(2) (Serial Attached SCSI) A serial version of the SCSI interface, which has been parallel since its inception in 1986. Ratified by ANSI in 2003 as the next-generation SCSI technology, SAS is a point-to-point architecture that uses a disk controller (host bus adapter) with four or more channels that operate simultaneously. Each full-duplex channel, known as a SAS port, transfers data at 3 Gbps in each direction with 6 Gbps scheduled for the next version. SAS also supports Serial ATA (SATA) drives, which can be mixed with SAS drives in a variety of configurations.
SAS Protocols
The Serial SCSI Protocol (SSP) is used for SAS-only drives, while the Serial ATA Tunneling Protocol (STP) is used to support SATA drives. When Expanders are used, the Serial Management Protocol (SMP) is employed. See SATA and SCSI. See also SSA.
Huge Scalability
SAS channels (ports) can each connect to a single drive or collectively to an expander switch. Expanders can connect up to 128 devices, whether they be host bus adapters or drives. One Fanout Expander can be used to connect Edge Expanders, and one system would be capable of supporting a total of 16,256 drives.
Dual Ports for Fault Tolerance
SAS drives use the same form factor as Serial ATA (SATA) for the cable connector, but add a second port for connection to two controllers or expanders for fault tolerance.
![]() | Reproduced with permission from Computer Desktop Encyclopedia. Copyright (c) 1981-2009 The Computer Language Company Inc. All rights reserved. |
Additional Resources
- Intel seeks new 'microserver' standard
- Why bother with a new standard?What Intel needs to do is use the pre-existing motherboard form factors like Micro-ATX and Mini-ITX. Why can't they just design a board in the Mini-ITX form factor for a single-socket Xeon 3400-series processor with ECC RAM and dual-GBe ports with the standard fare...
- Discussion threads 2009-10-30
- Teradata unveils cloud strategy, answer for Oracle's Exadata machine
- Data warehousing giant Teradata is outlining its cloud computing strategy including an internal cloud service and a public offering via Amazon Web Services. In addition, Teradata is rolling out an appliance it claims will provide a big performance boost. The announcements, timed for Teradata's partner conference in...
- Blog posts 2009-10-19
- SMART Selling in the SaaS world
- What we all could learn from Sonar6 Post #3 from the HR Technology show SaaS software as a service is supposed to cost less. At least that’s what all the vendors tell me. It’s also supposed to be easier to use and easier to...
- Blog posts 2009-10-09
- Dataram storage appliance squeezes more out of storage infrastructure
- At more than 40 years old, Dataram certainly isn't a technology start-up, but the memory company has come up with a new approach to storage optimization that could help midsize companies squeeze out more performance from their existing devices. The technology, called XcelaSAN, is an appliance that...
- Blog posts 2009-09-28
- Seagate's 2TB Barracuda XT, world's first SATA 6Gbps HDD
- It is still a SeageteIt is still a seagate, so it will fail very quickly.RE: Seagate's 2TB Barracuda XT, world's first SATA 6Gbps HDDAny word on the real world performance of SATA 6Gpbs vs. SAS drives?RE: Seagate's 2TB Barracuda XT, world's first SATA 6Gbps HDDHow about smaller capacities? I...
- Discussion threads 2009-09-22
- Pliant talks up lower energy consumption, cost savings of its new enterprise flash technology
- Start-up storage vendor Pliant Technology has begun shipping a new class of enterprise flash drives to OEMs for evaluation and qualification that should become available in commercial format by the end of September 2009. The technology, called Lightning, is a cache-less enterprise flash format that is designed...
- Blog posts 2009-09-15
- Am I a big whiner about Gmail's downtime?
- Establish Down-Time Procedures. Move on.Google Apps is a GREAT resource.Whining for something you get for freeNTyes you areand on top of it you give the M$ shills something to hang on.I've never looked into it, but does Google Gears help......when / if Google Apps is down?Teachers are hardly unique...
- Discussion threads 2009-09-03
- Xeon 5500 (Nehalem) servers: a group test
- Intel's Xeon 5500 processor has made a big splash in the server world as the major manufacturers each have their own brands featuring the 45nm Nehalem architecture. But which one is best? ZDNet UK's Alan Stevens puts the top models to the test and chooses a winner: ...
- Blog posts 2009-09-02
- Packaged software, an accident of history
- "government engineered" ????"dysfunctional business model"Sounds like someone is looking for a new "revenue stream"!This sounds suspiciously like the "lease a car" vs "rent a car" debate. Change the looks of the same old clunker to "generate sales" without really improving anything.Feudal Europe had the royalty owning the land and...
