It is not, however, going to be simply RHELs twin in every way.
When Oracle first announced the release of Unbreakable Linux, many people saw it as a purely anti-Red Hat move. Larry Ellison, Oracles CEO, doesnt like competition. What he likes is winning.
If that means cutting Red Hat out of the deal for Oracles enterprise databases, not to mention getting some revenge for Red Hat stealing JBoss out of his grasp, then so be it.
Something funny has happened along the way. Unlike companies like CentOS, StartCom and White Box Enterprise Linux, which make no bones about simply taking RHELs code, taking out the Red Hat branding, recompiling it and selling it, Oracle is taking Unbreakable Linux down a different path.
Some of these additions were only to be expected. For example, Oracle is open-sourcing an OCI (Oracle Call Interface) database driver for PHP. According to Oracle, this brings "breakthrough scalability to PHP applications" and enhances its viability as a development environment for mission-critical applications.
This driver supports Oracle Database 11g features such as connection pooling and fast application notification so a single x86 server can support, Oracle claims, tens of thousands of database connections at higher availability.