Amusing implications

[Matthew Selsky]

On Mon, Feb 04, 2019 at 01:39:48PM -0500, Eric S. Raymond via devel wrote:
> I found a documentation error.
> 
> The page for the modem driver says:
> 
>     This driver requires a 9600 bps modem with a Hayes-compatible command
>     set and control over the modem data terminal ready (DTR) control line.
>     The actual line speed ranges from 1200 bps with USNO to 14,400 bps
>     with NIST. The modem setup string is hard-coded in the driver and may
>     require changes for nonstandard modems or special circumstances. It
>     can be overridden by setting the extended system variable
>     "modem_setup" via ntpq.
> 
> But look at this:
> 
> 		setup = get_ext_sys_var("modemsetup");
> 		if (setup != NULL)
> 			modem_setup = estrdup(setup);
> 
> Yes, that's right, the embedded underscaore in "modem_setup" is wrong.
> And we didn't do that - I checked Classic and the documentation bug
> dates back at least to 2012.  Probably earlier, I can't be bothered
> to do a full bisect on this.

No, we added that incorrect documentation in 2016. See https://gitlab.com/NTPsec/ntpsec/commit/d88b9dc4d1629885ec6500ff295110e8a512e025

> The system variable you might poke to make it work is misdocumented.
> And the misdocumentation has lingered for at least 7 years.  That's
> long enough for a human to be declared legally dead.

We misdocumented it.  2 years ago.

> I'll fix it, but I think what we *ought* to do is nuke the whole sorry mess.
> Any objections?

Someone asked about it on the ntp questions list. See http://lists.ntp.org/pipermail/questions/2017-July/041261.html  So there seems to be some usage of it, by real users.

Per https://www.nist.gov/pml/time-and-frequency-division/services/automated-computer-time-service-acts, ACTS in Colorado received 2,000 calls per day, and ACTS in Hawaii receives 100 calls per day.  The page was last updated in April 2018, but the statistics might be older.

Regarding commercial usage, the Symmetricom S300 contains a built-in modem for connection to ACTS, PTB, etc, per https://www.microsemi.com/document-portal/doc_view/135082-syncserver-s300-high-performance-enhanced-security-gps-network-time-server  eBays shows quite a few for sale per https://www.ebay.com/sch/i.html?_from=R40&_trksid=m570.l1313&_nkw=SyncServer+s300&_sacat=0

So calling it dead might be premature.  Now, if it doesn't meet our accuracy thresholds, that's another story.

Thanks,
-Matt