What is the proper way to tell the system that a SATA drive is being swapped?

[Stan Shankman]

Greetings,

I want to setup a hot-swap SATA II drive bay on my computer. I will use
removable drive sleds. I want to be able plug and unplug SATA II drives
willy-nilly. I do not want to have to shutdown the system (Windows XP Pro)
to do the swap. I have been reading that I will need some software to tell
Windows that I am about to remove a SATA II drive.

Has anyone done this?

When I plug in a USB device to my computer, I am expected to place a request
to the system before I remove it. I believe that I must do the same for the
SATA drives.

But how should I do that?

I have found some third party software on the web: Driveswap32 (from
drivesap.com)

Is this what I must use? Or are other solutions available?
What is the recommended way to deal with hot-swap SATA drive issue?

One of the things that is bugging me most, is that given the usefulness of
what I am trying to do, and in light of the fact the one reads all over the
place that SATA drives are hot-swappable, I find that virtually nobody is
doing it. There is great confusions surrounding what is meant by a
hot-swappable controller. Why is that?

And please note that I am note talking about hot-swapping RAID drives. I
want to use a SATA drive bay in a way very much analogue to a floppy drive.
I want to be able to plug and unplug drives at will.

Anyone?

Thanks all,
- Stan Shankman

 

[Gerry Cornell]

Stan

I cannot advise on your specific questions but make sure System
Restore is not monitoring the drive as it is likely that you will
not be able to use restore points if it is.
--

Hope this helps.

Gerry
~~~~
FCA
Stourport, England

Enquire, plan and execute
~~~~~~~~~~~~~~~~~~~

 

[Anna]

Greetings,

I want to setup a hot-swap SATA II drive bay on my computer. I will use
removable drive sleds. I want to be able plug and unplug SATA II drives
willy-nilly. I do not want to have to shutdown the system (Windows XP Pro)
to do the swap. I have been reading that I will need some software to tell
Windows that I am about to remove a SATA II drive.

Has anyone done this?

When I plug in a USB device to my computer, I am expected to place a
request to the system before I remove it. I believe that I must do the
same for the SATA drives.

But how should I do that?

I have found some third party software on the web: Driveswap32 (from
drivesap.com)

Is this what I must use? Or are other solutions available?
What is the recommended way to deal with hot-swap SATA drive issue?

One of the things that is bugging me most, is that given the usefulness of
what I am trying to do, and in light of the fact the one reads all over
the
place that SATA drives are hot-swappable, I find that virtually nobody is
doing it. There is great confusions surrounding what is meant by a
hot-swappable controller. Why is that?

And please note that I am note talking about hot-swapping RAID drives. I
want to use a SATA drive bay in a way very much analogue to a floppy
drive.
I want to be able to plug and unplug drives at will.

Anyone?

Thanks all,
- Stan Shankman

Stan:
There are two basic requirements for SATA hard drives to be "hot-pluggable"
(we prefer that designation rather than "hot-swappable"), to wit...
1. The SATA HD must have this capability. The manufacturer must specifically
indicate that the drive is hot-pluggable capable. BTW, both the earlier SATA
HDs having an interface data rate of 150 Gb/s and the latest so-called SATA
II HDs having an interface data rate of 300 Gb/s can be hot-pluggable. Don't
assume that merely because the drive is designated SATA II it is inherently
hot-pluggable, although I have to admit that every SATA II HD we've worked
with so far (WD, Hitachi, and Samsung) has proven to be hot-pluggable; and,
2. The motherboard must support hot-plugging capability, i.e., its SATA
controller provides this hot-plugging support.

(An aside; it's considered a misnomer to refer to the newer SATA HDs having
an interface data rate of 300Gb/s as "SATA II" drives. Presumably they
should be referred to as "SATA 300Gb/s" or "SATA-IO" (the "IO" referring to
"International Organization"). But, of course, it seems everyone *does"
refer to these drives as "SATA II".)

One other consideration...

SATA native hot plug as defined by the specification requires the use of the
15-pin SATA power connector, *not* the 4-pin Molex power plug commonly used
to connect IDE devices.

