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Serial ATA, Here and Now
Xev writes "We have heard a lot about this new technology; over at HEXUS.net they have a review of a retail drive. The first on the internet, it is interesting to see the performance of the unit as well as the hotswap feature, and other new functions. Is this a solution to cheaper hot swap?"
Is it just me, or were the first several pages of this "article" written by cutting and pasting directly from Seagate's own product description and SATA white papers?
That they then split the article out over a zillion "pages" to pump up their ad impression numbers is insult on top of injury.
News for Nerds. Stuff that Matters? Like hell.
Something is up? Thats a nice way of saying their server is dying under the load of thousands of geeks.
Click here to print review
Review Title: Seagate ST380023AS Hard Drive
Reviewer: Simon Maltby
Date of Review: 30th December 2002
Sample Provided by Seagate
Introduction to SATA
Seagate UK kindly have supplied us with one of their new Serial ATA hard drives. We take a look at the new SATA format and attempt to determine what the new format means in real life. Will SATA produce any real improvement in performance?
Before we begin looking at the physical drive it is worth reading a little about the SATA format. The following extract from Seagate's web site provides us with an insight into the serial ATA standard and more importantly it's expected development path.
About the Serial ATA (SATA) format
Most desktop storage systems today use a parallel bus interface referred to as Ultra ATA/100. The parallel ATA interface has been in use on desktop systems as the mainstream internal storage inter-connect, since the 1980\'s (over 15 years!). Today\'s PCs demand higher speeds, more robust data integrity and flexibility for innovative smaller designs. Physically and electrically, the current parallel bus has run into limitations that will prevent this bus from providing higher speeds of data transfers. The move to a new technology is inevitable in the eyes of industry leaders such as Intel, Dell, Seagate, Maxtor and APT.
These same leaders formed the SerialATA.org and are highly dedicated to bringing this new technology to the forefront of today\'s PCs. Serial ATA is designed to overcome the limitations of parallel ATA while providing scalability for years to come. Setting the goal to be compatible and at cost parity with current parallel ATA drives when in volume, the SerialATA organization is promoting the adoption of Serial ATA in all systems where ATA drives are being used today.
Serial ATA... the future?
What is Serial ATA?
Serial ATA is a \"serial\" architecture as opposed to today\'s \"parallel\" ATA internal disc drive bus. Serial ATA wraps many bits of data into a packet and then at a higher speed (up to 50% higher) than parallel, transfers the packet of data down the wire to or from the host. Today Cyclic Redundancy Checking (CRC) is performed on the data being transmitted back and forth but not on the commands. Serial ATA integrates CRC on the command and data packet level for enhanced bus reliability. Cyclic redundancy code detects all single and double-bit errors and ensures detection of 99.998% of all possible errors. A Serial ATA drive can transfer data at 150MB/sec on the bus to the host system with extremely reliable accuracy and the Serial ATA interface will continue to allow scalability for a very long time.
Generation 1 Generation 2 Generation 3
Approximate Data Rate 150mb/sec 300mb/sec 600mb/sec
Approximate Bus Speed 1.5gb/sec 4gb/sec 6gb/sec
Approximate Introduction Fall of \'02 Mid \'04 Mid \'07
Additional Benefits
In addition to a faster, more reliable bus, Serial ATA improves cabling and connectors for a robust yet simpler integration. Gone are the days of bent pins and clumsy cabling and needless returned hard drives. Serial ATA cables are thinner and longer for improved system airflow and innovative system designs such as small form factor and consumer electronic boxes. Connectors are easier to snap into place without any pins but rather a blind-mate type of connection. Without the wide cables, system integrators can easily route the longer data cables (1 meter) within the system for simplicity or innovative designs.
Seagate Technology, A Native in Serial ATA Still in its early market entry stage, Serial ATA provides immediate benefits to desktop users. Serial ATA, an innovative new interface, allows continued performance growth, enhanced data reliability, and overall improved system dynamics above and beyond what Parallel can efficiently continue to provide.
