NAME

       sg_turs - send one or more SCSI TEST UNIT READY commands

SYNOPSIS

       sg_turs  [--delay=MS]  [--help]  [--low]  [--num=NUM] [--number=NUM] [--progress] [--time]
       [--verbose] [--version] DEVICE

       sg_turs [-d=MS] [-n=NUM] [-p]  [-t] [-v] [-V] DEVICE

DESCRIPTION

       This utility sends one or more SCSI TEST UNIT READY commands to the DEVICE.  This  may  be
       useful  for  timing the per command overhead.  Note that TEST UNIT READY has no associated
       data, just a 6 byte command (with each byte a zero) and a returned SCSI status value.

       This utility supports two command line syntaxes, the preferred one is shown first  in  the
       synopsis  and  explained  in  this section. A later section on the old command line syntax
       outlines the second group of options.

OPTIONS

       Arguments to long options are mandatory for short options as well.

       -d, --delay=MS
              this option causes a delay of MS milliseconds to occur before each TEST UNIT  READY
              command is issued.

       -h, --help
              print out the usage message then exit.

       -l, --low
              when  [--progress]  is not being used, this utility tries to complete the SCSI TEST
              UNIT READY command(s) as quickly as possible. Usually it calls a  library  function
              to  do  each  TUR (sg_ll_test_unit_ready). With this option it uses the lower level
              sg_pt interface (see sg_pt.h) to save a little time on each TUR.

       -n, --num=NUM
              performs TEST UNIT READY NUM times. If not  given  defaults  to  1.   These  suffix
              multipliers are permitted: c C *1; w W *2; b B *512; k K KiB *1,024; KB *1,000; m M
              MiB *1,048,576; MB *1,000,000; g G GiB *1,073,741,824; and GB *1,000,000,000 . Also
              a  suffix  of the form "x<n>" multiplies the leading number by <n>. Alternatively a
              hex number may be given, prefixed by either '0x' or has a trailing 'h'.

       --number=NUM
              same as --num=NUM. Added for compatibility with sg_requests and other utilities  in
              this  package.  The  sg_request  utility  has  taken  over  the role of polling the
              progress indication which was originally assigned to the TEST UNIT  READY  command.
              This is a change by T10.

       -O, --old
              Switch to older style options. Please use as first option.

       -p, --progress
              show progress indication (a percentage) if available. If --num=NUM is given, NUM is
              greater than 1 and an initial progress indication was detected  then  this  utility
              waits  30 seconds before subsequent checks.  If the --delay=MS option is given then
              it will wait for that number of milliseconds instead of 30 seconds.  Exits when NUM
              is  reached  or there are no more progress indications.  Ignores --time option. See
              NOTES section below.

       -t, --time
              after completing the requested number of TEST  UNIT  READY  commands,  outputs  the
              total duration and the average number of commands executed per second.

       -v, --verbose
              increase level or verbosity.

       -V, --version
              print version string then exit.

NOTES

       The  progress  indication  is optionally part of the sense data. When a prior command that
       takes a long time to complete (and typically precludes other  media  access  commands)  is
       still  underway,  the  progress  indication  can  be used to determine how long before the
       device returns to its normal state. Around SPC-3 T10 changed  the  preferred  command  for
       polling the progress indication from TEST UNIT READY to REQUEST SENSE (see the sg_requests
       utility).

       The SCSI FORMAT command for disks used with  the  IMMED  bit  set  is  an  example  of  an
       operation  that takes a significant amount of time and precludes other media access during
       that time. The IMMED bit set instructs  the  FORMAT  command  to  return  control  to  the
       application  client  once the format has commenced (see SBC-3). Several long duration SCSI
       commands associated with tape drives also use the progress indication (see SSC-3).

       The DEVICE is opened with a read-only flag (e.g. in Unix with the O_RDONLY flag).

       Early standards suggested that the SCSI TEST UNIT READY command be used  for  polling  the
       progress  indication. More recent standards seem to suggest the SCSI REQUEST SENSE command
       should be used instead.

EXIT STATUS

       The exit status of sg_turs is 0 when it is successful (e.g. in the case  of  a  mechanical
       disk,  it is spun up and ready to accept commands). For this utility the other exit status
       of interest is 2 corresponding to the "not ready" sense key. For other exit status  values
       see the sg3_utils(8) man page.

OLDER COMMAND LINE OPTIONS

       The options in this section were the only ones available prior to sg3_utils version 1.23 .
       Since then this utility defaults to the newer command line options which can be overridden
       by  using  --old  (or  -O)  as the first option. See the ENVIRONMENT VARIABLES section for
       another way to force the use of these older command line options.

       -d, --delay=MS
              this option causes a delay of MS milliseconds to occur before each TEST UNIT  READY
              command is issued.

       -n=NUM performs  TEST  UNIT  READY  NUM  times. If not given defaults to 1.  Equivalent to
              --num=NUM in the main description.

       -N, --new
              Switch to the newer style options.

       -p     show progress indication (a percentage) if available.  Equivalent to --progress  in
              the main description.

       -t     after  completing  the  requested  number  of TEST UNIT READY commands, outputs the
              total duration and the average number of commands executed per second.   Equivalent
              to --time in the main description.

       -v     increase level of verbosity.

       -V     print out version string then exit.

ENVIRONMENT VARIABLES

       Since  sg3_utils  version  1.23  the environment variable SG3_UTILS_OLD_OPTS can be given.
       When it is present this utility will  expect  the  older  command  line  options.  So  the
       presence  of  this  environment variable is equivalent to using --old (or -O) as the first
       command line option.

AUTHORS

       Written by D. Gilbert

COPYRIGHT

       Copyright © 2000-2020 Douglas Gilbert
       This software is distributed under the GPL version 2. There is NO warranty; not  even  for
       MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

SEE ALSO

       sg_inq, sg_requests (sg3_utils)