Crash Survival Crash SurvivalSooner or later your Mac will crash. Eventually software fails, sometimes for inexplicable reasons, or simply because an application or system file has come into conflict with another piece of software.
Hopefully, after a crash, your computer will start up as usual, although in some instances you may have to reinstall the application or document that was open at the time of the crash. However, an unusual icon displayed at startup usually indicates that the data on the drive is damaged.
You can often fix such damage by inserting the Mac OS Installer CD-ROM or Disk Tools floppy disk and running Disk First Aid. Next, zap the PRAM (see below) and check the machine’s hardware. If this doesn’t work you’ll have to format the drive and reinstall your software and data. Of course, this assumes that you’ve got a full backup of the drive.
You did do a backup, didn’t you?
The Startup ProcessWhen a Mac is turned on the startup initialisation process begins. The power-on self-test (POST) procedure checks the machine’s hardware, including its RAM. If successful, the Mac produces the familiar C major chord, the ‘Quadra sound’ or some other friendly noise.
The Startup Manager in the Mac’s ROM then searches for a startup disk in the following order:-
If there’s a valid System file, a Happy Mac appears, the Boot Blocks are read from the startup disk and the system is loaded into memory. Optional files in the System Folder called StartUpScreen or Startup Movie are then executed, assuming they exist. StartUpScreen is a picture file containing a PICT resource whilst Startup Movie is a QuickTime movie file.
Once these are launched the machine loads the contents of the Extensions folder, followed by files in the Control Panels folder. Files in Startup Items are then opened and the Finder starts to run.
When a Mac is started it can show one or more of the following four icons:-
Happy MacThis indicates that your Mac has passed its POST and found a valid system. It should be followed by the Welcome to Macintosh window or by images in the StartUpScreen or StartUp Movie file. The desktop should appear after the system files and the contents of Startup Items have loaded.
In some instances the Happy Mac appears, only to be followed by the Query Disk icon (see below), indicating that a valid system exists but the Boot Blocks can’t be read due to damaged disk formatting. The only solution is to format the drive from scratch: other strategies don’t work!
Sad MacThis is the nightmare scenario, indicating that your Mac has failed its POST. It’s often accompanied by a G# major ascending chord (the ‘notes of death’), a ‘crash’ sound or a rather painful instrumental sound. This situation can be caused by problems with system software or a hardware fault.
First of all, you should disconnect peripheral devices, in particular external SCSI disk drives, and try again. If that fails, try removing any additional hardware, such as expansion cards, and start again. Following this, try starting from the Mac OS CD-ROM or the Disk Tools diskette supplied with older versions of the Mac OS. Sadly, if this doesn’t work you may have to visit an engineer.
Some machines display Sad Mac numbers, indicating the nature of a hardware fault. However, they only provide a clue and can get confused by other software errors. Here are some examples:-
| Sad Mac Number | Possible Cause |
|---|---|
| 00000000 | RAM error |
| 00000002 | RAM error |
| 00000003 | RAM error |
| 00000004 | RAM error |
| 0000000E | RAM error |
| 00000001 | ROM error |
| 0000000F | Other hardware |
All of these could be the result of system problems, especially if accompanied by sounds. But they can also be caused by peripheral devices such as monitors, hard disks or expansion cards.
The sounds a Mac generates can provide further clues, although these can also be misleading if there are software problems. The following are for an ancient model, the Mac II:-
| Sound | Possible |
|---|---|
| No | ROM |
| Single | Logic |
| One | RAM |
| One | RAM |
| Four | System |
| Rising | Video |
| Eight | Memory |
Typical sounds produced by other models on failure include:-
| Model | Sad Mac Sound |
|---|---|
| Mac II | Chimes |
| Quadra AV | Drums |
| Mac LC | Flute |
| PowerMac | Car Crash |
Query DiskThis usually indicates the POST was successful but a valid system or data can’t be found on any drive, in which case you may have to reinstall the system. If this is preceded by a Happy Mac (see above) it may indicate a problem with the formatting of your startup drive.
The icon also appears if there are problems with any device connected to the SCSI port, so try pulling out the connector. If this doesn’t work your drive data may be damaged. This means that you must repair your hard disk, requiring you to restart the machine using the Mac OS CD-ROM or, failing this, the Disk Tools diskette supplied with older versions of the Mac OS.
