of 32 MB, or 2 GB. If a device supports SATA Word 105 at 8 then it should be able to trim 16 GB in a single TRIM (DATA SET MANAGEMENT) command. SCSI SCSI provides the UNMAP command (a full analog of TRIM), and the WRITE SAME command (10 and 16 variants) with the UNMAP flag set. SD/MMC The MultiMediaCard and SD ERASE (CMD38) command provides similar functionality to the ATA TRIM command, although it requires that erased blocks be overwritten with either zeroes or ones. eMMC 4.5 further defines a DISCARD sub-operation that more closely matches ATA TRIM in that the contents of discarded blocks can be considered indeterminate (i.e., "don't care"). NVM Express The NVM Express command set has a generic Dataset Management command set, for hinting the host's intent to the storage device on a set of block ranges. One of its operations, DEALLOCATE performs trim. It also has a WRITE ZEROES command that provides a DEALLOCATE hint and allows the disk to trim and return zeroes. Disadvantages Some deniable encryption schemes involve making the whole disk look like random garbage. Using TRIM defeats this layer of plausible deniability as the all-zero (or all-one) blocks created easily indicate what blocks are used. It has been argued disabling TRIM might be suspicious too. The original version of the TRIM command has been defined as a non-queued command by the T13 subcommittee, and consequently can incur massive execution penalty if used carelessly, e.g., if sent after each filesystem delete command. The non-queued nature of the command requires the driver to first wait for all outstanding commands to be finished, issue the TRIM command, then resume normal commands. TRIM can take a lot of time to complete, depending on the firmware in the SSD, and may even trigger a garbage collection cycle. This penalty can be minimized in solutions that periodically do a batched TRIM, rather than trimming upon every file deletion, by scheduling such batch jobs for times when system utilization is minimal. This TRIM disadvantage has been overcome in Serial ATA revision 3.1 with the introduction of the Queued TRIM Command. Faulty drive firmware that misreports support for queued TRIM or has critical bugs in its implementation has been linked to serious data corruption in several devices, most notably Micron and Crucial's M500 and Samsung's 840 and 850 series. The data corruption has been confirmed on the Linux