Subject: |
RE: Python EPICS interface (pyepics 3.1.1) double waveform record (NLEM = 65535 ) record handling exception |
From: |
"Jeff Hill" <[email protected]> |
To: |
"'Andrew Johnson'" <[email protected]>, <[email protected]> |
Date: |
Mon, 18 Apr 2011 16:28:55 -0600 |
> > or how
> > EPICS would deal with arrays approaching 2Gb.
>
> I think the only issue would be that there has to be enough RAM in the
> IOC for the multiple copies of the data that are made between the device,
> record and CA server.
>
Currently another issue, on 64 bit hosts, will be no arrays larger than
roughly 4294967279 Bytes - which is actually pretty close to 2GB.
Perhaps I shouldn?t be surprised that it didn?t take that long to get from
16kB to 4GB!
Jeff
______________________________________________________
Jeffrey O. Hill Email [email protected]
LANL MS H820 Voice 505 665 1831
Los Alamos NM 87545 USA FAX 505 665 5107
Message content: TSPA
With sufficient thrust, pigs fly just fine. However, this is
not necessarily a good idea. It is hard to be sure where they
are going to land, and it could be dangerous sitting under them
as they fly overhead. -- RFC 1925
> -----Original Message-----
> From: [email protected] [mailto:tech-talk-
> [email protected]] On Behalf Of Andrew Johnson
> Sent: Wednesday, April 13, 2011 9:11 AM
> To: [email protected]
> Subject: Re: Python EPICS interface (pyepics 3.1.1) double waveform
> record (NLEM = 65535 ) record handling exception
>
>
> On Wednesday 13 April 2011 09:23:43 Matt Newville wrote:
> > > I am also interested to know how far we can go with the array size in
> > > EPICS and PyEPICS interface.
> >
> > There is no explicit limit on array size that doesn't exist in EPICS.
> > With Area Detector, it's not unusual for us to be transferring 8Mb
> > arrays. I don't know what the largest verified array size is, or how
> > EPICS would deal with arrays approaching 2Gb.
>
> I think the only issue would be that there has to be enough RAM in the
> IOC for
> the multiple copies of the data that are made between the device, record
> and
> CA server. The record obviously has to have the storage for its copy,
> and the
> CA server reserves EPICS_CA_MAX_ARRAY_BYTES + a little bit for buffering
> on
> the way out. Whatever device support you're using might want its own
> copy as
> well, but that might be avoidable depending on the actual code in use.
>
> - Andrew
> --
> An error is only a mistake if you don't learn from it.
> When you learn something from it, it becomes a lesson.
- References:
- Python EPICS interface (pyepics 3.1.1) double waveform record ( NLEM = 65535 ) record handling exception Ritesh Sugandhi
- Re: Python EPICS interface (pyepics 3.1.1) double waveform record (NLEM = 65535 ) record handling exception Ritesh Sugandhi
- Re: Python EPICS interface (pyepics 3.1.1) double waveform record (NLEM = 65535 ) record handling exception Matt Newville
- Re: Python EPICS interface (pyepics 3.1.1) double waveform record (NLEM = 65535 ) record handling exception Andrew Johnson
- Navigate by Date:
- Prev:
RE: ca.py - Throws error - workaround Jeff Hill
- Next:
RE: Does EPICS Base support multi-thread on vxWorks 6.3? Jeff Hill
- Index:
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
<2011>
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
- Navigate by Thread:
- Prev:
Re: Python EPICS interface (pyepics 3.1.1) double waveform record (NLEM = 65535 ) record handling exception Andrew Johnson
- Next:
24-bit digitizer ICS-710 EPICS driver is available Hu, Yong
- Index:
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
<2011>
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
|