I believe the specification also calls for a requirement that the power &
signal cables be connected/disconnected simultaneously in order for native
SATA hot plugging to be supported. This, of course, can be accomplished
through the use of equipping one's desktop computer with mobile racks
containing removable SATA HDs (I believe you called them "drive sleds").

I might add that while experimenting with the hot-plugging capability of the
above-mentioned SATA drives while they were connected as external devices,
we've connected/disconnected the drives without regard to any simultaneous
connection or disconnection of the data & power connectors and we suffered
no ill effects in terms of data corruption or damage to the drives.

Incidentally, you may be aware that motherboards containing an eSATA port
("e" for external) have recently reached the market. It provides a wonderful
capability in that a SATA HD connected to that external port is treated by
the system as an *internal* HD with all the advantages inherent in that
configuration. I can foresee the not-too-distant day when USB/Firewire
external hard drives will go the way of ZIP drives because of the
considerably superior performance of a SATA HD as compared to a USB/Firewire
EHD, together with the fact that a user will be able to have at hand a
*bootable* OS on an external device.
Anna

 

[Anna]

Stan:
There are two basic requirements for SATA hard drives to be
"hot-pluggable" (we prefer that designation rather than "hot-swappable"),
to wit...
1. The SATA HD must have this capability. The manufacturer must
specifically indicate that the drive is hot-pluggable capable. BTW, both
the earlier SATA HDs having an interface data rate of 150 Gb/s and the
latest so-called SATA II HDs having an interface data rate of 300 Gb/s can
be hot-pluggable. Don't assume that merely because the drive is designated
SATA II it is inherently hot-pluggable, although I have to admit that
every SATA II HD we've worked with so far (WD, Hitachi, and Samsung) has
proven to be hot-pluggable; and,
2. The motherboard must support hot-plugging capability, i.e., its SATA
controller provides this hot-plugging support.

(An aside; it's considered a misnomer to refer to the newer SATA HDs
having an interface data rate of 300Gb/s as "SATA II" drives. Presumably
they should be referred to as "SATA 300Gb/s" or "SATA-IO" (the "IO"
referring to "International Organization"). But, of course, it seems
everyone *does" refer to these drives as "SATA II".)

One other consideration...

SATA native hot plug as defined by the specification requires the use of
the 15-pin SATA power connector, *not* the 4-pin Molex power plug commonly
used to connect IDE devices.

I believe the specification also calls for a requirement that the power &
signal cables be connected/disconnected simultaneously in order for native
SATA hot plugging to be supported. This, of course, can be accomplished
through the use of equipping one's desktop computer with mobile racks
containing removable SATA HDs (I believe you called them "drive sleds").

I might add that while experimenting with the hot-plugging capability of
the above-mentioned SATA drives while they were connected as external
devices, we've connected/disconnected the drives without regard to any
simultaneous connection or disconnection of the data & power connectors
and we suffered no ill effects in terms of data corruption or damage to
the drives.

Incidentally, you may be aware that motherboards containing an eSATA port
("e" for external) have recently reached the market. It provides a
wonderful capability in that a SATA HD connected to that external port is
treated by the system as an *internal* HD with all the advantages inherent
in that configuration. I can foresee the not-too-distant day when
USB/Firewire external hard drives will go the way of ZIP drives because of
the considerably superior performance of a SATA HD as compared to a
USB/Firewire EHD, together with the fact that a user will be able to have
at hand a *bootable* OS on an external device.
Anna

Whoops! My reference to the data interface rates of SATA HDs in my post
above was, of course, incorrect. Please substitute "150 Mb/s" & "300 Mb/s"
instead of the incorrect Gigabyte reference.
Anna

 

[Stan Shankman]

Anna,



Thank you for your wonderful reply. It is good to know that somebody out
there is reading my posts.

If I have not misunderstood you, it seems that you are indeed telling me
that I can accomplish the hot-swapping the way I envision it. That is good.

But your reply does pose a few more questions:

For example: What is the difference between a hot-swappable SATA drive and
one that is not? Are you sure you did not mean that it is the controller
that one must choose to be hot-swappable and not the drive? Because I
remember reading that all SATA drives are hot-swappable. You see how
disconcerting it is for me to receive such contrary information? And don't
misunderstand me, I'm not saying that you are wrong, I'm simply pointing out
how confusing SATA information seems to be on the web. In fact, I have yet
to read a success story from anyone that has setup a SATA mobile rack the
way I wish to do it. Your post has come as close as any to assuring me that
it can be done.



