System Locks up overnight

[samsc]

internet report of freeze with usb hub:

Meanwhile, MacFixIt reader Ben reports another, USB-related freeze trigger for the Mac mini:


"I've also notice random, regular lock-ups with my Mac mini. I seemed to have narrowed it down to the USB. If I have either my Canon LiDE 35 scanner or my SanDisk ImageMate 8 in 1 media reader (SDDR-88) plugged in, after a period of time (sometimes hours, sometimes days) my Mac mini will lock. Looking in the /var/log/system I see what looks like an attempt to access the USB devices followed by the inevitable hard reboot I had to perform. I'm not sure if it's the devices, but two different types of devices and two different manufacturers make me think it's something with the USB software/hardware subsystem or the Belkin Hi-Speed USB 2.0 7-Port Hub I have my USB devices plugged into."

http://www.macfixit.com/article.php?...05041107171246

this report is from a mac-mini its quite possibly a related hardware issue.

[tylerr]

Its kinda funny that this problem is ongoing and semingly unsolveable. I recently threw up my hands and paid my $45 to CDW for a pro to look into the problem. He had the machine running for 24 hours with no problems.

I love computers.

[tylerr]

How about this.

I use unpowered USB hubs in my systems. Is it possible that I could be overloading the USB system with the CIB, Dongle, and USB for the UPS plugged in without auxiliary power?

I still love computers.

Tyler

[samsc]

it is always possible that unpowered usb hubs might get overloaded with power requirements of peripherals.

cib takes quite a lot of power. its close to the usb limit.

but cib disconnection shouldnt cause any freezing unless something else is happening.

do you still love computers?

does your problem move when you change the peripheral from computer to computer?

did you try a different hub?
Or try powering the hub?

[tylerr]

is there some nifty little application out there that will tell me the utilization of the available USB power?

[samsc]

there is the USB Prober application - its in the utilities folder.
this shows what devices think they are consuming.
i dont think there is any active monitoring of current available.

[tylerr]

Now here is something interesting.

In the system profiler if you click on USB it will tell you that there is 500ma available on each buss. Or at least that is how I am interpreting it. Now if you look at your USB Key and CIB you will notice that they both draw 500ma. if that is the case and I am reading all this right it never should have worked with an un-powered USB hub. That would be a 1A load on a 500ma service. It doesn't work in lighting so why did it seem to work in the world of Apple.

Thoughts?