HFS+ was initially retrofitted to support the transition to a UNIX-based OS and has been augmented throughout the years to add new features, including compression, journaling support, and whole disk encryption ( FileVault 2) to name a few. Marking the switch to Intel-based processors, Apple introduced OS X, a redesigned operating system based on UNIX that was capable of running on the new hardware. Mac OS Extended ( HFS+) was introduced in 1998 for Mac OS 8.1, the previous iteration of the desktop operating system found on Apple's computers which ran on IBM's PowerPC processors.