/usr/bin/sg_read

Usage: sg_read  [blk_sgio=0|1] [bpt=BPT] [bs=BS] [cdbsz=6|10|12|16]
                count=COUNT [dio=0|1] [dpo=0|1] [fua=0|1] if=IFILE
                [mmap=0|1] [no_dfxer=0|1] [odir=0|1] [skip=SKIP]
                [time=TI] [verbose=VERB] [--help] [--verbose]
                [--version]   where:
    blk_sgio 0->normal IO for block devices, 1->SCSI commands via SG_IO
    bpt      is blocks_per_transfer (default is 128, or 64 KiB for default BS)
             setting 'bpt=0' will do COUNT zero block SCSI READs
    bs       must match sector size if IFILE accessed via SCSI commands
             (def=512)
    cdbsz    size of SCSI READ command (default is 10)
    count    total bytes read will be BS*COUNT (if no error)
             (if negative, do |COUNT| zero block SCSI READs)
    dio      1-> attempt direct IO on sg device, 0->indirect IO (def)
    dpo      1-> set disable page out (DPO) in SCSI READs
    fua      1-> set force unit access (FUA) in SCSI READs
    if       an sg, block or raw device, or a seekable file (not stdin)
    mmap     1->perform mmap-ed IO on sg device, 0->indirect IO (def)
    no_dxfer 1->DMA to kernel buffers only, not user space, 0->normal(def)
    odir     1->open block device O_DIRECT, 0->don't (def)
    skip     each transfer starts at this logical address (def=0)
    time     0->do nothing(def), 1->time from 1st cmd, 2->time from 2nd, ...
    verbose  increase level of verbosity (def: 0)
    --help|-h    print this usage message then exit
    --verbose|-v   increase level of verbosity (def: 0)
    --version|-V   print version number then exit

Issue SCSI READ commands, each starting from the same logical block address