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Enterprise-class ATA Drives
dfung writes "This has been mindlessly discussed many times before here, but Western Digital has now introduced real enterprise-class ATA drives with SCSI-like performance specs and 30% lower price. So now you can buy a real 10K rpm ATA drive. Interestingly enough, they mention the reason for the traditional difference in price between ATA and SCSI which I never have seen mentioned here - it has to do with testing costs, not controller electronics|platter quality|etc. Another interesting tidbit is that 160 million ATA drives were sold last year. I saw about 2 million of them stacked up in the aisles at Fry's Electronics yesterday, but that sure is a lot of drives."
SATA offers all the speed benefits of SCSI (such as command queueing and device initiated data transfer). In addition, it is one drive per channel. But "wait," you say, "servers need lots of drives in raid5 on each channel!!!" One drive per channel is a blessing in disguise.
From time to time I've seen drive logic fail (as opposed to surface errors), which often brings down the entire SCSI channel. With raid5, you can only afford to lose one drive and perhaps a couple hot spares. Certainly not 14 drives in one shot. SCSI is many pinned, and SCSI raid adapters are designed to have many drives on each channel. One drive per interface is extremely costly and impractical. In this respect, SATA is more robust.
"If one drive per channel serial interfaces are so good, why weren't the used in the first place," you might wonder. Modern high clock rate microcontroller technology permits much higher frequency twisted pair serial interfaces that can offer superior bandwidth to older parallel, ribbon cable interfaces. If SCSI were being designed today it would look something like firewire, which I'm sure you're not biased against. Don't be fooled by the ATA moniker.
That large of a cache on a HD is really just more room to quickly dump data without actually having to write it to the hard drive immediately. Helps you get fastest possible data transfer when doing I/O with your drive, and on the scale of bag for your buck it isn't that expensive over their normal 2M cache drive.
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This is a Serial ATA drive, which the article even mentions (second paragraph: "...Enterprise Serial advanced technology attachment..."), but then proceeds to call it an ATA drive (instead of SATA) for the rest of the article.
Here's a somewhat less misleading article.
Maxtor released their 10K drives. Rapture series drives are limited to 36GB I believe (1 plater), have a 5 year warrenty, and rated for 1.3 million operating hours (I think its 1.3 million, might be wrong). These drives are SATA, and are hot-swappable. And you too can own one for about $140-160. Which when you look at the price of SCSI, its VERY cheap.
We were all warned a long time ago that MS products sucked, remember the Magic 8 Ball said, "Outlook not so good"
i believe you are thinking of different things.
chips and tech becomes mature and their FAILURE RATE decreases. mature technology does not cost less to test. On the whole SCSI is still a more complex technology, and I would not be surprised if tested with higher margin / more thoroughly due to the "enterprise level reliability" thing.
besides, as devices gets more complex and more "mature," generally the testing costs increase because you have all these new features, plus the old features, plus the shit that keeps it backwards compatible, to test. you can do better on the profit margin / cost side by making ships that have a lower failure rate, but that does not mean chips gets tested less, or it takes shorter to test them. On the contrary, it usually goes the other way.
Anyhow, example: RAMBUS was expensive because it was a "cutting edge" manufacturing process. the output impedence of the chips had to be controled very precisely, which is difficult to do and a lot of it failed at test - driving up the cost. as process matured, less failed and price came down. but each chip still went through the same routine, and sat the same amount of time on the testers* and took the same number of pin-capacities**, so the TESTING COST stays the same***.
* as memory size increase, they sit longer, usually
** similarly, wider buses takes more pins
*** so in the end testing cost usually increases.
separate the two concepts.
My life in the land of the rising sun.
This month's issue pits IBM's best IDE vs. a Seagate Cheetah SCSI.
The Winner? The SCSI drive by a margin of more than 30%. There is still a huge difference, especially in the random seek and file transfer areas.
Don't be dense, to do 14 (actually 12 is the most I know of) IDE drives you get a controller that has 12 interface channels and a controller chip. The speed per channel is meaningless because with the IDE solution the only bottleneck is the host bus and the speed of the interface chip, no single drive is going to saturate it's single line. Also did you read the article and notice the waranty one these drives? Yeah 5 years just like the SCSI drives. These drives are basically SCSI 10K rpm drives with an ATA controller board, hook em up to the right IDE host controller and you have a solution that will save you 30% on your storage costs, which is substantial for many enterprises.
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