Doug Murray, SLAC, May 2022
Revision 1.0, 04-May-2022, Initial Version.
BSAS is the Beam Synchronous Acquisition Service, which acquires data synchronized with each beam pulse from devices in SLAC's LCLS Accelerator, and records it in files using the Hierarchical Data Format (HDF).
BSAS-SC refers to the system associated with the superconducting Linac (LCLS-II), while BSAS-NC is associated with the normal conducting Linac (LCLS-I).
This software is typically installed on a supported Linux system at SLAC, such as a Redhat Enterprise Linux server, version 7 or higher.
NOTE: This software will not currently build on Windows or standard MacOS systems having case-insensitive file systems.
Download the files to start development work. Use git to retrieve the source code and documentation:
git clone --recursive https://github.com/drm-slac/bsas-sc.gitThis will retrieve the software with standard EPICS directories already configured for use at SLAC. The recursive flag is required because the HDF template library is included as a submodule. The resulting directory is named bsas-sc by default and contains several entries:
*Table 1*. **Files and Directories**| File or Directory Name | Purpose |
|---|---|
| commonApp/ | Template and Code libraries used in more than one program |
| configure/ | Files used to build software in the EPICS environment |
| documentation/ | Documents in their raw format, used to build final documents in the doc directory, created when the make command runs |
| highfiveApp/ | The submodule suporting the HDF5 format for generated data files |
| Makefile | Used by the make tool to build the software |
| managerApp/ | Software to manage the running processes which acquire or record the BSAS data |
| mergerApp/ | Software which acquires data from the EPICS IOCs and makes it available in a single, merged table |
| nttableApp/ | Software which support the NTTable type in EPICS v7, and provides a template for the merged output table's format |
| README.md | This file |
| RELEASE_SITE | Used by the EPICS system to define site-specific details of the build and operating environments at SLAC. |
| test/ | Contains several programs capable of testing various aspects of the EPICS environment |
| writerApp/ | Software which reads the merged NTTable from the mergerApp, either locally or across a network, and records that data in HDF5 format |
From any account having the standard SLAC development environment set, just type make to build the software. The EPICS build system is used to build the software.
A bin directory will be created and software will be installed within an architecture specific subdirectory. For example, on a Redhat Enterprise 7 machine, software will be installed under bin/rhel7-x86_64/. On a Redhat 6 machine, the software will be placed under bin/rhel6-x86_64/. A doc directory will also be created with documentation installed.
The mergerApp and writerApp are primary components which are started and restarted as necessary by the managerApp. When working on different host computers, as they typically are, the mergerApp and writerApp each have their own instance of the managerApp monitoring them. If the merger and writer are working on the same host computer, for testing scenarios for example, a single manager instance can monitor them both.jj
The system can acquire data from several IOCs, gathered to one server then transmit that data to another computer to record the data is a specific format.
The mergerApp, writerApp and managerApp can be configured by editing a simple ascii file. More details can be found in the BSAS-SC Users Manual located in the doc directory.