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Sorry, i will never do that !

the word "Yet" was a mistake.

Though Apple should make them hot-swappable !


At first I thought: No Way! But the more I think about it you might be right. I have an external drive I use on my old G4 Mac Tower and I plug it in and out and never think about even shutting the G4 down.
 
Hot swap has more to do with the software drivers than hardware, though there is a hardware aspect to it. On windows systems, it's part of the AHCI driver. I'm not aware of this ability built-in to OS X, but is on 3rd party drivers for SATA controllers or RAID controllers.

On the hardware side, there's a chip called an Inrush Current Limiter. Basically, it's an electronic fuse to protect the PSU.
 
One of the problems that needs to be solved when hot swapping components is how the various pins make contact. Not all pins will make contact at the same time, so you run the risk of damaging components if things don't come together "just right". Considering that Apple is using the standard connectors that come on the hard drives, I don't think it's practical to make them hot-swappable. If you need hot-swappable drives, go Firewire or USB.
 
One of the problems that needs to be solved when hot swapping components is how the various pins make contact. Not all pins will make contact at the same time, so you run the risk of damaging components if things don't come together "just right". Considering that Apple is using the standard connectors that come on the hard drives, I don't think it's practical to make them hot-swappable. If you need hot-swappable drives, go Firewire or USB.
Um, No. The connectors used are backplane types, and contain both the power and data signals. Contact is at the same time for all intent, and isn't an issue. The driver support takes care of that aspect anyway (polling timings).

Hot swapping is practical, but does need a little additional attention to both the drivers and hardware (current limiting). It's rather simple actually, but does require additional development time, and components, increasing the cost.

If it's not considered necessary, hot swap capabilities will usually get skipped in favor of lower costs. FW and USB do require it, so it's present. It always seems to come down to money. ;) :p
 
Wouldn't swapping the drives mean opening the case when running which is generally bad for the computer anyway.
 
Wouldn't swapping the drives mean opening the case when running which is generally bad for the computer anyway.
In all likelihood, it would be open, close, remove the drive from the sled, attach the new drive, open, reinstall, and close. So No, not really, as the door wouldn't be open for any real length of time. ;)
 
It is possible to hot swap sata drives but it depends on the hardware implementation (wether or not the controller / drivers allow for it - some do and some don't). In this case, the definitive answer is in the manual.
 
I've done this on a Power Mac G5...

Connect a hard drive to the lower drive bay while the machine was running. Nothing happened. It didn't mount, and disk utility didn't see it until I rebooted.
 
Connect a hard drive to the lower drive bay while the machine was running. Nothing happened. It didn't mount, and disk utility didn't see it until I rebooted.

That's kind of a mute point because the G5 and Mac Pro have different SATA controllers.
 
But it implies it's not a software issue...
Actually, No. :eek:

The X Serve is a rackmount system, meant for enterprise use. This implies RAID, particularly hardware implementations, which must have hot-swap capabilities. So Apple included the Inrush Current Limiters either on the board, or installed on their RAID Pro card. Ideally, they're installed on the board, just in case the RAID is in fact software based for cost savings. It also runs the SERVER version of OS X, which contains the software support.

So you get both parts needed on the X Serve. :)
 
In response to the physical implications of hot-swapping, SATA has the grounds make contact before the pins... FYI. I can see how if everything did not line up correctly in IDE that would screw things up.

As for the Inrush Current Limiter... Isn't that just a circuit with a resistor and a big inductor? Physics happens to be grinding my gears with finals coming up, and would really like to rattle off a part number to irk my physics prof. :p
 
NO. They are NOT hot-swappable. You'd probably just fry the drive/computer.

LOL
Not likely. Sticking the drive in with the computer running will not cause any problems (yes I have done it) however the drive would not mount until you reboot because (as has already been stated) the internal drive bays are not hot-swappable.
 
In response to the physical implications of hot-swapping, SATA has the grounds make contact before the pins...
Yup. :)

I was primarily thinking in terms of not being able to insert on an angle as is possible with IDE. Not nearly the time delay between contacts.

FYI. I can see how if everything did not line up correctly in IDE that would screw things up.
This is definitely an issue with IDE.

As for the Inrush Current Limiter... Isn't that just a circuit with a resistor and a big inductor? Physics happens to be grinding my gears with finals coming up, and would really like to rattle off a part
number to irk my physics prof. :p
There's a few ways. The simplest and most common, is either a fixed resistor or thermistor.

But there are IC's used as well (PFC). Here's an example (NCP 1650DR2/G) by On Semiconductor. :D

Just print out the data sheet for your professor. ;) :p
 
The simplest and most common, is either a fixed resistor or thermistor.

Epic facedesk moment. Current is inversely proportional to resistance (V=IR) - for some reason, I was thinking that an inductor would be a better on the whole as the current is then based off of an exponential function. However, it approaches a limit as time goes to positive infinity, so the actual voltage across the inductor grows fairly rapidly and then slows. lim time->negative infinity was what I was thinking...

[/most random physics rant ever]

Oddly enough, I'm only half-sure that my physics professor would understand that datasheet. Electrician in the Navy, had to learn circuits the right way (we learn positive charge flows; protons, anyone?) and did her postdoc with string theory. Electronics may not be her thing, but I would like to get the idea of what each pin does (and the purpose therof) before I actually wing out the stapler with a group of pages which many answers may reference with the words "see attached" :D

Sorry to move off-topic, its late and I've been up too long writing a lab.
 
Epic facedesk moment. Current is inversely proportional to resistance (V=IR) - for some reason, I was thinking that an inductor would be a better on the whole as the current is then based off of an exponential function. However, it approaches a limit as time goes to positive infinity, so the actual voltage across the inductor grows fairly rapidly and then slows. lim time->negative infinity was what I was thinking...

[/most random physics rant ever]
I've had my moments, so you're not alone. :D

Oddly enough, I'm only half-sure that my physics professor would understand that datasheet. Electrician in the Navy, had to learn circuits the right way (we learn positive charge flows; protons, anyone?) and did her postdoc with string theory. Electronics may not be her thing, but I would like to get the idea of what each pin does (and the purpose therof) before I actually wing out the stapler with a group of pages which many answers may reference with the words "see attached" :D

Sorry to move off-topic, its late and I've been up too long writing a lab.
The schematics should help immensely. ;)

As you can see, there's a lot more to it than just a simple current limiter like a thermistor. ;)
 
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