If the drive selected in the Startup Disk control panel isn’t available, this icon can appear momentarily before the machine discovers a valid system on another drive, causing it to finally show the Happy Mac. If you don’t have another drive, just insert the Mac OS CD-ROM or Disk Tools diskette. If this successfully starts your machine you don’t have to restart again, although you may prefer to do so in order to use your original system setup.
Damaged DiskSimilar to the above, indicating that the POST was successful but the only system that could be found is damaged. This may require you to reinstall the system, although you should check any attached SCSI drives first, including connections and SCSI ID numbers. If possible, try restarting your Mac with all external devices disconnected.
Conflicts between extensions or control panels can cause a crash at startup, which usually occurs after the Happy Mac icon appears. Typically, this happens whilst Welcome to Macintosh is being shown (in which case you’ll see a small bomb icon in the frame) or while an alternative startup image is being displayed. In any event, it’s best to restart the computer and hold down the Space bar, thereby activating Extensions Manager, which can be used to disable the offending items.
If crashes keep happening at startup you should try each of the following in turn:-
Other problems, such as a flashing Happy Mac, an empty box instead of Welcome to Macintosh or a shimmering startup box can sometimes be fixed by trashing the Finder Preferences file in the Preferences folder. To rectify the problem you should start up from another drive and remove this file. Some minor settings may need to be adjusted afterwards.
During startup you can press various key combinations to change the machine’s behaviour, such as:-
| Key(s) | Effect |
|---|---|
| Space | Starts |
| Shift | Starts |
| ⌘-Shift-Option | Starts |
| ⌘-Shift-Option | Starts |
| ⌘-Shift-P-R | Zap |
| ⌘-Option | Rebuild |
| C | Starts |
Whilst in use, your Mac can be controlled using the following keys:-
| Key(s) | Effect |
|---|---|
⌘- | Interrupt |
| ⌘-Ctrl- | Reset |
| ⌘-Option-Escape | Forces front |
Some machines also have hardware Interrupt or Reset buttons, as described below.
This button, frequently located at the rear of the computer and designated by a circular symbol, intercepts the operation of the processor. If your machine doesn’t have a button you should press ⌘- instead. Such an interrupt is only really useful if you’ve installed a debugger such as MacsBug, from the Apple Programmers and Development Association (APDA). To use MacsBug just put its file in your System Folder and restart the machine.
This is often adjacent to the Interrupt button and usually designated by a triangular symbol. If your machine doesn’t have a button just press ⌘-Ctrl-, although on some PowerBook models you must press Shift-fn-Ctrl- and on an iMac ⌘-Shift-Option-. This forces the machine to restart, losing all data in memory, and should only be used when there’s no other way out of a crash.
Repairing Damaged DisksStartup problems are usually caused by corrupted data or faulty formatting on the internal drive.
Before assuming that you have disk problems you should look at other possibilities. For example, if your Mac starts normally but you have difficulties with particular documents or applications, then the problem may be related to corrupt files, in which case your drive is probably intact.
In this situation, the first line of attack is to find and remove the offending items. If your problem’s limited to one document you could try repairing it with special utilities, although you’re likely to end up trashing it. If the trouble is restricted to one application, whatever document you’re working on, the application itself may be damaged (in which case you should install it again) or it may be incompatible with your version of the Mac OS or other extensions and control panels.
In addition, many applications create files in the System Folder, particularly in the Preferences folder. You can eliminate these from your investigations by quitting the application, dragging the files out of the folder (and onto the desktop) and restarting the application: in some cases you may need to restart the Mac as well. If this doesn’t help you can return the files to their original location.
Disk Repair SoftwareTo repair your drive properly you must have a CD-ROM or diskette containing a valid version of the Mac OS as well as appropriate disk utilities. Ideally you should use the Mac OS CD-ROM or the Disk Tools diskette supplied with your Mac OS, containing appropriate versions of:-
However, if your internal drive is a non-Apple drive you may need use the formatting application supplied with your drive instead of Drive Setup or HD SC Setup. The disk containing such an application should also contain a workable version of Mac OS for starting your computer.
Other useful software includes:-
You can create a ‘bootable’ CD containing a system an your favourite utilities as follows:-
Getting a Mac startedYou should be able to start your machine using the Mac OS CD-ROM, the Disk Tools diskette supplied with older versions of the Mac OS or a specially-prepared ‘bootable’ CD.
The following points apply to an older system that can be started from a diskette:-
Once started, your computer may automatically make minor repairs to the hard disk, a process that’s similar to rebuilding the desktop.
