Are all SATA cables the same?

[Metspitzer]

I know there are SATA2 and SATA3 SSD drives. Are the cables
different?

--
Stephanie: What did you do today?
Leonard Hofstadter: Well, I'm a physicist, so I just thought about stuff.
Stephanie: That's it?
Leonard Hofstadter: I wrote some of it down.

[Jan Alter]

"Metspitzer" <Kilo...@charter.net> wrote in message
news:lhe5h891g21p9ujd4...@4ax.com...

The cable ends are all the same for connection. However, I have seen SATA
cables listed to carry data at higher and lower speeds. Check Newegg.com out
to compare one variety of cable to another.

As for SATA2 and SATA3 SSD drives they each have a distinct through put
speed before getting to the cable itself.

--
Jan Alter
bea...@verizon.net

[Flasherly]

On Feb 6, 3:19 pm, Metspitzer <Kilow...@charter.net> wrote:
> I know there are SATA2 and SATA3 SSD drives. Are the cables
> different?

Depends on the designer...

Designers use a number of techniques to reduce the undesirable effects
of [noise in -fl] such unintentional coupling. One such technique used
in SATA links is differential signaling. This is an enhancement over
PATA, which uses single-ended signaling. The use of fully shielded
twin-ax conductors, with multiple ground connections, for each
differential pair improves isolation between the channels and reduces
the chances of lost data in difficult electrical environments.

http://upload.wikimedia.org/wikipedia/commons/thumb/f/f4/SATA3-TwinAxCable.jpg/220px-SATA3-TwinAxCable.jpg

[Loren Pechtel]

On Wed, 06 Feb 2013 15:19:57 -0500, Metspitzer <Kilo...@charter.net>
wrote:

>I know there are SATA2 and SATA3 SSD drives. Are the cables
>different?

Backwards compatible, not necessarily forward-compatible. An
el-cheapo SATA2 might not be good enough to handle SATA3. The plugs
are the same, though.

[Metspitzer]

I have red, gray, black and blue SATA cables? How would you know?

[Metspitzer]

On Wed, 06 Feb 2013 17:24:15 -0500, Metspitzer <Kilo...@charter.net>

wrote:

>On Wed, 06 Feb 2013 14:10:10 -0800, Loren Pechtel
><lorenp...@hotmail.com> wrote:
>
>>On Wed, 06 Feb 2013 15:19:57 -0500, Metspitzer <Kilo...@charter.net>
>>wrote:
>>
>>>I know there are SATA2 and SATA3 SSD drives. Are the cables
>>>different?
>>
>>Backwards compatible, not necessarily forward-compatible. An
>>el-cheapo SATA2 might not be good enough to handle SATA3. The plugs
>>are the same, though.
>
>I have red, gray, black and blue SATA cables? How would you know?

I see that some of them are marked. The oldest cables I have are red.
They are marked 26AWG. I am guessing they are SATA 2. The newest
cables I have are blue. They are also marked 26AWG, but they are also
marked 6Gbps/3Gbs.

It is a shame. The red cable is the one I really wanted to use
because it is 24 inches long. I already know, longer is not better
when you are talking about computer cables.

[Charlie Hoffpauir]

On Wed, 06 Feb 2013 17:53:34 -0500, Metspitzer <Kilo...@charter.net>

I usually buy all my cables of any type from Monoprice, so I chaecked
their web site for SATA cables, and it seems they have SATA cables
rated or 6 Gbps in red, blue and black (plus other colors) in various
lengths, up to 36 inches. Check out:

[Charlie Hoffpauir]

Oops, sent that by mistake before finishing. URL is

http://www.monoprice.com/products/search.asp?keyword=sata+cables

[Loren Pechtel]

On Wed, 06 Feb 2013 17:53:34 -0500, Metspitzer <Kilo...@charter.net>

wrote:

>On Wed, 06 Feb 2013 17:24:15 -0500, Metspitzer <Kilo...@charter.net>
>wrote:
>
>>On Wed, 06 Feb 2013 14:10:10 -0800, Loren Pechtel
>><lorenp...@hotmail.com> wrote:
>>
>>>On Wed, 06 Feb 2013 15:19:57 -0500, Metspitzer <Kilo...@charter.net>
>>>wrote:
>>>
>>>>I know there are SATA2 and SATA3 SSD drives. Are the cables
>>>>different?
>>>
>>>Backwards compatible, not necessarily forward-compatible. An
>>>el-cheapo SATA2 might not be good enough to handle SATA3. The plugs
>>>are the same, though.
>>
>>I have red, gray, black and blue SATA cables? How would you know?
>
>I see that some of them are marked. The oldest cables I have are red.
>They are marked 26AWG. I am guessing they are SATA 2. The newest
>cables I have are blue. They are also marked 26AWG, but they are also
>marked 6Gbps/3Gbs.

