Serial Data

SAS

Serial Attached SCSI (SAS) is the next evolution of SCSI beyond Ultra320. It utilizes serial, point-to-point, switched architecture and promises to greatly expand upon the existing capabilities of its parallel predecessor. Serial Attached SCSI intends to leverage the 20 years of proven SCSI legacy middleware/software that is entrenched in the enterprise, as well as deliver a powerful small form factor connection scheme, capable of achieving substantially better performance and scalability than parallel SCSI offers today.

Explore SAS Explore SAS
SAS Sierra M124A   The SAS Sierra M124A Protocol Test System is Teledyne LeCroy's 7th generation protocol analyzer system that provides 100% accurate protocol capture of both SAS (SAS 3.0) and SATA (SATA 3.0). The industry's most widely used test platform for SAS and SATA features unmatched analysis and debug capabilities to help pinpoint problems at every layer of the protocol.
SAS Sierra M6-4   The Sierra Protocol Test System is the 6th generation in the leading line of SAS/SATA protocol test solutions from the leading manufacturer of protocol test systems. Designed for the current evolution of both SAS (SAS 2.0) and SATA (SATA 3.0), the new Sierra product family sets new standards for performance while incorporating a complete range of features in a single, economical system.
SATA Sierra M6-1   SATA Protocol Test System
SAS Sierra M6-2   The Sierra Protocol Test System is the 6th generation in the leading line of SAS/SATA protocol test solutions from the leading manufacturer of protocol test systems. Designed for the current evolution of both SAS (SAS 2.0) and SATA (SATA 3.0), the new Sierra product family sets new standards for performance while incorporating a complete range of features in a single, economical system.
SAS Sierra M6-1   The portable single port multifunctional analyzer system for SAS2 and SATA (6G)
Advisor T3   Teledyne LeCroy’s Advisor T3 is an ultra portable SuperSpeed USB analyzer that delivers market leading accuracy at an extraordinary price. Designed to put precision USB protocol test tools in the hands of every engineer, the Advisor includes all the essential features for SuperSpeed USB debug.
SAS bus D   The SASbus D decode annotation option is available for most Teledyne LeCroy oscilloscopes. It permits link and data layer decoding of 1.5, 3, 6, or 12 Gb/s SAS physical layer signals. Decode information is annotated on the physical layer waveform. Various sections of the protocol are color-coded to make it easy to understand the protocol traffic.
ProtoSync   The ProtoSync option further leverages the supported Teledyne LeCroy decode annotation options (PCIEbus D, USB3bus D, USB2bus D, USB2 HSICbus D, SATAbus D, SASbus D, FCbus D) installed on the oscilloscope.
QPHY-SAS2   The Teledyne LeCroy QPHY-SAS2 Test Solution provides automated control for the SDA 8 Zi series of oscilloscopes for performing all of the transmitter physical layer tests as described by version 1.01 of the UNH IOL Serial Attached SCSI (SAS) Consortium SAS-2 6Gb/s Physical Layer Test Suite. This specification covers targets and initiators running at 1.5 Gb/s, 3.0 Gb/s and 6.0 Gb/s.
QPHY-SAS3   The QPHY-SAS3 Test Solution provides automated control of the SDA 8 Zi-A and LabMaster 10 Zi oscilloscopes for performing all of the transmitter physical layer tests as described by the T10 SAS-3 specification. This specification covers targets and initiators running at 1.5 Gb/s, 3.0 Gb/s, 6.0 Gb/s, and 12.0 Gb/s.
Protocol Analysis

SAS Test and Verification: Teledyne LeCroy's new SASTracer is the first protocol analyzer designed from the ground up to address these unique characteristics of SAS including wide-links and Serial ATA interoperability. Based on Teledyne LeCroy's modular UPAS chassis, SASTracer includes a single plugin for monitoring 2 Wide links; and its expandable by adding a second plugin to monitor "4-wide" links. It displays multilane traffic interleaved and synchronized to a common reference clock. It also preserves the logical relationship between SSP initiators and targets by automatically grouping all frames that are part of a common transaction.

Serial ATA interoperability with SAS backplanes provides unprecedented flexibility for system designers in the storage arena. SAS and SATA will coexist side by side - possibly within the same storage enclosure. The ability to test and verify both protocols with a single instrument will become a necessity. In addition to STP support, the SASTracer has been designed with plug and play compatibility for pure SATA (1.5 and 3Gbps) protocol traffic. SASTracer will include a SATA software option that allows pure Serial ATA traffic to be recorded and verified using Teledyne LeCroy's Serial ATA analyzer software.

Teledyne LeCroy's expertise with high performance serial technologies has rewarded the industry with a modular chassis that can accommodate link rates of up to 12Gbps. This provides a highly portable platform for Serial Attached Storage analysis that is expandable for the higher bandwidth applications in the future. As the industry's first bi-lingual analyzer, SASTracer is clearly the most cost effective solution for validating SAS and SATA product designs.

SAS (Serial Attached SCSI) Overview

Serial Attached SCSI (SAS) is the next evolution of SCSI beyond Ultra320. It utilizes serial, point-to-point, switched architecture and promises to greatly expand upon the existing capabilities of its parallel predecessor. Serial Attached SCSI intends to leverage the 20 years of proven SCSI legacy middleware/software that is entrenched in the enterprise, as well as deliver a powerful small form factor connection scheme, capable of achieving substantially better performance and scalability than parallel SCSI offers today. 

Table 1. Disk Drive Interface Comparison

SAS analyzers, SAS analyzer, SAS protocol analyzers, sas protocol analyzer

Features

High Availability: As with SATA, Serial Attached SCSI is a high-speed, point-to-point technology initially designed to operate at speeds up to 3Gb/sec. System designers have found that point-to-point serial connections are inherently more reliable than shared bandwidth parallel connections. As a result, point-to-point serial connections have become the preferred method for implementing high-availability systems. Serial Attached SCSI will add dual-ported connections on to SAS based disk drives. This is a key requirement of high-availability SANs that call for redundant paths to all devices in the system.

Introducing SCSI Expanders: Serial Attached SCSI takes advantage of these VLSI advances to enable a highly scalable connection scheme and to allow the connection topology to grow through the use of "expanders." Expanders provide the necessary fan-out to create large enterprise-worthy configurations while maintaining legacy compatibility with SCSI software. SCSI Management protocol (SMP) is used to manage expanders. It establishes PHY control, configures route information, and performs discovery and link negotiation for individual SAS connections.

An important characteristic of Expanders is their ability to aggregate bandwidth by combining multiple physical links into a "Wide" port. These wide ports can function as intelligent switches and can independently send commands across one physical path with data being returned over a different physical path. This increases the complexity of SAS test and debug because it requires users to monitor multiple links concurrently to record all dwords associated with a single SCSI transaction.

SATA Compatibility: One of the most revolutionary of all the additions being offered by Serial Attached SCSI is the announcement that the SAS connector will be form-factor compatible with SATA. SATA drives will plug directly into Serial Attached SCSI connectors and if supported in the system, will transparently operate as SATA device. This allows systems to be deployed that can use either Serial Attached SCSI drives, for their high performance and high availability characteristics, or SATA drives that will provide a lower-cost-per-megabyte storage platform.

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