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<== Date ==> <== Thread ==>

Subject: Re: initialize of mbbi state labels
From: "Bob Dalesio" <ldalesio@lanl.gov>
To: "Hoff, Lawrence" <hoff@bnl.gov>, tech-talk@aps.anl.gov
Date: Mon, 03 Mar 2003 13:35:23 -0700
I would put it into the device support initialization area -
It can be done at initiallization.


Device support has a pointer to the record - so it's able to write directly into the fields ZNAM, ONAM, etc....

At initialization, there should be no channel access clients connected that could request these strings before they are initialized.

A problem would be if the assignment of these values can change. Channel access clients monitor the value as a short and only send the string assignments at connection time. So that is a possible problem. If they can change - you may want to map them from a static assigment to the dynamic values in the device support only - and not export the fact that the strings are assigned different values at different times.


On Mon, 03 Mar 2003 15:29:32 -0500 "Hoff, Lawrence" <hoff@bnl.gov> wrote:

EPICS philosophical question of the day........


Suppose there is a piece of equipment which can be put into
one of several modes of operation. Suppose also that the set of possible
modes depends on the hardware configuration of the equipment. Suppose
finally that the set of possible modes can be queried programmatically.


What is the "best" way to populate the "ZRST", "ONST", ...
fields of the record?


	Query the device during the "record init" phase, and
programmatically fill in the fields?

Edit the .db file to conform to the known H/W configuration,
and re-edit as needed if the H/W changes?


Other?

What are pros and cons of various approaches.

One example of such H/W are certain frame grabbers which have
H/W image processing built onto daughter cards. There are different
sets of image processing algorithms available with different daughter
cards attached.


Another example is a transient recorder with options for
stored waveform length, which are ultimately constrained by the amount
of memory installed.


-- Larry


Bob Dalesio ldalesio@lanl.gov 410 557 0297 Maryland 505 667 3414 Los Alamos 505 699 1632 Cell Phone 505 667 6087 Our Secretary (Lisa Marie)

Replies:
Re: initialize of mbbi state labels Hoff, Lawrence
References:
initialize of mbbi state labels Hoff, Lawrence

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