Now regarding that "hot-swap / hot-plug" terminology:

I have read where other people on the web seem to make some big hoop-de-doo
distinction between the two terms and insist that what I'm attempting to do
should properly be called "hot-plugging". But for the purpose of describing
what I wish to do, I still believe that "hot-swapping" is the more
appropriate term.

Think about it. - Consider a person who momentarily removes a hard drive,
causing the operating system to go into a tizzy, and then upon reinstalling
it (or "hot-plugging" it back in) the operating system would simply
pick-up-the-beat and resume normal operation. (Now, I am not saying that
this is what Windows XP will do, I am just using this as a hypothetical
example to demonstrate a line of reasoning.) I would agree that that
qualifies as "hot-plugging". And to exemplify this idea even more, envision
a case where, say, the disk buffers have not yet been flushed when a drive
is removed, and then once the same drive is "hot-plugged" back in, the
operating system senses its return and simply resumes normal operation. Yet,
in keeping with the same scenario, that does not necessarily imply that one
could replace that drive with a different one. You see? But what I want to
do is remove the drive entirely, and then replace it with a different drive.
In other words, I really do want to swap the drive. Don't you see that the
term "hot-swap" is the more appropriate description of that action? Yes,
"hot-plug" does mean that the drive itself can be connected and disconnected
with the power and signaling lines still functioning. But hot-swapping,
while it is hot-pluggable must take it several steps further. There are a
good deal of additional considerations:



1) XP's 'restore-point' functionality must be properly dealt with

2) The operating system's disking engine must be able to mount and dismount
drives in a seamless fashion

3) The drive controller must me able to recognize that a drive has been
exchanged and flush its own buffers (I can see that a special hot-swap SATA
driver would be called for.)

4) User interface notification must be invoked



Theirs probably even more issues, but at the moment they do not come to
mind.





Anyway, enough said about all that.



Oh, by the way, I think you still have those transfer rates wrong. It is
150Mb/s and 3.0Gb/s.

Note that the 3Gb drives have a transfer rate 20 times faster than the older
150 drives. Which does not translate to a likewise increase in overall drive
performance due to several other bottlenecks.





But I am excited to hear what you have been saying. And I thank you for it.

Can you elaborate a bit more on your success?

Are you really able to simply reach over to a SATA rack, turn the key,
remove the drive, and then install a different one? I thought special
software was required to do that. After all, what is that driveswap32
software for? Why would it be sold if it were not needed?

So I hope to hear back from you and I hope you especially address that
issue.



Thanks again,

- Stan Shankman

 

[Anna]

can be hot-pluggable. Don't assume that merely because the drive is
designated
& signal cables be connected/disconnected simultaneously in order for
native SATA hot plugging to be supported. This, of course, can be
accomplished
is treated by the system as an *internal* HD with all the advantages
inherent in that configuration. I can foresee the not-too-distant day when

Anna,

Thank you for your wonderful reply. It is good to know that somebody out
there is reading my posts.

If I have not misunderstood you, it seems that you are indeed telling me
that I can accomplish the hot-swapping the way I envision it. That is
good.

But your reply does pose a few more questions:

For example: What is the difference between a hot-swappable SATA drive and
one that is not? Are you sure you did not mean that it is the controller
that one must choose to be hot-swappable and not the drive? Because I
remember reading that all SATA drives are hot-swappable. You see how
disconcerting it is for me to receive such contrary information? And don't
misunderstand me, I'm not saying that you are wrong, I'm simply pointing
out
how confusing SATA information seems to be on the web. In fact, I have yet
to read a success story from anyone that has setup a SATA mobile rack the
way I wish to do it. Your post has come as close as any to assuring me
that
it can be done.

Now regarding that "hot-swap / hot-plug" terminology:

I have read where other people on the web seem to make some big
hoop-de-doo
distinction between the two terms and insist that what I'm attempting to
do
should properly be called "hot-plugging". But for the purpose of
describing
what I wish to do, I still believe that "hot-swapping" is the more
appropriate term.

