| .TH SG_SCAN "8" "May 2013" "sg3_utils\-1.36" SG3_UTILS |
| .SH NAME |
| sg_scan \- scans sg devices (or SCSI/ATAPI/ATA devices) and prints |
| results |
| .SH SYNOPSIS |
| .B sg_scan |
| [\fI\-a\fR] |
| [\fI\-i\fR] |
| [\fI\-n\fR] |
| [\fI\-w\fR] |
| [\fI\-x\fR] |
| [\fIDEVICE\fR]* |
| .SH DESCRIPTION |
| .\" Add any additional description here |
| .PP |
| If no \fIDEVICE\fR names are given, sg_scan does a scan of the sg |
| devices and outputs a line of information for each sg device that is |
| currently bound to a SCSI device. If one or more \fIDEVICE\fRs are given |
| only those devices are scanned. |
| Each device is opened with the O_NONBLOCK flag so that the scan will |
| not "hang" on any device that another process holds an O_EXCL lock on. |
| .PP |
| Any given \fIDEVICE\fR name is expected to comply |
| with (to some extent) the Storage Architecture Model (SAM see www.t10.org). |
| Any device names associated with the Linux SCSI subsystem (e.g. /dev/sda |
| and /dev/st0m) are suitable. Devices names associated with ATAPI |
| devices (e.g. most CD/DVD drives and ATAPI tape drives) are also suitable. |
| If the device does not fall into the above categories then an ATA |
| IDENTIFY command is tried. |
| .PP |
| In Linux 2.6 and 3 series kernels, the lsscsi utility may be helpful. Apart |
| from providing more information (by data\-mining in the sysfs pseudo file |
| system), it does not need root permissions to execute, as this utility |
| would typically need. |
| .SH OPTIONS |
| .TP |
| \fB\-a\fR |
| do alphabetical scan (i.e. sga, sgb, sgc). Note that sg device nodes with |
| an alphabetical index have been deprecated since the Linux kernel 2.2 |
| series. |
| .TP |
| \fB\-i\fR |
| do a SCSI INQUIRY, output results in a second (indented) line. If the device |
| is an ATA disk then output information from an ATA IDENTIFY command |
| .TP |
| \fB\-n\fR |
| do numeric scan (i.e. sg0, sg1...) [default] |
| .TP |
| \fB\-w\fR |
| use a read/write flag when opening sg device (default is read\-only) |
| .TP |
| \fB\-x\fR |
| extra information output about queueing |
| .SH NOTES |
| This utility was written at a time when hotplugging of SCSI devices |
| was not supported in Linux. It used a simple algorithm to scan sg |
| device nodes in ascending numeric or alphabetical order, stopping |
| after there were 4 consecutive errors. |
| .PP |
| In the Linux kernel 2.6 series, this utility uses sysfs to find which |
| sg device nodes are active and only checks those. Hence there can be |
| large "holes" in the numbering of sg device nodes (e.g. after an |
| adapter has been removed) and still all active sg device nodes will |
| be listed. This utility assumes that sg device nodes are named using |
| the normal conventions and searches from /dev/sg0 to /dev/sg4095 |
| inclusive. |
| .SH EXIT STATUS |
| The exit status of sg_scan is 0 when it is successful. Otherwise see |
| the sg3_utils(8) man page. |
| .SH AUTHORS |
| Written by D. Gilbert and F. Jansen |
| .SH COPYRIGHT |
| Copyright \(co 1999\-2013 Douglas Gilbert |
| .br |
| This software is distributed under the GPL version 2. There is NO |
| warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. |
| .SH "SEE ALSO" |
| .B lsscsi(8) |
