sg3_utils/doc/sg_test_rwbuf.8 - backupdr - Git at Google

 .TH SG_TEST_RWBUF "8" "November 2012" "sg3_utils\-1.35" SG3_UTILS
 .SH NAME
 sg_test_rwbuf \- test a SCSI host adapter by issuing dummy writes
 and reads
 .SH SYNOPSIS
 .B sg_test_rwbuf
 [\fI\-\-addrd=AR\fR] [\fI\-\-addwr=AW\fR] [\fI\-\-help\fR]
 [\fI\-\-quick\fR] \fI\-\-size=SZ\fR [\fI\-\-times=NUM\fR] [\fI\-\-verbose\fR]
 [\fI\-\-version\fR] \fIDEVICE\fR
 .PP
 or an older deprecated format
 .B sg_test_rwbuf
 \fIDEVICE\fR \fISZ\fR [\fIAW\fR] [\fIAR\fR]
 .SH DESCRIPTION
 .\" Add any additional description here
 .PP
 sg_test_rwbuf writes and reads back \fISZ\fR bytes to the internal buffer of
 \fIDEVICE\fR (e.g. /dev/sda or /dev/sg0). A pseudo random pattern is
 written to the data buffer on the device then read back. If the same pattern
 is found 'Success' is reported. If they do not match (checksums unequal) then
 this is reported and up to 24 bytes from the first point of mismatch are
 reported; the first line shows what was written and the second line shows
 what was received. For testing purposes, you can ask it to write \fIAW\fR or
 read \fIAR\fR additional bytes.
 .SH OPTIONS
 Arguments to long options are mandatory for short options as well.
 .TP
 \fB\-r\fR, \fB\-\-addrd\fR=\fIAR\fR
 Read an additional \fIAR\fR bytes (than indicated by \fISZ\fR) from the data
 buffer. Checksum is performed over the first \fISZ\fR bytes.
 .TP
 \fB\-w\fR, \fB\-\-addwr\fR=\fIAW\fR
 Write an additional \fIAW\fR bytes (than indicated by \fISZ\fR) of zeros
 into the data buffer. Checksum is generated over the first \fISZ\fR bytes.
 .TP
 \fB\-h\fR, \fB\-\-help\fR
 Print out a usage message the exit.
 .TP
 \fB\-q\fR, \fB\-\-quick\fR
 Perform a READ BUFFER descriptor command to find out the available data
 buffer length and offset, print them out then exit (without testing
 with write/read sequences).
 .TP
 \fB\-s\fR, \fB\-\-size\fR=\fISZ\fR
 where \fISZ\fR is the size of buffer in bytes to be written then read and
 checked. This number needs to be less than or equal to the size of the
 device's data buffer which can be seen from the \fI\-\-quick\fR option.
 Either this option or the \fI\-\-quick\fR option should be given.
 .TP
 \fB\-t\fR, \fB\-\-times\fR=\fINUM\fR
 where \fINUM\fR is the number of times to repeat the write/read to buffer
 test. Default value is 1 .
 .TP
 \fB\-v\fR, \fB\-\-verbose\fR
 increase verbosity of output.
 .TP
 \fB\-V\fR, \fB\-\-version\fR
 print version number (and data of last change) then exit.
 .SH NOTES
 The microcode in a SCSI device is _not_ modified by doing a WRITE BUFFER
 command with its mode set to "data" (0x2) as done by this utility. Therefore
 this utility is safe in that respect. [Mode values 0x4, 0x5, 0x6 and 0x7
 are the dangerous ones :\-)]
 .PP
 \fBWARNING\fR: If you access the device at the same time (e.g. because it's
 a hard disk with a mounted file system on it) the device's buffer may be
 used by the device itself for other data at the same time, and overwriting
 it may or may not cause data corruption! \fBHOWEVER\fR the SPC\-3 draft
 standard does state in its WRITE BUFFER command: "This command shall not
 alter any medium of the logical unit when data mode ... is specified". This
 implies that it _is_ safe to use this utility with devices that have mounted
 file systems on them.
 Following this theme further, a disk with active mounted file systems may cause
 the data read back to be different (due to caching activity) to what was written
 and hence a checksum error.
 .SH EXIT STATUS
 The exit status of sg_test_rwbuf is 0 when it is successful. Otherwise see
 the sg3_utils(8) man page.
