EPICS Controls Argonne National Laboratory

Experimental Physics and
Industrial Control System

2002  2003  2004  <20052006  2007  2008  2009  2010  2011  2012  2013  2014  2015  2016  2017  2018  2019  2020  2021  2022  2023  2024  Index 2002  2003  2004  <20052006  2007  2008  2009  2010  2011  2012  2013  2014  2015  2016  2017  2018  2019  2020  2021  2022  2023  2024 
<== Date ==> <== Thread ==>

Subject: Re: primitive data types, was: ICE and TIPC
From: Ralph Lange <[email protected]>
To: EPICS Core Talk <[email protected]>
Cc: Kay-Uwe Kasemir <[email protected]>
Date: Sat, 30 Jul 2005 00:44:15 +0200
Kay-Uwe Kasemir wrote:

The gateway, on the other hand, needs to understand the data,
so that it can send updates to different clients using
different deadbands.
This mean we have to nail the basic types down.

Or would the gateway only fan data out to multiple clients
if they use the same subscription request (filter, events),
so that the gateway can treat the data as an octet array?

My guess is that if the Gateway would keep a separate copy of the data for each different subscription request, it would end up being quite useless - or: much less useful. It would have to keep multiple copies of the same data just because clients wanted a slightly different filter (e.g max update rate). Not efficient. It would completely lose its functionality to shield the IOC from misbehaving clients: If e.g. a single client would subscribe to the same channel many times with a slightly changed max-update-rate, every single connection would lead to another subscription down to the IOC. Using that knowledge you could write a ten-liner that kills an IOC through a Gateway. Not good.

The Gateway needs to understand the data.
We have to nail the basic types down.

I would prefer the type info thing to be a struct (type, bitwidth, ...) rather than a large enum.

I would rather not call these types "network" types because they are mandatory for DataAccess even if there is no network involved. The network must support them, too - sure. Just as every other app or layer that uses DataAccess.

Ralph


Replies:
Re: primitive data types, was: ICE and TIPC Kay-Uwe Kasemir
References:
RE: ICE and TIPC Jeff Hill
Re: ICE and TIPC Marty Kraimer
primitive data types, was: ICE and TIPC Kay-Uwe Kasemir

Navigate by Date:
Prev: Re: ICE and TIPC Ralph Lange
Next: Re: primitive data types, was: ICE and TIPC Kay-Uwe Kasemir
Index: 2002  2003  2004  <20052006  2007  2008  2009  2010  2011  2012  2013  2014  2015  2016  2017  2018  2019  2020  2021  2022  2023  2024 
Navigate by Thread:
Prev: primitive data types, was: ICE and TIPC Kay-Uwe Kasemir
Next: Re: primitive data types, was: ICE and TIPC Kay-Uwe Kasemir
Index: 2002  2003  2004  <20052006  2007  2008  2009  2010  2011  2012  2013  2014  2015  2016  2017  2018  2019  2020  2021  2022  2023  2024 
ANJ, 02 Feb 2012 Valid HTML 4.01! · Home · News · About · Base · Modules · Extensions · Distributions · Download ·
· Search · EPICS V4 · IRMIS · Talk · Bugs · Documents · Links · Licensing ·