Firewire drive limit on single tower?

Discussion in 'Mac Pro' started by bunkre, Jan 10, 2007.

  1. bunkre macrumors member

    Mar 10, 2004
    I apologize if this is a dupe, but i couldn't find one in search:

    Is there a limit to the amount of HD space you can setup via firewire to a single machine?

    My boss wants to chain up at least 3 Lacie 1 terabyte triple interface drives using one of our old powermacs. We'd be probably using a quicksilver, but maybe a G5. He went ahead and bought the drives before asking me :rolleyes:
  2. Qianlong macrumors regular

    Oct 23, 2004

    FireWire Frequently Asked Questions

    What is FireWire / IEEE-1394?

    FireWire technology was first invented by Apple Computer in the early 1990s and then was adopted by the IEEE as a standard (IEEE-1394) in 1995. FireWire is a cross-platform high-speed serial technology that can move large amounts of data between computers and peripheral devices.

    What are the System Requirements for using a FireWire drive?

    * Power Macintosh G3 B/W, G4, iMac DV (G3 B/W needs "G3 Firmware Update 1.1")
    * Mac OS 8.6 or greater
    * Apple's FireWire drivers version 2.3.3 or greater
    * Compatible Hard Disk Formatting Software

    Can I daisy-chain with FireWire drives or do I need a hub, like with USB?

    As with SCSI, FireWire is a daisy-chainable technology. All FireWire products (and nearly all FireWire devices) have two FireWire ports and either port can be used for connecting to the host computer or connecting another FireWire device. While FireWire hubs (often referred to as repeaters) are available, they are typically only used when attaching large numbers of devices simultaneously, or with devices that only have one FireWire port (such as digital cameras).

    Since FireWire can daisy-chain like SCSI, do I need to terminate the last device and keep track of what ID numbers I can use?

    No, FireWire is a truly user-friendly system. Every FireWire device has its own unique ID code (sort of like a fingerprint -- no two devices have the same code). FireWire does not require the use of terminators.

    How many FireWire devices can I attach to my computer?

    The IEEE-1394 standard for FireWire sets a limit of 63 FireWire devices per computer. When connecting directly to your computer, there should be no more than 16 cable lengths between the computer's FireWire port and the last FireWire device.

    How long can my FireWire cable be?

    Without using a FireWire Hub or Repeater the maximum recommended cable length is 4 meters between devices. Are FireWire drives hot swappable?

    Yes, with the following recommendations:

    * Never unplug any FireWire device that is being actively accessed by the operating system (such as a file copy).
    * Unplugging a device while it is being used may result in a system crash and the loss of the ability to recover the data already written to the drive.
    * If you want to unplug a FireWire disk drive you must first drag the mounted drive icon to the trash to dismount it. After the drive is dismounted then it can be unplugged.
    * If using a CD creation utility or backup software, it is recommended that you exit the application before disconnecting the device.

    Are there any known conflicts with other FireWire based devices?

    We are not aware of any hardware conflicts at this time.

    Can multiple computers share my FireWire drive at the same time?

    No. The Mac operating system does not have the ability to share the drive between users simultaneously.

    Can I add multiple FireWire devices?

    Yes. Simply hook up the device cable to an unused port, either on your computer or the second port at the back of your FireWire drive. Keep in mind some devices such as digital cameras only have one FireWire port, so they must be at the end of a chain. You do not need to worry about device addresses or device termination. There are two rules to keep in mind: first, there is a limit of 63 FireWire devices per computer, and second, there should be no more than 16 cable lengths between the computer and the last FireWire device.

    Known Limitations and Issues (FireWire):

    Follow the guidelines listed below for connecting FireWire devices to your computer. If these instructions are not followed, your computer and other FireWire devices may not work correctly. For more information about using and troubleshooting FireWire devices, see the onscreen Help (available in your computer’s Help menu).

    * Do not connect more than 63 devices (including computers) at one time.
    * Do not connect devices so that any two devices have more than 16 cables directly between them.
    * Do not connect FireWire cables in a way that forms a ring of devices. Do not plug both ends of one cable into the same device.
    * Unused FireWire connections should be left empty. There are no terminators for FireWire connections.
    * Connect devices that require power from FireWire directly to the computer.
    * Do not unplug a FireWire device or eject a CardBus card while it is being used. For example, do not unplug a FireWire disk while copying files onto it.

    Using Multiple FireWire Devices at the Same Time

    Power Macintosh computers can transfer perfect digital video (DV) on FireWire when no other devices are using the FireWire bus. If you have problems transferring digital video, make certain that no other FireWire devices are being used at the same time. Turning on a DV camera that is already connected may cause a FireWire hard disk to stop working. If this happens, turn off the camera and verify that the hard disk has recovered. Then unplug the FireWire cable from the camera, turn the camera on, and reconnect the FireWire cable to the camera. Check with the hard disk vendor for a possible firmware update to prevent this problem.

    Using FireWire With a PowerBook

    If a PowerBook computer with a FireWire CardBus card inserted will not start up, eject the card and restart the computer again.

    Do not allow a PowerBook computer to sleep while it is receiving digital video. The video input may not continue when the computer wakes up.

    Do not try to eject a FireWire CardBus card while the card is loaded and live. To eject the card, first shut down the PowerBook to release the driver, and then press the card eject button to remove the card.
  3. bunkre thread starter macrumors member

    Mar 10, 2004

    so anyway, does OSX or the machine's hardware have a limit to the total hard drive space? will it freak out after the 5th terabyte or something? i thought i had heard of there being a limit for internals, but never heard of one for externals.

  4. yellow Moderator emeritus


    Oct 21, 2003
    Portland, OR
    The hardware limitation (of HD size) in older G4s is strictly for internal disks on the IDE bus. OS X can support volumes of up to 16TBs, I believe. Your real question is if you can stripe a bajillion FW drives together, and still get decent thruput from FW400.
  5. bunkre thread starter macrumors member

    Mar 10, 2004
    ah, thanks Yellow!

    yeah, im not even that concerned about throughput speeds, just as long as it works. this will just be old jobs archived for a small office.

    thanks again.

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