Human Interface Guidelines/Design Fundamentals/Key Design Principles - Revision history

Hryanjones: /* Accessibility */ Broken link -- found what appears to be a decent replacement.

2013-01-18T10:39:02Z

Accessibility: Broken link -- found what appears to be a decent replacement.

← Older revision		Revision as of 06:39, 18 January 2013
Line 68:		Line 68:
	* Providing an enlarged print/icon option for folks whose vision is less than 20/20 (but who still can see things that are somewhat enlarged - e.g. 18 point fonts)		* Providing an enlarged print/icon option for folks whose vision is less than 20/20 (but who still can see things that are somewhat enlarged - e.g. 18 point fonts)
	* Using the keyboard without needing to press more than one key at a time (all modifiers must work with AccessX functionality)		* Using the keyboard without needing to press more than one key at a time (all modifiers must work with AccessX functionality)
	* Supporting programmatic access to the GUI (which for us will mean supporting [http://developer.gnome.org/~~doc/API~~/2.0/atk/ ATK] in Sugar and all activites)		* Supporting programmatic access to the GUI (which for us will mean supporting [http://developer.gnome.org/atk/2.0/atk.html ATK] in Sugar and all activites)
	* Either shipping with some number of assistive technology applications (is a screen reader an "activity"?), or making them easy to download		* Either shipping with some number of assistive technology applications (is a screen reader an "activity"?), or making them easy to download
	* Providing some way for a user to discover accessibility support and enable what they need (Windows XP & Vista offer an "accessibility wizard" for this purpose; we don't have good upstream technology from GNOME we can take for this unfortunately; the Ubuntu accessibility folks are perhaps furthest along in thinking about this)		* Providing some way for a user to discover accessibility support and enable what they need (Windows XP & Vista offer an "accessibility wizard" for this purpose; we don't have good upstream technology from GNOME we can take for this unfortunately; the Ubuntu accessibility folks are perhaps furthest along in thinking about this)

Mokurai: /* Usability */ Add link

2009-09-15T20:46:20Z

Usability: Add link

← Older revision		Revision as of 16:46, 15 September 2009
Line 13:		Line 13:

	====Usability====		====Usability====
	OLPC places an emphasis on discoverability and usability due to our [[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—and in practice not all children will expect the same things—there is no substitute for user testing.		OLPC places an emphasis on [[Discovery\|discoverability]] and usability due to our [[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—and in practice not all children will expect the same things—there is no substitute for user testing.

	====Simplicity====		====Simplicity====

FGrose at 21:37, 19 July 2009

2009-07-19T21:37:43Z

← Older revision		Revision as of 17:37, 19 July 2009
Line 10:		Line 10:
	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 [[OLPC:Hardware_specification\|hardware specifications]]). Thus, developers must make every effort to write efficient code while minimizing memory usage.		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 [[OLPC: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 [[~~Design Team/~~Human Interface Guidelines/The Laptop Experience/Zoom Metaphor#Home\|Home]] screen features an activity ring that contains icons representing each instance of an open [[~~Design Team/~~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.		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 [[Human Interface Guidelines/The Laptop Experience/Zoom Metaphor#Home\|Home]] screen features an activity ring that contains icons representing each instance of an open [[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====		====Usability====
	OLPC places an emphasis on discoverability and usability due to our [[~~Design Team/~~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—and in practice not all children will expect the same things—there is no substitute for user testing.		OLPC places an emphasis on discoverability and usability due to our [[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—and in practice not all children will expect the same things—there is no substitute for user testing.

	====Simplicity====		====Simplicity====
Line 35:		Line 35:

