[DSP-10] A Clock Question

[Baker, Donn B]

Hi Bob,
You have discovered (again) one of the real problems of computing. :-)
You have also indicated the only correct solution... run the system clock on UTC, and correct locally for local time, if desired. Its application specific, and usually only is of concern when working with the "general public."

I've always kept my logs in GMT, and now UTC.  There shouldn't be a reason, let alone a need, to use local time for the DSP software, station logs, etc.  Go for it !!

73 Donn
WA2VOI/0


> -----Original Message-----
> From: dsp-10-bounces at mailman.qth.net
> [mailto:dsp-10-bounces at mailman.qth.net]On Behalf Of Bob Larkin
> Sent: Sunday, March 12, 2006 1:30 PM
> To: dsp-10 at mailman.qth.net
> Cc: Ernest P Manly
> Subject: [DSP-10] A Clock Question
> 
> 
> Hello All,
> 
> I am in the process of "unifying" the clocks used inside the 
> DSP-10 program 
> UHFA.  This is spurred on by wanting to have automatic, 
> precision setting 
> of the clock from a GPS.  I have that part more-or-less under 
> control, but 
> I am seeing complications in the handling of time zones, and 
> particularly 
> daylight time.
> 
> First a couple of comments. DOS allows for time zones through the 
> environmental variable TZ, which can be read and applied.  
> The C routines 
> use this to automatically change the offset for daylight 
> time, if this is 
> specified, i.e., "SET TZ=PST8PDT"
> 
> DOS does NOT change the computer time in April and October, it only 
> automatically adjusts for it when computing GMT from local 
> time. If you do 
> not use the DOS command TIME it will be wrong.  Windows (I 
> don't know which 
> versions) allows for automatic time change, if Windows is run.
> 
> All of this becomes very simple if the TIME command is set to 
> GMT and the 
> environment is "SET TZ=GMT0"
> With this, the program never checks for daylight time, and, 
> it turns out, 
> all the clock operations can run from a single software time 
> source (the 
> source that has the daylight info does not have fractional 
> seconds, and 
> visa versa).
> 
> Tell me what kind of problems running everything in GMT would 
> create for 
> people?  I have always done this, but I know others have used 
> local time in 
> some way.
> 
> Many thanks,
> Bob Larkin  W7PUA
> 
> PS- It may not be obvious, but internally to UHFA GMT is a 
> must, as it is 
> needed for Moon calculations, Sun calculations, and PUA43 
> code stirring.
> 
> 
> _______________________________________________
> DSP-10 mailing list
> DSP-10 at mailman.qth.net
> http://mailman.qth.net/mailman/listinfo/dsp-10
>