[ntp:questions] Befuddled and confused, again...

Geoff Powell geoff at g8kbz.demon.co.uk
Mon Feb 15 22:12:27 UTC 2010

In article <slrnhnjf0c.7se.unruh at wormhole.physics.ubc.ca>, unruh
<unruh at wormhole.physics.ubc.ca> writes
>On 2010-02-15, Dave Baxter <spam at goes.nowhere.com> wrote:
>> On 2010-02-14, Dave Baxter <spam at goes.nowhere.com> wrote:
>>> [quoted text muted]
>> GPSD as in Global Positioning System Diciplined.
>No idea what gpsd stands for. It is program used to read the signals
>from a gps receiver and deliver them to ntpd via the shm refclock. 

Global Positioning System Daemon.

The home site, http://gpsd.berlios.de, specifically states that Linux
and OpenBSD are currently fully supported. Other open source Unixen
should be easy to port to.

>> Yes, it uses the DCD line (I think) to input the PPS signal from the GPS 
>> receiver, a Garmin GPS16LVS in this case.  It's all configured and 
>> working on a Win2k box, with the Meinberg port, but I want that physical 
>> machine for something else, so I'm trying to get the FreeBSD version 
>> going.

gpsd understands this out-of-the-box. Read the website, and the

Your copy of ntpd will likely need recompilation, since there is
anecdotal evidence that the Shared Memory Driver is not routinely
compiled in. ntpd will get no data from gpsd without that driver.

However, if you don't need to be able to get at the GPS output anywhere
else (serial port sharing is difficult) gpsd is not needed. ntpd driver
20 (NMEA) or 22 (ATOM) should work. Or maybe you'll need the Oncore
driver - depends on which GPS you decide to use.

>Now, I am not sure whether gpsd will run on bsd, but I suspect it should
>not be hard to convert it to do so. The ioctl calls to the serial port
>or parallel port may well be different, but there are very few of them
>in the code. 

>> I still do not know the exact path needed for the Make.conf file.
>Sorry, I do not know what this question means. 
The stated path, /etc/make.conf, is directly equivalent to e.g.

Read the left-hand '/' as the root directory - or C:\ under Windows.
/etc is a sub-directory of this, and make.conf lives inside it.

N.B. Unixen use '/' as a path separator.

It has been mentioned upthread that make.conf is not required - it is
only necessary if you want specific environmental or optimisation
tweaks. This would not be wise for a Unix newbie - among whom I include

Hope this helps.

Geoff Powell

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