	====Adaptability====		====Adaptability====
	Several use conditions should be taken into consideration in designing activities: the laptop has both a grayscale (sunlight) mode and a color (backlight) mode; the mesh—while always available—may or may not be connected to the Internet at the time the activity is active; the laptop may be configured in either laptop mode (keyboard and touchpad exposed) or [[~~Design Team/~~Human Interface Guidelines/The Sugar Interface/Input Systems#"Hand-held" Mode\|handheld mode]] (game controller, camera, microphone and speakers only). Signal strengths, and therefore bandwidth, may fluctuate, and at times activity partipants may even drop off temporarily. Activities should handle all of these cases with care. E.g., temporary loss of connectivity should be handled silently, and reconnection of an individual to an activity they were previously participating in should happen with no noticeable side-effects as outlined in the guidelines for [[~~Design Team/~~Human Interface Guidelines/Activities/Activity Basics#Activity Robustness\|activity robustness]].		Several use conditions should be taken into consideration in designing activities: the laptop has both a grayscale (sunlight) mode and a color (backlight) mode; the mesh—while always available—may or may not be connected to the Internet at the time the activity is active; the laptop may be configured in either laptop mode (keyboard and touchpad exposed) or [[Human Interface Guidelines/The Sugar Interface/Input Systems#"Hand-held" Mode\|handheld mode]] (game controller, camera, microphone and speakers only). Signal strengths, and therefore bandwidth, may fluctuate, and at times activity partipants may even drop off temporarily. Activities should handle all of these cases with care. E.g., temporary loss of connectivity should be handled silently, and reconnection of an individual to an activity they were previously participating in should happen with no noticeable side-effects as outlined in the guidelines for [[Human Interface Guidelines/Activities/Activity Basics#Activity Robustness\|activity robustness]].

	====Recoverability====		====Recoverability====
Line 41:		Line 41:
	Recoverability is fundamental to encouraging exploration. With creative exploration among OLPC's main goals, it therefore becomes an issue of high importance on the laptops. When children know they have a fallback plan—a way back to the current state of things—they will much more frequently go beyond their comfortable boundaries and experiment with new tools and new creative means of expression.		Recoverability is fundamental to encouraging exploration. With creative exploration among OLPC's main goals, it therefore becomes an issue of high importance on the laptops. When children know they have a fallback plan—a way back to the current state of things—they will much more frequently go beyond their comfortable boundaries and experiment with new tools and new creative means of expression.

	The [[~~Design Team/~~Human Interface Guidelines/The Laptop Experience/The_Journal\|journal]] provides a partial notion of recoverability, since its auto-journaling amounts to maintaining an automatic incremental backup. The ability, for children, to choose to "keep" anything they're working on in its current state furthers this idea.		The [[Human Interface Guidelines/The Laptop Experience/The_Journal\|journal]] provides a partial notion of recoverability, since its auto-journaling amounts to maintaining an automatic incremental backup. The ability, for children, to choose to "keep" anything they're working on in its current state furthers this idea.

	However, the primary and essential means of recoverability remains the ability to undo one's actions. Of course, the notion of undo/redo becomes complicated in the realm of collaborative editing, which imposes a limitation on the extent to which undos are possible, since collisions could often occur between the things one child wants to undo and the things another child has already changed since those were done. Nonetheless, we are dedicated to providing this functionality to every extent possible, and [[~~Design Team/~~Human Interface Guidelines/Activities\|activities]] should strive to support this to the best of our ability.		However, the primary and essential means of recoverability remains the ability to undo one's actions. Of course, the notion of undo/redo becomes complicated in the realm of collaborative editing, which imposes a limitation on the extent to which undos are possible, since collisions could often occur between the things one child wants to undo and the things another child has already changed since those were done. Nonetheless, we are dedicated to providing this functionality to every extent possible, and [[Human Interface Guidelines/Activities\|activities]] should strive to support this to the best of our ability.

	(Future revisions of the [[~~Design Team/~~Human Interface Guidelines/The Sugar Interface/Input Systems#Keyboard\|keyboard]] may even have an undo/redo key to further strengthen this idea.)		(Future revisions of the [[Human Interface Guidelines/The Sugar Interface/Input Systems#Keyboard\|keyboard]] may even have an undo/redo key to further strengthen this idea.)

	====Interoperability====		====Interoperability====
Line 55:		Line 55:
	====Transparency====		====Transparency====

	OLPC also hopes to encourage the children using the laptops to explore the technology under the surface. Towards this end, a [[~~Design Team/~~Human_Interface_Guidelines/The Laptop Experience/View Source\|view source]] key has been added to the laptop keyboards, providing them with instant access to the code that enables the activities that they use from day to day. This key will allow those interested to peel away layers of abstraction, digging deeper into the codebase as they learn.		OLPC also hopes to encourage the children using the laptops to explore the technology under the surface. Towards this end, a [[Human_Interface_Guidelines/The Laptop Experience/View Source\|view source]] key has been added to the laptop keyboards, providing them with instant access to the code that enables the activities that they use from day to day. This key will allow those interested to peel away layers of abstraction, digging deeper into the codebase as they learn.