A true \"Native\" Serial ATA solution offers customers the \"Real McCoy\" in Serial ATA technology. By implementing Serial ATA technology, not only on the physical layer of the drive, but also in the ATA controller link and transport layers, Seagate drives can communicate from the drive to the host directly up to the full 150MB/sec speed on the bus. In addition, the native solution incorporates command queuing, which can be a big performance boost in operating systems that can take advantage of that type of function. Some drive manufacturers may not immediately offer these \"native\" Serial ATA features on their 1st generation Serial ATA drives due to the difficulty of this integration.
The Test Drive I
The drive it\'s self looks just like any other computer hard disk drive. Consistent with other Seagate barracuda drives this one is very well built, solid and as attractive as a rectangular box of metal and plastic can be. The label clearly identifies the drive and provides setup information.
Review Model Seagate ST380023AS
Size 80gb
Speed 7,200rpm
Seek Time (Average) 9ms
Interface Serial ATA
Here is the description of the drive from Seagate\'s web site...
Seagate\'s Barracuda ATA V with Serial ATA Interface leverages the mechanics of the industry\'s quietest 7200 rpm desktop drive. The Barracuda ATA V offers 80GB and 120GB capacities with an 8MB cache for mainstream, high performance PCs, and entry-level servers. The product features all FDB motors, superior reliability and the next generation interface - Serial ATA. The SATA Barracuda includes Seagate\'s exclusive 3D Defense System and a one-year limited warranty.
Features Benefits
7,200 RPM desktop performance Improves overall PC performance
350 Gs nonoperating shock Protects drive from shock and vibration
3D Defense System Industry\'s most comprehensive drive and data protection system
DiscWizard software World\'s best disc installation software utility
SoftSonic(TM) FDB motor Quietest acoustics on any desktop drive
8-Mbyte cache buffer Improved performance
Serial ATA interface Fastest data transfer rates
The Test Drive II
SATA drives can not be connected to your computer with the standard IDE and Molex power connectors as becomes clear when viewing the back of the drive. Two new interfaces are need to use the drive. If you have a motherboard with serial ATA support you will have probably been supplied with an SATA data cable as shown below. However you will also need a Molex to SATA power conversion lead which is not supplied with either the motherboard or hard drive. I can foresee this power lead becoming a source of frustration for many people ordering SATA drives, hopefully when the drives hit the retail market the cable will be supplied with the hard drive.
Connecting the drive is very easy indeed. The SATA connectors are very well designed and will only fit the correct way round. There are no pins to bend or break as the fittings are more like USB than IDE.
Currently motherboards with SATA connectors run via the PCI bus. Some have connection via a SATA RAID controller, but our test board used a single SATA connector which is linked to a stand alone SATA controller chip. Once installed and booted the drive was displayed in the Bios taking the place of the primary IDE device. Windows XP located the drive as new hardware and the drive was fully visible. The Seagate drive is fully SMART enabled. This gives access to drive monitoring information including temperature.
Benchmarks I
Test Setup
* DFI NB80-EA Granite Bay motherboard
* P4 2.66Mhz CPU, 512MB DDR3500 RAM
* Seagate 80GB SATA150 Hard Disk Drive
* Maxtor 120GB 8MB ATA133 Cache Hard Drive on IDE
* Maxtor 60GB 2MB ATA100 Cache Hard Drive
* 2 Weston Digital 80GB 8MB Cache drives on Promise Raid Controller on Raid0
* Speedfan utility for SMART monitoring including hard drive temperature
HD Tech - Read Results Graph
The HD Tech benchmark is recognised as the most comprehensive hard drive test available. The benchmark evaluates the Hard drives performance across the whole drive regardless of how the drive is partitioned. It is common for performance to drop the further into the drive the test goes. This is due to the sectors at the end of the disk being physically further from the drives starting point.
Seagate SATA ATA150
Maxtor ATA133
The graphs above show two interesting trends. Although the computer was able to read information from the Maxtor drive faster than the Seagate drive, the opposite is true when it comes to writing data. The Seagate drive shows a consistent write speed with a few downward troughs, where as the Maxtor drive shows a few peaks in performance. Secondly although both drives show the expected reduction in read speed the further into the drive the test goes, the Seagate drive shows a slower decline dropping from circa 40k to 25k. The Maxtor drops more steeply from 50k down to 25k.
