What is the difference b/w ATA H.D.D & SATA H.D.D?
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ATA is parallel data transfer, whereas S-ATA (Serial ATA) is Serial.
ATA (which is the same as IDE) uses an 40 pin ribbon cable to connect to the system, of which 16 are used for sending data (2 bytes at a time)
SATA uses a much narrower 7 pin data cable, only one of the pins is used to transfer data serially (1 bit at a time basically). However it does so at 150MBPS, as opposed to ATA, which is 133 MBPS max.
Simply,
EIDE or IDE is a big clunky cable that can hook up two drives on one channel.
SATA or Serial ATA is a small cable that runs to one drive and is a bit faster today (it promises greater speeds in the near future).
If your someone who has some need for a faster drive then SATA is for you however EIDE is sitll impressive.
Data integrity is also more stable with SATA. This is in due to the maxiumum throughput of PATA cables. When transfer speeds exceeded 66MB/s, they needed to use 80 conductor IDE cable because the data would become fragmented. The extra conductors on the 80 wire cable are grounded to sheild the data lines. However now we have reached the peak of the 80 conductor IDE cable at 133MB/s.
Serial vs Paralell.
What's at the heart of the matter is this. What is the most effeicent way of getting the data from the device to the buss. When data is serialized, you can do equal work with less connectors. So you jump from a 80 pin conductor (With a 40 pin connector) dual drive connector on current IDE/Paralell ATA drives to a 7 pin SINGLE DRIVE connection. The two greatest benefits are this. Reduced overhead: The ATA controller does not have to determine which drive it is talking to when ever sending a signal to a drive. On a single connector, it know which drive it is sending it's signal to. Increased data bus from 100/133mghz to 150 mghz.
But there are other benefits as well.
Improved air flow in the case as a result of smaller and much easier managed cables.
SATA was actually designed with RAID in mind. Paralell ATA was not.
The future of SATA is a lot brighter as well. PATA has maxed out at 100 (133 is not necessarily a standard, just a spec that a lot of manufaturers have conformed to), while SATA is sitting at 150mghz right now, the next 2 steps will double the previous standard. 300mghz, then 600mghz. The theoretical max is well into the ghz range, and hard drive manufaturers will have a LOT of work to do in getting their drives to pump that raw data to come even close to kepping up with 600mghz, let alone anything above that!
Lastly, there was mention of things like higher RPM speeds, etc. That actually has nothing to do with the interface. You can spin a drive as fast as you like. The question is how much are you willing to pay for it. It's all a matter of cost. You could easily build a computer to run 1,000 times faster then any current desktop on the market, but the costs would be insane.
You can learn more about SATA and the benefits over PATA form this paper here... It's Semi technical, but a good read (2 pages).
ftp://download.intel.com/t
<<Considering that they have yet to build drives that can get data on-off the actual disc faster than 60 MB/Sec the fact that a controller can send it through a wire at 133MB/Sec (or whatever) is pretty much irrelevant.>>
If this is true then a FibreChannel or Ultra320 SCSI drive is no faster than an IDE drive.
Lol, yeah its a mess isnt is Bonez.
Ok, not to dis anyone but theres a few misconceptions i can see (we all have to learn tho, me included)
1) SATA, IDE and SCSI are not all different things. SATA is still IDE, just its gone from PATA IDE to SATA IDE. (SCSI is totally different).
2) SATA doesnt transfer anything faster than anything else. Its just an interface standard. The fact that 150 is faster than 133 doesnt mean the drives automaticaly work 12% faster. 150 is just an agreed ceiling that wont be reached for some time. (Think about it, If it was reached then it would be a bottleneck and theyd have to re-design the standard again).
So to clarify, SATA does not transmit at 150MB/s. PATA does not transmit at 133 or 100.
An Analogy: A car wheel can work over 200 MPH but only very few models can push one that fast. Most cars mechanical limitation is way less than 200Mph, (much like a HDD has a mechanical limitation on spindle speed) but in time, more and more cars will reach it 200MPH, so the wheel will be redesigned to be safer at faster speeds - the ceiling will be raised to say, 300Mph?!