	To enable such layered exploration, OLPC has written much of what can be in [[Python]], a scripting language, to enable children to view the source code. This means, aside from general good practice, code should be both readable and well commented. The [http://www.python.org/dev/peps/pep-0008/ PEP 8] style guidelines for Python provide an excellent resource, and OLPC recommends that developers follow the practices laid out therein unless a compelling reason exists not to do so.		To enable such layered exploration, OLPC has written much of what can be in [[Python]], a scripting language, to enable children to view the source code. This means, aside from general good practice, code should be both readable and well commented. The [http://www.python.org/dev/peps/pep-0008/ PEP 8] style guidelines for Python provide an excellent resource, and OLPC recommends that developers follow the practices laid out therein unless a compelling reason exists not to do so.

FGrose: moved Design Team/Human Interface Guidelines/Design Fundamentals/Key Design Principles to Human Interface Guidelines/Design Fundamentals/Key Design Principles: restructure

2009-07-07T12:59:28Z

moved Design Team/Human Interface Guidelines/Design Fundamentals/Key Design Principles to Human Interface Guidelines/Design Fundamentals/Key Design Principles: restructure

← Older revision	Revision as of 08:59, 7 July 2009
(No difference)

FGrose at 17:29, 5 July 2009

2009-07-05T17:29:45Z

← Older revision		Revision as of 13:29, 5 July 2009
Line 1:		Line 1:
	<div style="background-color: #FFF; margin-left:auto; margin-right: auto; width: 95%;">		<div style="background-color: #FFF; margin-left:auto; margin-right: auto; width: 95%;">
	<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}}		<noinclude>{{Translations}}{{GoogleTrans-en}}</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}}
			{{TOCright}}

	===Key Design Principles===		===Key Design Principles===

FGrose: /* Performance */

2009-05-09T00:53:06Z

Performance

← Older revision		Revision as of 20:53, 8 May 2009
Line 8:		Line 8:

	====Performance====		====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.		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 [[OLPC: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 [[Design Team/Human Interface Guidelines/The Laptop Experience/Zoom Metaphor#Home\|Home]] screen features an activity ring that contains icons representing each instance of an open [[Design Team/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.		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 [[Design Team/Human Interface Guidelines/The Laptop Experience/Zoom Metaphor#Home\|Home]] screen features an activity ring that contains icons representing each instance of an open [[Design Team/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.

FGrose: /* Accessibility */

2009-05-09T00:51:27Z

Accessibility

← Older revision		Revision as of 20:51, 8 May 2009
Line 61:		Line 61:
	====Accessibility====		====Accessibility====

	There are lots of things to think about that relate to accessibility in a set of human interface guidelines. We've just started hashing out general accessibility issues at the [[Accessibility]] page.		There are lots of things to think about that relate to accessibility in a set of human interface guidelines. We've just started hashing out general accessibility issues at the [[OLPC:Accessibility]] page.

	Broadly speaking, the user interface of the GUI shell and of activities must address the following accessibility issues:		Broadly speaking, the user interface of the GUI shell and of activities must address the following accessibility issues:

FGrose: /* Security */

2009-05-09T00:43:46Z

Security

← Older revision		Revision as of 20:43, 8 May 2009
Line 24:		Line 24:

	====Security====		====Security====
	Security is detailed elsewhere in this wiki (See [[Bitfrost]]). Our goal is to protect against five categories of "bad things" software can do:		Security is detailed elsewhere in this wiki (See [[OLPC:Bitfrost]]). Our goal is to protect against five categories of "bad things" software can do:
	# damaging the laptop;		# damaging the laptop;
	# compromising privacy;		# compromising privacy;