Think about it. - Consider a person who momentarily removes a hard drive,
causing the operating system to go into a tizzy, and then upon
reinstalling
it (or "hot-plugging" it back in) the operating system would simply
pick-up-the-beat and resume normal operation. (Now, I am not saying that
this is what Windows XP will do, I am just using this as a hypothetical
example to demonstrate a line of reasoning.) I would agree that that
qualifies as "hot-plugging". And to exemplify this idea even more,
envision
a case where, say, the disk buffers have not yet been flushed when a drive
is removed, and then once the same drive is "hot-plugged" back in, the
operating system senses its return and simply resumes normal operation.
Yet,
in keeping with the same scenario, that does not necessarily imply that
one
could replace that drive with a different one. You see? But what I want to
do is remove the drive entirely, and then replace it with a different
drive.
In other words, I really do want to swap the drive. Don't you see that the
term "hot-swap" is the more appropriate description of that action? Yes,
"hot-plug" does mean that the drive itself can be connected and
disconnected
with the power and signaling lines still functioning. But hot-swapping,
while it is hot-pluggable must take it several steps further. There are a
good deal of additional considerations:

1) XP's 'restore-point' functionality must be properly dealt with

2) The operating system's disking engine must be able to mount and
dismount
drives in a seamless fashion

3) The drive controller must me able to recognize that a drive has been
exchanged and flush its own buffers (I can see that a special hot-swap
SATA
driver would be called for.)

4) User interface notification must be invoked

Theirs probably even more issues, but at the moment they do not come to
mind.

Anyway, enough said about all that.


Oh, by the way, I think you still have those transfer rates wrong. It is
150Mb/s and 3.0Gb/s.

Note that the 3Gb drives have a transfer rate 20 times faster than the
older
150 drives. Which does not translate to a likewise increase in overall
drive
performance due to several other bottlenecks.

But I am excited to hear what you have been saying. And I thank you for
it.

Can you elaborate a bit more on your success?

Are you really able to simply reach over to a SATA rack, turn the key,
remove the drive, and then install a different one? I thought special
software was required to do that. After all, what is that driveswap32
software for? Why would it be sold if it were not needed?

So I hope to hear back from you and I hope you especially address that
issue.

Thanks again,

- Stan Shankman

Stan:
First of all, I'd rather not get into a semantic discussion re the
difference between "hot-plugging" & "hot-swapping". If you're more
comfortable with the latter term, that's fine. I've no problem with it.

As to your questions...

With respect to the "driveswap32" program you mention - I'm not familiar
with that piece of software. We haven't used so-called "drive swapping
software" in a long time. We found them to be unreliable and problematic at
best. This, of course, was with respect to removable PATA hard drives in
their mobile racks. We've never used that type of software re SATA drives.

Ordinarily one common scenario (in our experience) where hot-plugging comes
into play is where the user has booted to his or her working HD and now
wants to connect another HD to access data from that secondary drive. With
that second removable SATA hot-pluggable capable HD in its mobile rack
(supported by the motherboard as I previously noted), you need only connect
the drive to the system (via the keylock or whatever mechanism is used by
the rack) and the drive will be recognized by the system. Subsequently, you
can disconnect & remove that secondary drive from the system without any
problem re data corruption or damage to the drive (at least based upon our
experience to date - around four months). And, of course, connect another
secondary SATA HD if so desired.

The second common scenario (actually probably more common than the first one
mentioned) is where the user employs the SATA HD as an external device,
i.e., the drive is physically residing outside the computer. The SATA signal
(data) cable is, in this instance, directly connected to one of the
motherboard's SATA connectors and receives its power directly from the
computer's power supply. Or, in the case of some newer motherboards that are
equipped with an eSATA ("e" for external) port, the drive's signal cable is
connected to that port. The beauty of this arrangement is that the system
treats the "external" SATA HD as an internal device. As such it is
bootable. In any event, the hot-pluggable "external" SATA drive can be
connected/disconnected without any problem (at least none that we've
detected so far) identical to the way one would use a USB/Firewire external
hard drive.

In the example you gave I can't quite grasp under what circumstances one
would boot to their working HD and then desire to disconnect that drive and
connect another HD. Disconnecting the boot drive would, of course, cause an
improper shutdown of the system, would it not?
Anna