A growing number of embedded-system developers are seeking access to small and fast database-management systems for their projects. There was little need in the past for databases driven by embedded systems. But, the requirements of data-acquisition and analysis systems controlled through networks or the Internet has opened the door to better on-device storage and decision-making logic.
At least two established database vendors are targeting embedded database needs, and offering Linux alternatives. Centura Software's db.linux provides an embeddable solution that requires only about 200 kbytes of memory—even less if the database is read-only. It supports both relational and network database models, and has the ability to support over four billion records in a single database.
In a similar vein, Sybase's SQL Anywhere permits development on Linux platforms. Its memory requirement, though, is substantially higher, at a minimum of four Mbytes. SQL Anywhere's Adaptive Server Anywhere is mostly intended for handheld computers and larger embedded systems, like information kiosks and industrial automation systems. It supports larger database, field, and record sizes than db.linux, as well as large stored procedures for executing programs in response to database activities.
Not many embedded developers have to turn to incorporating databases yet. But, there's an increasing use of embedded systems as part of multitiered data systems that may include instruments and automation systems, PCs, and server systems. Databases will become part of embedded architectures as more data is generated from real-time monitoring and control activities.