Experimental Physics and
Industrial Control System

Mark Rivers via Tech-talk <[email protected]> · Tue, 4 Dec 2018 02:37:33 +0000

New releases of the following areaDetector modules are now available.

areaDetector R3-4
ADCore R3-4

These are from the R3-4 release notes for ADCore:

### ADSrc/asynNDArrayDriver.h, asynNDArrayDriver.cpp
* Fixed a serious problem caused by failure to lock the correct mutex when plugins called
  incrementQueuedArrayCount() and decrementQueuedArrayCount().
  This caused the Acquire and Acquire_RBV PVs to occasionally get stuck in the 1 (Acquire) state when acquistion
  was complete.  It might have also caused other problems that were not reported.
  This problem was introduced in R3-3.

* Fixed a race condition in the asynNDArrayDriver destructor.
  This was causing occasional failures in the Travis unit tests.

### NDPluginCodec
* New plugin written by Bruno Martins to support compressing and decompressing NDArrays.

* Compressors currently supported are JPEG (lossy) and Blosc (lossless).

* NDArray has a new .codec field that is the string name for the compression in use.
  It is empty() for no compression.
  It also has a new .compressedSize field that stores the compressed size in bytes.
  This may be less than .dataSize, which is the actual allocated size of .pData.

* The converters between NDArrays and NTNDArrays support this new codec field.

* Currently the main use case will be to transport compressed NTNDArrays using pvAccess.

* The ImageJ pvAccess viewer now supports decompression of all of the compressors supported by this plugin.
  This can greatly reduce network bandwidth usage when the IOC and viewer are on different machines.

* We also plan to enhance the HDF5 file plugin to support writing NDArrays that are already compressed,
  using the Direct Chunk Write feature. This should should improve performance.

### NDPluginDriver, NDPluginPva, NDPluginStdArrays
* Added new base class parameter and record MaxByteRate.
  This allows control of the maximum data output rate in bytes/s.
  If the output rate would exceed this then the output array is dropped and DroppedOutputArrays is incremented.
  This can be useful, for example, to limit the network bandwidth from a plugin.

* Added new MaxArrayRate and MaxArrayRate_RBV records.
  These are implemented in the database with calc records.
  They write and read from MinCallbackTime but provide units of arrays/sec rather than sec/array.

* Optimization improvement when output arrays are sorted.
  Previously it always put the array in the sort queue, even if the order of this array was OK.
  That introduced an unneeded latency because the sort task only runs periodically.
  It caused ImageJ update rates to be slow, because the PVA output then comes in bursts,
  and some arrays are dropped either in the pvAccess server or client (not sure which).
  Now if the array is in the correct order it is output immediately.

### NDPluginCircularBuff
* Added new FlushOnSoftTrg record that controls whether the pre-buffer is flushed OnNewArray (previous behavior, default),
  or Immediately when a software trigger is received.  Thanks to Slava Isaev for this.

### NDFileTIFF
* Allow saving NDArrays with a single dimension.

### OPI files
* NDStatsTimeSeriesBasicAll.adl, NDStatsTimeSeriesCentroidAll.adl, NDStatsTimeSeriesPlot.adl
  * Changed X axis from point number to time.
****************************************************************************************

The home page is here:
http://cars.uchicago.edu/software/epics/areaDetector.html

The top-level documentation is here:
http://cars.uchicago.edu/software/epics/areaDetectorDoc.html

Installation instructions are here:
https://github.com/areaDetector/areaDetector/blob/master/INSTALL_GUIDE.md

areaDetector release notes are here:
https://github.com/areaDetector/areaDetector/blob/master/RELEASE.md

ADCore release notes are here:
https://github.com/areaDetector/ADCore/blob/master/RELEASE.md

Mark

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System