Sign in with
Sign up | Sign in
Your question

ESATA enclosures

Last response: in Storage
Share
December 19, 2011 6:01:28 PM

I need an eSATA 3.5" enclosure, but I am confused about the specs.

I thought these were passive devices, so...

Why do the enclosures list max HD capacity?

Why do the enclosures specify speed or SATA type? Aren't SATA Type I, II, and III connectiors the same connector? Aren't all eSATA connectors the same?

It seems to me that the enclosure shouldn't care whether it house a 500GB SATA I drive or a 2.5TB SATA III drive.


More about : esata enclosures

a b G Storage
December 19, 2011 6:32:45 PM

A 3.5" drive cannot be passive, only 2.5". The 3.5 just draw too much power and therefore need their own power source. Technically there is a eSataP (powered) but this never really got mainstream adoption, so we have to fiddle with power cables.

I personally use something similar to this http://www.newegg.com/Product/Product.aspx?Item=N82E168... but not this exact model. This one requires a port multiplier eSata port (which I don't have) so instead I chose a model with 2x eSata connectors at the back. The limitations don't usually mean anything. Manufacturers only test a few drives, and just say we tested X and Y and these worked, can't guarantee bigger works so it's just to cover their asses. I've not found any problems yet with large drives, although I've stayed away from drives larger than 2.2tb for good reason.

As for sata 1-2-3 just different speeds really. If your putting in a mechanical drive, meaning not SSD, you won't notice a performance difference as even sata1 isn't saturated by most mechanical drives.
m
0
l
a c 302 G Storage
December 19, 2011 7:04:02 PM

"Real" eSATA enclosures require a buffer circuit to convert between the eSATA signalling voltages to the PC and the SATA signalling voltages to the hard drive. Very few people, or manufacturers, bother with actually doing this - even my ASUS motherboard came with an SATA header to eSATA back panel. Technically, this is out of spec and may fail at any time.

So there are two possibilities. One, the buffer circuit was built at a time where certain capacities, or more likely SATA speeds, did not exist and so the buffer is not certified to handle them. Much more likely, all these values are advertising rubbish and any properly buffered eSATA enclosure will work with any size drive and any SATA speed.

We it me, I'd buy the first one that I could get my hands on, ensure that it has said buffer, and try the experiment.
m
0
l
Related resources
December 19, 2011 11:25:21 PM

WyomingKnott said:
"Real" eSATA enclosures require a buffer circuit to convert between the eSATA signalling voltages to the PC and the SATA signalling voltages to the hard drive. Very few people, or manufacturers, bother with actually doing this - even my ASUS motherboard came with an SATA header to eSATA back panel. Technically, this is out of spec and may fail at any time.

So there are two possibilities. One, the buffer circuit was built at a time where certain capacities, or more likely SATA speeds, did not exist and so the buffer is not certified to handle them. Much more likely, all these values are advertising rubbish and any properly buffered eSATA enclosure will work with any size drive and any SATA speed.

We it me, I'd buy the first one that I could get my hands on, ensure that it has said buffer, and try the experiment.


It does make sense that there would be a difference in enclosures based on the buffer size - although none of the enclosures I looked at even mention a buffer. Perhaps, specifying drive size and speed is a round-about way of telling you what size buffer the unit has...

Or, did you mean the buffer is supposed to be on the motherboard (or controller card)?

My computer does have an eSata external header which is connected to a connection labeled "eSATA" on the motherboard, rather than simply a SATA connector.

Turns out that the cheapest with a fan also has the marketing hype about drive size, which OS's it will work with, etc. They had one without a fan for $16.95, but I bought this one:

http://www.newegg.com/Product/Product.aspx?Item=N82E168...
m
0
l
December 19, 2011 11:37:05 PM

Supermuncher85 said:
A 3.5" drive cannot be passive, only 2.5". The 3.5 just draw too much power and therefore need their own power source. Technically there is a eSataP (powered) but this never really got mainstream adoption, so we have to fiddle with power cables.

I personally use something similar to this http://www.newegg.com/Product/Product.aspx?Item=N82E168... but not this exact model. This one requires a port multiplier eSata port (which I don't have) so instead I chose a model with 2x eSata connectors at the back. The limitations don't usually mean anything. Manufacturers only test a few drives, and just say we tested X and Y and these worked, can't guarantee bigger works so it's just to cover their asses. I've not found any problems yet with large drives, although I've stayed away from drives larger than 2.2tb for good reason.

As for sata 1-2-3 just different speeds really. If your putting in a mechanical drive, meaning not SSD, you won't notice a performance difference as even sata1 isn't saturated by most mechanical drives.


I was thinking about passive with reference to data transfer and physical connections.
m
0
l
a c 302 G Storage
December 20, 2011 11:47:31 AM

Ehh, I wasn't clear enough. The buffer doesn't have a size; it just translates the signals from one voltage level to another. The only issue that I can imagine is an early model not being fast enough to keep up with SATA III signalling.

Considering that this is the day and age of SATA III, and they advertise that as capable of working with SATA II, maybe there is actually a speed limitation on the buffers. I was speculating; I have neither tested nor looked up specifications. Maybe I'll drop Rosewill tech support a question. Let us know if it works for you.

EDIT: Just sent the inquiry to Rosewill; inquiring minds want to know
m
0
l
December 20, 2011 2:34:29 PM

WyomingKnott said:
Ehh, I wasn't clear enough. The buffer doesn't have a size; it just translates the signals from one voltage level to another. The only issue that I can imagine is an early model not being fast enough to keep up with SATA III signalling.

Considering that this is the day and age of SATA III, and they advertise that as capable of working with SATA II, maybe there is actually a speed limitation on the buffers. I was speculating; I have neither tested nor looked up specifications. Maybe I'll drop Rosewill tech support a question. Let us know if it works for you.

EDIT: Just sent the inquiry to Rosewill; inquiring minds want to know


I'll be interested in hearing what they have to say.

I'll report back once I receive and setup the drive and enclosure.
m
0
l
a c 302 G Storage
December 20, 2011 6:19:51 PM

And here is the meat of Roswill's reply:
Unfortunately since Rosewill is not the direct manufacture and has limited
specification information on buffer speeds. Rosewill support can only comment on the
transfer rates up to 4.8 Gbps with USB 3.0 and this is the only data available to us
to forward to the public user on speed performance.

Not informative. And they don't know, either.
m
0
l
a b G Storage
December 20, 2011 6:28:35 PM

If you look at the spec of SATAII/III host chip set like Marvell, Silicon Image their SATA signal is ready of eSATA connection...

The different eSATA and SATA is one has more GND shield to protect the signal integrity from RFI, EMI. This ALSO mean signal in eSATA will be attenuate. This is WHY the new SATAII/III spec are eSATA compatible, where SATAI is not


THERE IS NO SATA to eSATA chipset out there, also you DO NOT want that, cuz it will introduce latency to the signal, make thing slower
m
0
l
!