- Discussion threads 2009-08-24
- HF Holidays Gets in Step With Customers
- The UK's largest walking and leisure activity holiday provider, HF Holidays has 50,000 customers each year including 35,000 guests in its 17 country house properties. The challenge was to integrate data sources to create a single customer view then provide new insights to improve marketing and optimise campaigns - to...
- Case studies 2009-08-01
- Enhancing Sales and Operations Planning With Forecasting Analytics and Business Intelligence
- Since the unconstrained demand forecast is such an important part of an organization's S&OP process, it should be based to a large extent on statistical techniques as opposed to judgmental techniques. Many organizations develop demand forecasts utilizing a group's product knowledge as the primary driver. When used as part of...
- White papers 2009-08-01
- Dynamic Risk Classification for Anti-Money Laundering: SAS Anti-Money Laundering Enables Financial Institutions to Meet Expanded Requirements for Due Diligence
- Financial institutions are finding it necessary to strengthen their Anti-Money Laundering AML platforms to stem the tide of illicit financial transactions and meet new regulatory mandates. For enterprises with moderate to high risk exposures, this calls for a rigorous automated system based on dynamic risk assessment. Financial institutions need a...
- White papers 2009-08-01
- Merchandising Initiative Helps Rocket One of the Fastest-Growing US Retailers to the Top of the S&P 500
- As retailers worldwide battle the recession, one chain has actually come out stronger. Charlotte, NC-based Family Dollar led the S&P 500 in stock appreciation and has garnered national attention for continued positive revenue, earnings and same-store sales increases. The challenge was to increase sales by ensuring that each store stocks...
- Case studies 2009-08-01
- IBM goes deeply predictive, announces acquisition of SPSS
- IBM dropped a big bombshell at the start of any already action-packed day for the analyst community. At this moment, I’m sitting, along with several dozen of my peers from Forrester and other firms, at the IBM Smart Analytics System launch event in Hawthorne NY. I’ll blog on IBM’s other...
- Blog posts 2009-07-28
- Is Your IT Shop Mature Enough for Cloud Computing?
- Recently, I’ve written about software vendors being or not being ready for cloud computing. I’ve also written about large consultancies being able to support their clients as they move to the cloud. These consultancies and systems integrators are taking the cloud mainstream. Last week, I spoke...
- Blog posts 2009-07-27
- Prosecutor: Cybercrime will follow the cloud
- Prosecutor: Cybercrime will follow the cloudWrongConsumers dont want the tether to the mother ship.Consumers want a product in their hand in this case optical disk that they can put in a drawer and use if their pc blows up.Logical or not. Tangible product for their $ is what the consumer...
- Discussion threads 2009-07-13
- IBM gives Mobile County Public Schools power to be proactive
- When IBM PR folks sent me their press release on their recent efforts with the Mobile County Public Schools in Alabama, I was moderately impressed. They were harnessing a lot of data for educators but it hardly seemed revolutionary in this era of data-driven instruction. Then...
- Blog posts 2009-07-12
- Fido Uses SAS to Connect With High-Margin Customers and Products
- In an industry marked by intense competition and rapid expansion, Fido Solutions Inc. has been at the forefront of the development of wireless telecommunications and fast mobile data connectivity in Canada. The challenge was to determine the most profitable customers and products for marketing activities in the competitive telecom market....
- Case studies 2009-07-01
- Text Mining for Safety: Develop Your Untapped Reserves of Unstructured Data for Health, Safety and Environmental Improvements
- To ensure the overall health of the enterprise and its safety and environmental conditions, companies prepare and file detailed incident (and near-incident) reports. Monitoring these events and performing timely analysis leads to effective remediation efforts. Many incident management systems are cumbersome and unavailable at the job site, causing some events...
- White papers 2009-07-01
- HP StorageWorks 2000i G2 Modular Smart Array (MSA2000i G2) 700 Mailbox Exchange 2007 Storage Solution
- The information discussed in this solution brief highlights the tested performance results and configuration best practices for an Exchange server supporting 700 Exchange users. Testing was performed with the HP StorageWorks 2000i G2 Modular Smart Array using twenty (20) 146 GB 10K rpm SAS disks for Exchange database storage and...
- White papers 2009-07-01
Premier Vendor Content Whitepapers, webcasts & resources from our Power Center Sponsors
SmartPlanet
- Thought-provoking progressive ideas on diverse topics that intersect with technology, business, and life, and matter to the world at large. Visit SmartPlanet
- More from IBM
- How to Drive Better Business Outcomes with Exceptional Web Experiences Download the eBook
- Driving Business Agility through SOA Connectivity & Integration Read the White Paper from IBM
- Linking Decisions and Information for Organizational Performance Read the Tom Davenport study




