motor record distribution drvGpib bug

["Ronald L. Sluiter" <sluiter@aps.anl.gov>]

Kevin Peterson (UNI-CAT) and I diagnosed a bug that is in all R3.13.x
versions of the motor record distribution.  The bug is in the interface
between the motor record device drives (gpibIO.c) and the EPICS base GPIB
driver; drvGpib.  The bug results in very intermittent ibLinkTask memory
access faults.

As a quick fix, R4-9-6 of the motor record distribution has been
released with the task priorities of the all GPIB capable controllers
lower than ibLinkTask's priority.

All users of the R3.13.x version of the motor record distribution that
use GPIB to communicate to Newport controllers (i.e., Newport
MM4000/5/6, MM3000, PM500, ESP300/100), should upgrade to
the R4-9-6 version.

http://www.aps.anl.gov/upd/people/sluiter/epics/motor/index.html