• Block Device Driver Service: UniStore II allows the file system to treat the OneNAND flash memory like any other block device for connecting to any file system. The file system stores and retrieves the logical sector through Media Driver of the UniStore II. XSR maps the logical sector location to the physical sector location at which the data is to be written.
• Expands Life Span: UniStore II prolongs device life span by wear-leveling algorithms that level the erase count of OneNAND flash operation evenly. It levels the usage of every block in a device.
• Supports Multi-volume and Multi-devices: UniStore II allows using two volumes of OneNAND flash memory at once. A volume consists of four devices each and can be tied with the same kind of OneNAND devices.
• Partition Information Management: UniStore II manages partition information separated from the user data. UniStore II stores the partition information in reserved area of OneNAND flash memory.

High Reliability

1. Power Handler
   UniStore II implements proprietary algorithm for efficient Error Correction Code (ECC) for 1 bit failure correction and Error Detection Code (EDC) for 2 bit failure detection which ensure data integrity. Also, it efficiently solves OneNAND bit-flipping issues.
2. Invalid Block Management
   UniStore II maps out all invalid blocks which may occur within OneNAND flash memory; initial invalid blocks which may be manufactured initially, and run-time invalid blocks which may occur during the flash operation.
3. Write Protection
   UniStore II provides the write protection to prevent a corruption of critical data from malicious operations or system malfunctions. It guarantees security of system data as preventing the access of the users.

System Performance Enhancement

1. FAT Cleanser
   FATFS (File Allocation Table File System) only modifies FAT entries, but does not delete the invalid sector. FAT Cleanser monitors the FATFS's operation and requests XSR to delete the invalid sector when the next write operation occurs. After the deletion, XSR does not need to manage the deleted invalid sector any more. Therefore, it improves the system performance.
2. Garbage collection
   UniStore II removes the invalid sectors when no more valid sector is remained within the sector.
3. DCOP
   UniStore II supports DCOP (Deferred Check Operation) that enhances the performance of write and erase operation by deferring and scheduling the operation for efficient CPU processing. XSR in UniStore II provides the invalid block management routine for the previous operation failure.

System Robustness
Power Handler : UniStore II provides advanced algorithms for the cases of the sudden power-loss. It guarantees the robustness with the power-loss recovery according to the Power Model Policy of Symbian OS.

Utility
Supports Boot-loader : UniStore II provides a boot-loader for bootstrapping and loading the operating system. UniStore II can boot the operating system faster than ever before.
OneNAND Writer : UniStore II supports OneNAND Writer to write OS image to OneNAND flash memory with MultiICE for debugging, image write, etc.

Easily integrated installable File systems/Simple Integration
UniStore II supports FAT and ROFS (Read Only File System) and is easily integrated with them.