tom2u

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Is it possible to unplug the power to a Sata hard drive without damaging the drive or data on the drive? Could one install a switch to the yellow or red wires (12v and 5v positive wires) to do this better?

I'd like to be able to also control which hard drives the OS sees on start up by only powering up certain ones. This would control which OS starts. Every OS would be on its own small Sata SSD.
 
if you power off a HDD and it happens to be in a write state you will lose data and could damage the HDD.

It's easy if you have a newer MB that allows which drive to boot to By pressing a Hot hey during the post.
..You set the bios priority to the Drive with the OS most used.
..Then during the post you hit the Key to bring up The Boot menu. On my Gigabyte MB it is F12, on my Asrock MB it is F11.
...... The drive you select will come up as C:\
...... This does NOT change boot priority. If you reboot, You will boot to the drive set as #1 in bios, Or you can hit the "Key" to reboot back to the drive you are using or change to a 3rd OS.
.. NOTE with this you can still see and write to all drive, just one caution drive letters will change depending on what OS Drive you boot to - BUT Will revert back to what is set when booting to your primary OS drive.
.. This is what I do with a System with seperate drives with different OSs.

Note: while all drives would be powered on, unless used their Idle power will be very low so "powering them Off" saves very little.
 

tom2u

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> If you power off a HDD and it happens to be in a write state you will lose data and could damage the HDD.

Ah right. It hasn't "parked" yet. I was worried about that.
I wonder if there's any way to "park" it or get it out of its write state while its on. I looked for an Eject option on the right click menu options for the hard drive but there wasn't any.

The reason I want to manually power them on and of is because when I'm not using them I don't want to see them in the Windows Explorer My Computer list. I suppose I could use an eSata dock but then I'm plugging and unplugging them in all the time. Not good. I want all of them to be C: when plugged in. I'm wanting to use Win7 64bit, XP 32bit, and OS X if I can get it installed later.
 

Saintarthur

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Sorry, maybe a little clarification is needed here,

Use Hotswap to spin down the drive, it will tell you when it has completed. Then you can pull the power plug on the drive or, in this case, flip your switch. You'll want to flip the power on all the lines at the same time, the 5, 12, and if it's connected the 3.3V.

To reconnect, turn back on the power and use hotswap to search for new devices (you can use device manager from windows to do this too.)


P
 

tom2u

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That sounds like one useful program. Unfortunately it doesn't work on my present OS: XP 64bit. But I can use it later when I dump this useless OS. :)

Question: Is there one wire I can disconnect to power down the drive or will I have to have a multiple pole switch to handle 2 or 3 wires?
 
To put the swith in one line would not be advisable. You have two power lines, the +12 V (oranger or yellow wire) and the +5 V (Red wire) for a 3 1/2 in HDD. You should remove power from both the +12 V and the +5 V. Reason is there may be a interreaction (ie a bias) that could result in a circuit having an over current condition).
 

Saintarthur

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That's odd, there's a 64 bit version there in the download too and I used to use it on my pc at home when I had XP 64 installed.
They must have changed something in it. Maybe try an older version, 1.1.0.1 or so.

(Very simplified here so don't jump down my throat any of the more propeller-headed guys out there): Effectively the 5V drives the baseboard of a hard drive, the 12V drives the two motors, head and spindle and the 3.3V powers the logic (on-board memory)on most (cheap) sata connectors the 3.3V isn't connected because the 5V line is good enough to run most logic (hence USB flash memory)
It depends on what you want to risk really. if you shut off just the 12V, yes the motors will stop running but the driver circuitry will still keep trying to spin it up and will fail out or in the worst case burn out.
If you stop the 5V... look just don't do that, it's too hard to explain but it's really high probability of screwing up the base board.
As for cutting the ground line... well if the engineers did their job perfectly, there's no problem but if not, adios to your drive.

Just get a mini 2 pole switch and connect the 5V (red) and 12V (yellow) to it that should do the trick well.

Having said all this, when you spin down the drives with Hotswap or disable the drive in Device manager they disappear from windows explorer too.
Alternatively if you just want them to disappear and are not really too worried about the energy used, just remove the drive letter from disk management (diskmgmt.msc)
I can post you a cmd script to do/undo this last thing if you'd like.

P
 

tom2u

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> Alternatively if you just want them to disappear and are not really too worried about the energy used, just remove the drive letter from disk management (diskmgmt.msc)

So I'd have to use that script every time I want to change how Windows Explorer displays every time I power up the computer? Then with a different OS I'd have to reset the drive letters again?
 

Saintarthur

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Effectively, yes. Could put it in startup though. A little tricky the first time then you don't have to think about it anymore.
You're only left with the problem of how to choose your operating system, but a couple of menu items should do that fairly easily for you.
 

tom2u

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I must say I like the sound of a mechanical switch far better. That way the hard drives are IN or OUT. Its definitive. Kind of like changing the volume in Sounds. Sometimes it works right away, sometimes its not. Is it the right device? Is the Service started? The right driver? Does the window have focus? Bah! One selector switch and a volume control right by my monitor is the way to do it. One possible audio output and input. In a second I get things done right with no fiddling with Menu items, arrow keys or mice. Some things software just sucks at. Go mechanical as often as you can. Think of the endless menus and submenus we're subjected with. Wouldn't it be nice to just punch a switch and BAM - its done. :)
 

Neville Hillyer

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Has anybody any experience of removing power only from SATA drives?

Will it harm the electronics if data lines are connected without 3, 5 and 12 volt power?

Does removing logic power only disable the motors and will this do any harm?

I only plan to do this when the computer is powered down so I am not concerned about data loss issues.

My Mac SATA board has no facilities to power down the drives properly.