An Embedded Linux Distribution for the Data Acquisition Hardware of the Compact Muon Solenoid Experiment at CERN

In 2025, the Large Hadron Collider (LHC) at CERN would be upgraded to be a High-Luminosity Large Hadron Collider (HL-LHC). It would result in increased frequency and intensity of particle collisions at the centre of various experiment detectors located along the circumference of the HL- LHC. This master thesis gives a brief background about the LHC, the CMS experiment, the CMS data acquisition network (CMS-DAQ) and the Phase-II upgrade on the CMS-DAQ network. The upgrade of electronics in the CMS-DAQ would see the introduction of around 1000 Xilinx Zynq UltraScale+ MPSoC (Multi-Processor System-on-Chip) based customised embedded controllers in the CMS data acquisition network. All these newly introduced MPSoC would require a customised operating system for their hardware platforms. To this end, this master thesis elaborates upon the important Linux boot components and the process of booting Linux on the Xilinx Zynq UltraScale+ MPSoC. This thesis document demonstrates the process of building a customised Linux distribution for the Zynq UltraScale+ MPSoC using PetaLinux Tools. This thesis document presents a qualitative comparison between the PetaLinux Tools and the Yocto Project so that developers can choose a tool-chain better suited to their requirements. To ensure support for the hardware platforms and because of existing expertise at CERN to support the CentOS Linux distribution, this thesis document demonstrates the process of porting a mainstream CentOS 8 kernel 4.18 and the building of CentOS 8 root file system for the Zynq UltraScale+ based ZCU102 evaluation board. To recommend an easy-to-maintain, modifiable and manageable booting mechanism, this thesis document also presents a qualitative and quantitative analysis of different booting configurations and root file system storage mechanisms along with read-write performances of different root file system storage mechanisms (SD Card and NFS server). Based on these findings, this thesis document recommends a particular boot configuration as well as a root file system storage mechanism for the Zynq UltraScale+ based embedded controllers in the CMS data acquisition network. This thesis document demonstrates the process to implement an automated network boot process of embedded Linux on the Xilinx ZCU102 Evaluation board and also explains the ways in whichchallenges associated with the network boot can be dealt with. Once these systems are installed in the CMS-DAQ network, it is important to administer software updates or install software on the CentOS 8 root file system of the different Zynq UltraScale+ based hardware platforms that are running the CentOS 8 kernel 4.18. This master thesis demonstrates two different methods of administration of software updates to the CentOS 8 root file system. This thesis document also elaborates upon the qualitative distinctions between these two software update methods and recommends use cases for these two different methods in the CMS data acquisition network.