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UMASS(4) Kernel Interfaces Manual UMASS(4) NAME umass -- USB Mass Storage Devices driver SYNOPSIS device da device scbus device pass device usb device umass In loader.conf(5): umass_load DESCRIPTION The umass driver provides support for Mass Storage devices that attach to the USB interface. If the appropriate hardware is detected, the driver will be loaded au- tomatically by devmatch(8). To load the driver manually at boot time, use the umass_load command at the loader(8) prompt, or add it to loader.conf(5). To use the driver in a custom kernel, usb(4) and at least one of uhci(4), ohci(4), ehci(4), or xhci(4) must be configured in the kernel. Additionally, since umass uses the SCSI subsystem and sometimes acts as a SCSI device, it requires da(4) and scbus(4) to be included in the kernel. HARDWARE The umass driver supports USB Mass Storage devices such as: • USB thumb drives • USB hard disk drives • USB floppy drives EXAMPLES Rescan all slots on a multi-slot flash reader, where the slots map to separate LUNs on a single SCSI ID: camcontrol rescan 0:0:0 camcontrol rescan 0:0:1 camcontrol rescan 0:0:2 camcontrol rescan 0:0:3 Typically only the first slot will be enabled at boot time. This as- sumes that the flash reader is the first SCSI bus in the system and has 4 slots. SEE ALSO cfumass(4), ehci(4), ohci(4), uhci(4), usb(4), xhci(4), camcontrol(8) HISTORY The umass driver appeared in FreeBSD 4.3. AUTHORS The umass driver was written by MAEKAWA Masahide <bishop@rr.iij4u.or.jp> and Nick Hibma <n_hibma@FreeBSD.org>. This manual page was written by Nick Hibma <n_hibma@FreeBSD.org>. FreeBSD 15.0 October 9, 2025 UMASS(4)
NAME | SYNOPSIS | DESCRIPTION | HARDWARE | EXAMPLES | SEE ALSO | HISTORY | AUTHORS
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