I'm just trying out a

  ahc0 at pci2 dev 10 function 0: Adaptec 29160 Ultra160 SCSI adapter
  ahc0: aic7892: Ultra160 Wide Channel A, SCSI Id=7, 32/253 SCBs
  st0 at scsibus0 target 2 lun 0: <HP, C5683A, C111> tape removable

tape drive for the first time, and while dumping a tiny filesystem,
I got a number of

  ahc0:SCB 0xf - timed out
  >>>>>>>>>>>>>>>>>> Dump Card State Begins <<<<<<<<<<<<<<<<<
  Dumping Card State while idle, at SEQADDR 0x8
  Card was paused
  ACCUM = 0x4, SINDEX = 0x27, DINDEX = 0x23, ARG_2 = 0x3
  HCNT = 0x0 SCBPTR = 0x0

and

  7800 p0 DL      0:00.00 dump -0u /home 

in other words "in disk" "pages locked in core"

  # mt status
  mt: /dev/nrst0: Device busy

Do you know how to clear this process/make the drive respond?

Cheers,

Patrick