Provided by: sg3-utils_1.46-1build1_amd64 bug


       sg_xcopy - copy data to and from files and devices using SCSI EXTENDED COPY (XCOPY)


       sg_xcopy  [bs=BS]  [conv=CONV]  [count=COUNT]  [ibs=BS]  [if=IFILE] [iflag=FLAGS] [obs=BS]
       [of=OFILE] [oflag=FLAGS] [seek=SEEK] [skip=SKIP] [--help] [--version]

       [app=0|1]  [bpt=BPT]  [cat=0|1]   [dc=0|1]   [fco=0|1]   [id_usage={hold|discard|disable}]
       [list_id=ID] [prio=PRIO] [time=0|1] [verbose=VERB] [--on_dst|--on_src] [--verbose]


       Copy  data to and from any files. Specialized for "files" that are Linux SCSI devices that
       support the SCSI EXTENDED COPY (XCOPY) command.

       This utility has similar syntax and semantics  to  dd(1)  but  with  no  "conversions"  is

       The first group in the synopsis above are "standard" Unix dd(1) operands. The second group
       are extra options added by this utility.  Both  groups  are  defined  below  in  combined,
       alphabetical order.

       By  default  the  XCOPY command is sent to OFILE. This can be changed with the --on_src or
       iflag=xflag options which cause the XCOPY command to be sent to IFILE  instead.  Also  see
       the section on ENVIRONMENT VARIABLES.

       In  the SPC-4 standard the T10 committee has expanded the XCOPY command so that it now has
       two variants: "LID1" (for a List Identifier length of 1  byte)  and  "LID4"  (for  a  List
       Identifier length of 4 bytes). This utility supports the older, LID1 variant which is also
       found in SPC-3 and earlier. While the LID1 variant in  SPC-4  is  command  level  (binary)
       compatible  with  XCOPY  as defined in SPC-3, some of the command naming has changed. This
       utility uses the older, SPC-3 XCOPY names.

       The ddpt utility supports the same xcopy(LID1) functionality as this utility with the same
       options  and  flags.  Additionally  ddpt  supports  a  subset of xcopy(LID4) functionality
       variously called "xcopy version 2, lite" or ODX.  ODX is a  market  name  and  stands  for
       Offloaded Data Xfer (i.e. transfer).


              if 1 start the destination of the copy at the end of OFILE. This assumes that OFILE
              is a regular file. The default is 0 in which  case  the  destination  of  the  copy
              starts  at  the beginning of OFILE (possibly offset be SEEK). This option cannot be
              used with the seek=SEEK option.

              each IO transaction will be made using BPT blocks (or less if near the end  of  the
              copy).  Default  is 128 for logical block sizes less that 2048 bytes, otherwise the
              default is 32. So for bs=512 the reads and writes will each convey 64 KiB  of  data
              by  default  (less  if  near  the end of the transfer or memory restrictions). When
              cd/dvd drives are accessed, the logical block size is typically 2048 bytes and  bpt
              defaults to 32 which again implies 64 KiB transfers.

       bs=BS  where BS must be the logical block size of the physical device (if either the input
              or output files are accessed via SCSI commands). Note that this differs from  dd(1)
              which  permits  BS to be an integral multiple. Defaults to the device logical block

              sets the SCSI EXTENDED COPY command segment descriptor CAT bit to 0 or 1  (default:
              0). The CAT bit (in conjunction with the PAD bit) controls the handling of residual
              data. See section HANDLING OF RESIDUAL DATA for details.

              all CONV arguments are ignored.

              copy COUNT blocks from IFILE to OFILE. Default is the minimum  (IFILE  if  dc=0  or
              OFILE  if  dc=1)  number of blocks that SCSI devices report from SCSI READ CAPACITY
              commands or that block devices (or their partitions) report. Normal files  are  not
              probed for their size. If skip=SKIP or seek=SEEK are given and the count is derived
              (i.e. not explicitly given) then the derived count is scaled back so that the  copy
              will not overrun the device. If the file name is a block device partition and COUNT
              is not given then the size of the partition rather  than  the  size  of  the  whole
              device  is  used. If COUNT is not given (or count=-1) and cannot be derived then an
              error message is issued and no copy takes place.

              sets the SCSI EXTENDED COPY command segment descriptor DC bit to 0 or  1  (default:
              0).  The  DC  bit  controls whether COUNT refers to the source (dc=0) or the target
              (dc=1) descriptor.

              sets the SCSI EXTENDED COPY command segment descriptor FCO bit to 0 or 1  (default:
              0).  The  Fast  Copy  Only  (FCO)  bit set will result in the copy being done but a
              technique faster than SCSI READ and WRITE commands.  If the copy cannot but done in
              a  faster  manner  then  a sense key of "Copy aborted" with and additional sense of
              "Fast copy not possible" is returned.

       ibs=BS if given must be the same as BS given to 'bs=' option.

