On 2020-12-07, Martin Gregorie wrote:

> On Mon, 07 Dec 2020 15:55:32 +0000, Ahem A Rivet's Shot wrote:
>
>> On Mon, 07 Dec 2020 14:50:01 +0000 Adam Funk 
>> wrote:
>>
>>> I was just wondering about what kind of situation needs the external
>>> clock so the time is accurate *before* NTP starts working.
>>
>>  It rather depends on how long might elapse before reaching a time
>> server, if there's any danger of that being a long time then a RTC is
>> very helpful, if you're sure of a time server immediately after boot
>> then it's pretty much useless.
>
> Don't forget that an old GPS unit, provided it has serial NMEA0183 output
> which many of them had, can be used by ntpd as a primary time reference.
> These can be connected to an RPI via a USB-serial adapter. There is a
> reference driver for ntpd that allows it to accept an NMEA0183 primary
> time stream.

(Not that I need something like this, but it's interesting.)

I don't think an old GPS unit would be able to get a signal in my
"network cupboard", which is a shelf in the back of a wardrobe under
the stairs from the 1st to 2nd floors, & not on an outside wall.


--
Let me tell you what I think of bicycling. I think it has done more to
emancipate women than anything else in the world. I stand and rejoice
every time I see a woman ride by on a wheel.       ---Susan B. Anthony

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