Author: Bob
Sheffield
Intel Corporation
Serial Attached SCSI (SAS) extends the SCSI roadmap well beyond the limitations of parallel busses. Parallel SCSI has achieved geometric improvement over the last 20 years by doubling the bandwidth in each subsequent generation: from 8 MB/s (megabytes per second) to 320MB/s over its lifetime. SAS’s link rate of 3Gb/s (gigabits per second), delivers 300MB/s if accounting for 8b/10b encoding. SAS is 20 MB/s slower than parallel SCSI point to point, often creating confusion about which interface is faster. This article evaluates three key features of SAS which provide performance and scaling well beyond parallel SCSI:
- Full duplex
- Switched transport
- Wide ports
