identifies each notable operating system and the first version supporting the command. Additionally, older solid-state drives designed before the addition of the TRIM command to the ATA standard will need firmware updates, otherwise the new command will be ignored. However, not every drive can be upgraded to support trimming. The support for TRIM also varies by what the particular filesystem driver on the operating system is capable of, since only a program with an understanding of what parts of the disk are free space can safely issue the command, and on the system level this ability tends to lie in the filesystem driver itself. RAID issues , support for the TRIM command is not implemented in most hardware-based RAID technologies. However, software RAID implementations often do include support for TRIM. Windows Windows 10 offers support for TRIM in SSD ID volumes using the "optimize drives" option when configuring a RAID volume. macOS The macOS RAID driver does not support TRIM. This is true for all versions of Mac OS X from 10.7 through macOS 10.12.x. TRIM is supported for RAID (0,1,4,5 & 10) volumes when using the third-party SoftRAID® application, including TRIM support with non-Apple SSD devices. (Note: TRIM for non-Apple SSD devices must be specifically enabled using the terminal command "sudo trimforce enable") Linux TRIM is available with RAID volumes in post-January-2011 releases of the Linux kernel's dmraid, which implements BIOS-assisted "fake hardware RAID" support, and which now passes through any TRIM requests from the filesystem that sits on the RAID array. Not to be confused with dmraid, Linux's general-purpose software RAID system, mdraid, has experimental support for batch-based (rather than live, upon file deletion) TRIM on RAID 1 arrays when systems are configured to periodically run the mdtrim utility on filesystems (even those like ext3 without native TRIM support). In later versions of Linux, e.g. Red Hat Enterprise Linux 6.5 and beyond, mdraid supports actually passing through TRIM commands in real-time, rather than just as a batch job. However, Red Hat recommends against using software RAID levels 1, 4, 5, and 6 on SSDs with most RAID technologies, because during initialization, most RAID management utilities (e.g. Linux's mdadm) write to all blocks on the devices to ensure that checksums (or drive-to-drive verifies, in the case of RAID 1 and 10) operate properly, causing the SSD to believe that all blocks other than in the spare area are in