Usage: sgm_dd  [bs=BS] [count=COUNT] [ibs=BS] [if=IFILE] [iflag=FLAGS]
               [obs=BS] [of=OFILE] [oflag=FLAGS] [seek=SEEK] [skip=SKIP]
               [--help] [--version]

               [bpt=BPT] [cdbsz=6|10|12|16] [dio=0|1] [fua=0|1|2|3]
               [sync=0|1] [time=0|1] [verbose=VERB] [--dry-run]
               [--nocopy] [--progress] [--verbose]

  where:
    bpt         is blocks_per_transfer (default is 128)
    bs          must be device logical block size (default 512)
    cdbsz       size of SCSI READ or WRITE cdb (default is 10)
    count       number of blocks to copy (def: device size)
    dio         0->indirect IO on write, 1->direct IO on write
                (only when read side is sg device (using mmap))
    fua         force unit access: 0->don't(def), 1->OFILE, 2->IFILE,
                3->OFILE+IFILE
    if          file or device to read from (def: stdin)
    iflag       comma separated list from: [direct,dpo,dsync,excl,fua,
                null]
    of          file or device to write to (def: stdout), OFILE of '.'
                treated as /dev/null
    oflag       comma separated list from: [append,dio,direct,dpo,dsync,
                excl,fua,null]
    seek        block position to start writing to OFILE
    skip        block position to start reading from IFILE
    sync        0->no sync(def), 1->SYNCHRONIZE CACHE on OFILE after copy
    time        0->no timing(def), 1->time plus calculate throughput
    verbose     0->quiet(def), 1->some noise, 2->more noise, etc
    --dry-run|-d    prepare but bypass copy/read
    --help|-h       print usage message then exit
    --nocopy|-n     prevent copy apart to of=/dev/null
    --progress|-p    outputs progress report every 2 minutes
    --verbose|-v    increase verbosity
    --version|-V    print version information then exit

Copy from IFILE to OFILE, similar to dd command
specialized for SCSI devices for which mmap-ed IO attempted