26AWG is the wire size. That says very little about how fast they can
work. The 6gbs/3gbs marking is a clear indication that that's a SATA3
cable.

[TVeblen]

On 2/6/2013 3:19 PM, Metspitzer wrote:
> I know there are SATA2 and SATA3 SSD drives. Are the cables
> different?
>

The specification for the CABLE in SATA2 and SATA3 are the same.

The one new difference is positive locking clamps on the connectors of
new cables.

The issue of good quality vs poor quality cable continues from SATA2.
While the wires are all 26g, the quality of the copper and the amount of
shielding are different from manufacturer to manufacturer.

Either Maximum PC or Tom's Hardware did a test of SATA cables about a
year back to see if there was any difference in performance between
regular SATA cables and "SATA3" cables. They even jerry-rigged a 24 ft
long cable and tested that to. The result: unless you are splitting
hairs - not much.

[TVeblen]

I mis-remembered. It was 6 feet, not 24!
Here is the article:
http://www.maximumpc.com/article/features/your_sata_cable_slowing_down_your_data_transfers_max_pc_investigates

[Flasherly]

On Feb 7, 6:58 am, TVeblen <Killtherob...@hal.net> wrote:
> On 2/6/2013 3:19 PM, Metspitzer wrote:
>
> > I know there are SATA2 and SATA3 SSD drives. Are the cables
> > different?
>
> The specification for the CABLE in SATA2 and SATA3 are the same.
>
> The one new difference is positive locking clamps on the connectors of
> new cables.
>
> The issue of good quality vs poor quality cable continues from SATA2.
> While the wires are all 26g, the quality of the copper and the amount of
> shielding are different from manufacturer to manufacturer.

That tells me there's potentially HD/controller problems & issues to
misinterpreted for lack of a better cable. For instance, I'm not
especially happy with defragmentation routines from a HD running off a
plugin or aftermarket SATA controller. When troubleshooting it
they'll be a range of factors to look at, although I didn't think
cables conceivably could be one of them.

[Metspitzer]

On Wed, 06 Feb 2013 15:19:57 -0500, Metspitzer <Kilo...@charter.net>
wrote:

>I know there are SATA2 and SATA3 SSD drives. Are the cables
>different?

Sadly, all this is mute for me. I bought a new hard drive with 6Gbps,
but after opening up the computer the controller is only SATA 2 :(

[Mike Tomlinson]

En el art�culo <pto7h8t9atjh15f4i...@4ax.com>, Metspitzer
<Kilo...@charter.net> escribi�:

>Sadly, all this is mute for me. I bought a new hard drive with 6Gbps,
>but after opening up the computer the controller is only SATA 2 :(

It doesn't matter, because no hard drive is going to be able to max out
a SATA3/6Gbps interface.

--
(\_/)
(='.'=)
(")_(")

[Ting Hsu]

On Feb 7, 1:02 pm, Mike Tomlinson <m...@jasper.org.uk> wrote:
> En el artículo <pto7h8t9atjh15f4idoo2b91jfg9l38...@4ax.com>, Metspitzer
> <Kilow...@charter.net> escribió:

>
> >Sadly, all this is mute for me.  I bought a new hard drive with 6Gbps,
> >but after opening up the computer the controller is only SATA 2  :(
>
> It doesn't matter, because no hard drive is going to be able to max out
> a SATA3/6Gbps interface.

Just to further the point, the typical 7200rpm hard drive does about
130MB/s, which is about 1Gbps, when going full out (a rare event).
Only SSDs break the 3Gbps barrier (SSDs tend to do 500MB/s or 4Gbps).
--
// T.Hsu

[The Daring Dufas]

On 2/7/2013 1:04 PM, Ting Hsu wrote:
> On Feb 7, 1:02 pm, Mike Tomlinson <m...@jasper.org.uk> wrote:

>> En el art�culo <pto7h8t9atjh15f4idoo2b91jfg9l38...@4ax.com>, Metspitzer
>> <Kilow...@charter.net> escribi�:

>>
>>> Sadly, all this is mute for me. I bought a new hard drive with 6Gbps,
>>> but after opening up the computer the controller is only SATA 2 :(
>>
>> It doesn't matter, because no hard drive is going to be able to max out
>> a SATA3/6Gbps interface.
>
> Just to further the point, the typical 7200rpm hard drive does about
> 130MB/s, which is about 1Gbps, when going full out (a rare event).
> Only SSDs break the 3Gbps barrier (SSDs tend to do 500MB/s or 4Gbps).
> --
> // T.Hsu
>

So the SATA III drive will work in a computer with a SATA II controller
and doesn't care about the speed limit of the controller because it will
never be able to transfer data faster anyway? O_o

TDD

[TVeblen]

Pretty much. A spinning hard drive just does not reach half the speed of
SATA2 (3Gbps) on a good day. A 10,000 RPM drive might approach it.

[The Daring Dufas]

Cool, I want a 1tb or better drive for my Dell Precision 390 and it has
a SATA II controller. I've noticed SATA III drives tend to be less
expensive than SATA II drives so I could always move the drive to a
newer supercalifragilisticexpialidocious computer when I assemble one. ^_^

TDD

[Loren Pechtel]

On Thu, 7 Feb 2013 18:02:11 +0000, Mike Tomlinson <mi...@jasper.org.uk>
wrote:

There's nothing out there that can max a SATA3 yet but he said all he
has is a SATA2--and that will limit transfers with a good SSD.

[Loren Pechtel]

So long as it isn't a good SSD that's the case. You will lose
performance off a good SSD, though.

[Mike Tomlinson]

En el art�culo <kf12aj$4kc$1...@dont-email.me>, The Daring Dufas <the-
daring...@stinky-finger.net> escribi�:

>So the SATA III drive will work in a computer with a SATA II controller
>and doesn't care about the speed limit of the controller because it will
>never be able to transfer data faster anyway? O_o

Yes. You need SATA3 for SSDs.

The latest crop of 4Tb hard drives (1TB per platter) have SATA3
interfaces, but it's pretty pointless because their maximum sustained
transfer rate is still only about 160MB/s, which is well within SATA2's
300MB/s.

[Mike Tomlinson]

En el art�culo <lu48h89al68ep4sm6...@4ax.com>, Loren
Pechtel <lorenp...@hotmail.com> escribi�:

>
>There's nothing out there that can max a SATA3 yet but he said all he
>has is a SATA2--and that will limit transfers with a good SSD.

Yes, and he also said "I bought a new hard drive with 6Gbps". We're
talking about his hard drive, not an SSD.

[Metspitzer]

On Fri, 8 Feb 2013 03:01:33 +0000, Mike Tomlinson <mi...@jasper.org.uk>
wrote:

This drive says 6Gbs. Is that not supposed to be the transfer rate?
http://www.newegg.com/Product/Product.aspx?Item=N82E16822148840

[TVeblen]

It's marketing. It says it has a 6Gbps interface, and that is provably
true, but it remains that the maximum transfer rate of the drive will
come nowhere near that.

There is one true fact listed that might benefit from a SATA3 interface:
"SATA 6Gb/s interface optimizes burst performance"
But I doubt even the burst rate of a spinning drive will reach 3Gbps.

[The Daring Dufas]

I'm not so flush with money that I can afford to buy any SSD storage.
I'll be lucky enough to come up with the cash for a whirligig drive. ^_^

TDD

[Mike Tomlinson]

En el art�culo <bgr8h81je1jo0cqlh...@4ax.com>, Metspitzer
<Kilo...@charter.net> escribi�:

>This drive says 6Gbs. Is that not supposed to be the transfer rate?

It's the transfer rate of the SATA link between the drive's cache and
the controller, yes. What you're interested in, the *real-world*
benchmark, is the transfer rate off the platter, which is nowhere near
as fast.

Let's say you're loading a 100MB file. The drive has a 64MB cache, not
all of which will be available for caching reads. The drive can fill
the cache and transfers from that to the controller will be at 6Gbit/s
(about 580MBps), but once the cache is exhausted, the rest of the file
can only flow to the controller as fast as it comes off the platter,
which is about 160MB/s for a 5400rpm drive, and that's a maximum reading
from the outer edges of the platter. It'll be considerably slower
reading from the inner areas of the disk.