 .SH AUTHORS
 Written by D. Gilbert and K. Garloff
 .SH COPYRIGHT
 Copyright \(co 2000\-2012 Douglas Gilbert, Kurt Garloff
 .br
 This software is distributed under the GPL version 2. There is NO
 warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
	.TH SG_TEST_RWBUF "8" "November 2012" "sg3_utils\-1.35" SG3_UTILS
	.SH NAME
	sg_test_rwbuf \- test a SCSI host adapter by issuing dummy writes
	and reads
	.SH SYNOPSIS
	.B sg_test_rwbuf
	[\fI\-\-addrd=AR\fR] [\fI\-\-addwr=AW\fR] [\fI\-\-help\fR]
	[\fI\-\-quick\fR] \fI\-\-size=SZ\fR [\fI\-\-times=NUM\fR] [\fI\-\-verbose\fR]
	[\fI\-\-version\fR] \fIDEVICE\fR
	.PP
	or an older deprecated format
	.B sg_test_rwbuf
	\fIDEVICE\fR \fISZ\fR [\fIAW\fR] [\fIAR\fR]
	.SH DESCRIPTION
	.\" Add any additional description here
	.PP
	sg_test_rwbuf writes and reads back \fISZ\fR bytes to the internal buffer of
	\fIDEVICE\fR (e.g. /dev/sda or /dev/sg0). A pseudo random pattern is
	written to the data buffer on the device then read back. If the same pattern
	is found 'Success' is reported. If they do not match (checksums unequal) then
	this is reported and up to 24 bytes from the first point of mismatch are
	reported; the first line shows what was written and the second line shows
	what was received. For testing purposes, you can ask it to write \fIAW\fR or
	read \fIAR\fR additional bytes.
	.SH OPTIONS
	Arguments to long options are mandatory for short options as well.
	.TP
	\fB\-r\fR, \fB\-\-addrd\fR=\fIAR\fR
	Read an additional \fIAR\fR bytes (than indicated by \fISZ\fR) from the data
	buffer. Checksum is performed over the first \fISZ\fR bytes.
	.TP
	\fB\-w\fR, \fB\-\-addwr\fR=\fIAW\fR
	Write an additional \fIAW\fR bytes (than indicated by \fISZ\fR) of zeros
	into the data buffer. Checksum is generated over the first \fISZ\fR bytes.
	.TP
	\fB\-h\fR, \fB\-\-help\fR
	Print out a usage message the exit.
	.TP
	\fB\-q\fR, \fB\-\-quick\fR
	Perform a READ BUFFER descriptor command to find out the available data
	buffer length and offset, print them out then exit (without testing
	with write/read sequences).
	.TP
	\fB\-s\fR, \fB\-\-size\fR=\fISZ\fR
	where \fISZ\fR is the size of buffer in bytes to be written then read and
	checked. This number needs to be less than or equal to the size of the
	device's data buffer which can be seen from the \fI\-\-quick\fR option.
	Either this option or the \fI\-\-quick\fR option should be given.
	.TP
	\fB\-t\fR, \fB\-\-times\fR=\fINUM\fR
	where \fINUM\fR is the number of times to repeat the write/read to buffer
	test. Default value is 1 .
	.TP
	\fB\-v\fR, \fB\-\-verbose\fR
	increase verbosity of output.
	.TP
	\fB\-V\fR, \fB\-\-version\fR
	print version number (and data of last change) then exit.
	.SH NOTES
	The microcode in a SCSI device is _not_ modified by doing a WRITE BUFFER
	command with its mode set to "data" (0x2) as done by this utility. Therefore
	this utility is safe in that respect. [Mode values 0x4, 0x5, 0x6 and 0x7
	are the dangerous ones :\-)]
	.PP
	\fBWARNING\fR: If you access the device at the same time (e.g. because it's
	a hard disk with a mounted file system on it) the device's buffer may be
	used by the device itself for other data at the same time, and overwriting
	it may or may not cause data corruption! \fBHOWEVER\fR the SPC\-3 draft
	standard does state in its WRITE BUFFER command: "This command shall not
	alter any medium of the logical unit when data mode ... is specified". This
	implies that it _is_ safe to use this utility with devices that have mounted
	file systems on them.
	Following this theme further, a disk with active mounted file systems may cause
	the data read back to be different (due to caching activity) to what was written
	and hence a checksum error.
	.SH EXIT STATUS
	The exit status of sg_test_rwbuf is 0 when it is successful. Otherwise see
	the sg3_utils(8) man page.
	.SH AUTHORS
	Written by D. Gilbert and K. Garloff
	.SH COPYRIGHT
	Copyright \(co 2000\-2012 Douglas Gilbert, Kurt Garloff
	.br
	This software is distributed under the GPL version 2. There is NO
	warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.