External SATA drive for laptop

I have a laptop and I need the ability to attach a much faster drive
for some work that I'm doing.

The laptop doesn't have firewire so I'm looking at either USB2 or
buying a PCMCIA SATA card.

I presume that using SATA as an interface would be significantly
faster. Does hotplugging work fine in this situation, are there any
drawbacks?

I'm going to be holding a large database on the disk, so latency is
much more important than throughput.

Graham

Previously wrote:
I have a laptop and I need the ability to attach a much faster drive
for some work that I'm doing.

The laptop doesn't have firewire so I'm looking at either USB2 or
buying a PCMCIA SATA card.

I presume that using SATA as an interface would be significantly
faster. Does hotplugging work fine in this situation, are there any
drawbacks?

Whether hotplugging works depends on your OS and hardware. As to
the speed, that depends on the PCMCIA card and your PCMCIA bus.
If it is an old 16 bit bus, then it can transfer about 1MB/sec.
A newer 32 bit one can transfer more, but the controller and
the SATA adapter may each slow things down.

I'm going to be holding a large database on the disk, so latency is
much more important than throughput.

Then I would think that SATA has a slight edge, but USB (as long as
it is 2.0) should be o.k., too. And USB hotplug does work reliably
in my experience.

Arno

Arno Wagner wrote:
Previously wrote:
I have a laptop and I need the ability to attach a much faster drive
for some work that I'm doing.

The laptop doesn't have firewire so I'm looking at either USB2 or
buying a PCMCIA SATA card.

I presume that using SATA as an interface would be significantly
faster. Does hotplugging work fine in this situation, are there any
drawbacks?

Whether hotplugging works depends on your OS and hardware. As to
the speed, that depends on the PCMCIA card and your PCMCIA bus.
If it is an old 16 bit bus, then it can transfer about 1MB/sec.
A newer 32 bit one can transfer more, but the controller and
the SATA adapter may each slow things down.

It's a Pentium-M based laptop with a 33Mhz 32bit Cardbus slot. By my
reckoning that should be around 1Gb/s.

I'm pretty sure that even the 16bit slots are significantly faster than
1MB/sec, but it's been many years since i've worked in that hardware
space. I'd have thought that since PCMCIA seems to support ATA pretty
much natively, it'd have a very low command translation overhead.

USB's endpoint based architecture is quite a departure from the way the
hardware oprerates so i'd expect it to be slower.

This will be primarily for WIn XP Pro, although might be occasionally
used in Linux.

I'm going to be holding a large database on the disk, so latency is
much more important than throughput.

Then I would think that SATA has a slight edge, but USB (as long as
it is 2.0) should be o.k., too. And USB hotplug does work reliably
in my experience.

Perhaps I can find a dual mode enclosure that will run both USB2 and
SATA, that way I can fall back on USB if the SATA doesn't pan out.

Previously wrote:

Arno Wagner wrote:
Previously wrote:
I have a laptop and I need the ability to attach a much faster drive
for some work that I'm doing.

The laptop doesn't have firewire so I'm looking at either USB2 or
buying a PCMCIA SATA card.

I presume that using SATA as an interface would be significantly
faster. Does hotplugging work fine in this situation, are there any
drawbacks?

Whether hotplugging works depends on your OS and hardware. As to
the speed, that depends on the PCMCIA card and your PCMCIA bus.
If it is an old 16 bit bus, then it can transfer about 1MB/sec.
A newer 32 bit one can transfer more, but the controller and
the SATA adapter may each slow things down.

It's a Pentium-M based laptop with a 33Mhz 32bit Cardbus slot. By my
reckoning that should be around 1Gb/s.

Equal to 125MB/s. In practice more like 50MB/s maximum, unless the
system is very well tuned. Still enough for a single modern disk
allmost at full linear speed.

I'm pretty sure that even the 16bit slots are significantly faster than
1MB/sec, but it's been many years since i've worked in that hardware
space.

I had a laptop with one and did benchmarks. It was that slow.