The graphs below show the results of all the HD Tech tests carried out during the review. As the benchmark requires unpartitioned drives to test writing speeds only two drives were able to be tested, the Seagate SATA and the Maxtor 120GB 8MB Cache.
Read speed average results
Write speed average results
The Seagate SATA drive did not perform as well as we had hoped in the read tests. Performance was lower than the other 8MB Cache drives whether in a raid configuration or straight forward IDE. The drive is far from being slow, but with the same 8MB Cache and the equivalent of ATA150 transfer speeds we hoped for more. Despite the average scores showing lower the Seagate drive did display better consistency across the drive as a whole and also proved significantly better in the write tests, some 30% better than the Maxtor.
Benchmarks II
Sandra Benchmark
The Sandra benchmark is less reliable than the HD Tech because it tests a partition rather than the whole drive and as we have seen performance changes depending on where on the drive the partition is located. When testing for the review we ensured that all the test drives had the same sized partition and that it was at the start of the physical disk.
The results show the same story as HD tech, although we are unable to break down the Sandra scores to establish where the Seagate drive falls down.
General Usage
Hot Swapping
An interesting attribute associated with SATA devices is that they should be \'Hot Swappable\', that means that you should be able to move devices around while your operating system is running. On the face of it this would be very useful. Care must be taken when moving hard disks around because while the internal discs are spinning damage can be caused easily. With the SATA drive installed as a non system disk we were able to disconnect the drive with windows XP running. Unlike USB device when removed, windows did not realise that the drive was no longer connected and it remained visible!
Noise
Seagate have produced a very well built drive in the ST380023AS. The casing is very solid and the mechanism well balanced. As a result it is most defiantly the quietest hard disk drive I have ever used. If you are looking for an ultra quiet drive then this one should be on your shopping list.
Reliability
The test drive was run continually for a week cycling the Sandra benchmark. Although the drive can get quite hot, rising to 45c under very heavy load, it performed without fault. SMART monitoring did not detect any problems during our testing. It should be remembered that a weeks hard testing does not give any real indication of the drives long term reliability, but we can take a great deal of comfort from the fact that the IDE Barracuda drives have proven to be one of the most reliable in the market thus far.
Price
Although SATA drives have not hit the retail market place in the UK yet The 80GB Seagate drive is expected to retail for circa £115 including VAT. This puts a small premium on the SATA format.
Conclusion
The read performance of the Seagate ST380023AS was not as good as we had hoped for. On the other hand write performance was better than we hoped for. In summary one fact is clear, the SATA interface works differently to the IDE interface and when you consider that this is a first generation SATA drive, linked to a motherboard that has the SATA interface located on the PCI bus, limiting it's potential, the overall performance is very good indeed.
The benefits of ultra fast data writing would make this drive ideal for write hungry tasks like video rendering or data backup. The Seagate drive itself is very well made and seems to be very robust. Its quiet operation makes it ideal for inclusion in a system where quietness is of benefit.
Serial ATA is in its infancy. Seagate have produced an excellent hard disk drive at the high quality end of the market place which should be very well received. I for one will be very sorry to have to part with this drive when Seagate ask for it back.
Pros
* Very Quiet
* Robust
* Very fast write performance
* Simple SATA data cable connection
Cons
* Needs power adapter (Not supplied)
* Slower read performance than expected
* SATA comes at a price premium
I'm currently building a computer for a good friend of mine, and we had planned on building in a Serial ATA RAID for fault tolerance.
Yeah, well... We had all the parts weeks ago... all except the !@X&@! serial ATA drives. Nobody had 'em, and nobody could get 'em. We also couldn't find Serial ATA mobile racks to mount the RAID drives... apparently nobody has those either.
We ended up having to use standard Parallel ATA drives (spare me the "SCSI R0XX0R5!!" flames... this is RAID on the semi-cheap, and it's not a server).
Ah well, nice to see that Somebody can finally lay their hands on these.
Even if a man chops off your hand with a sword, you still have two nice, sharp bones to stick in his eyes.
I didn't have a clue what serial ATA was (I'm not a hardware person), so I did a search and found The Serial ATA Working Group web site. That site has an interesting picture showing the difference in cables between parallel and serial cables here . The benefit (with the smaller cables), is that it is easier to maneuver the drives in PC cases. Other benefits of serial ATA are discussed at the web site.
