Linux has much software available because it uses the UNIX® application programming interface and UNIX object and executable file formats. Much of the public domain and open-source software of the last two decades has been written for UNIX and is now available for Linux, and third-party software developers have been providing products for flavors of UNIX for years such as AIX from IBM, Solaris™ from Sun Microsystems, and HP/UX from Hewlett-Packard. The number of device drivers available for Linux is large and growing and the source code is almost always free. Linux has a good reputation for reliability and network and file system performance.