[olpc-nz] [OLPC-AU] Testing Summary: Auckland NZ - 19 March 2011

[James Cameron]

On Mon, Mar 21, 2011 at 10:04:46PM +1300, Tom Parker wrote:
> Uggh. More about what I'm trying to do. After collecting the power logs
> from each XO, I want to work out which correspond to "today". This is
> surprisingly difficult when the XOs have some semi-random time zone and
> our testing sessions often span a day boundary in the GMT time zone. So
> I wrote a script to rename the log files to my local time. I
> (foolishly ??) chose to do this in python. I'm running on my laptop, not
> the XO and it's beginning to sound like I should give up and use java
> where SimpleDateFormat would be my friend. 
> 
> I could maybe make a mapping between the three letter timezone and the
> longer timezone name and work out how to change timezones within the
> script before parsing, but surely there has to be a better way?

The problem is much simpler ... by being impossible ... the timezone is
_missing_ from the log, and you can't reliably reconstruct it,
especially since you are also testing builds that have a timezone set
already.  The timezone abbreviation that is present isn't unique.

You _can_ reliably reconstruct the UTC offset of the timezone, which
might be enough for your purposes.

Take the first log line after <StartData>, and use this as the date of
the file.  You might then take a punt and relate this to the DATE line,
or take into account rhe BUILD: line.  ;-)

However, you will need to assume the XO's RTC or hardware clock
$(hwclock) is set properly.  In OpenFirmware I use "wifi networkname"
followed by "ntp-set-clock".  In Linux, I use "ntpdate pool.ntp.org &&
hwclock --systohc --utc".  Do it first in Linux to see the total drift
so far.  In current builds the RTC may drift backward, see #10757.

Looking at file pwr-CSN74804D7E-110319_092045.csv we see the first data
line is:

1300492245,52,6379990,-1155598,3053,6583214,Discharging,startup

... and this is ...

$ TZ=Australia/Darwin date --date=@1300492245
Sat Mar 19 09:20:45 CST 2011

... which matches the DATE: line ...

DATE: Sat Mar 19 09:20:45 CST 2011

-- 
James Cameron
http://quozl.linux.org.au/