Solve : USB sata or ide?

1.	Solve : USB sata or ide?
Answer» I am looking at an External Hard Drive USB 2.0 One of them take 2. SATA Drives and you can have one T.B. of Hard Drive of Hard Drive space with both of them. And I know that SATA transfers Data faster then IDE. What I don't understand is if I have an IDE USB Drive or I have aSATA USB Drive they both have to send Data to the computer through the USB Cable. So even if the SATA Drive will have a faster transfer rate when the Data is leaves the Drive it can only go to the computer as fast as the SBU 2.0 connection RIGHT?? If this is true then I can have an IDE USB Drive and they will STILL be a fast please helpOk I need some help understanding what is going on? I just foundout that SATA 1. Transfer Rate is 1 . 5 Gbps and SATA 2 Transfer Rate is 3 . 0 Gbps. And the External Enclosure I am looking at has a Tranfer Rate of 480 Mbps and it connects to the computer USB 2.0 and USB Transfer Rate is 400 Mbps. Now what I need to know is the Enclosure take SATA 1. and 2. so dose SATA 1. realy transfer data at 1 . 5 Gbps that is realy a LOT??? If so if I ran a SATA 1. drive and it only tranfer through the USB cable the USB only tranfers data at 400 Mbps. I would be lossing a lot of speed what am I not understanding or getting? Save cash and the hassle buy a flash drive.Quote from: nymph4 on July 15, 2008, 10:44:03 AM So even if the SATA Drive will have a faster transfer rate when the Data is leaves the Drive it can only go to the computer as fast as the SBU 2.0 connection RIGHT?? If this is true then I can have an IDE USB Drive and they will still be a fast please help Yes, the limiting factor is the USB connection.Ok I was doing some looking around for SATA Drives and found that SATA 2. Drives say they have a Transfer Rate of 3.0 Gbps but then it says the Real Speed is 300 MBps So does this meen that SATA 2. Drives do not Transfer Data at 3 . 0 Gbps if so what is that 3 . 0 Gbps Tranfer speed that I keep seeing??SATA II is really a misnomer but commonly refers to SATA drives with transfer speeds of 3.0Gbps (giga bits per second). a) 8 Bytes/bit b) There is overhead associated with the hard drive - 20%. c) Therefore, (3 Gbps/8 Bytes/bit).8 = 300 MBps (mega bytes* per second) The same analysis holds for 1.5 Gbps (SATA I) drives.Well I thought it was something like that. But what I meen is they say SATA Tranfer is 3 Gbps and that is 3 Billion Bits Per Sec. That is a Lot more then saying 300 MBps witch is 300 Million Bytes Per Sec.That's right. But, 300 MBps = 2.4 billion bits per second. If you divide that by the 'efficiency' of the data transfer protocol of 80%, you get 2.4/.8 = 3 billion bits per second claimed transfer speed.I think I have it they say SATA Tranfer Rates is 3.0 Gbps but out of that only 300 MBps is halding are Data that we are Transfering RIGHT??? So every Second SATA Transfers 3 Gbp But 8 Bytes out of every Second is for the Over Head and not for us RIGHT??? And if IDE Drives are 133 MBps and SATA is 300 MBps SATA is still faster RIGHT??? Do I have all three of these right Quote from: merlin on August 06, 2008, 03:42:13 PM Save cash and the hassle buy a flash drive. Save us some grief and don't post until you actually have something useful to say.Quote from: nymph4 on August 08, 2008, 06:53:48 PM I think I have it they say SATA Tranfer Rates is 3.0 Gbps but out of that only 300 MBps is halding are Data that we are Transfering RIGHT??? So every Second SATA Transfers 3 Gbp But 8 Bytes out of every Second is for the Over Head and not for us RIGHT??? And if IDE Drives are 133 MBps and SATA is 300 MBps SATA is still faster RIGHT??? Do I have all three of these right Your understanding is not quite right. First - The 3.0 Gbps number refers to the frequency ('speed') of a drive's electronics. The SATA drive has electronics which are capable of communicating with the motherboard at 3.0 Gbps. So the drive's electronics run at a frequency of 3.0 Gbps. However, the communication between the motherboard and the hard drive is governed by a protocol (specification) which requires that the data exchange between the motherboard and the hard drive is coded in a particular way. This coding requirement reduces the speed at which the hard drive can actually communicate data back and forth to the motherboard because the hard drive has to do 'work' on the data to encode it. This 'loss of