[ntp:questions] new driver development

David L. Mills mills at udel.edu
Mon Mar 28 15:01:13 UTC 2011


Bruce & Co.,

You may not be aware that all Spectracom devices are supported with one 
driver, all TrueTime devices are supported with one driver, all 
telephone modem services are supported with one driver, all Austron 
devices are supported with one driver, all Heath devices are supported 
with one driver  and most GPS receivers are supported with one driver. 
This happened with many hours of dedicated effort on the part of 
refclock developers. You can appreciate the serious pushback in creating 
a new driver if a similar one is already available. An appropriate plan is

[common interface code]
#ifdef POSIX
...
#else
...
#endif

Dave

Bruce Lilly wrote:

>On Fri, 18 Mar 2011 04:51:40 +0000, Harlan Stenn wrote:
>
>
>  
>
>>I don't see this one.  If "flag1 0" (the current default) means SVID,
>>and we decide that "flag1 1" means POSIX, what is the issue?  How is
>>that significantly different from changing 127.127.28.x to 127.127.y.x ?
>>    
>>
>
>Among others,
>  1. The following is workable:
>        server 127.127.28.1 ...
>
>        server 127.127.y.1 ...
>
>     Your proposal in this respect, viz.:
>        server 127.127.28.1 ...
>        fudge 127.127.28.1 flag1 0 ...
>
>        server 127.127.28.1 ...
>        fudge 127.127.28.1 flag1 1 ...
>
>     simply won't work. IOW, one can have 4 units ea. using different
>     drivers, but one cannot have multiple devices sharing the same
>     driver and unit numbers but differing flags (or ttl, etc.)
>
>  2. With separate drivers, each can perform appropriate initialization
>     via the clock_init function pointer in its struct refclock
>     structure.  One cannot alter the way that works based on flag or ttl
>     values as neither are accessible; the prototype is:
>       void (*clock_init) (void);
>     I.e. no pointer to a peer structure.
>
>
>  
>
>>They are separate issues.  We support timespec where it exists.  We want
>>to support timespec under SHM regardless.
>>    
>>
>
>If I thought that was feasible, I would have done it and submitted 
>patches a year ago.
>
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>  
>




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