File server

The File server provides shared access to the filing systems, a client-side interface that hides the clientserver architecture and a framework for dynamically mounting plug-in file systems, with physical storage of files associated with each filing system. File systems and reference media drivers are provided for the following types of media:
internal RAM drive
internal NOR Flash
internal NAND Flash
ATA/CF
MultiMediaCard (MMC)
Secure Digital (SD) memory card (including both the user and protected areas of these devices).
Main features:
file system drivers can be added when required without having to reboot
clients can register for notification of file-server events, for example, entries changing in given directory, changing disk or disk space crossing a specified threshold
interoperability with other systems, the VFAT filing system (in both FAT16 and FAT32 formats)is used for removable media
all filing systems guarantee data integrity in the face of unexpected power loss.
　
Standard library:
Base also contains middleware widely used across Symbian OS. Here is the main functionality:
The C standard library
A relational database access API. Two DBMS implementations are provided: a small and relatively lightweight client-side implementation and a client-server implementation for when multiple clients must have write access to a database. Databases can be manipulated either through a subset of SQL or through a Symbian OS proprietary C++ API
A stream store that defines two major abstractions – streams (an abstract interface to convert between an object's internal and external representations) and stores (an abstract interface to manipulate a network of streams). Stores allow externalizing and internalizing data structures as complex as whole application documents or databases. Several implementations are provided for both streams and stores including memory-based and permanent file stores. It is possible to define stackable streams doing pre-processing, for example encryption and decryption streams are provided.