I'd have thought that since PCMCIA seems to support ATA pretty
much natively, it'd have a very low command translation overhead.

The benmarks I did were with a network card.

USB's endpoint based architecture is quite a departure from the way the
hardware oprerates so i'd expect it to be slower.

So-so. I find that I get something like 25MB/s for external disks.

This will be primarily for WIn XP Pro, although might be occasionally
used in Linux.

Then you need to check that the card is supported by Linux if you
use SATA. USB should be uncritical.

I'm going to be holding a large database on the disk, so latency is
much more important than throughput.

Then I would think that SATA has a slight edge, but USB (as long as
it is 2.0) should be o.k., too. And USB hotplug does work reliably
in my experience.

Perhaps I can find a dual mode enclosure that will run both USB2 and
SATA, that way I can fall back on USB if the SATA doesn't pan out.

I think there are some. The ones I saw actually took an ATA disk
and then offerd SATA and USB externally.

Arno

wrote in message
oups.com...
I have a laptop and I need the ability to attach a much faster drive
for some work that I'm doing.

The laptop doesn't have firewire so I'm looking at either USB2 or
buying a PCMCIA SATA card.

I presume that using SATA as an interface would be significantly
faster. Does hotplugging work fine in this situation, are there any
drawbacks?

It's a Pentium-M based laptop with a 33Mhz 32bit Cardbus slot. By my
reckoning that should be around 1Gb/s.

I'm pretty sure that even the 16bit slots are significantly faster than
1MB/sec, but it's been many years since i've worked in that hardware
space. I'd have thought that since PCMCIA seems to support ATA pretty
much natively, it'd have a very low command translation overhead.

USB's endpoint based architecture is quite a departure from the way the
hardware oprerates so i'd expect it to be slower.

This will be primarily for WIn XP Pro, although might be occasionally
used in Linux.

I'm going to be holding a large database on the disk, so latency is
much more important than throughput.

Then I would think that SATA has a slight edge, but USB (as long as
it is 2.0) should be o.k., too. And USB hotplug does work reliably
in my experience.

Perhaps I can find a dual mode enclosure that will run both USB2 and
SATA, that way I can fall back on USB if the SATA doesn't pan out.


grahamsz:
Let me add a few thoughts for your consideration...

Assuming there are no connectivity issues involving the PCMCIA SATA card
with the SATA HD (not that there should be but I haven't as yet worked with
that specific type of card)...

There are considerable advantages in utilizing a SATA HD as an external
device for your laptop. I'm speaking here, of course, in terms of a direct
SATA-to-SATA connection as would be the case with the SATA HD connected
directly to the PCMCIA SATA card.

1. The data transfer rate would be significantly faster as compared with a
USB/Firewire device.
2. The system will treat the SATA HD as an *internal* HD so that if you use
the SATA HD as the repository of a clone of your laptop's internal HD (using
a disk imaging program, e.g., Symantec's Norton Ghost or Acronis True
Image), which I assume is a primary objective of yours, the SATA HD will be
bootable - unlike a USB/Firewire external HD. Perhaps I should say "may be
bootable" in this case. Now that I think about it I'm uncertain as to
whether the connection to the PCMCIA SATA card would permit a boot from that
device. Would you have this information/documentation available?
But even assuming that boot capability did not exist, in my view that would
not negate the desirability of using this approach because of the
considerably superior performance of the SATA drive vis-a-vis a USB/Firewire
external HD.
3. In virtually every case, the SATA drive will be "hot pluggable" - similar
to that of a USB/Firewire EHD.

Should you go this route, you will, of course, need an enclosure for the
SATA HD that provides for a direct SATA-to-SATA connection as well as
provides power to the drive. There are a number of these enclosures on the
market, many (if not most) of which are combo units, i.e., provide both USB
& SATA connections. A Google search should point you to a number of vendors
carrying this type of equipment.