Even if you're loading a file small enough to fit entirely within the
drive's cache, there's read latency, access time and fragmentation to
consider. The OS has to read the file table and determine which sectors
on the drive constitute the full file, then the drive has to move the
heads to the right part of the disk (seek time) and wait for the
required sector to pass under the head (access time) then load them into
the cache. This latency means that in reality, even files which
theoretically would fit within the cache will not transfer at anything
like the full SATA interface speed.

SSDs don't suffer from this problem - they don't have mechanics to move
around to locate sectors, and so seek time and access time are to all
intents and purposes instant. That's why they are so much faster.

[The Daring Dufas]

That's a good price but I want an enterprise level drive with a higher
MTBF rating. It will cost more but I may want to stick it in a server
I plan to put together for the office here. ^_^

TDD

[Metspitzer]

On Fri, 8 Feb 2013 04:09:22 +0000, Mike Tomlinson <mi...@jasper.org.uk>
wrote:

I feel like Penny on the Big Bang Theory.

I know you think you are explaining this to me, but you are really
not. :)

[Mike Tomlinson]

En el art�culo <vou8h8t7n4cka6h38...@4ax.com>, Metspitzer
<Kilo...@charter.net> escribi�:

>I know you think you are explaining this to me, but you are really
>not. :)

It's hardly rocket science. ;-)

[The Daring Dufas]

Would the 6Gbs controller work better for a RAID since it may have to
handle more data being tossed at it by multiple drives at a higher rate? O_o

TDD

[Sjouke Burry]

TVeblen <Killth...@hal.net> wrote in
news:kf1tb7$mll$1...@dont-email.me:

If the disk has a nice big internal cache, it will for short bursts
with pre-fetched data, use the full speed of the sata link.

[The Daring Dufas]

That's what I was assuming about the internal cache memory. Now I'm
wondering about the data rates of hybrid drives where the SSD is melded
with a mechanical disk drive. ^_^

TDD

TDD

[bru...@topmail.co.nz]

On Thursday, 7 February 2013 04:19:57 UTC+8, Metspitzer wrote:
> I know there are SATA2 and SATA3 SSD drives. Are the cables
> different?
>

Check out this review:
http://www.maximumpc.com/article/features/your_sata_cable_slowing_down_your_data_transfers_max_pc_investigates

[Mark F]

On Thu, 07 Feb 2013 23:02:13 -0500, TVeblen <Killth...@hal.net>
wrote:

> On 2/7/2013 10:17 PM, Metspitzer wrote:
> > On Fri, 8 Feb 2013 03:01:33 +0000, Mike Tomlinson <mi...@jasper.org.uk>
> > wrote:
> >

> >> En el artículo <kf12aj$4kc$1...@dont-email.me>, The Daring Dufas <the-
> >> daring...@stinky-finger.net> escribió:

> >>
> >>> So the SATA III drive will work in a computer with a SATA II controller
> >>> and doesn't care about the speed limit of the controller because it will
> >>> never be able to transfer data faster anyway? O_o
> >>
> >> Yes. You need SATA3 for SSDs.
> >>
> >> The latest crop of 4Tb hard drives (1TB per platter) have SATA3
> >> interfaces, but it's pretty pointless because their maximum sustained
> >> transfer rate is still only about 160MB/s, which is well within SATA2's
> >> 300MB/s.
> >
> > This drive says 6Gbs. Is that not supposed to be the transfer rate?
> > http://www.newegg.com/Product/Product.aspx?Item=N82E16822148840
> >
>
> It's marketing. It says it has a 6Gbps interface, and that is provably
> true, but it remains that the maximum transfer rate of the drive will
> come nowhere near that.
>
> There is one true fact listed that might benefit from a SATA3 interface:
> "SATA 6Gb/s interface optimizes burst performance"

Correct

> But I doubt even the burst rate of a spinning drive will reach 3Gbps.

A SATA 3 spinning drive might burst faster than 3Gbps. I might even
keep up this speed for a bunch of blocks being read from the drive's
cache. Might even be able to maintain the rate for a few blocks
being written or, in unlikely case, for the same track being written
several times pieces in just the right order.

On the other hand, the data rate within a single transfer always be
6Gbps.

[Mark F]

On Thu, 07 Feb 2013 07:03:23 -0500, TVeblen <Killth...@hal.net>
wrote:

I would think that the most important problem would be data errors on
the cables. These will be corrected by retransmission and probably
the data is buffered someplace, so cables causing only 1 mission
in 10000 you won't even see a speed difference. Even for much higher
error rates you would only have some overhead and a retransmission of
some number of blocks with no rotational delays, so not much slowup.

