VMWare Architecture Notes
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Example VIB Definition
What is the altbookbank Partition
https://serverfault.com/questions/278895/how-is-the-altbootbank-partition-used-in-esxi
VMWare Architecture Document
https://www.vmware.com/content/dam/digitalmarketing/vmware/en/pdf/techpaper/ESXi_architecture.pdf
What is dcism
Appears to be the iDRAC service module
ESXi Log File Locations
https://docs.vmware.com/en/VMware-vSphere/7.0/com.vmware.vsphere.security.doc/GUID-832A2618-6B11-4A28-9672-93296DA931D0.html
I suspect anything related to updates should be found in the hostd.log file on the ESXi server itself.