Making RepairsTo repair a drive you should begin with the utilities provided by Apple. Follow this sequence to avoid common problems:-
This is only a guide. For example, if you’ve just obtained a new drive you should check the SCSI IDs first. If you’ve recently added extensions or control panels you should check these for clashes.
If a disk appears on the desktop but won’t start up you could try using Norton’s Disk Doctor to repair the Boot Blocks and then install a new system.
Mounting a Hard DiskA drive that doesn’t appear on the desktop has failed to mount. Try each of the following in sequence until the drive appears:-
To re-bless the System Folder you can try one of the following methods:-
Recovering FilesHaving got your hard drive to work you’ll need to check that your files are intact. At this point it’s too late to worry about your backup methods.
If all files are present and correct you’ve nothing to worry about anyway. However, if some or all the files are missing, or you’ve had particularly serious problems, you should erase the disk and start again: but only do this if you’ve got a complete set of backup disks!
Even if you do have backups it’s best to install the Mac OS itself from scratch since the System Folder on your backup disks could also be corrupt. Having said this, the process of restoring a highly customised System Folder by hand can be extremely tedious.
Sometimes the original data isn’t visible on a drive, usually because the files are damaged or the disk’s directory is faulty. If you haven’t got any backup don’t erase the disk. Instead, use a recovery utility such as Norton’s File Saver to reconstruct the files using either a Directory Scan or Volume Scan. The unerased files can then be transferred to floppy disk.
Having saved your files you can use Drive Setup, HD SC Setup or a your own drive’s setup application to erase the disk using a high level format. Having done this, you can install a pristine Mac OS. Only then can you replace all your applications and files to their original locations.
CrashesA crash can occur whenever a software request generates an unexpected result. Typically, this occurs when one application intrudes into the memory space allocated to another program: this is known as an exception error or invalid page fault. In some situations an application may try to execute an unrecognised command: this is known as an illegal operation.
These or other faults can cause either a bomb or a freeze, as described below.
The cryptic messages shown in bomb dialogues shouldn’t be taken too seriously, since they’re created as the system software collapses. In theory, you have a choice between Restart and Continue, although most applications don’t incorporate the necessary routines to make this effective. If Restart works, all data is lost; if not you’ll have to force a reset instead. If the Continue button operates you must select Special ➡ Restart or Shut Down as soon as possible.
In this situation no dialogue appears and you may be unable to move the pointer or it may get locked into stopwatch mode or disappear entirely. In many instances the menubar clock also grinds to a halt, dialogues are locked in position or lack any content. In some situations however, you may be able to use one of following key combinations:-
| Keys | Effect |
|---|---|
| ⌘-. | Stops current |
| ⌘-S | Saves current |
| ⌘-Option-Escape | Forces front |
If you manage to escape from the situation you must select Special ➡ Restart or Shut Down at the earliest possible opportunity.
If you suffer from regular crashes, whatever the application, you should:-
You can avoid some crashes by simply taking notice of what the system tells you. For example, if you see a message saying that the Finder has unexpectedly quit and that you should save your files and restart your machine then you should do it. If not, you’ll probably have a crash and lose your data.
www.rgaros.nl/gestalt/index.html to see a list of Gestalt selectors. You can also click here to see the results of a test on a PowerBook G3.Viruses are portions of executable computer code, created by intelligent but misdirected individuals who get some kind of pleasure from upsetting other people’s computers. Generally speaking, viruses are conveyed via applications, although they are also found in documents that contain macros, such as Word files and in Web files that contain Java commands.
If you don’t have access to the Internet, use reputable software and rarely exchange files with others, you’re unlikely to experience a virus. Other users should take the following precautions:-
Selecting Special ➡ Shutdown in the Finder clears the memory (RAM), apart from the 256 bytes of Parameter RAM (PRAM) used for assembling the Desktop.
Selecting Special ➡ Restart implements a software reset, directing the processor back to its starting point. Although the main memory isn’t actually cleared, allowing corrupt data to remain, this is subsequently overwritten in normal use.
Before either of these operations, the Mac OS checks that all files are correctly saved or closed, that items in the Shutdown Items folder have been run and that the ‘Desktop file’ and contents of the PRAM have been properly updated. The size and position of Finder windows are also memorised so they’ll appear correctly the next time you use the machine.
©Ray White 2004.