speed' is said to be 20% - which means that the drive's electronics are 80% 'efficient' at communicating with the motherboard. But the drive's electronics are not the limiting factor in the drive's ability to transfer data - the limiting factor is the electro-mechanical-magnetic nature of the drive itself. The fastest drives today can only actually transfer data at ≈120 MBps, less than 1/2 the actual capability of the electronics. The 'nature' of PATA (IDE) drives and SATA drives is the same, therefore, the current actual performance of PATA drives and SATA drives is about the same, everything else equal. Your original proposition placed another constraint - the use of the USB interface. A high speed USB 2.0 interface has a theoretical maximum throughput (data exchange) of 480 Mbps or 60 MBps. Again, there is coding 'loss' or inefficiency on the interface - ≈10%, so the max transfer rate is ≈54 MBps. This is well below the actual transfer rate of either a PATA or SATA drive; therefore, it will make no difference which type of drive is in the enclosure - they will perform the same, everything else equal. Ok so SATA one has a Transfer speed of 1 . 5 Gbps but the real Transfer speed is 150 MBps. And SATA two Transfer speed is 3 Gbps but the real Transfer speed is 300 MBps. So both are slower then they say I get this. But what did you meen when you posted that a SATA 3 Gbps is just how fast it talks to the motherboard but that is not the Data Transfer speed? Data can only go as fast a the device talks to the motherboard so if it talks to the board at 3 Gbps then it Transfers Data 3 Gbps? If I don't have it I will still do more readingQuote from: nymph4 on August 09, 2008, 09:10:04 PM Data can only go as fast a the device talks to the motherboard so if it talks to the board at 3 Gbps then it Transfers Data 3 Gbps? If I don't have it I will still do more reading @nymph4 - you are wonderful In a sense you are right - a hard drive cannot transfer data at a rate faster than the frequency (speed) of its electronics. But that only is an ISSUE for the maximum speed that data can move across the SATA/motherboard interface. SATA II (you and I will use this term, but, remember, it is not an 'official' designation) cannot transfer data any faster than 3.0 Gbps. In actual fact, data transfer speeds do not approach this theoretical maximum. You must read the rest of what I said about the factors that limit the 'real' transfer speeds - the coding protocol, and, most importantly, the nature of the hard drive itself. The limiting factor is not the drive electronics, but, rather, the physical nature of the hard drive itself. Current hard drive technology does not allow a drive to spin fast enough nor have a high enough magnetic density to come even close to the potential of the drive electronics. That's the bad news - the good news is that technology, over time, will improve the electro-magnetic-physical characteristics of the hard drive to approach, and surpass, the promise of the 3.0 Gbps data transfer. I don't know if "you have it" or not - but I'm starting to repeat myself! Please read what I've written about the limits to the theoretical transfer speeds and see if it doesn't make sense to you. The situation right now is like a bicycle on an expressway - the expressway (drive electronics/motherboard interface) can handle much more speed, but the bicycle (hard drive physical nature) just can't go any faster. Ok I think I have it the SATA interface can go 3 Gbps but the Hard Drive can not Tranfer Data that fast. So how can they Advertize 3 Gbps when it will not go that fast it will not Transfer Data that fast?Quote from: nymph4 on August 10, 2008, 12:59:30 PM Ok I think I have it the SATA interface can go 3 Gbps but the Hard Drive can not Tranfer Data that fast. Absolutely right Quote from: nymph4 on August 10, 2008, 12:59:30 PM So how can they Advertize 3 Gbps when it will not go that fast it will not Transfer Data that fast? Very good question and my answer is opinion not fact. The entire tech industry is full of marketing hype overstating performance/capacities (or claiming theoretical performance instead of 'real' performance) in an attempt to sell, sell, sell. Look at hard drive storage capacities, marketing departments have re-defined "mega bytes" to overstate capacities. Look at advertised broadband speeds and compare them to actual speeds.