I'm assuming your current laptop's HD is a PATA drive, so that there would
be no pressing need for you to purchase a 2 1/2" HD since it could not serve
as a possible replacement for your laptop's internal HD. Presumably you
would obtain a 3 1/2" (desktop PC) HD I would think, although if you might
consider a 2 1/2" SATA HD for some not-yet-anticipated future needs
obviously the enclosure would have to be designed for that component. I
would guess those are currently available as well although all the one's
I've come across have been designed to accommodate 3 1/2" drives. No doubt a
Google search will turn up something.
Anna

Up

Hello,
I completely agree with Anna about external SATA storage advantages
and I'm convinced that this support will be more developped on
laptops sooner or later...

No driver required with XP. It is hot-swapable (by default). And in
Windows system, there is the choice between performance or hot-swap
mode.

As my HD enclosure can be connected in FW/USB2/SATA, I have compared
on "heavy" softwares (audio & video editing), large
files loading and copying, etc... and it is quite faster and more
stable even than my internal 7200tps 2.5" HD!

I have a cheap/generic PCMCIA SATA controller card, based on a
SIL3112 chipset, that looks like that :
http://media.ldlc.com/photosldlc/00/...00405361_2.jpg

Unfortunately I have just one problem : I found no issue to boot WinXP
on the external sata HD :crybaby:
Even pressing F6 during the install process, and once SIL3112
SATALINK drivers are installed, Windows can't "see" any
partition on the sata drive.
I think I've missed something... but what?

Any idee??

Previously cedrouby wrote:
Hello,
I completely agree with Anna about external SATA storage advantages
and I'm convinced that this support will be more developped on
laptops sooner or later...

I also agree with this. Adding an eSATA port to a laptop
if both obvious and should not be a major cost factor.

No driver required with XP. It is hot-swapable (by default). And in
Windows system, there is the choice between performance or hot-swap
mode.

You get the same with Linux, although the approach is a bit different.
Linux needs a driver, but the standard kernel driver is sufficient.
(Linux even allows you to use or remove the IDE driver, so needing
a driver is not a drawback, as long as it is a kernel-driver...)
As for performance or hot-swap, that would be normal mount or
"sync" mount. Hot-swapping for SATA in Linux is still problematic,
(it is unreliable and therefore not available in the "stable"
kernels), but this should be solved in the not too distant future.

As my HD enclosure can be connected in FW/USB2/SATA, I have compared
on "heavy" softwares (audio & video editing), large
files loading and copying, etc... and it is quite faster and more
stable even than my internal 7200tps 2.5" HD!

Not ruprising.

I have a cheap/generic PCMCIA SATA controller card, based on a
SIL3112 chipset, that looks like that :
http://media.ldlc.com/photosldlc/00/...00405361_2.jpg

Unfortunately I have just one problem : I found no issue to boot WinXP
on the external sata HD :crybaby:

That should be a controller limitation and vanish with a
laptop-integrated controller.

Even pressing F6 during the install process, and once SIL3112
SATALINK drivers are installed, Windows can't "see" any
partition on the sata drive.
I think I've missed something... but what?

Any idee??

This is very likely a problem with the cards BIOS or the driver.
Can you create partitions on an empty disk?

Arno

cedrouby wrote:
Hello,
I completely agree with Anna about external SATA storage advantages
and I'm convinced that this support will be more developped on
laptops sooner or later...


I sure wish we could just get USB3 instead. USB has made great strides
in reducing the number of different connectors and cables needed, and is
so far backwards-compatible. I would rather see another backwards
compatible generation than something different.

"timeOday" wrote:
cedrouby wrote:
Hello,
I completely agree with Anna about external SATA storage advantages
and I'm convinced that this support will be more developped on
laptops sooner or later...


I sure wish we could just get USB3 instead. USB has made great strides
in reducing the number of different connectors and cables needed, and is
so far backwards-compatible. I would rather see another backwards
compatible generation than something different.

The only thing "different" needed to implement External SATA is
to put an eSATA connector on the back of the laptop. It's just a
more secure connector (physically) and includes shielding.
Otherwise, it's compatible physically and electrically with regular
SATA cables. Since SATA is faster than USB, I'd much rather
use a SATA link to the external hard drive.

*TimDaniels*