[2] The operating system automatically manages the contents of the drive so the most frequently accessed files are stored on the faster flash storage, while infrequently used items move to or stay on the hard drive.
The Fusion Drive was announced as part of an Apple event held on October 23, 2012, with the first supporting products being two desktops: the iMac and Mac Mini with OS X Mountain Lion released in late 2012.
[3] Fusion Drive remains available in subsequent models of these computers, but was not expanded to other Apple devices: the latest MacBook and Mac Pro models use exclusively flash storage, and while this was an optional upgrade for the mid-2012 non-Retina MacBook Pro discontinued by Apple, it replaced the standard hard disk drive in October 2021 instead of complementing it in the fashion of Fusion Drive.
Apple's Fusion Drive design incorporates proprietary features with limited documentation.
It has been reported that the design of Fusion Drive has been influenced by a research project called Hystor.