[ntp:questions] help with setting up NTP on windows with a USB GPS

Dave Baxter spam at goes.nowhere.com
Fri Dec 4 09:57:26 UTC 2009


In article <517b0b0d-1557-4c0e-b6b4-2d92d627258c@
2g2000prl.googlegroups.com>, davehart at gmail.com says...
> 
> On Dec 1, 13:58 UTC, Dave Baxter wrote:
> > What colateral effects will the serialpps.sys driver have on the other
> > com port, as that will be used for controling the radio (data lines
> > only.)   Also, what effect would it have on, or be affected by, the CPU
> > loading of the needed DSP routines that kick off once every few seconds.
> 
> The effect compared to using serial.sys is quite similar.
> serialpps.sys adds a new "ioctl" which software other than ntpd won't
> know about or use.  Until the first time that ioctl is called by a
> given process, serial.sys behaves identically.  After the first call
> to that ioctl, the interrupt handler for "modem status" line changes
> (including DCD) squirrels away a system timestamp and cycle counter
> value at each DCD clear->asserted transition, retrievable via the same
> ioctl.
> 
> serialpps.sys timekeeping performance compared to the "user-mode PPS"
> hack is relatively marginal under optimal circumstances, as David
> Taylor has demonstrated.  The more loaded the box, the more likely
> serialpps.sys's interrupt-time timestamping of DCD will be
> substantially more accurate than ntpd doing the same thing from user
> mode.
> 
> Cheers,
> Dave Hart

Hi Dave..

I tried last night to "install" your serialPPS driver, onto the Win2k 
machine I have temporaraly made available to try all this.

Sadly, all I get are errors like...

"'reg' is not recognized as an internal or external command,
operable program or batch file."

So, I guess it's a delicate manual install for Windows then?  XP has the 
'reg' command, but 2000 does not.

Appologies if you've answered this in the past, but I can never seem to 
go back in time, with these news reader systems, and Google Groups wont 
let me in at the moment.

Dave Baxter.




More information about the questions mailing list