              sets the SCSI EXTENDED COPY command parameter list field called LIST ID USAGE to  0
              if  the  argument  is  'hold',  to 2 if the argument is 'discard', or to '3' if the
              argument is 'disable'.
              If the device has the ability to hold data (as indicated by "held data limit" being
              greater  than  zero)  then  id_usage  defaults  to  'hold' otherwise it defaults to

              read from IFILE instead of stdin. If IFILE  is  '-'  then  stdin  is  read.  Starts
              reading at the beginning of IFILE unless SKIP is given.

              where  FLAGS  is a comma separated list of one or more flags outlined below.  These
              flags are associated with IFILE and are ignored when IFILE is stdin.

              sets the SCSI EXTENDED COPY command parameter list field called LIST IDENTIFIER  to
              ID.  ID  should  be a value between 0 and 255 (inclusive). ID usually defaults to 1
              unless id_usage=disable in which case it defaults to 0.

       obs=BS if given must be the same as BS given to 'bs=' option.

              write to OFILE instead of stdout. If OFILE is '-' then writes to stdout.  If  OFILE
              is /dev/null then no actual writes are performed.  If OFILE is '.' (period) then it
              is treated the same way as /dev/null (this  is  a  shorthand  notation).  If  OFILE
              exists then it is _not_ truncated; it is overwritten from the start of OFILE unless
              'oflag=append' or SEEK is given.

              where FLAGS is a comma separated list of one or more flags outlined  below.   These
              flags  are  associated  with  OFILE  and  are  ignored when OFILE is /dev/null, '.'
              (period), or stdout.

              sets the SCSI EXTENDED COPY command parameter list field called PRIORITY  to  PRIO.
              The default value is 1.

              start  writing  SEEK  bs-sized  blocks from the start of OFILE.  Default is block 0
              (i.e. start of file).

              start reading SKIP bs-sized blocks from the start of IFILE.   Default  is  block  0
              (i.e. start of file).

              when  1, times transfer and does throughput calculation, outputting the results (to
              stderr) at completion. When 0 (default) doesn't perform timing.

              as VERB increases so does the amount of debug output sent to stderr.  Default value
              is  zero  which  yields  the  minimum amount of debug output.  A value of 1 reports
              extra information that is not repetitive. A value 2 reports cdbs and responses  for
              SCSI  commands  that  are  not  repetitive  (i.e. other that READ and WRITE). Error
              processing is not considered repetitive. Values of 3 and 4  yield  output  for  all
              SCSI commands (and Unix read() and write() calls) so there can be a lot of output.

       -h, --help
              outputs usage message and exits.

              send  the XCOPY command to the output file/device (i.e. OFILE). This is the default
              unless overridden by the --on_src or iflag=xflag  options.  Also  see  the  section
              below on ENVIRONMENT VARIABLES.

              send the XCOPY command to the input file/device (i.e. IFILE).

       -v, --verbose
              equivalent to verbose=1. When used twice, equivalent to verbose=2, etc.

       -V, --version
              outputs version number information and exits.


       Here is a list of flags and their meanings:

       append causes  the  O_APPEND flag to be added to the open of OFILE. For regular files this
              will lead to data appended to the  end  of  any  existing  data.   Cannot  be  used
              together  with  the  seek=SEEK option as they conflict.  The default action of this
              utility is to overwrite any existing data from the beginning of  the  file  or,  if
              SEEK is given, starting at block SEEK. Note that attempting to 'append' to a device
              file (e.g.  a disk) will usually be ignored or may cause an error to be reported.

       excl   causes the O_EXCL flag to be added to the open of IFILE and/or OFILE.

       flock  after opening the associated file (i.e. IFILE and/or OFILE) an attempt is  made  to
              get  an  advisory  exclusive lock with the flock() system call. The flock arguments
              are "FLOCK_EX | FLOCK_NB" which will cause the lock to be taken if available else a
              "temporarily  unavailable"  error is generated. An exit status of 90 is produced in
              the latter case and no copy is done.

       null   has no affect, just a placeholder.

       pad    sets the SCSI EXTENDED COPY command segment descriptor PAD bit.  The  PAD  bit  (in
              conjunction  with  the CAT bit) controls the handling of residual data.(See section
              HANDLING OF RESIDUAL DATA for details.

       xcopy  has no affect; for compatibility with ddpt.


       The pad and cat bits control the handling of residual data. As the data can  be  specified
       either in terms of source or target logical block size and both might have different block
       sizes residual data is likely to happen in these cases.  If both logical block  sizes  are
       identical these bits have no effect as residual data will not occur.

       If  none  of these bits are set, the EXTENDED COPY command will be aborted with additional

       If only the cat bit is set the residual data will  be  retained  and  made  available  for
       subsequent  segment  descriptors.  Residual  data  will  be discarded for the last segment

       If the pad bit is set for the source descriptor only, any residual data for both source or
       destination will be discarded.

