This chapter describes the restrictions on save data. The specifications for card-based applications and downloadable applications are unified as much as possible for Nintendo 3DS systems. Consequently, unless specified otherwise, the restrictions and rules that must be followed for save data are the same for both card-based and downloadable applications.
Be sure to also support the items described in chapter 3.4 Save Data and Extra Data: Common Items.
3.2.1 Save Data Rollback Prevention Feature for Downloadable Applications
The Nintendo 3DS system provides a feature that can detect save data rollback in downloadable applications.
Now that this feature is available, the market features a mixture of applications where save data rollbacks are possible and applications where they are not. If you are planning to severely penalize the user (for example, by formatting all save data) if your application detects a rollback, Nintendo recommends notifying the user that rollbacks are prohibited in the manual, when save data is created, or at some other similar point.
The save data rollback prevention feature for downloadable applications is designed to protect against improper operations, such as copying data from an SD card onto a PC and then re-writing that data back onto the SD Card at a later point so that the same data can be loaded an unlimited number of times. When using this feature the application is able to detect rollback of save data by taking an application-unique value and saving it to both the system and the save data. These shared values are updated and re-synchronized each time save data is written. The specifications of this feature mean that in some situations it can detect save data rollback without that being the user's intention. For example, consider a case where siblings share a single Nintendo 3DS system but play with separate SD Cards; in this case, depending on the specifications of the application, the feature might detect a rollback every time data is written to the new SD Card after SD Cards are swapped. However, swapping between two or more SD Cards does not fall under the standard norms for usage set by Nintendo, so there is no requirement for the application to support such a possibility.
No required guideline items.
3.2.2 Accessing the Save Data of Other Applications
On Nintendo 3DS, it is possible for applications to access the save data regions of other applications. Do not access save data created by an application that is released by a different publisher. Contact Nintendo at support@noa.com if your application needs to access the save data of an application not released by your same publisher. Your application may freely create or delete data files within the data archives of any title released by the same publisher.
3.2.2.1 Prohibition of Accessing the Save Data of Applications Released by a Different Publisher
Guideline Item |
It is prohibited to access the save data of applications that are released by a different publisher.
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Software to Be Tested |
All applications.
|
Test Method |
Go to the CXI tab of Master Editor and check the content of the OtherUserSaveDataId1, OtherUserSaveDataId2, and OtherUserSaveDataId3 fields, or the AccessibleSaveDataIds fields.
|
Pass/Fail Determination |
Passes either if the fields are blank (all zeros), or the unique IDs of applications released by the same publisher are displayed.
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3.2.3 Screen Display While Writing Data
If a write operation lasts for more than a split second without notifying the user, the user might think that the write has completed and power off the system. If the application uses automatic data redundancy, then the save data would roll back to its state before the write. However, if the user powers off the system in the middle of a write and the application does not use automatic data redundancy, the save data could be corrupted. If your application does not create redundant save data, then for any save data writes that may exceed 3 seconds your application must display some on-screen indication that data is being written. Make sure that the on-screen indication does not disappear until the write is complete. In general, use a text-based message as your on-screen indication that data is being written. If your application uses an icon or some other non-text display to inform the user, then explain its meaning within the application before using such a display. If you explain this display in the manual instead of within the application, you must submit the relevant portions of the manual to Lotcheck.
See the Nintendo 3DS Performance Tips for a benchmark for writing speeds. Factor in the slowest described writing speed when designing your application.
It is acceptable to extend the display time longer than the actual write to ensure that the user has adequate time to understand the indication.
For example, in Figure 3-1 Display of "Writing in Progress" Indication During Writes Lasting Over 3 Seconds, neither Case 1 nor Case 2 is acceptable for the following reasons. In Case 1, the on-screen indication disappears before the write is finished. In Case 2, the indication is not yet displayed when the application starts to save the data. It is perfectly acceptable to start displaying the indication before the write begins, and to stop displaying it after the write ends, as indicated in Case 3.
Furthermore, if the screen remains completely static during a write, users might mistakenly believe that the application has locked up. In such cases, users could accidentally corrupt their save data by powering off the system even though an on-screen write indication is being displayed. As a result, if the application does not use automatic data redundancy on its save data and the writing time exceeds 5 seconds, you must animate some part of the screen so that the player does not mistake this for a lock-up. However, formatting save data is an exception to this guideline even though this is of course a write process. This is because the data is completely recreated.
This guideline only applies to save data that does not have automatic redundancy. However, Nintendo still recommends displaying a "writing in progress" indication for extra data or for save data that does have automatic redundancy. Due to application specifications or user playstyle, it is possible for fatal errors to be caused by the corruption of extra data or the rollback of save data. Following the recommendation can help avoid such errors.
3.2.3.1 Support for Screen Display While Writing Data
Guideline Item |
The application must display some on-screen indication while writing save data.
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Software to Be Tested |
Applications that write to save data without automatic data redundancy.
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Exceptions |
If the following cases apply:
|
Test Method |
Write to save data.
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Pass/Fail Determination |
All Applications: Passes if all of the following conditions are met.
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When a text message is displayed as the "writing in progress" indication: Passes if the following is met in addition to meeting the conditions for All Applications.
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When an icon or other non-text indication is displayed as the "writing in progress" indication: Passes if at least one of the following is met in addition to meeting the conditions for All Applications.
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3.2.3.2 Support for Animation Display While Writing Data
Guideline Item |
The application must display an animation somewhere on the screen while writing save data.
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Software to Be Tested |
Applications that write to save data without automatic data redundancy.
|
Exceptions |
If the following cases apply:
|
Test Method |
Write to save data.
|
Pass/Fail Determination |
Passes if the application displays an animation somewhere on the screen.
|
3.2.4 Save Data Size
If your application must exceed 50 MB for its save data region, contact Nintendo at support@noa.com in advance regarding the purpose for which you will use the space.
For downloadable applications, the size required to download the application ends up including the save data size, so allocating an unnecessarily large size for actual save data is not desirable from the application standpoint.
If there is no reason to do otherwise, Nintendo recommends setting the save data size for downloadable applications to either 128 KB or 512 KB, which are the two available options for CARD1.
3.2.4.1 Save Data Size Restrictions
Guideline Item |
Applications may not create save data files larger than 50 MB. |
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Software to Be Tested |
Downloadable applications, and any applications that use CARD2. |
Test Method |
Check the content of the Save Data Size field displayed in Master Editor’s CXI tab. |
Pass/Fail Determination |
Passes if the numeric value displayed is 50 MB or less. |