[OLPC-AU] hwclock accuracy

[Jerry Vonau]

On Thu, 2011-01-27 at 15:30 +1100, James Cameron wrote:
> On Wed, Jan 26, 2011 at 06:09:02PM -0600, Jerry Vonau wrote:
> > That actually makes things worse, try installing ntpdate and run it with
> > the stock /etc/adjtime file, now the real time clock is set to localtime
> > as that is the first time hwclock is run.
> > 
> > http://osdir.com/ml/fedora-olpc-list/2009-08/msg00102.html
> > 
> > http://dev.laptop.org/ticket/9705
> 
> http://dev.laptop.org/ticket/10605 in particular.
> 
> Until these problems are fixed, please change your build; remove
> /etc/adjtime from /etc/rwtab, change the third line of /etc/adjtime to
> be UTC, copy the zoneinfo file for to /etc/localtime, install ntpdate,
> and write a script in /etc/NetworkManager/dispatcher.d/99-ntpdate 
> 
> #!/bin/sh
> if [ "$2" = "up" ]; then
>   ntpdate ${YOUR_NTP_SERVER} && \
>     hwclock --systohc
> fi
> 
> This will attempt to synchronise the time when the laptop connects to
> infrastructure wireless.  (It can't be done at boot by
> /etc/init.d/ntpdate because there is no network connection then).
> 
> You will also need to set timezone in Sugar, since it ignores
> /etc/localtime.  Setting it in /etc/localtime is not enough.  GNOME and
> text console timezone are correct.
> 

https://dev.laptop.org.au/projects/xo-au/repository

Well on the way, thanks for the heads up for /etc/rwtab

> Choose an appropriate NTP server.  pool.ntp.org might not be the best
> for a large population of school based laptops.
> 
> Consider a longer timeout for ntpdate.  The default may not be suitable
> for a class of laptops on a shared wet string.
> 
> The above tested on os860.
> 
> To read the RTC in OpenFirmware:
> 
> 	ok select /rtc get-time decimal .s
> 
> The values are least significant first.
> 
Thanks again,

Jerry