Answer»

I am looking at an External Hard Drive USB 2.0

One of them take 2. SATA Drives and you can have one T.B. of Hard Drive of Hard Drive space with both of them.

And I know that SATA transfers Data faster then IDE.

What I don't understand is if I have an IDE USB Drive or I have aSATA USB Drive they both have to send Data to the computer through the USB Cable.

So even if the SATA Drive will have a faster transfer rate when the Data is leaves the Drive it can only go to the computer as fast as the SBU 2.0 connection RIGHT??

If this is true then I can have an IDE USB Drive and they will STILL be a fast please helpOk I need some help understanding what is going on?

I just foundout that SATA 1. Transfer Rate is 1 . 5 Gbps and SATA 2 Transfer Rate is 3 . 0 Gbps.

And the External Enclosure I am looking at has a Tranfer Rate of 480 Mbps and it connects to the computer USB 2.0 and USB Transfer Rate is 400 Mbps.

Now what I need to know is the Enclosure take SATA 1. and 2. so dose SATA 1. realy transfer data at 1 . 5 Gbps that is realy a LOT???

If so if I ran a SATA 1. drive and it only tranfer through the USB cable the USB only tranfers data at 400 Mbps. I would be lossing a lot of speed what am I not understanding or getting? Save cash and the hassle buy a flash drive.Quote from: nymph4 on July 15, 2008, 10:44:03 AM

So even if the SATA Drive will have a faster transfer rate when the Data is leaves the Drive it can only go to the computer as fast as the SBU 2.0 connection RIGHT??

If this is true then I can have an IDE USB Drive and they will still be a fast please help

Yes, the limiting factor is the USB connection.Ok I was doing some looking around for SATA Drives and found that SATA 2. Drives say they have a Transfer Rate of 3.0 Gbps but then it says the Real Speed is 300 MBps

So does this meen that SATA 2. Drives do not Transfer Data at 3 . 0 Gbps if so what is that 3 . 0 Gbps Tranfer speed that I keep seeing??SATA II is really a misnomer but commonly refers to SATA drives with transfer speeds of 3.0Gbps (giga bits per second).

a) 8 Bytes/bit

b) There is overhead associated with the hard drive - 20%.

c) Therefore, (3 Gbps/8 Bytes/bit)*.8 = 300 MBps (mega bytes per second)

The same analysis holds for 1.5 Gbps (SATA I) drives.Well I thought it was something like that.

But what I meen is they say SATA Tranfer is 3 Gbps and that is 3 Billion Bits Per Sec.
That is a Lot more then saying 300 MBps witch is 300 Million Bytes Per Sec.That's right. But, 300 MBps = 2.4 billion bits per second. If you divide that by the 'efficiency' of the data transfer protocol of 80%, you get 2.4/.8 = 3 billion bits per second claimed transfer speed.I think I have it they say SATA Tranfer Rates is 3.0 Gbps but out of that only 300 MBps is halding are Data that we are Transfering RIGHT???

So every Second SATA Transfers 3 Gbp
But 8 Bytes out of every Second is for the Over Head and not for us RIGHT???

And if IDE Drives are 133 MBps and SATA is 300 MBps SATA is still faster RIGHT???

Do I have all three of these right

Quote from: merlin on August 06, 2008, 03:42:13 PM

Save cash and the hassle buy a flash drive.

Save us some grief and don't post until you actually have something useful to say.Quote from: nymph4 on August 08, 2008, 06:53:48 PM

I think I have it they say SATA Tranfer Rates is 3.0 Gbps but out of that only 300 MBps is halding are Data that we are Transfering RIGHT???

So every Second SATA Transfers 3 Gbp
But 8 Bytes out of every Second is for the Over Head and not for us RIGHT???

And if IDE Drives are 133 MBps and SATA is 300 MBps SATA is still faster RIGHT???

Do I have all three of these right

Your understanding is not quite right.

First - The 3.0 Gbps number refers to the frequency ('speed') of a drive's electronics. The SATA drive has electronics which are capable of communicating with the motherboard at 3.0 Gbps. So the drive's electronics run at a frequency of 3.0 Gbps. However, the communication between the motherboard and the hard drive is governed by a protocol (specification) which requires that the data exchange between the motherboard and the hard drive is coded in a particular way. This coding requirement reduces the speed at which the hard drive can actually communicate data back and forth to the motherboard because the hard drive has to do 'work' on the data to encode it. This 'loss of speed' is said to be 20% - which means that the drive's electronics are 80% 'efficient' at communicating with the motherboard.