On the other hand, many drives record such errors in SMART data that
is not easily resetable, if at all. This leads at least some SMART
analyzing programs to forever after say that the drive has "warning"
SMART status.

In particular, I have a
Seagate ST3200064NS drive with
"(C7) Ultra DMA CRC Error Count" of 10 and
a Seagate ST32000641AS with a count of 3, as well as about
6 other drives with counts of 2 or 1.

(I think that the errors happened when I was operating the drives
outside of a system and bumped into something while a test was
running. In any event, the cable that was used in the test
is no longer connected to the drives which are now inside of
systems and in most cases connected to another adaptor.)

I looked at the Maximum PC article and didn't see any SMART data,
which to me would have been the most interesting thing after not
seeing any drastic reduction in throughput.

[TVeblen]

That is a very good article. Thanks!

[Loren Pechtel]

On Thu, 07 Feb 2013 22:17:17 -0500, Metspitzer <Kilo...@charter.net>
wrote:

But you'll only actually see that when transferring from the drive's
cache.

[Loren Pechtel]

On Fri, 8 Feb 2013 03:03:19 +0000, Mike Tomlinson <mi...@jasper.org.uk>
wrote:

>En el artículo <lu48h89al68ep4sm6...@4ax.com>, Loren
>Pechtel <lorenp...@hotmail.com> escribió:

>>
>>There's nothing out there that can max a SATA3 yet but he said all he
>>has is a SATA2--and that will limit transfers with a good SSD.
>
>Yes, and he also said "I bought a new hard drive with 6Gbps". We're
>talking about his hard drive, not an SSD.

I've seen people use "hard drive" to refer to a SSD.

[Mark F]

On Fri, 08 Feb 2013 19:56:08 -0800, Loren Pechtel
<lorenp...@hotmail.com> wrote:

> On Thu, 07 Feb 2013 22:17:17 -0500, Metspitzer <Kilo...@charter.net>
> wrote:
>
> >On Fri, 8 Feb 2013 03:01:33 +0000, Mike Tomlinson <mi...@jasper.org.uk>
> >wrote:
> >

> >>En el artículo <kf12aj$4kc$1...@dont-email.me>, The Daring Dufas <the-
> >>daring...@stinky-finger.net> escribió:

> >>
> >>>So the SATA III drive will work in a computer with a SATA II controller
> >>>and doesn't care about the speed limit of the controller because it will
> >>>never be able to transfer data faster anyway? O_o
> >>
> >>Yes. You need SATA3 for SSDs.
> >>
> >>The latest crop of 4Tb hard drives (1TB per platter) have SATA3
> >>interfaces, but it's pretty pointless because their maximum sustained
> >>transfer rate is still only about 160MB/s, which is well within SATA2's
> >>300MB/s.

Some people use port multipliers, so there is interference even with
two
drives at 300MB/s, perhaps in RAID or disk cloning operations.

Three drives multiplexed would definitely see the interference
whenever 3 drives were busy, but most users would find 4 spinning
drives multiplexed to be fine as long as the didn't try to clone
two multiplexed drives. (I think having 3 RAIDed spinning drives
sharing a port on a 300MB/s port would be fine.)

[Jan Alter]

<bru...@topmail.co.nz> wrote in message
news:685cdd78-8e96-4429...@googlegroups.com...

Great article.
Thanks.

--
Jan Alter
bea...@verizon.net

[Paul]

Loren Pechtel wrote:
> On Wed, 06 Feb 2013 17:53:34 -0500, Metspitzer <Kilo...@charter.net>
> wrote:
>
>> On Wed, 06 Feb 2013 17:24:15 -0500, Metspitzer <Kilo...@charter.net>
>> wrote:
>>
>>> On Wed, 06 Feb 2013 14:10:10 -0800, Loren Pechtel
>>> <lorenp...@hotmail.com> wrote:
>>>
>>>> On Wed, 06 Feb 2013 15:19:57 -0500, Metspitzer <Kilo...@charter.net>

>>>> wrote:
>>>>
>>>>> I know there are SATA2 and SATA3 SSD drives. Are the cables
>>>>> different?

