Attached SCSI Timeline - from
|StorageSearch.com was the first
publication to provide a dedicated
Serial Attached SCSI
page in November 2001,
the same month in which the new standard was first publicly announced.|
for many years this web address you're seeing now - was the home page for SAS
news. You can still see
versions in the internet archive (when it's working).
functioning silicon for this was demonstrated in January 2004 by LSI Logic. Host
Bus Adapters and chipsets supporting this new standard start shipping to
storage system designers in April/May 2004 from various companies.
Here's a timeline of how SAS moved from vaporware to reality.
- November 2004 - Serial Attached SCSI moved into the
top 20 most popular subjects viewed by STORAGEsearch readers for the first time.
- February 2005 - IBM ships SAS in x366 servers
- May 2005 - Hitachi Ships 15K RPM SAS Hard Drives
- June 2005 - HP announces that SAS will be used in
ProLiant Dual-Core AMD Opteron-based servers
- September 2005 - LSI Logic discloses that Dell and
Sun will soon ship SAS based servers
- October 2005 - Seagate & Adaptec Launch 1/2
Price SAS Starter Kit
- December 2005 - Maxtor & LSI Logic Offer Rebate
to Early SAS Adopters
- January 2006 - StorCase ships first removable SAS
- July 2006 - SAS enters the top 10 storage searches
STORAGEsearch.com readers for the
- April 2007 - Hitachi
announces 15k RPM, 300GB SAS HDDs.
how did SAS play out in the SSD market?
- April 2008 - Seagate
Technology starts volume shipments of 7,200 RPM SAS compatible terabyte
Click here for the SAS SSD
timeline - which is updated with real-time news upto October 2011
mastering serial SCSI|
|Serial Attached SCSI -
how it was positioned at the outset|
|SAS technology enables SCSI interface solutions
to the next-generation Direct Attach Storage enterprise server, storage
systems, and high-performance workstation markets while retaining device-level
backward compatibility. |
The SAS standard defines a device-level
enterprise storage interface incorporating SCSI command sets, serial
point-to-point interconnections, dual porting, increased addressability and the
ability to scale to small form factors. Because the SAS physical layer is
compatible with Serial ATA (SATA), users will have the choice of populating
their systems with SAS or SATA hard disk drives, or a combination of both.
a joint press release by LSI
Logic and Tabernus
|Why is the new Serial SCSI standard
necessary? (StorageSearch.com's viewpoint 2001)|
storage - typically upto 50% of the potential performance in modern
server processors is wasted.
Serial Attached SCSI (SAS) provides a
software compatible upgrade for directly attached SCSI storage which provides
much higher performance than Ultra320 SCSI. So this is the least pain next step
for SCSI users. Although, as with all new technology there is a learning curve.
The popularity of Internet SCSI (iSCSI) protocol
products in the second half of 2003 proved that the base of server owners who
are familiar with SCSI - will go a long way to adopt new connectivity options
which leverage concepts they trust and are familiar with. Asimilar evolution
took place with Ethernet, which started as a 3Mbps standard and still looks
viable at 10Gbps. Computer users like stuff that is newer faster and cheaper,
but we all know that "newer" also means "buggier" if we are
the first users. Anything that reduces the amount of new code and risk along
the way gets our vote.
SAS will meet the threat (albeit late in
marketing terms) from Serial
USB 2. In fact SAS uses the
same electrical interface and cables as SATA. That's good news if you're worried
about stocking even more types of cables. It also simplifies the rollout of new
test equipment - because
products designed for SATA can be adapted to SAS more simply (in theory by
20+ years ago, when SCSI started, it suited the
clock speeds and cable transmission driving capabilities of the TTL compatible
logic which was the standard at the time. SCSI was also easy to connect using
standard low technology ribbon cable. Since then, most of the enhancements in
the SCSI standard have focused on getting it to work faster, using higher clock
speeds, a wider data bus, lower logic levels and differential signals.
Attached SCSI is the first real attempt in SCSI history to lower cost and
simplify the physical connection. Past performance upgrades came from increasing
the number of cable cores. But the new high speed serial SCSI cables should be
cheaper than the lower performance parallel SCSI ones which they replace. And
you won't have to worry any more about those termination nightmares. It's
simpler in a serial system to automatically monitor signal quality and
dyamically adjust to the cable and connector transmission characteristics.
|these were key educational articles introducing SAS|
|the Benefits of SAS for
|This introduction to Serial Attached SCSI
(written by Adaptec
) gives you an idea of the performance, compatibilities, applications and
roadmap for this new directly attached disk connection standard. |
new SAS products not only provide an upward migration path for parallel SCSI
applications but also open the door to a new class of high performance high
reliability enterprise systems.
...read the article
|Serial Attached SCSI -
Delivering Flexibility to the Data Center |
| by LSI and
you think you already know SAS because you know SATA and traditional SCSI then
Sometimes disruptive technologies wear an unassuming
disguise. In fiction, Clark Kent, Frodo Baggins and Buffy Summers at first seem
harmless, but we see them change into Superman, the Ring Bearer and the Slayer.
SAS too comes cloaked in plain garb - with a physical layer which
looks a lot like SATA. But like the Incredible Hulk there are muscles rippling
under that shirt - and you would be wrong to dismiss SAS so lightly. There's a
lot more inside this interface than it says on the box as this informative
article reveals. ...read