I/O Interfaces
Interface Comparisons
Compatibility of SAS and SATA
• SAS & SATA share a common connector
• SATA can be plugged into a SAS Interface
– Not SAS into SATA
• Speed will negotiate to lowest common
denominator
– including 1.5 Gb/s
• Transmission mode will negotiate to Half Duplex
Form factor compatible with SATA: allows for SATA drives to connect to a
SAS backplane, which obviates the need to install an additional SATA
controller just to attach a DVD-writer, for example.
Note that SAS drives are not usable on a SATA bus and have their physical
connector keyed to prevent any plugging into a SATA backplane.
SAS defined interface speeds of 3 and 6 Gb/s
SATA defined interface speeds of 1.5, 3 and 6 Gb/s
If they are interconnected, the resulting negotiation will run at the interface
speed of the slowest connected device. It will also negotiate to half duplex in
support of the SATA interfaces.