>>>> Backwards compatible, not necessarily forward-compatible. An
>>>> el-cheapo SATA2 might not be good enough to handle SATA3. The plugs
>>>> are the same, though.
>>> I have red, gray, black and blue SATA cables? How would you know?
>> I see that some of them are marked. The oldest cables I have are red.
>> They are marked 26AWG. I am guessing they are SATA 2. The newest
>> cables I have are blue. They are also marked 26AWG, but they are also
>> marked 6Gbps/3Gbs.
>
> 26AWG is the wire size. That says very little about how fast they can
> work. The 6gbs/3gbs marking is a clear indication that that's a SATA3
> cable.

26AWG means 26 American Wire Gauge. And has nothing to do with how
the wire works. Wire gauge might be important for maximum current
flow say, but for signal transmission, the currents aren't that
large.

The SATA cable is set up to have a characteristic impedance, which affects
how high frequency signals propagate. The location of the wire mates
(diff pair), the insulation material, position of shield or drain wire,
matter to the construction. Maybe you could change the wire gauge,
adjust the dimensions a bit, and it would still work. But more than
just the wire diameter would be a factor.

As far as I know, the intention was to use the same cables for both
SATA II and SATA III. A vendor extolling the virtues of a cable
they're selling, is selling FUD (feat uncertainty doubt).

I don't know if there is any difference in length spec for SATA III
or not. But I think they wanted to be able to use the same cables,
so there wouldn't have to be something distinctive on the cables
to tell them apart.

This is *not* how you test cables. You can use a digital storage scope
with eye diagram software, and get the real answer as to whether a
given setup is passing or failing. If the spec says the max cable
length is X, you don't make a 3X cable and test it. There is no point
to that. It's outside the spec. Maybe it gives an impression of the
margin available in the chip interfaces, but the eye diagram can
tell you much the same thing, without potentially screwing up an
SSD to prove it works.

http://www.maximumpc.com/article/features/your_sata_cable_slowing_down_your_data_transfers_max_pc_investigates

A SATA II eye diagram. Blue repetitive waveform, must not touch
the red colored pass/fail points. This example has plenty of
margin. Not likely to be any transmission errors here.

http://www.fujitsu.com/img/EDG/product/asic/ipmacro/sata-2.jpg

I couldn't find an eye diagram for SATA III, but this is a
device running at SATA III rates. And you can see the signal
is still clean. Amazingly clean actually, considering the
frequency.

http://www.maximintegrated.com/images/appnotes/4648/4648Fig05.gif

Paul

[Paul]

Metspitzer wrote:

>
> I feel like Penny on the Big Bang Theory.
>
> I know you think you are explaining this to me, but you are really
> not. :)

Data coming off the platter, inside the drive. We could represent
a transferred sector like this. The disk is relatively slow, compared
to the cabling.
__ __ __ __ __
__| |__| |__| |__| |__| |__

The transfer on the cable goes faster. The transfer takes less
time. Both diagrams are carrying the same amount of data.
_ _ _ _ _
_| |_| |_| |_| |_| |_

When you're reading data off the disk, the cable is so much
faster, the transfers are not continuous. This is what
happens on a read operation on a hard drive. The hard drive
cannot "keep the cable full", and the cable gets to "rest"
between bursts. The cable only transmits data, when enough
to "fill a packet" is available. SATA uses packets to transfer
data. The disk has sectors. The SATA cable has packets.
_ _ _ _ _ _ _ _ _ _
_| |_| |_| |_| |_| |_ _| |_| |_| |_| |_| |_

On a write, the host can send to the disk drive in a
continuous burst, at the high speed of the cable.
The drive cannot keep up. Eventually, the disk drive
RAM cache fills up. The cache is a temporary storage
area, meant to "take up the slack" between the fast
cable, and the slow hard drive.
_ _ _ _ _ _ _ _ _ _
_| |_| |_| |_| |_| |_| |_| |_| |_| |_| |_ . . .

When the cache is full on a write, the host can only send
new data when there is space in the cache. The transfer pattern
on the cable settles down, until it looks like the read
transfer diagram. Like this. The hard drive platter and
heads are pretty well running continuously while this
write operation is taking place (lower trace in the graph).
Notice that again, the 6Gbit/sec SATA cable gets to "rest"
between burst. And the bursts exist, because the cable
protocol is packet based, and not byte based.
_ _ _ _ _ _ _ _ _ _
_| |_| |_| |_| |_| |_ _| |_| |_| |_| |_| |_

__ __ __ __ __ __ __ __ __ __
__| |__| |__| |__| |__| |__| |__| |__| |__| |__| |__

Did I mention, I love ASCII art diagrams ? :-)

HTH,
Paul