Scott Wasson and I were wandering the IDF Tech Showcase area last month and ran across the SATA International Organization booth. This booth in particular caught our interest because they were showcasing the latest SATA spec, SATA 2.5. We were both curious to see what had changed with SATA 2.5, and what ensued led me to make this post.
When the first SATA spec that we started seeing on drives and motherboards was revision 1.0 or some letter derivative of it (e.g. 1.0a). The folks in charge of making the specs eventually changed their name to SATA II, note that SATA II was the name of the organization defining the SATA spec, not a new SATA spec. The SATA II organization defined a number of extensions to the SATA 1.0a spec, including things like NCQ and 3.0Gb/s signaling, both of which were optional extensions to the specification.
Of course the vendors and drive manufacturers alike started referring to drives that supported the 3.0Gbs transfer rates as SATA II drives and thus everyone assumed that SATA II or SATA 2.0 was the logical successor to SATA 1.0. Given what I've just said, that wasn't true, in fact SATA 2.0 was never a spec, SATA II was simply the name of the organization that defined the spec.
In order to clear up the confusion, the SATA II folks (the organization) changed their name from SATA II to SATA-IO (Serial ATA International Organization) and released a new SATA specification, SATA 2.5. SATA 2.5 is the actual successor to the SATA 1.0a specification. What does SATA 2.5 offer that the previous SATA specifications did not? Actually nothing at all, SATA 2.5 is nothing more than what manufacturers and vendors were incorrectly referring to as SATA II or SATA 2.0. The new spec is just here to reduce confusion.
The problem is that most of the advantages of SATA 2.5 over SATA 1.0a are optional extensions. For example, although the 3.0Gb/s interface is included in the SATA 2.5 specification, it isn't required. So you can have a drive that adheres to the SATA 2.5 spec, but only features a 1.5Gb/s transfer rate. The same goes for NCQ, Hot Plug, eSATA, Staggered Spin-Up, and the rest of the SATA 2.5 features.
The SATA-IO folks want to see manufacturers and vendors begin referring to drives by the features they support, not by what specs they adhere to. The idea is that you'd see a drive listed as a SATA 3.0Gb/s drive, or SATA 1.5Gb/s + NCQ Support, not as a SATA 2.5 drive.
Hopefully this post has helped reduce some of the confusion about the matter :)
When the first SATA spec that we started seeing on drives and motherboards was revision 1.0 or some letter derivative of it (e.g. 1.0a). The folks in charge of making the specs eventually changed their name to SATA II, note that SATA II was the name of the organization defining the SATA spec, not a new SATA spec. The SATA II organization defined a number of extensions to the SATA 1.0a spec, including things like NCQ and 3.0Gb/s signaling, both of which were optional extensions to the specification.
Of course the vendors and drive manufacturers alike started referring to drives that supported the 3.0Gbs transfer rates as SATA II drives and thus everyone assumed that SATA II or SATA 2.0 was the logical successor to SATA 1.0. Given what I've just said, that wasn't true, in fact SATA 2.0 was never a spec, SATA II was simply the name of the organization that defined the spec.
In order to clear up the confusion, the SATA II folks (the organization) changed their name from SATA II to SATA-IO (Serial ATA International Organization) and released a new SATA specification, SATA 2.5. SATA 2.5 is the actual successor to the SATA 1.0a specification. What does SATA 2.5 offer that the previous SATA specifications did not? Actually nothing at all, SATA 2.5 is nothing more than what manufacturers and vendors were incorrectly referring to as SATA II or SATA 2.0. The new spec is just here to reduce confusion.
The problem is that most of the advantages of SATA 2.5 over SATA 1.0a are optional extensions. For example, although the 3.0Gb/s interface is included in the SATA 2.5 specification, it isn't required. So you can have a drive that adheres to the SATA 2.5 spec, but only features a 1.5Gb/s transfer rate. The same goes for NCQ, Hot Plug, eSATA, Staggered Spin-Up, and the rest of the SATA 2.5 features.
The SATA-IO folks want to see manufacturers and vendors begin referring to drives by the features they support, not by what specs they adhere to. The idea is that you'd see a drive listed as a SATA 3.0Gb/s drive, or SATA 1.5Gb/s + NCQ Support, not as a SATA 2.5 drive.
Hopefully this post has helped reduce some of the confusion about the matter :)
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NicholasTaylor - Sunday, September 11, 2005 - link
I've done quite a bit of reading on this subject lately, and I have to say it was this short article that finally made me get the whole picture.Spoonbender - Thursday, September 8, 2005 - link
Sheesh, what on earth are they thinking?First, naming the organization SATA II is just asking for trouble. Second, making two different names for a spec which doesn't actually offer any improvement (other than optional features)?
And third, using two different names for the spec (1.0a and 2.5), but *not* the one everyone else actually uses, SATA 2?
Are they stupid? Or just living on a different planet?
When even manufacturers use the wrong name, isn't it time to reconsider your naming conventions a bit?
ceefka - Thursday, September 8, 2005 - link
There is also the notion that the chipset/controller as well as the HDD must support a feature like NCQ. All in all, this needs much more publicity to get the fact straight.VooDooAddict - Wednesday, September 7, 2005 - link
Wait let me get this straight ...they finnaly have a non-confusing name for the standard (SATA 2.5), but they don't leverage it with requiring a feature set?I guess they are just a puppet for the drive companies and not a true standards organization.
xtknight - Wednesday, September 7, 2005 - link
So in 3 words, "SATA2.5" means nothing?Scrogneugneu - Thursday, September 8, 2005 - link
In fact, it means "This drive is certified to maybe have some very nice options".In other words, yeah, it does mean nothing...
jebo - Wednesday, September 7, 2005 - link
This post did clear the confusion. Interestingly, I was just looking at SATA IO's site yesterday trying to figure out all this mess myself.The thing that doesn't make one iota of sense to me is how all the SATA 2.5 specs are optional? Good Lordy. Don't these people realize it's so much easier on everybody involved to lump all the features into one standard? A conversation with a non-familiar person is so much easier if I can say "look at the package and see if it says SATA 2.5 on it" rather than "does it say 3.0gb/s? Does it say NCQ? Hot pluggable?" Not to mention if you wanna brag about your system (in a signature on a forum, perhaps) you have to list out all the features of your hard drives instead of the clean, concise, "SATA 3" or etc. Pffft.