Cool Mac Gear

Turns out that the multi-lingual dialog that has popped up several times on my iBook over the past six months telling me to restart my computer is the genteel new face Mac OS X 10.2 Jaguar has put on kernel panics. I had experienced the odd kernel panic in OS 10.1, but they used to show up as a bunch of UNIX code superimposed over the Desktop image.

According to Apple, "A kernel panic is a type of event that occurs when the core (kernel) of an operating system receives an instruction in an unexpected format or that it fails to handle properly. "

The interesting conundrum of course is what is causing these occasional crap outs. The web page kindly brought to my attention by an anonymous correspondent (see letter below) suggests that there are three main potential causes of kernel panics, In summary:

1. A directory failure or user accidently moving .kext files that should be left alone. The directory may fail, due to an accident caused by Norton Utilities or Systemworks, which may at random corrupt a directory even when trying to repair it. Norton Anti-Virus will not do this, but Disk Doctor and Speed Disk have a history of doing this.

2. Peripherals that aren't Mac OS X native may cause a kernel panic, ...Mac OS X 10.2.5 has been known to kernel panic at certain USB hubs, and it is recommended you upgrade to 10.2.6 to avoid this issue.

3. RAM and motherboards are the least likely suspect in kernel panics, but if you just have a new system, and or just installed new memory and you get a kernel panic, that's the most likely place to start looking.

In the case of the kernel panic I had last Thursday, the iBook started right back up and worked fine over the next two days. On Saturday, I decided to see if I could discern any problem with the disk directory that might have tripped the system up. I booted into OS 9 and ran Disk Warrior on my OS X partition ( I don't have the OS X version of DW).

Disk Warrior took a very long time to construct a new directory. I don't know how long exactly, because after the progress bar took 20 minutes to move the first quarter inch, I left the machine to its own devices and went for a 2 mile hike. When I returned, the process was complete, and I let Disk warrior replace the directory. It didn't find very much out of order. The report read thus:

All file and folder data was easily located.

• Errors, if any, in the directory structure such as tree depth, header node, map nodes, node size, node counts, node links, indexes and more have been repaired.

• 1 folder had a directory entry with an incorrect custom icon flag that was repaired.

While I was at it, I decided to install the OS 10.2.6 update (I have been running 10.2.3), which was accomplished without incident. I was pleasantly gratified to observe that either the directory rebuild, the system upgrade, or a combination of both seemed to have resulted in a noticeable improvement in speed, which was already pretty good in OS 10.2.3. Or at least it did at first. As I put the finishing touches on this column, after less than two days of uptime, the memory use is maxed out again and the pageout parade has started (4634 so far), with a commensurate slowdown in Finder performance that seems even a little draggier than things were in 10.2.3. C'est la vie. Other than that, OS 10.2.6 seems to run happily on the iBook, and nothing appears so far to have been broken. I did have to reinstall TypeIt4Me.

As for the kernel panic, beats me. My provisional guess is that it may be related to USB. I havea Keyspan 4-port externally-powered USB hub connected to the iBook with three mice, a Wacom graphics tablet, and an ADB external keyboard (connected through a Griffin iMate adapter). One of the mice it is also an ADB unit and plugged into the ADB keyboard. And then there is the USB microphone headset for my dictation software. This all points a fairly heavy load on the USB bus, I suppose, although I have used a similar array of assorted USB and ADB peripherals (indeed mostly the same ones) with my Pismo PowerBook on a bus-powered USB hub and have had no problems.

In Mac OS X: The Missing Manual, David Pogue says that kernel panics are "almost always the result of a hardware glitch." Since I haven't deleted or altered any of OS X's files, and Disk Warrior didn't turn up any serious directory issues, I suspect that may be some transient glitch with USB, that happens after the memory has been maxed out for days and there are a gaggle of swap files created. If I recall accurately, these panics have also happened just after the iBook has awakened from sleep.

Anyway, it will be interesting to see if the phenomenon recurs in OS 10.2.6

Pageouts

From: Berl Oakley

Many people have noted that OSX 10.2 and later have reduced battery life. I have found this to be the case as well. I now get 60-90 min and got a lot more in 10.1.5. At least one part of the problem is that the hard drive never seems to go to sleep any more. It seems to me that the high rate of pageouts would prevent the hard drive from sleeping. Any thoughts?

Berl Oakley

Hi Berl;

I'm hardly qualified to comment first hand, since I've only run my iBook battery down once since purchasing the machine more than six months ago. It gets used mainly as a portable desktop substitute. I have heard that Jaguar is harder on battery life, but when I tried it last week, after three hours, I was down to 10% battery charge, and considering that I was on the Internet (modem) much of that time, kept the backlight at normal brightness, the hard drive spun up,, and took no power conservation measures, I would say that was acceptable battery life. I'm currently running OS 10.2.3.