Dfarning: fix camelcase links

2009-04-08T04:09:34Z

fix camelcase links

← Older revision		Revision as of 00:09, 8 April 2009
Line 45:		Line 45:
	However, the primary and essential means of recoverability remains the ability to undo one's actions. Of course, the notion of undo/redo becomes complicated in the realm of collaborative editing, which imposes a limitation on the extent to which undos are possible, since collisions could often occur between the things one child wants to undo and the things another child has already changed since those were done. Nonetheless, we are dedicated to providing this functionality to every extent possible, and [[Design Team/Human Interface Guidelines/Activities\|activities]] should strive to support this to the best of our ability.		However, the primary and essential means of recoverability remains the ability to undo one's actions. Of course, the notion of undo/redo becomes complicated in the realm of collaborative editing, which imposes a limitation on the extent to which undos are possible, since collisions could often occur between the things one child wants to undo and the things another child has already changed since those were done. Nonetheless, we are dedicated to providing this functionality to every extent possible, and [[Design Team/Human Interface Guidelines/Activities\|activities]] should strive to support this to the best of our ability.

	(Future revisions of the [[~~DesignTeam~~/Human Interface Guidelines/The Sugar Interface/Input Systems#Keyboard\|keyboard]] may even have an undo/redo key to further strengthen this idea.)		(Future revisions of the [[Design Team/Human Interface Guidelines/The Sugar Interface/Input Systems#Keyboard\|keyboard]] may even have an undo/redo key to further strengthen this idea.)

	====Interoperability====		====Interoperability====

Dfarning: fix camelcase links

2009-04-07T22:25:10Z

fix camelcase links

← Older revision		Revision as of 18:25, 7 April 2009
Line 10:		Line 10:
	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.		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 [[~~DesignTeam~~/Human Interface Guidelines/The Laptop Experience/Zoom Metaphor#Home\|Home]] screen features an activity ring that contains icons representing each instance of an open [[~~DesignTeam~~/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.		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 [[Design Team/Human Interface Guidelines/The Laptop Experience/Zoom Metaphor#Home\|Home]] screen features an activity ring that contains icons representing each instance of an open [[Design Team/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====		====Usability====
	OLPC places an emphasis on discoverability and usability due to our [[~~DesignTeam~~/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—and in practice not all children will expect the same things—there is no substitute for user testing.		OLPC places an emphasis on discoverability and usability due to our [[Design Team/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—and in practice not all children will expect the same things—there is no substitute for user testing.

	====Simplicity====		====Simplicity====
Line 35:		Line 35:

	====Adaptability====		====Adaptability====
	Several use conditions should be taken into consideration in designing activities: the laptop has both a grayscale (sunlight) mode and a color (backlight) mode; the mesh—while always available—may or may not be connected to the Internet at the time the activity is active; the laptop may be configured in either laptop mode (keyboard and touchpad exposed) or [[~~DesignTeam~~/Human Interface Guidelines/The Sugar Interface/Input Systems#"Hand-held" Mode\|handheld mode]] (game controller, camera, microphone and speakers only). Signal strengths, and therefore bandwidth, may fluctuate, and at times activity partipants may even drop off temporarily. Activities should handle all of these cases with care. E.g., temporary loss of connectivity should be handled silently, and reconnection of an individual to an activity they were previously participating in should happen with no noticeable side-effects as outlined in the guidelines for [[~~DesignTeam~~/Human Interface Guidelines/Activities/Activity Basics#Activity Robustness\|activity robustness]].		Several use conditions should be taken into consideration in designing activities: the laptop has both a grayscale (sunlight) mode and a color (backlight) mode; the mesh—while always available—may or may not be connected to the Internet at the time the activity is active; the laptop may be configured in either laptop mode (keyboard and touchpad exposed) or [[Design Team/Human Interface Guidelines/The Sugar Interface/Input Systems#"Hand-held" Mode\|handheld mode]] (game controller, camera, microphone and speakers only). Signal strengths, and therefore bandwidth, may fluctuate, and at times activity partipants may even drop off temporarily. Activities should handle all of these cases with care. E.g., temporary loss of connectivity should be handled silently, and reconnection of an individual to an activity they were previously participating in should happen with no noticeable side-effects as outlined in the guidelines for [[Design Team/Human Interface Guidelines/Activities/Activity Basics#Activity Robustness\|activity robustness]].

