In this Wikipedia link PCI Express I found a diagram of pcie where the cpu is connected to the pcie bus and devices through the root complex and then I saw this link Host adapter which says that the host bus adapter connects the system bus (which is the bus the cpu uses to communicate with ram , I guess) to a storage and network devices which may be using the pcie bus .
Question : Is the host bus adapter considered to be the pcie root complex in that case
Question : Is the host bus adapter considered to be the pcie root complex in that case
No, because that is not even the case. Devices called "HBA" are usually meant to attach a more specialized bus to the existing PCI system bus.
For example, a very common type of HBA would be a PCI device that connects a SCSI bus to the host (as in the Wikipedia page).
The PCIe root complex itself is not usually called a HBA as the PCI bus is usually considered part of the host already.
