Access/PalmSource has released an SQL-based filesystem for embedded devices under the LGPL (Lesser General Public License). Libsqlfs implements a POSIX-style hierarchical filesystem as an SQLite database file, and was originally developed to provide a registry of system and application configuration data for mobile phones, according to Access.

Access says it originally created Libsqlfs for its Access Linux Platform (ALP), a forthcoming software stack for mobile phones. In the context of ALP, libsqlfs was used to implement a registry for system settings and application configuration data. The registry aims to comply with requirements from the Open Mobile Alliance's Device Management working group, and includes the capability of limiting access to secure settings to applications with “specific credentials,” according to Access.

Other touted features of libsqlfs include:

• Implemented as add-on to SQLite database
• A single SQLite database file provides applications with a full read/write, POSIX-style hierarchical filesystem
  • Easily moved around, backed up, or restored
• Space-efficient writable storage
• Useful for applications that need structured storage, “such as embedding documents within documents, or management of configuration data or preferences,” Access says
• Can be built as shared library, or as a FUSE module (Linux File System in User Space) “to allow a libsqlfs database to be accessed via OS level file system interfaces by normal applications”
• Supports POSIX file system semantics
• Combines benefits of a real database, such as transactions and concurrency control, with SQL access to file system metadata
  • Control over the schema allows additional metadata, such as value types, permissions, and access control lists
  • Can accommodate small preference values such as a number, and large binary objects such as an video clip

Michael Kelley, PalmSource's senior vice president of engineering, stated, “The motivation for creating a filesystem to database-file bridge originated with our need for ALP to be able to store and retrieve application and system preferences. We evaluated what is available today, and decided to write a software library specifically to address this issue.”

Bill Weinberg, senior analyst with the Open Source Development Labs, stated, “[This announcement] demonstrates [PalmSource's] capability to build communities around embedded software, and their commitment to free open source software.”

Availability

LibSQLfs is available now, for download, here.

Access/PalmSource will offer a hands-on technical session involving SQLite, and possibly libsqlfs as well, this Wednesday, as part of its Access Developer Day co-located with LinuxWorld this week in San Francisco.

 
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