	====Recoverability====		====Recoverability====
Line 41:		Line 41:
	Recoverability is fundamental to encouraging exploration. With creative exploration among OLPC's main goals, it therefore becomes an issue of high importance on the laptops. When children know they have a fallback plan—a way back to the current state of things—they will much more frequently go beyond their comfortable boundaries and experiment with new tools and new creative means of expression.		Recoverability is fundamental to encouraging exploration. With creative exploration among OLPC's main goals, it therefore becomes an issue of high importance on the laptops. When children know they have a fallback plan—a way back to the current state of things—they will much more frequently go beyond their comfortable boundaries and experiment with new tools and new creative means of expression.

	The [[~~DesignTeam~~/Human Interface Guidelines/The Laptop Experience/The_Journal\|journal]] provides a partial notion of recoverability, since its auto-journaling amounts to maintaining an automatic incremental backup. The ability, for children, to choose to "keep" anything they're working on in its current state furthers this idea.		The [[Design Team/Human Interface Guidelines/The Laptop Experience/The_Journal\|journal]] provides a partial notion of recoverability, since its auto-journaling amounts to maintaining an automatic incremental backup. The ability, for children, to choose to "keep" anything they're working on in its current state furthers this idea.

	However, the primary and essential means of recoverability remains the ability to undo one's actions. Of course, the notion of undo/redo becomes complicated in the realm of collaborative editing, which imposes a limitation on the extent to which undos are possible, since collisions could often occur between the things one child wants to undo and the things another child has already changed since those were done. Nonetheless, we are dedicated to providing this functionality to every extent possible, and [[~~DesignTeam~~/Human Interface Guidelines/Activities\|activities]] should strive to support this to the best of our ability.		However, the primary and essential means of recoverability remains the ability to undo one's actions. Of course, the notion of undo/redo becomes complicated in the realm of collaborative editing, which imposes a limitation on the extent to which undos are possible, since collisions could often occur between the things one child wants to undo and the things another child has already changed since those were done. Nonetheless, we are dedicated to providing this functionality to every extent possible, and [[Design Team/Human Interface Guidelines/Activities\|activities]] should strive to support this to the best of our ability.

	(Future revisions of the [[DesignTeam/Human Interface Guidelines/The Sugar Interface/Input Systems#Keyboard\|keyboard]] may even have an undo/redo key to further strengthen this idea.)		(Future revisions of the [[DesignTeam/Human Interface Guidelines/The Sugar Interface/Input Systems#Keyboard\|keyboard]] may even have an undo/redo key to further strengthen this idea.)
Line 55:		Line 55:
	====Transparency====		====Transparency====

	OLPC also hopes to encourage the children using the laptops to explore the technology under the surface. Towards this end, a [[~~DesignTeam~~/Human_Interface_Guidelines/The Laptop Experience/View Source\|view source]] key has been added to the laptop keyboards, providing them with instant access to the code that enables the activities that they use from day to day. This key will allow those interested to peel away layers of abstraction, digging deeper into the codebase as they learn.		OLPC also hopes to encourage the children using the laptops to explore the technology under the surface. Towards this end, a [[Design Team/Human_Interface_Guidelines/The Laptop Experience/View Source\|view source]] key has been added to the laptop keyboards, providing them with instant access to the code that enables the activities that they use from day to day. This key will allow those interested to peel away layers of abstraction, digging deeper into the codebase as they learn.

	To enable such layered exploration, OLPC has written much of what can be in [[Python]], a scripting language, to enable children to view the source code. This means, aside from general good practice, code should be both readable and well commented. The [http://www.python.org/dev/peps/pep-0008/ PEP 8] style guidelines for Python provide an excellent resource, and OLPC recommends that developers follow the practices laid out therein unless a compelling reason exists not to do so.		To enable such layered exploration, OLPC has written much of what can be in [[Python]], a scripting language, to enable children to view the source code. This means, aside from general good practice, code should be both readable and well commented. The [http://www.python.org/dev/peps/pep-0008/ PEP 8] style guidelines for Python provide an excellent resource, and OLPC recommends that developers follow the practices laid out therein unless a compelling reason exists not to do so.