A single PATA drive averages perhaps 35MB/s today, far below the ATA max of 133 - my ide raid array pulls 60 MB/s according to sisoft sandra, 2 drives in parallel and still 60 is way under the 133 standard. The move to SATA has only changed the way the drive transmits data to the motherboard, the spindle speed is the same, the access times of the heads are the same, therefore SATA based drives are NO FASTER than equivalent PATA drives. (and has been shown in numerous tests at storage review).
Overall, measuring like for like, the SATA interface is *slightly* more efficient than PATA, only by a very very small margin, however most companies have just taken the pata board and slapped on a p to s bridge cancelling out the miniscule advantage to be had.
3) Limitations: PATA is not limited by cable type (we can improve signalling easily enough), its the PCI bus. On the motherboard, IDE is run as an attachment of the PCI bus. The PCI bus has a limitation of 33Mhz. Working out the bandwidth using a bit of zen mathematics gives a maximum b/w of ...... yes, you guessed it ...... 133MB/s. Thats why PATA will never exceed 133MB/s, it cannot work faster than the bus that it is on.
SATA is a different matter. Initially the first SATA controllers were also part of the PCI bus but soon after were moved onto their own connection (direct to the southbridge) offering 150MB/s on each channel. Sooner or later HDD manufacturers will get over their current mechanical limitations and then the SATA standard will provide more headroom, however we are a _loooooong_ way off from that.
How will that happen? Theres 3 ways HDDs can speed up.
a) Faster spindle speed
b) Faster head access times
c) Greater platter data density
a) and b) have their own penlties and barriers with c) being the main way that performance gradually increases from generation to generation. Right now we are expecting 90 Gig platters to arrive very soon, currently the newer drives have 80 gig platters with the bulk of mainstream drives having a 60 gig platter. Naturally if you can cram more data into the same physical space then you will get a higer bit for bit transfer rate from the same spindle speed.
The fastest IDE drives (the 10K Raptors) in a fast raid 0 configuration still barely challenge the 100MB/s bar, PATA would have been adequate for these but its getting close. With PATA, only multiple drive setups come anywhere close to challenging the maximum 133MB/s, but when you give each channel (and therefore each drive) 150MB/s then its going to need a huge leap in drive technology to use anything near that for a very long time.
Hope all that makes sense? :-)
Yes crazijoe ... That's what I'm saying...
Want a comparison??
Note: Maxtor and Western Digital no longer even provide this information in their spec sheets.
~ Do you think maybe they DON'T WANT YOU TO KNOW that all their advertising HYPE about the interface transfer rate is useless information??
Sustained (or Average) Head to Disc Xfer rates for different types of Seagate drives:
UDMA100 7200RPM ~~~ ~~~ ~~~ ~~~ 58 MB/s
160GB, 8MB Cache
ST3160023A
SATA 7200RPM ~~ ~~~ ~~~ ~~~ ~~~ 58 MB/s
160GB,8MB Cache
ST3160023AS
Ultra320 SCSI 10,000RPM ~~ ~~~ ~~~ 59.5 MB/s
146GB, 8MB Cache
ST3146707LC
FiberChannel 10,000RPM ~ ~ ~~~ ~~~ 59.5 MB/s
146GB, 8MB Cache
ST3146707FC
~~~~
Since about 1998/1999~ish the interface transfer rate means little.
The Performance bottle neck is the *mechanicals* and not the interface of the drive.
UDMA, SATA, SCSI ~~ Doesn't really matter much *at this time*.
~~~~
PCBONEZ
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by: leewPosted on 2004-12-26 at 23:23:02ID: 12905146
Interface. The way it connects to the computer. In addition, SATA drives can transfer data to the computer at roughly 12% faster speeds (133 MB/sec fastest ATA, 150 MB/sec fastest SATA). There are also a few SATA drives that can run at faster RPMs (fastest ATA RPM is 7200, fastest SATA RPM is 10,000, fastest SCSI is 15,000 RPM). Faster RPMs generally mean faster access to your data.