activities and interfaces should be designed in such a way as to be simple and intuitive to users of all age groups, nationalities, and levels of computer experience. At the same time, we don't wish to impose unnecessary limitations on the software either. Instead, we hope to create a platform suitable for all kinds of creative expression which provides a low floor to the inexperienced, but doesn't impose a ceiling upon those who are. This is a worthy goal, but will require a genuine effort on the part of developers, who must take many aspects of design into account. The following list, while certainly not comprehensive, provides a starting point for such considerations.
====Performance====
The OLPC laptop bucks the trend of "more, faster, fatter"; we aim to provide a computer tailored to the needs of children in the context of their learning, not to the needs of frantic video games or office applications. We are, however, working within constraints of component cost, robustness, and power consumption. To satisfy these constraints, we have opted for NAND flash rather than a hard disk and a modest 256MB of memory (Please see [[Hardware_Specification|hardware specifications]]). Thus, developers must make every effort to write efficient code while minimizing memory usage.
Since there is no swap space on the laptop, only a limited number of activities can run concurrently; the Sugar UI exposes these details directly to the children. The [[OLPC Human Interface Guidelines/The Laptop Experience/Zoom Metaphor#Home|Home]] screen features an activity ring that contains icons representing each instance of an open [[OLPC Human Interface Guidelines/Activities|activity]]. The size of the ring segment that a given activity occupies represents its overall memory usage; when the ring fills up, no additional activities may be launched until some resources have been freed. Take these limitations into account as you develop activities, since they will have a greater impact on the performance of your software on the laptop than on other platforms.
====Usability====
OLPC places an emphasis on discoverability and usability due to our [[OLPC_Human_Interface_Guidelines/Design Fundamentals#Know_Your_Audience|target audience]]. Usability has everything to do with the actual behavior of the activities, the layout of the buttons and tools, and the feedback that the interface provides to the children when they interact with it. Ultimately, the design decisions that make your activities usable will depend greatly on the type of activity you are developing, and it will be up to you to consider carefully the kinds of interactions that the children will expect when presented with it. As a general rule, if the interface provided does what the child expects it to, you are off to a good start. However, since it is quite difficult to know what they will expect
<noinclude>{{Translations}}</noinclude>{{hig-subnav-inter|p_link=Design Fundamentals/Know Your Audience|p_label=Know Your Audience|c_section=Design Fundamentals|c_page=Key Design Principles|n_link=The Laptop Experience/Introduction|n_label=The Laptop Experience}}
===Key Design Principles===
''Low floor, no ceiling:'' this mantra should guide your development efforts for OLPC. All activities and interfaces should be designed in such a way as to be simple and intuitive to users of all age groups, nationalities, and levels of computer experience. At the same time, we don't wish to impose unnecessary limitations on the software either. Instead, we hope to create a platform suitable for all kinds of creative expression which provides a low floor to the inexperienced, but doesn't impose a ceiling upon those who are. This is a worthy goal, but will require a genuine effort on the part of developers, who must take many aspects of design into account. The following list, while certainly not comprehensive, provides a starting point for such considerations.
====Performance====
The OLPC laptop bucks the trend of "more, faster, fatter"; we aim to provide a computer tailored to the needs of children in the context of their learning, not to the needs of frantic video games or office applications. We are, however, working within constraints of component cost, robustness, and power consumption. To satisfy these constraints, we have opted for NAND flash rather than a hard disk and a modest 256MB of memory (Please see [[Hardware_Specification|hardware specifications]]). Thus, developers must make every effort to write efficient code while minimizing memory usage.
Since there is no swap space on the laptop, only a limited number of activities can run concurrently; the Sugar UI exposes these details directly to the children. The [[OLPC Human Interface Guidelines/The Laptop Experience/Zoom Metaphor#Home|Home]] screen features an activity ring that contains icons representing each instance of an open [[OLPC Human Interface Guidelines/Activities|activity]]. The size of the ring segment that a given activity occupies represents its overall memory usage; when the ring fills up, no additional activities may be launched until some resources have been freed. Take these limitations into account as you develop activities, since they will have a greater impact on the performance of your software on the laptop than on other platforms.
====Usability====
OLPC places an emphasis on discoverability and usability due to our [[OLPC_Human_Interface_Guidelines/Design Fundamentals#Know_Your_Audience|target audience]]. Usability has everything to do with the actual behavior of the activities, the layout of the buttons and tools, and the feedback that the interface provides to the children when they interact with it. Ultimately, the design decisions that make your activities usable will depend greatly on the type of activity you are developing, and it will be up to you to consider carefully the kinds of interactions that the children will expect when presented with it. As a general rule, if the interface provided does what the child expects it to, you are off to a good start. However, since it is quite difficult to know what they will expect