Taming the beast
- Article 2 of 53
- iCreate, April 2004
Apple has made plenty of noise about how stable OS X is as an Operating System, but that doesn't mean that things won't go wrong. And when they do you'll be stuck. Join us as we show you how to fix every common Panther problem and apply corrective medicine to a sickly Mac.
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The Unix world is not so trusting. Every single file and folder on a Unix computer has a list of things that users can do it, depending upon who they are and what “groups” they belong to: the file’s owner might be able to read it and edit it; the computer’s group of admin staff might be able to read the file but not edit the contents of the file; everyone else might be able to see that the file’s there but not doing anything with it.
Unfortunately, it’s not always obvious to the average Mac user what permissions a file or folder has. So unsuspectingly, you might drop a folder into the Trash, then try to empty it, only to discover that you don’t have the permissions to delete one of the files in the folder. Panther, fortunately, has made it easier to discover and remedy this problem than earlier versions of OS X: it will at least warn you that you’re about to drag a locked file into the trash unlike 10.0 say, which apart from providing no warning, would force you to take the file out the trash, unlock it (assuming you had the right permissions), put it back in and then empty the trash. Now, you can open the Trash, highlight files or folders while they’re still in there, and select Get Info from the Finder’s Edit menu to discover what your permissions are and then alter them.
You won’t be able to do this or run any troubleshooting software, however, unless you have an administrator account (you can tell from your User Account Systems Preference whether you have a “standard” or “admin” account). If you aren’t an administrator, there’s a whole lot of things you won’t be able to do in OS X, and almost nothing you can do to fix it if it goes wrong in any substantial way. If you are intent on fixing your own Mac, make sure you have an administrator account to hand even if you don’t log in using it, otherwise you won’t be able to affect any files except your own ones – particularly not any system files.
At the moment, I’m assuming you’re got a computer in some kind of working order. But what if yours just sits there quietly, doing nothing, when you try to start it up? Now it could be a hardware problem at this stage: a lightning strike has nuked your hard drive, for instance. But we’re hoping otherwise. Check your power leads aren’t loose; unplug all your peripherals (with the exception of your keyboard and mouse); see if moving the power plug to a different socket helps; if you’ve added an Airport card, additional memory, or PCI card, try taking them out again (remembering to de-static yourself first); if you’re using a laptop and you’re not running off the mains, plug in the power adaptor and remove the battery – a flat battery can sometimes confuse your laptop into believing it has no power even when the power adaptor is plugged in; if you happen to have a spare power lead or battery, try using it instead of your regular one, in case there’s something wrong with it. If none of that works, your luck’s probably out and it’s time to get the hardware specialists in.
But there’s still more that can go wrong between pushing the power button and getting to your desktop. As soon as you press that button and power reaches your Mac’s circuitry, it looks to something called Open Firmware to tell it what to do next. This is a chip containing a slew of settings about devices, such as your Mac’s memory, and which device to boot off. Sometimes, poor old Open Firmware gets a bit confused and you need to reset its data so it can start from the beginning and let you boot up. To get to the Open Firmware prompt, you’ll need to hold down four keys at start-up: Apple, Alt, O, and F (for Open Firmeware). Then you’ll be presented with a nasty grey screen and an arrow prompt. Just type these commands in and you’ll be fine though: reset-nvram (hit enter); set-defaults (hit enter); reset-all (hit enter). The machine should reboot, and if you’ve found the correct source of your problem, all should be well.
There’s another set of settings, including the date and time, stored in yet another chip called the PRAM. Just as Open Firmware can get confused, so can PRAM. Flush it with another ambidextrous set of key strokes at start-up (Apple, Alt, P and R) if you’re having some trouble getting past the boot panel that has all those “Starting Network Services” type messages.
In rare situations, you might not make it that far. You get the Apple logo and then nothing. This is usually a symptom of a corrupt “kernel”. Think of the kernel as the foundations of the operating system: on it is built everything that makes the computer do anything more than show you a grey screen. If the kernel is corrupt (or missing. I’ve seen people boot their computers into OS 9 then move their System, Applications and Library folders, together with all the files beginning “mach”, into a folder marked “OS X stuff” to make it neater for them when they’re using OS 9), you’re screwed, although a brave soul can try to copy across a clean one from another copy of OS X.
More likely, however, something that communicates with the kernel directly is to blame – a common symptom of this is the “kernel panic” screen, which tells you something is wrong with your computer and needs to be restarted (the OS X 10.0–10.1 kernel panic message was nasty white text on black background dumped on your screen with no clues as to what was happening). Usually, that’s a peripheral that’s gone wrong or a badly written piece of software for connecting a peripheral to the computer that’s known as a driver. Unplugging all your peripherals is a good way to test for possible causes of a repeating kernel panic, but usually, they are infrequent and unpredictable things. Running the Apple Hardware Test CD that came with your computer can also help find hardware problems: boot off it like an OS X installer CD and then run the tests to see what might be wrong.
The hardware test CD is also useful for the opposite problem: the peripheral or printer that has no effect whatsoever on the Mac. If you can’t print, the System Profiler in your utilities folder and the hardware test CD can both tell you if your Mac is receiving signals from your invisible printer or not. If it can’t, you may have a dodgy lead or you may have too many peripherals connected to an unpowered USB hub, overloading it and forcing it to turn off all its attached devices. If the signals are getting through, you may need to fire up a copy of Printer Setup Repair (see walkthrough) to repair your printing system. Or you may not have the right drivers installed for your printer (a common problem for devices such as printers and scanners; it’s far less likely for digital cameras, hard drives, portable USB drives, external CD drives and other forms of storage); fortunately, you can usually download the correct drivers from the manufacturer’s web site.
If you do get as far as the boot panel – but no further – make a note of which service stopped the Mac in its track; if it’s something that relies on having a network, for example, you’ll know there’s probably something up with your network settings. Holding down the Shift key at start up can help you get passed these boot-up problems: it puts the computer into Safe Mode (another one of those ideas Apple has started to borrow from Microsoft) which loads a minimal system and allows you to get into the Mac’s graphics-based interface to change settings, if possible. If it’s not, it’s time to learn some more sets of start-up key strokes (somehow, holding down F8 at start up to get all these choices seems preferable): V; and Apple and S. The former puts you in verbose mode: bye, bye eye candy; hello, nasty white on black text. It may not be pretty, but you’ll get all the messages of distress your computer may have been putting out until this point and maybe a clue as to what’s causing the problem. The second set of key strokes puts the computer into Single User mode: you are given only a command line and nothing else. Together, assuming you have the Unix experience necessary, you may be able to hold out against that looming OS X reinstall you’ve been fearing.
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