[tatar]

Could someone explain, why my iMac G5 PPC freezes?
It's not happening that often, once in a few days, and it doesn't last long, ten, to twenty seconds.
I'm not able to move the pointer, and to use the keyboard; entire screen is still, and if I happen to listen to some music, the sound I get, is like when a CD player gets stuck.
The machine is being constantly hooked to the Internet, but I don't think, that is really the matter. I'm running the Mac on a latest Leopard.
Thanks.

Aleksandar

[P]

Could be absolutely anything, likely software. What OS do you use? Could possibly be the old lookupd bug, but that's just a guess.

I suggest that you check some of the relevant log files to see if there are any hints. The Console app is in the Utilities folder inside Applications.

[Big Mac]

It has nothing to do with the Mac being connected to the Internet all the time. This obviously should not be happening - it's a major problem (either OS or hardware related). I think what you're experiencing is a severe Kernel Panic, because audio skipping repeatedly is what often occurs during a KP.

You need to do troubleshooting of the problem to determine whether the problem is related to your hard drive, RAM, OS corruption or something else.

[imitchellg5]

Could be a billion things. Bad RAM, not enough RAM, bad HDD, not enough free space on HDD, corrupt OS files.

[Big Mac]

Not enough RAM would never cause that problem, nor would lacking free HD space. There is something very wrong with the Mac in question. It could be bad RAM, a bad hard drive, a corrupt OS or a dying motherboard. I almost forgot about the bad capacitor problem that iMac G5s had - very well could be that.

[P]

Never say never, Big Mac. Lack of HD space is a possibility, if somewhat unlikely, and there is at least one known OS bug (in 10.4 anyway) that causes this.

[seanc]

Hard drive failure will often cause everything to lock up for moments. Run SMART Utility. Post a screenshot. Volitans Software- Makers of SMART Utility for the Mac

[tatar]

Hi,
well, so many suggestions, I almost don't know what to start checking first.
OK, I tried the Smart Utility, and the program couldn't find any errors on the HD. So I'm guessing, that's that.
What should I do next; but for that, I would need a bit detailed guidance.
Thanks.

Aleksandar
PS: As I've mentioned in my first post, I'm running the machine with the latest Leopard, i.e. 10.5.8

[tatar]

OK,
I checked how it looks when the Kernal panic occurs, i.e. the message shows on the screen, saying, to restart the computer, hold the Power button... and so on. I'm not getting any messages before the issue happens.
The RAM memory's two gigs, but I'm not doing anything like, video, music or image editing; just emailing, and internet surfing.
There's was about ten gigs free space on the HD, last time the computer froze.
Right, so, how do I check those parts you've all suggested; RAM, HD, OS, Motherboard, Capacitor (is the capacitor in question, power supply related, as I've changed the entire power supply recently).
As for consulting Console app, I couldn't find any logs prior to 23rd of this month, and that is when the last freeze happened.


Aleksandar

[tatar]

I thought of one more thing, although I think, it's not really relevant; I'm not shutting down my computer, i.e. I let it sleep overnight, and just when the sluggishness gets too annoying, I shut the machine down for a couple of minutes...

Aleksandar

[Big Mac]

RAM - if you have third party RAM installed, remove it and test with just the original Apple module.

Hard Drive - Startup up from a different drive and test your computer that way to see if the problem disappears. If you need one, buy an external Firewire hard drive, start up with the OS DVD and install the OS on the external drive. Then boot from the external drive (you can change the drive you boot from either by using the Startup pane of System preferences or by holding the Option key at startup).

Motherboard/Capacitors - Open your iMac and inspect the motherboard. There will be large cylindrical objects on it, and if you see orange stuff on top of them, then you have the bulging/leaking capacitor problem.

[seanc]

Regarding SMART Utility, please click the 'Show All' next to attributes.

Does the raw value column for the 'reallocated sector count' have anything other than 0? Same question for 'current pending sector' and 'offline uncorrectable sector'.

[tatar]

So far, I've done only the Smart utility test again, and all three counts are showing 0.
For other stuff, I need more time, especially, as I'm not sure I understand how to perform practically all of them...
Thanks...

Aleksandar
PS: The freezing didn't occur for three, four days now; maybe all's not that bad.

[tatar]

OK,
for the RAM, I used Rember software, and after running it with three loops, there were no issues shown.
HD I tried verifying with Disk utility, and the report said, the HD appears to be OK. I don't know, if I should be concerned with the term, "appears".
Is there anything else I could try...?

[tatar]

Oh, and yes,
after checking the capacitors, I found not a single one bulged, or with any kind of residue on it...

[seanc]

How much RAM do you have?

Can you keep Activity Monitor (Applications > Utilities >) open and when it freezes, monitor how much free memory you have and what is using up the CPU usage.

[tatar]

It is a two gigs RAM.
I will try with the Activity Monitor on next time. Meanwhile, here're few first entries from the Console. I think the first log was recorded right about the time, when the last freeze occurred (yesterday; and before that, the machine was performing optimally for a week):
Mar 27 14:36:26 S0106000d9347a958 [0x0-0x16016].org.gudy.azureus2[115]: DEBUG::Sat Mar 27 14:36:26 PDT 2010::com.aelitis.azureus.core.networkmanager.Virt ualChannelSelector::select::352:
Mar 27 14:36:26 S0106000d9347a958 [0x0-0x16016].org.gudy.azureus2[115]: Caught exception on selector.select() op: Bad file descriptor
Mar 27 14:36:26 S0106000d9347a958 [0x0-0x16016].org.gudy.azureus2[115]: TCPNetworkManager$4::run::188,AEThread2$threadWrap per::run::294
Mar 27 14:36:26 S0106000d9347a958 [0x0-0x16016].org.gudy.azureus2[115]: java.io.IOException: Bad file descriptor
Mar 27 14:36:26 S0106000d9347a958 [0x0-0x16016].org.gudy.azureus2[115]: at sun.nio.ch.PollArrayWrapper.poll0(Native Method).
Got no idea, what to deduce from all this...

[seanc]

That's just telling me Azureus, your torrent client, broke.

[tatar]

OK;
could you just detail, what reading I should mind, as there is bunch of them in the Activity Monitor...?

[seanc]

Any that have a high usage of CPU or memory. You can use the column headers to arrange the list.

[tatar]

Someone suggested, the Azureus, the Vuze torrent might be the cause of the freezing. When I was looking at the Activity Monitor, Vuze was eating up most of the Virtual Memory, up to 1.2 gigs, and, sometimes with up to 20 CPU. And that's the rate, when I had the Vuze running, but no data transfers. I'm presuming, when the traffic starts, the Virtual Memory consumption increases to boot. The rest of the apps, way below that, with Safari, at little over 100 megs. The thing I can't figure out, is something denoted, as, ct_loader_agent, which is gobbling up 6.73 GB, but always with zero CPU; maybe that is quite nothing out of ordinary...
So, I've removed the entire Vuze folder, and will see, would everything go smoothly as before...

[tatar]

To whom it may concern...
Well it seems, the Vuze was clogging the RAM once in a while, as there's been a week now, the computer has been working without any glitches...
Thanks to all involved in this thread.