A server technician is upgrading a system by connecting SATA-based solid-state drives (SSDs) to an existing SAS backplane managed by a PCIe hardware RAID controller. The installation is successful. However, when the technician attempts the reverse configuration by connecting a SAS hard drive directly to a motherboard's native SATA controller port in a desktop system, the drive is not recognized and fails to function. Which of the following explains the technical reason for this outcome?
- SAS controllers and backplanes are engineered with backward compatibility for the SATA protocol, whereas native SATA controllers lack the software command set and signal logic required to communicate with SAS drives.Cevap
- BThe SAS drive requires an AHCI controller driver update within the desktop operating system before the native SATA motherboard port can negotiate protocol speed.
- CSAS drives require dedicated PCIe bus lanes for data transmission, which prevents standard motherboard SATA controllers from initializing them.
- DSATA motherboard ports supply insufficient electrical voltage to power the dual-port signaling logic built into enterprise SAS drives.
Cevap
SAS host controllers and backplanes are designed with backward compatibility to accept SATA protocol drives through SATA Tunneling Protocol (STP), but native SATA motherboard controllers do not support SAS command sets or signaling logic, preventing SAS drives from working on SATA ports.
SAS hardware controllers and backplanes implement the SATA Tunneling Protocol (STP) to achieve backward compatibility with SATA hard drives and SSDs. However, this compatibility is strictly one-directional; native consumer SATA host controllers lack the physical hardware logic, dual-port signaling, and SCSI command set needed to communicate with SAS drives.
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SAS and SATA Controller Backward Compatibility