       If  the  pad  bit  is  set for the target descriptor only any residual source data will be
       handled as if the cat bit is set, but any residual destination data will be padded to make
       a whole block transfer.

       If  the  pad  bit  is  set  for  both  source  and target any residual source data will be
       discarded, and any residual destination data will be padded.


       If the command line invocation does not explicitly (and  unambiguously)  indicate  whether
       the  XCOPY  SCSI  command  should  be  sent to IFILE (i.e.  the source) or OFILE (i.e. the
       destination) then a check is made for the presence of the  XCOPY_TO_SRC  and  XCOPY_TO_DST
       environment  variables.  If  either  one exists (but not both) then it indicates where the
       SCSI XCOPY command will be sent. By default the XCOPY command is sent to OFILE.


       Here are some retired options that are still present:

       append=0 | 1
              when set, equivalent to 'oflag=append'. When clear the action is to  overwrite  the
              existing file (if it exists); this is the default.  See the 'append' flag.


       Copying  data  behind an Operating System's back can cause problems. In the case of Linux,
       users should look at this link:
       This command sequence may be useful:
         sync; echo 3 > /proc/sys/vm/drop_caches

       Various numeric arguments (e.g. SKIP) may include multiplicative suffixes or be  given  in
       hexadecimal. See the "NUMERIC ARGUMENTS" section in the sg3_utils(8) man page.

       The  COUNT,  SKIP and SEEK arguments can take 64 bit values (i.e. very big numbers). Other
       values are limited to what can fit in a signed 32 bit number.

       All informative, warning and error output is sent to stderr so that dd's output  file  can
       be stdout and remain unpolluted. If no options are given, then the usage message is output
       and nothing else happens.

       If a device supports xcopy operations then it should set the 3PC  field  (3PC  stands  for
       Third  Party  Copy)  in  its standard INQUIRY response.  This utility will attempt a xcopy
       operation irrespective of the value in the 3PC field but if it is zero (cleared) one would
       expect the xcopy operation to fail.

       The    status    of    the    SCSI   EXTENDED   COPY   command   can   be   queried   with

       Currently only block-to-block transfers are implemented; IFILE and OFILE must refer  to  a
       SCSI block device.

       No  account  is  taken  of  partitions so, for example, /dev/sbc2, /dev/sdc, /dev/sg2, and
       /dev/bsg/3:0:0:1 would all refer to the same thing: the whole logical unit (i.e. the whole
       disk) starting at LBA 0. So any partition indication (e.g. /dev/sdc2) is ignored. The user
       should set SKIP,  SEEK and COUNT with information obtained from a command like  'fdisk  -l
       -u /dev/sdc' to account for partitions.

       XCOPY  (LID1)  capability  has been added to the ddpt utility which is in a package of the
       same name. The ddpt utility will run on  other  OSes  (e.g.  FreeBSD  and  Windows)  while
       sg_xcopy  only  runs  on  Linux.  Also  ddpt  permits the arguments to ibs= and ibs= to be


       Copy 2M of data from the start of one device to another:

       # sg_xcopy if=/dev/sdo of=/dev/sdp count=2048 list_id=2 dc=1
       sg_xcopy: if=/dev/sdo skip=0 of=/dev/sdp seek=0 count=1024
       Start of loop, count=1024, bpt=65535, lba_in=0, lba_out=0
       sg_xcopy: 1024 blocks, 1 command

       Check the status of the EXTENDED COPY command:

       # sg_copy_results --status --list_id=2 /dev/sdp
       Receive copy results (copy status):
           Held data discarded: Yes
           Copy manager status: Operation completed without errors
           Segments processed: 1
           Transfer count units: 0
           Transfer count: 0


       The signal handling has been borrowed from dd: SIGINT,  SIGQUIT  and  SIGPIPE  output  the
       number  of  remaining  blocks to be transferred and the records in + out counts; then they
       have their default action.  SIGUSR1 causes the same information to be output yet the  copy
       continues.  All output caused by signals is sent to stderr.


       The exit status of sg_xcopy is 0 when it is successful. Otherwise see the sg3_utils(8) man

       An additional exit status of 90 is generated if the flock flag is  given  and  some  other
       process holds the advisory exclusive lock.


       Written by Hannes Reinecke and Douglas Gilbert.


       Report bugs to <dgilbert at interlog dot com>.


       Copyright © 2000-2019 Hannes Reinecke and Douglas Gilbert
       This  software  is distributed under the GPL version 2. There is NO warranty; not even for


       There is a web page discussing sg_dd at

       A POSIX threads version of this utility called sgp_dd is in the sg3_utils package. Another
       version from that package is called sgm_dd and it uses memory mapped IO to speed transfers
       from sg devices.

       The lmbench package contains lmdd which is also interesting. For moving data to  and  from
       tapes see dt which is found at

       To  change  mode  parameters  that  effect  a SCSI device's caching and error recovery see

       See also dd(1), sg_copy_results(sg3_utils), ddrescue(GNU), ddpt,ddptctl(ddpt)