Sex - Find It
I could be wrong though--wouldn't be the first time ;)
Firewire is 400mbit, USB 2 is over 400mbit... but SCSI-160 is 160 mBYTE, which is considerably faster. The PCI bus is capable of 133ish mBYTEs per second throughput, significantly (8x) faster than 133mBIT. Of course, if you're going to be using SCSI-160 with any real intent for performance, you're going to be using a 64-bit 66MHz PCI bus/device (try finding quality cards that work in 32bit 33Mhz pci slots at 160). That is considerably faster, capable of transfering up to 512 mBYTES per second. That's not too bad, really, for such a general purpose I/O bus. Compare that to the cpu-ram interconnect speed of an Athlon, which is FAST at 2.1 gBYTE per second per cpu.
Firewire and USB are neat, and darned quick (quicker than most drives can go... by themselves) but 400 mBIT is really only about 40 megabytes (ok little more) per second max. Not even in the same league.
Pros: ...
Very Quiet
Sending serially, one bit at a time, is quieter than in parallel? I didn't know bits made so much noise
SATA will scale better than parallel ATA - PATA is hard to scale given its bus nature. SATA should scale well up to at least 600MBPS theoretical throughput.
SATA has a smaller footprint than PATA, thus making it more economical to implement in mainboards where PCB space is at a premium. There is also a reduction of signal wires, so again it is more economical to use the drives.
SATA's smaller cables also allow for more creative formfactors and cabling solutions. PATA had short, wide, and ugly cabling. SATA has longer spec cabling, and its much thinner than PATA's, so cable routing is easier for OEMs.
Simply put, in its current form SATA isn't really a revolution, it's an evolution of the ATA standard, more out of convenience than anything.
------- "From bored to fanboy in 3.8 asian girls" ----------
from what i can tell, These guys are addressing that very issue, considering that they're an adopter of it.
Join the TWIT army now!
Why the new connector? After all, it does plug, ultimately, in a standard ATX power supply. And they even provide a conversion cable ( == less reliable).
Sigged!
New because the old friction-fit molex power connectors suck.
Actually, it's for hot-swapability. The old molex power connectors would make your drive virtually glued in, and you'd have to jiggle it to get the contacts to fit. The new power connectors are designed for hot-swap operation. They're smaller, easier to slide in and out, and have longer ground wires which ensures the drive is grounded *before* any power is delivered. The same long-short wiring is used in the data cables, where the 3 grounding pins connect before the 4 data pins (two pairs using differential signalling) connect.
I'm not sure how you figure an adapter is less reliable. Have you *ever* had a molex power connector come apart on you unexpectedly? I count myself lucky if I can get them apart on purpose!
This early in the migration, there may be issues here and there, but when SATA becomes the standard, there will be connectors for it right on the PSU's cabling, and motherboards will support tons of SATA channels straight to the northbridge rather than ganged onto the PCI bus, and maybe hotswap drives will start to be the norm. Alright, not that last bit, but the first two should happen pretty quickly since SATA is cheaper for the manufacturer, as well as better for the consumer.
High-speed Road Trip (18.000KPH)
*beats head against wall*
Who gives a crap about the PCI bus speed, or the theoretical maximum throughput of the ATA bus? The drives can't generate more than ~50 MB/s sustained transfer rate anyway. Yup, that's right! ATA-66 is fast enough for every PATA and SATA drive on the market today.
Oh, sure, you'll spike the transfer rate when reading from cache. I've done the numbers before, and it's something like a 0.1 millisecond difference between ATA-66 and ATA-133, since the largest cache is a mere 8 MB.
You are correct about SATA being faster than PCI, but it just doesn't matter. Nor do the future possibilities of SATA-300 or -600. The hardware just isn't fast enough.
And just to cover all the bases, once SATA is integrated into the south bridge chipset it won't be reliant on PCI. In the case of nVidia chipsets (and any Athlon64/Opteron chipset) it would then go over HyperTransport, which is 800 MB/s. I'm not sure what the backplane speed on Intel chips is, but I believe it's faster than PCI.