Abstraction
“Backup” means “persistent” data in the IVI system where user configuration data and IVI service operational data are stored and preserved while the IVI system works. Even though IVI is battery-powered which looks similar to smartphones, electronic consumer devices, the power supply in IVI system can be unstable at ACC-ON and ACC-OFF for the system startup/shutdown. Therefore, the Backup Data Management module must ensure that no backup data is lost, no backup data is corrupted and the backup data is consistent while the system startup/shutdown lifecycle.
Another aspect on IVI system which is special rather than smartphone, electronic consumer devices is a much longer product lifetime, and that means the storage device must be available for a much longer time. So, in order to make the storage device lifetime longer, data write operation shall not happen every time when applications request. The Backup Data Management module needs to handle the read/write operation to the storage device at any given time.
This chapter describes the use cases with Backup Data Management(the function of backup as described above), the functional requirements for realizing the use cases, and the functions of the Basesystem that can be used as a sample implementation.
Use case
In the following table 1, use cases which need the backup management for services are described.
Table 1
| # | Item | User |
|---|---|---|
UC.BD.1 | Data protection in case of ACC-OFF or sudden power failure | Even when the driver presses the button for ACC-OFF or a sudden power failure occurs after changing the display settings of the navigation system, the display settings are retained and the driver uses the information. |
UC.BD.2 | Utilize the backup data | The driver searches for a destination using the search history stored in the navigation application. |
UC.BD.3 | Data attribute when the system battery is removed | Each OEM chooses whether to make each backup data stored in the IVI volatile or non-volatile when the battery is removed, for handling the backup data after the battery is removed. |
Functional Requirements
This table includes the functional requirements of Backup Data Management module.
Table 2
| # | Item | Related Use Case | Description |
|---|---|---|---|
RQ.BD.1 | Backup in case of sudden power off | UC.BD.1 | The Backup Data Management module shall prevent “backup” data loss if the power supply is stopped. |
RQ.BD.2 | Backup of system lifecycle | UC.BD.1 | IVI system shall preserve any "backup" data requested by IVI services/apps through system startup/shutdown lifecycle. |
RQ.BD.3 | Utilization of Backup data | UC.BD.2 | The data which needs to be read shall be readable by request from IVI services/apps. |
RQ.BD.4 | Data backup to non-volatile area | UC.BD.3 | The type of "backup" data shall be configurable, i.e. it can be configured to be either volatile or non-volatile when the system battery is removed. |
RQ.BD.5 | Storage memory requirement | UC.BD.1 | The Backup Data Management module shall minimize actual write operations to the storage device to make the lifetime as long as possible. |
Backup management in Basesystem
Reference implementation in Basesystem
In the implementation of Basesystem, the function module for Backup Data Management is Backup Manager.
As shown in the following figure 27, for example when a driver uses an application and a data backup request occurs, on receiving the request, Backup Manager writes the data to the specified storage with the specified offset and data size(ⅰ). When reading the data, Backup manager reads the data from the specified storage and sends it back to the application side(ⅱ). The above two functions are the roles of Backup Manager.
Figure 3
