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SG_TIMESTAMP(8) SG3_UTILS SG_TIMESTAMP(8)
NAME
sg_timestamp - report or set timestamp on SCSI device
SYNOPSIS
sg_timestamp [--elapsed] [--help] [--hex] [--milliseconds=MS] [--no-timestamp] [--origin]
[--raw] [--readonly] [--seconds=SECS] [--srep] [--verbose] [--version] DEVICE
DESCRIPTION
Sends a SCSI REPORT TIMESTAMP or SET TIMESTAMP command to the DEVICE. These commands are
found in the SPC-5 draft standard revision 7 (spc5r07.pdf).
If either the --milliseconds=MS or --seconds=SECS option is given (and both can't be
given) then the SET TIMESTAMP command is sent; otherwise the REPORT TIMESTAMP command is
sent.
The timestamp is sent and received from the DEVICE as the number of milliseconds since the
epoch of 1970-01-01 00:00:00 UTC and is held in a 48 bit unsigned integer. That same epoch
is used by Unix machines, but they usually hold the number of seconds since that epoch.
The Unix date command and especially its "+%s" format is useful in converting to and from
timestamps and more humanly readable forms. See the EXAMPLES section below.
OPTIONS
Arguments to long options are mandatory for short options as well.
-e, --elapsed
assume the timestamp in the REPORT TIMESTAMP is an elapsed time from an event such
as a power cycle or hard reset and format the output as '<n> days hh:mm:ss.xxx'
where hh is hours (00 to 23 inclusive); mm is minutes (00 to 59 inclusive); ss is
seconds (00 to 59 inclusive) and xxx is milliseconds (000 to 999 inclusive). If the
number of days is 0 then '0 days' is not output unless this option is given two or
more times.
-h, --help
output the usage message then exit.
-H, --hex
output the response to REPORT TIMESTAMP in ASCII hexadecimal on stderr. The re-
sponse is not decoded.
-m, --milliseconds=MS
where MS is the number of milliseconds since 1970-01-01 00:00:00 UTC to set in the
DEVICE with the SCSI SET TIMESTAMP command.
-N, --no-timestamp
when REPORT TIMESTAMP is called this option suppress the output of the timestamp
value (in either seconds or milliseconds). This may be useful in uncluttering the
output when trying to decode the timestamp origin (see the --origin option).
-o, --origin
the REPORT TIMESTAMP returned parameter data contains a "timestamp origin" field.
When this option is given, that field is decoded and printed out before the time-
stamp value is output. The default action (i.e. when the option is not given) is
not to print out this decoded field.
T10 defines this field as "the most recent event that initialized the returned de-
vice clock". The value 0 indicates a power up of hard reset initialized the clock;
2 indicates a SET TIMESTAMP initialized the clock while 3 indicates some other
method initialized the clock.
When used once a descriptive string is output (in a line before the timestamp
value). When used twice the value of the TIMESTAMP ORIGIN field is output (in deci-
mal, a value between 0 and 7 inclusive). When used thrice a line of the form 'TIME-
STAMP_ORIGIN=<value>' is output.
-r, --raw
output the SCSI REPORT TIMESTAMP response (i.e. the data-out buffer) in binary (to
stdout). Note that the --origin and --srep options are ignored when this option is
given. Also all error and verbose messages are output to stderr.
-R, --readonly
open the DEVICE read-only. The default action is to open the DEVICE read-write.
-s, --seconds=SECS
where SECS is the number of seconds since 1970-01-01 00:00:00 UTC to set in the DE-
VICE with the SCSI SET TIMESTAMP command. SECS is multiplied by 1000 before being
used in the SET TIMESTAMP command.
-S, --srep
report the number of seconds since 1970-01-01 00:00:00 UTC. This is done by divid-
ing by 1000 the value returned by the SCSI REPORT TIMESTAMP command.
-v, --verbose
increase the level of verbosity, (i.e. debug output).
-V, --version
print the version string and then exit.
EXIT STATUS
The exit status of sg_timestamp is 0 when it is successful. Otherwise see the sg3_utils(8)
man page.
NOTES
The TCMOS and the SCSIP bits in the Control extension mode page (see sdparm) modify the
actions of the timestamp held by a DEVICE.
Currently only the "Utilization usage rate based on date and time" parameters within the
Utilization log page (sbc4r09.pdf) use timestamps. See the sg_logs utility. Vendor spe-
cific commands and pages may also be using timestamps.
EXAMPLES
On Unix machines (e.g. Linux, FreeBSD and Solaris) the date command is useful when working
with timestamps.
To fetch the timestamp from a DEVICE and display it in a humanly readable form the follow-
ing could be used:
# sg_timestamp -S /dev/sdb
1448993950
# date --date=@1448993950
Tue Dec 1 13:19:10 EST 2015
# date -R --date="@1448993950"
Tue, 01 Dec 2015 13:19:10 -0500
The latter two date commands show different forms of the same date (i.e. 1448993950 sec-
onds since 1970-01-01 00:00:00 UTC). The sg_timestamp and date commands can be combined
using backquotes:
# date -R --date=@`sg_timestamp -S /dev/sdc`
Wed, 16 Dec 2015 20:12:59 -0500
To set the timestamp on the DEVICE to now (approximately) the following could be used:
# date +%s
1448993955
# sg_timestamp --seconds=1448993955 /dev/sdb
Those two command lines could be combined into one by using backquotes:
# sg_timestamp --seconds=`date +%s` /dev/sdb
AUTHORS
Written by Douglas Gilbert.
REPORTING BUGS
Report bugs to <dgilbert at interlog dot com>.
COPYRIGHT
Copyright (C) 2015-2018 Douglas Gilbert
This software is distributed under a FreeBSD license. There is NO warranty; not even for
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
SEE ALSO
sdparm(sdparm), sg_logs(sg3_utils)
sg3_utils-1.43 April 2018 SG_TIMESTAMP(8)
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