But the drive's electronics are not the limiting factor in the drive's ability to transfer data - the limiting factor is the electro-mechanical-magnetic nature of the drive itself. The fastest drives today can only actually transfer data at ≈120 MBps, less than 1/2 the actual capability of the electronics.

The 'nature' of PATA (IDE) drives and SATA drives is the same, therefore, the current actual performance of PATA drives and SATA drives is about the same, everything else equal.

Your original proposition placed another constraint - the use of the USB interface. A high speed USB 2.0 interface has a theoretical maximum throughput (data exchange) of 480 Mbps or 60 MBps. Again, there is coding 'loss' or inefficiency on the interface - ≈10%, so the max transfer rate is ≈54 MBps. This is well below the actual transfer rate of either a PATA or SATA drive; therefore, it will make no difference which type of drive is in the enclosure - they will perform the same, everything else equal.
Ok so SATA one has a Transfer speed of 1 . 5 Gbps but the real Transfer speed is 150 MBps.

And SATA two Transfer speed is 3 Gbps but the real Transfer speed is 300 MBps.

So both are slower then they say I get this. But what did you meen when you posted that a SATA 3 Gbps is just how fast it talks to the motherboard but that is not the Data Transfer speed?

Data can only go as fast a the device talks to the motherboard so if it talks to the board at 3 Gbps then it Transfers Data 3 Gbps?

If I don't have it I will still do more readingQuote from: nymph4 on August 09, 2008, 09:10:04 PM

Data can only go as fast a the device talks to the motherboard so if it talks to the board at 3 Gbps then it Transfers Data 3 Gbps?

If I don't have it I will still do more reading

@nymph4 - you are wonderful

In a sense you are right - a hard drive cannot transfer data at a rate faster than the frequency (speed) of its electronics. But that only is an ISSUE for the maximum speed that data can move across the SATA/motherboard interface. SATA II (you and I will use this term, but, remember, it is not an 'official' designation) cannot transfer data any faster than 3.0 Gbps. In actual fact, data transfer speeds do not approach this theoretical maximum.

You must read the rest of what I said about the factors that limit the 'real' transfer speeds - the coding protocol, and, most importantly, the nature of the hard drive itself. The limiting factor is not the drive electronics, but, rather, the physical nature of the hard drive itself. Current hard drive technology does not allow a drive to spin fast enough nor have a high enough magnetic density to come even close to the potential of the drive electronics. That's the bad news - the good news is that technology, over time, will improve the electro-magnetic-physical characteristics of the hard drive to approach, and surpass, the promise of the 3.0 Gbps data transfer.

I don't know if "you have it" or not - but I'm starting to repeat myself! Please read what I've written about the limits to the theoretical transfer speeds and see if it doesn't make sense to you.

The situation right now is like a bicycle on an expressway - the expressway (drive electronics/motherboard interface) can handle much more speed, but the bicycle (hard drive physical nature) just can't go any faster.
Ok I think I have it the SATA interface can go 3 Gbps but the Hard Drive can not Tranfer Data that fast.

So how can they Advertize 3 Gbps when it will not go that fast it will not Transfer Data that fast?Quote from: nymph4 on August 10, 2008, 12:59:30 PM

Ok I think I have it the SATA interface can go 3 Gbps but the Hard Drive can not Tranfer Data that fast.

Absolutely right

Quote from: nymph4 on August 10, 2008, 12:59:30 PM

So how can they Advertize 3 Gbps when it will not go that fast it will not Transfer Data that fast?

Very good question and my answer is opinion not fact.

The entire tech industry is full of marketing hype overstating performance/capacities (or claiming theoretical performance instead of 'real' performance) in an attempt to sell, sell, sell. Look at hard drive storage capacities, marketing departments have re-defined "mega bytes" to overstate capacities. Look at advertised broadband speeds and compare them to actual speeds.

Solve : USB sata or ide?

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