HDDs and SSDs are controlled by EMSs.
A SAS-format HDD has two ports, allowing redundant access by two EMSs. See Redundant EMS Control of SAS-Format Drives for a table which lists HDD slots and the EMSs that provide redundant access.
A SATA-format SSD has one port, so it can be accessed by only one EMS. See Nonredundant EMS Control of SATA-Format Drives for details.
Note - The Sun Flash Accelerator F40 PCIe Card is installed in an I/O card slot, not in a hard drive slot. See Sun Flash Accelerator F40 and F80 PCIe Cards.