Re: rec/devSup advise needed

[Andrew Johnson <anj@ast.cam.ac.uk>]

On Thu, 22 Aug 1996 08:08:02 -0500 Marty Kraimer <mrk@aps.anl.gov> wrote:

> 2) Come up with a nicer syntax for hardware link specifications.
> For example instead of:
> 
>    #L0 A2 C0 S0 @whatever
> 
>    It would have been better to use something like
>     AB(0,2,0,0,"whatever")
> 
>    For camac it would be
> 
>     CAMAC(b,c,n,a,f,"whatever")
> 
>    where b,c,n,a,f are all integer values
> 
> At the present time it is difficult for dbStaticLib to determine
> the link type given the link specification. If we add more link types
> and use a syntax similar to that for existing links it may become
> impossible.

Would it be possible to create new versions of the link specifications 
now, as synonyms for the old ones, persuading people to start converting 
to the new format so the old stuff can be deleted in some later release?  
I even wondered about doing host-side conversion from the old to the new 
formats, but I guess that may be harder for some applications.

IMHO the new formats should not be hard-coded anywhere other than the 
drivers/device support which use them; the "link_type" in the database 
"device" definition should be something else which is definable in an 
ascii file (and convertable into a VME_IO.h file for example, which can be 
#included by the device/driver).  This way anyone could add a new address 
type without needing to rebuild base, but you should still be able to 
retain backwards compatibility for existing device/driver support.

$0.02

- Andrew

  O o ._    Andrew Johnson, Royal Greenwich Observatory
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