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tomgrazioli

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Hot Swapping SATA Externals

Y'all,

I'm still playing with SATA external drives.  I find the difference between external SATA and USB 2.0 to be remarkable.  

My problem now is "hot swapping" the devices.  To be more clear, I have the SATA drive in an external enclosure that uses an eSATA cable connected to a bracket, then connected directly to the motherboard.  If I boot the computer with the drive connected and powered on it works as expected.  If I disconnect the drive and then reconnect it (connect a second drive), it does not come on line.  

For more detail, the motherboard is an ASUS M2N-MX with an Athlon 4200+ X2 64.  The OS is Windows 2003 Server with all the updates.  The external enclosures are a Vantec NexStar 3 and a SanMax PMD96S-SA.  I tried two different manufacturers to be more complete.  The SanMax is a tray that slides into a carriage that is inside a 5.25" bay.  Both behave the same way.

BTW, the Vantec will also connect via USB.  It works that way as expected.

What am I missing?  Or please point out my misconception.

Thanks in advance,

Tom
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Gary Case
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Are you doing a "Safely Remove" before removing the drive??
i think the sata protocol is not as table yet as it should ; read this (2003 doc) :
http://www.ata-atapi.com/sata.htm
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Sandeepraj

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tomgrazioli

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Thanks for the comments guys.

garycase - You wouldn't "Safely Remove" something that isn't on the system yet.  My tests included adding the device after the computer was running.

Sandeepraj - I'll dig into the documentation this evening and see if there's a reference to what I'm trying to do.

Somewhere in the past I read that SATA was to be hot swappable.  I was expecting (hoping) the emerging eSATA devices to work like USB.  Plug them in and they're recognized.  USB could work for the current application I'm involved with.  However, I have some clients that are backing up enormous amounts of data.  eSATA has the promise of high speed and low cost.  Ease of use is also important.  You'd be surprised at how many people don't want to restart their computer to change a drive.  It's certainly worth some time and expense to me to check this out.

Thanks,

Tom

P.S.  I'll bet there's a great debate about the merits and deficiencies of external hard drives compared to tape drives.
8-O
My question related to your comment "...  If I boot the computer with the drive connected and powered on it works as expected.  If I disconnect the drive and then reconnect it (connect a second drive), it does not come on line." => which implies you disconnected/reconnected with power on.

SATA II is designed for hot-swapping; but it DOES require hot-swap support in the controller;  so if the system isn't designed for it, it's not going to work.
>>  there's a great debate  <<  did you read my link ?
Reading carefully through the motherboard manual didn't provide any clues.  I did an internet search and found some articles.  On another model motherboard, the author was able to hot swap the SATA devices by setting the ICH7R to AHCI mode in the BIOS.  I suppose that's specific to Intel chipsets.  A little more research should tell me if the nVidia chipset on this motherboard will support hot swapping.  It's the nVidia nForce 590 SLI in case someone already knows the answer.

nobus - I read the link.  It read like the author had a bad experience with SATA drives.  And the article was 3 years old.  In this industry things change very quickly.

garycase - No offense was intended.  I was trying to clarify my tests with the second post.

Thanks,  Tom
yes, it is 3 years old (i put that in my post) but it clearly points out to some weak points in the sata protocol