Firewire devices causing freezes?

Question

Firewire devices causing freezes?

Hi All,

I have 8 external Lacie firewire drives. I do heavy, heavy movie editing so these are all used for backups.

I installed 3 Lacie PCI cards to accomodate all 8 firewire drives ... so each of them has an individual connection to the G5 (no daisy chaining).

For the drives i don't intend on using for a particular project, I unplug the power cords (from the ac wall outlet) but leave the firewire connection plugged into the computer.

My machine has been freezing more than the north pole. I e-mailed back and forth with a Lacie tech and he said i shouldn't have a firewire device unplugged from the ac wall outlet while the firewire cable is still plugged into the computer because this could cause problems.

Does anybody know if this is a bonafide no-no? The freezes are driving me nuts. If i truly can't unplug a firewire device from the ac wall outlet while the firewire cable is still plugged into the computer i'm going to have major problems getting my work done.

Feedback?

Paul

Posted on Sep 13, 2005 2:12 PM

Reply

Answer 1

Sep 13, 2005 3:29 PM in response to Paul Williams3

I have three firewire hard drives connected to one of my G5s. Each firewire hard drive is on its own dedicated channel, no shared busses, no daisy-chaining. I leave the drives turned off (power switch on the drives) when not in use.

I have not had the type of problems you have experienced, however, remember I'm turning them off at a power switch on the drive enclosures. The only difference I see between turning off by the power switch and unplugging the ac cord is the loss of a ground path from the external drive case, via the AC cable. However, some external drives, those powered by power bricks, may not have a ground path back to the AC outlet anyway, so I'm not really sure that is an issue.

My suggestions for you.

Plug your drives into power strips, so you can turn them off via a switch instead of unplugging AC cords.

Make sure the external drives, and the computer are powered from the same AC circuit. This will reduce or eliminate any ground reference issues between them.

Make sure you are using high quality firewire cables. Many OEM firewire cables are chosen because they are the least expensive cable available. Cheap firewire cables can have issues with both picking up noise, and propagating noise.

I'm not familiar with the Firewire controller cards your using, but one thing to consider is if each port is an independent channel, or if they are being serviced from one controller. This can lead to both performance issues, and shared problems, that is one drive having some type of issue effecting multiple firewire connections that you though were completely isolated from each other.

Hope this helps a bit.

Tom N.

Reply

Answer 2

Sep 13, 2005 4:25 PM in response to Tom Nelson1

Here is what the Lacie tech write to me in e-mail:

------------------------------------------------------------
Drives must be disconnected if they are not powered up - the FireWire bridges actually have a repeat function that must be powered in order to work correctly.

This is likely why you are having issues.

If they are connected via FireWire, they must be on; if you wish to turn them off, they must be disconnected.
------------------------------------------------------------

I have each of my drives connected to separate on/off switches all on the same circuit as the G5.

My gut is telling me i wasted a whole lot of money on all these drives.

I wonder how much these things will sell for on ebay? LOL!

Reply

Answer 3

Sep 13, 2005 4:43 PM in response to Paul Williams3

Out of curiosity, why is it important to you to be able to unplug the drives from the wall and leave the firewire cables connected? Why not just eject (dismount) the drives when you are not using them, and re-mount them when you need them.

Or, for that matter, why not just eject the drive and turn off the power switch?

Matt

Reply

Answer 4

Sep 13, 2005 5:04 PM in response to Matt Larson 29

Each drive pulls 1 amp of current. 8 drives would be quite a draw on the room circuitry. It's also a question of convenience, why have 8 drives power up when i only need one with the files i'm working with?

I did find an intersting entry in my "system.log". It says:

"localhost syslod: /dev/console: Input/Output error"

Similar entries have seemed to appear at every instance of a freeze when i was using my external drive.

This seems to be confirmed in the Apple glossary ( http://docs.info.apple.com/article.html?artnum=51916) which describes this error as "A message you get when there's a problem with the way information is being exchanged with peripheral devices."

The freezes seem to happen when i'm running TechTool and the screen saver kicks in. Hmmmmmm.

