Define verb DTHOST
  Image sys$system:DTHSTIMG.EXE
  Parameter p1,prompt="DTn:",value(required,type=$device),label=UNIT
  parameter p2,label=FNAM,prompt="tape:",value(type=$infile)
  Qualifier TYPE,value(required,type=$file)
! IMAGE mode is for non-vms-backup disk dumps, just N disk blocks
! per tape block, no labels or other info there.
  qualifier IMAGE
! skip just skips files before starting. We rewind the tape and
! skip these because we must know where we are.
  qualifier SKIP,value(required,type=$number)
  qualifier TRK,value(required,type=$number)
  qualifier CYL,value(required,type=$number)
  qualifier SEC,value(required,type=$number)
  qualifier TCACHE,value(required,type=$number)
  qualifier CACHE,value(required,type=$number)
! Add /norewind switch to be used with /skip:0 (and force skip:0)
! to assume the current tape location is the start of the disk
! image. If you have something weird like a TAR dump of a disk
! image of a virtual disk, and skip the header block somehow, this
! might prove useful. Rare, but it's easy...let's have it in there
! for the oddball who really must have it...
  qualifier NOREWIND
  qualifier IGNCRC
  qualifier FRCCRC
  qualifier IGNXOR
  qualifier CRC
  qualifier FILE
! file unused	;unused
  qualifier CLEAR
! Specify cache in pages (cache) or in tape blocks (tcache)
! not both. Better to make the user make up his mind rather
! than rely on some programmatic default.
 disallow CACHE and TCACHE
! Image mode means not vms backup. Disallow image mode and switches
! that have meaning for backup only, just to make this easier NOT
! to get messed up with. Won't help user who confuses this much,
! but /image mode is not a default. We need to help the user not
! play too meaninglessly.
 disallow IMAGE and CRC
 disallow IMAGE and IGNCRC
 disallow IMAGE and FRCCRC
 disallow IMAGE and IGNXOR
! Note: CLEAR switch is for FDHOST.MAR only. It just zeroes the
! reference count of the FD: unit in case aborting control tasks
! left this nonzero.
! Uses FDHSTIMG to create a read-only virtual disk out of a
! back/physical (or hsc backup) saveset or a disk dump to tape
! using dtdriver.