Evolution of I/O Interfaces
Parallel SCSI Single Interface
Serial Attach SCSI Dual Interfaces
Parallel ATA Single Interface
Serial ATA Single Interface
Fibre Channel Dual Interfaces FC
6.0 Gb/s 6.0 Gb/s
320 SAS SATA 4Gb/s
3.0 Gb/s 3.0 Gb/s
Here we see the evolution of I/O interfaces over time.
We start with parallel architectures used by ATA and SCSI and see that as the
parallel interface reaches its maximum performance potential, it defines the
starting point of the new serial architectures.
The exception to this is Fibre Channel which was developed as a serial
architecture from the beginning.
Also, the original drive interfaces were single connected options so provided
no resilience to failure. This included parallel SCSI, and both parallel and
serial ATA interfaces.
Serial Attached SCSI and Fibre Channel both implemented dual interfaces, to
be used as a primary and secondary interface for resilience.