Charles

Forced restarts not supposed to happen

From anonymous

Dear Charles,
When you get a four language screen saying you have to restart, you have been greated by the kernel panic. To fix it follow the steps mentioned in this FAQ:

http://www.macmaps.com/kernelpanic.html

It could be you have a bad directory making access to the kernel files sometimes force the computer into a panic, or you have bad RAM or a motherboard that don't speak well to the kernel. The kernel essentially your basic driver system within Mac OS X. If something is flawed there, or in the hardware that is connected to the machine, it will panic.

Sincerely,
anonymous

Thanks A. See the column above.

Charles

Re: Memory management musings

From Benjamin Huot

I have OS X 10.2.0 on a 700 Mhz eMac with 1 GB RAM and I only had OS X crash on me once - when I had to force quit the Vue D'Esprit installer. I never have to restart except when I turn off the power or when I was trying to restore iTunes or when I couldn't delete a download that crashed from Explorer. Maybe there is something wrong with these OS updates.

Ben Huot
http://homepage.mac.com/bearyandbow

Hi Ben;

You probably don't push your machine as hard as I do mine either. I usually have 15-20 programs open and lots of windows open and hidden or windowshaded, frequently test third-party software and system add-ons - often alpha or beta builds, etc.

Charles

More memory musings

From Bruce McL

Hello Charles

You are running OS X with only 1 GB free on it's partition! I would not allow one of my clients to do that. I think that invalidates a great deal of the grumbling and complaining about OS X I've read in your columns. I think it may even invalidate some of your product tests and reviews. Would some of the products that you had negative experiences with run better if the OS had some breathing room?

Give yourself at least a chance of success by reconfiguring the drive! From what I've read about HFS+ it will not work well if a drive is more than 75% full. Add the system's requirements for disk space and you are looking at leaving 1/3 of a drive empty just to make sure it runs well. If OS X, or a particular product, has problems because you don't leave enough room on your drive(s), it's not the fault of the developer or of Apple and should not be reported as such.

-Bruce McLaughlin

Hi Bruce;

Actually, I have more than 4 GB free on the OS X partition of my iBook drive, which I have been using for production since the beginning of June.

I don't dispute that 1 GB free, which is what is available on my Pismo PowerBook (currently mostly idled as a backup machine) OS X partition is insufficient, and that point has been discussed at length here on OS X Odyssey. There is actually more than 5 GB free on the Pismo drive, but it is partitioned four ways. Don't know how that affects overall performance, but it doesn't seem to be an HFS+ issue because OS 9 flies on that machine.

Apple notes:

"While the amount of disk space required depends on your computer and the way you are installing Mac OS X, you are recommended to have at least 3.0 GB of available space on your hard drive."

That would be before installation, which I would assume to leave not a lot more than 1 GB free after the install. Not ideal, but within parameters.

Speaking of which, if I ever thought my equipment/setup was compromising a review of a product, I would certainly say so. I don't believe it has -- within support parameters. I have been told by more than one reader that I have no business commenting on OS X at all based on its performance on G3 machines -- a position I consider equivalent to what emits from the south end of a northbound horse. The iBook, which is Apple's best-selling laptop, is a G3 and likely to remain so for some time yet. It is officially supported by OS X, and commenting on how OS X performs on it (or indeed any officially supported machine) is fair ball. Ditto for software. If it is advertised as being supported by G3 hardware, then its real-world performance on same is legitimately comment-worthy.

Charles

Memory Redux

From Michael W Snider

Charles,

By now you proabably have a good idea what I have to say about OS X and memory, but I'll try one more time and then shut up about it. Jaguar runs well, without memory problems, on 333mhz iMacs with 192mB RAM, 6mB VRAM and 3gB hard drives--I know, because I've got two of them. Something you've installed causes your problems. I know you get letters from people with the same complaints as you, but Charles, you and your audience have selected each other. If such problems were widespread, reviews in Wintel-centric magazines, at least, would not consistently praise the stability of OS X. Can you imagine David Coursey or John Dvorak not complaining if there were even a rumored problem?

Of course, you need what you need to do your work -- but it's not Apple's fault if system hacks like windowshading or resurrected Apple Menus cause performance and stability problems, nor can you expect Apple to address those kinds of problems.

Peace,
Michael

Hi Michael;

Just reporting my experiences, which have been remarkably similar on both my OS X machines in terms of stability, memory maxouts, etc. As I noted to Ben above, I do push my computers hard, and the nature of my work requires me to install and use a wide variety of third-party, hacks, and addons, (although I uninstall most of the system stuff after I'm finished checking it out). However, these circumstances and practices were the case when I was running OS 9 for production as well, and I had remarkably few issues with System stability in the Classic OS. I spend an awful lot more time running system maintenance and repair software with OS X than I ever did with OS 9.

That's my point. OS X has many advantages. I'm not inclined to go back to OS 9 now for a variety of reasons, but it sure did require a lot less care and feeding.

Charles

The OS X Odyssey archives may be accessed here:
http://www.applelinks.com/news/odyssey/

CM

Charles W. Moore