firewire IEEE 1394 or IEEE 1394a are they compatible?

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Level 2

154 points

firewire IEEE 1394 or IEEE 1394a are they compatible?

I am connecting a firewire hard drive to the iMac. I don’t Know if the drive is firewire IEEE 1394 or IEEE 1394a and the same with the Mac. Does this matter are they both compatible? Also is it true that I can only use an external start up disk that is connected by firewire and can not us USB?
Thanks for any help.

Intel iMac Core 2 Duo 2.4 Ghz 20" 2Gb of ram, iPod video 30GB, Mac OS X (10.5.5), external USB DVD, 250Gb, 750Gb external HDD USB, fire wire, card reader

Posted on Sep 18, 2009 8:47 AM

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Answer 1

varjak paw

Level 10

183,046 points

Sep 18, 2009 8:59 AM in response to John A

IEEE 1394a is Firewire 400, something with all Firewire hard drives support. Your drive may also support Firewire 800 (IEEE 1394b). If Firewire 800 is the only port your hard drive has and your iMac has only Firewire 400, you just need an FW800-to-FW400 adapter or cable.

is it true that I can only use an external start up disk that is connected by firewire and can not us USB?

No, it's not true. Your iMac should be able to boot off of a USB hard drive, though not all external drives work properly (some older drives may have firmware that doesn't support booting from a Mac).

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Answer 2

John A Author

Level 2

154 points

Sep 18, 2009 4:18 PM in response to varjak paw

Thanks for your info, much appreciated. So it is the case that might not support the boot up, not the drive itself? I ask this because the case I bought not long ago but the drive I put in the case is quite a bit older. Thanks again.

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Answer 3

myhighway

Level 5

7,270 points

Sep 19, 2009 9:22 AM in response to John A

correct, it is the case

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