Argonne National Laboratory

Experimental Physics and
Industrial Control System

1994  <19951996  1997  1998  1999  2000  2001  2002  2003  2004  2005  2006  2007  2008  2009  2010  2011  2012  2013  2014  2015  2016  2017  2018  2019  2020  Index 1994  <19951996  1997  1998  1999  2000  2001  2002  2003  2004  2005  2006  2007  2008  2009  2010  2011  2012  2013  2014  2015  2016  2017  2018  2019  2020 
<== Date ==> <== Thread ==>

Subject: Re: ca_pend_event question (VAX/VMS only)
From: hill@luke.atdiv.lanl.gov (Jeff Hill)
To: hill@luke.atdiv.lanl.gov, tcox@ssrl01.slac.stanford.edu
Cc: tech-talk@epics.aps.anl.gov
Date: Wed, 9 Aug 95 11:43:32 MDT
> Multinet (the preferred VMS TCP/IP) also provides a stub driver which emulates
> the DEC supplied UCX driver interface, so this is a possible route (but see
> below). 

I saw that also. Perhaps this is a way to deal with DEC CC's obnoxious 
involuntary replacement of recv with decc$recv. @#$%$!

> The problem with VMS at present is not so much that the Multinet library isn't
> thread safe, but that the VMS thread implementation is user mode rather than
> kernel mode. One consequence of this is that send/recv block the whole process,
> rather than the individual thread.

Ouch. I wasnt aware of this limitation.

> 
> I've developed code which solves this (for another project). I have jacket
> send/recv routines which are functionally equivalent to the Multinet ones,
> but actually block on condition variables which are then signalled by the
> QIO completion AST. Voila! Thread safe Multinet (equivalent) routines.
> email me if you want further information on this.

Does this include select?

> 
> In general, however, I think it would be bad practice to allow the VMS channel
> access routines to diverge (again) from the facilities available under Unix.
> The goal should be to provide a consistent interface across all OS's, even if
> this means a degree of `dumbing down'.
> 

Another possibility is to encapsulate the transport level calls so
that the socket interface is only one of several OS dependent 
communication API options.

Jeff

______________________________________________________________________
Jeffrey O. Hill			Internet	johill@lanl.gov
LANL MS H820			Voice		505 665 1831
Los Alamos, NM 87545 USA 	FAX		505 665 5107


Navigate by Date:
Prev: Re: Choice of hardware winans
Next: Re: ca_pend_event question (VAX/VMS only) 415
Index: 1994  <19951996  1997  1998  1999  2000  2001  2002  2003  2004  2005  2006  2007  2008  2009  2010  2011  2012  2013  2014  2015  2016  2017  2018  2019  2020 
Navigate by Thread:
Prev: Re: ca_pend_event question (VAX/VMS only) Jeff Hill
Next: Re: ca_pend_event question (VAX/VMS only) 415
Index: 1994  <19951996  1997  1998  1999  2000  2001  2002  2003  2004  2005  2006  2007  2008  2009  2010  2011  2012  2013  2014  2015  2016  2017  2018  2019  2020 
ANJ, 10 Aug 2010 Valid HTML 4.01! · Home · News · About · Base · Modules · Extensions · Distributions · Download ·
· Search · EPICS V4 · IRMIS · Talk · Bugs · Documents · Links · Licensing ·