I don't know what to do. I wonder how much a used G5 would go for on ebay? 🙂

Reply

Answer 5

Sep 14, 2005 4:21 AM in response to Paul Williams3

You can acheive the same effect, from an energy consumption standpoint, by turning the drive off with the switch on the back, and leavng it plugged in.

I suspect this will keep your freezes from happening.

Or, if you really want to unplug the drives from the wall, unplug the firewire cables as well.

Matt

Reply

Answer 6

Sep 14, 2005 7:03 AM in response to Paul Williams3

No offense to LaCie, but they don't make Firewire bridge boards, nor for that matter any of the components they use in LaCie drives. They simply assembly them and sell them (and they don't do the assembly either LOL). The comments about the firewire board having a repeater function is right, but wrong.

All firewire bridge boards allow for daisy chaining of firewire drives, this means the bridge board has a set of bi-directional buffers to allow signals from one firewire connector to be "repeated" on the second connector for daisy chaining purposes. In this sense, they are correct that the external hard drive needs to be turned on for the bi-directional buffers to work. But they are blowing wind on saying having a drive turned off would be causing your problems. Having a drive turned off would only prevent any daisy chained devices that are plugged into the turned off external drive from working. And since you have no daisy chained devices, it is not an issue.

My own guess is the problems lay in the LaCie firewire PCI adaptor card. I have no idea who's card they are actually using, and some OEM cards have had notable problems in he past.

I would suggest you try the following.

Remove the LaCie firewire/pci card.

Your G5 has I believe at least two, maybe three separate firewire channels (not ports)/ The Firewire 800 and the Firewire 400 ports are probably on separate controllers. I would suggest taking a couple of your drives, and plugging them into the two ports (you will need an 800-400 cable if your externals are 400). Then try using those two drives as you normally would, powering them off, powering them on, etc. If you don't experience the problems, try adding additional drives to the available Firewire ports on your G5. and continue your experiment. If all goes well and you don't have any problems, I would think the problem may be in compatibility with the card.

At this point you could buy another card. Rearrange your drives so they where daisy chained into groups, that is you would power up two or three drives at a time all connected via daisy chain to one Firewire port on your G5. Or add an additional Firewire card from another vendor, or a firewire hub too handle the additional ports needed.

Tom N.

Reply

Answer 7

Sep 14, 2005 9:48 AM in response to Tom Nelson1

Hi Tom,

I think what Lacie was saying is, you can have the drive turned off, just don't unplug the ac power cord while the firewire cable is still attached to the computer or you would kill the repeater process and cause problems. I've seen this in the past with daisy chaining when i unplugged the first drive in the daisy chain, the computer was unable to see the second drive (the daisy chained drive). But if i plug the first drive in - but not power it up - the second drive will be seen by the computer.

First thing this morning i pulled all 3 PCI cards out of the G5 and pulled all the RAM except the original, stock 512MB (X2) sticks. I've got the G5 running behind me right now and i'll leave it running until/if it crashes. If no crash, i intend on putting the RAM sticks back in (2 at a time of course) and repeating the process (Run until/if it crashes).

If it survives the reinstallation of all the RAM then i'll focus on the PCI cards ... which i also suspect as the problem right now. I'll reinstall each card one at a time (giving the machine a day between installations to show it is stable) with no firewire drives plugged in and see how far i get. If i can get the machine stable with all three PCI cards reinstalled (but with no drives plugged into them) then i'll know i need to reconfigure my external drive situation (More money out my rear! LOL!)

<<you would power up two or three drives at a time all connected via daisy chain to one Firewire port on your G5>>

I've tried this in the past with the drives. But i ran into serious problems. The G5 would start coming up with error messages saying i improperly dismounted my daisy chained drives (the second or third drives in the chain, not the first in the chain) when the drive still showed power and the drive was still appearing on the desktop and was 100% accessible when clicked. Apparently, the daisychained drive signals were being misinterpreted by the G5. This kept me from copying from one drive to the other in the daisy chain. It was this situation that led me to wiring each drive, individually, straight into the back of the G5 ... then this current freeze problem began.

I really wish if daisy chaining firewire drives was a known issue Lacie would have said something upfront before i purchased so many of these things ... i would have taken a completely different route.

Anyways, i appreciate your taking the time to respond. It's great to receive good advice and thoughtful responses.

Paul

Reply