Can you Insert Drive While Running Mac Pro ??

Discussion in 'Mac Pro' started by fab5freddy, May 25, 2009.

  1. fab5freddy macrumors 65816

    fab5freddy

    Joined:
    Jan 21, 2007
    Location:
    Heaven or Hell
    #1
    Can i insert a harddrive on my Mac Pro while it is running ?

    Just don't want to shock myself or the like.........
     
  2. Tallest Skil macrumors P6

    Tallest Skil

    Joined:
    Aug 13, 2006
    Location:
    1 Geostationary Tower Plaza
    #2
    NO. They are NOT hot-swappable. You'd probably just fry the drive/computer.
     
  3. fab5freddy thread starter macrumors 65816

    fab5freddy

    Joined:
    Jan 21, 2007
    Location:
    Heaven or Hell
    #3
    Oh Great! I didn't do it Yet!

    Thanks for saving my computer.
     
  4. Roy macrumors 6502

    Joined:
    Jul 6, 2006
    #4
    Leave off the "YET" part and read your manual.

    "A mind is a terrible thing to waste".
     
  5. Spanky Deluxe macrumors 601

    Spanky Deluxe

    Joined:
    Mar 17, 2005
    Location:
    London, UK
    #5
    A Mac Pro is an even worse thing to waste. :p
     
  6. fab5freddy thread starter macrumors 65816

    fab5freddy

    Joined:
    Jan 21, 2007
    Location:
    Heaven or Hell
    #6
    Sorry, i will never do that !

    the word "Yet" was a mistake.

    Though Apple should make them hot-swappable !
     
  7. Roy macrumors 6502

    Joined:
    Jul 6, 2006
    #7

    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.
     
  8. nanofrog macrumors G4

    Joined:
    May 6, 2008
    #8
    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.
     
  9. mchalebk macrumors 6502a

    Joined:
    Feb 4, 2008
    #9
    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.
     
  10. nanofrog macrumors G4

    Joined:
    May 6, 2008
    #10
    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
     
  11. remmy macrumors 6502a

    Joined:
    Jul 1, 2007
    #11
    Wouldn't swapping the drives mean opening the case when running which is generally bad for the computer anyway.
     
  12. nanofrog macrumors G4

    Joined:
    May 6, 2008
    #12
    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. ;)
     
  13. zmttoxics macrumors 65816

    zmttoxics

    Joined:
    May 20, 2008
    #13
    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.
     
  14. Dzokayi macrumors member

    Joined:
    Mar 12, 2009
    #14
    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.
     
  15. zmttoxics macrumors 65816

    zmttoxics

    Joined:
    May 20, 2008
    #15
    That's kind of a mute point because the G5 and Mac Pro have different SATA controllers.
     
  16. goMac macrumors 603

    Joined:
    Apr 15, 2004
  17. nanofrog macrumors G4

    Joined:
    May 6, 2008
    #17
    Yes, but unfortunately, a different animal. ;)
     
  18. goMac macrumors 603

    Joined:
    Apr 15, 2004
    #18
    But it implies it's not a software issue...
     
  19. nanofrog macrumors G4

    Joined:
    May 6, 2008
    #19
    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. :)
     
  20. xraydoc macrumors 604

    xraydoc

    Joined:
    Oct 9, 2005
    Location:
    192.168.1.1
    #20
    Moot. Moot point. Not "mute."
     
  21. Dr.Pants macrumors 65816

    Dr.Pants

    Joined:
    Jan 8, 2009
    #21
    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
     
  22. Darth.Titan macrumors 68030

    Darth.Titan

    Joined:
    Oct 31, 2007
    Location:
    Austin, TX
    #22
    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.
     
  23. nanofrog macrumors G4

    Joined:
    May 6, 2008
    #23
    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.

    This is definitely an issue with IDE.

    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
     
  24. Dr.Pants macrumors 65816

    Dr.Pants

    Joined:
    Jan 8, 2009
    #24
    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.
     
  25. nanofrog macrumors G4

    Joined:
    May 6, 2008
    #25
    I've had my moments, so you're not alone. :D

    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. ;)
     

Share This Page