Q: My iMac G4 started suddenly glitching

If I didn't know the history of the machine, I'd say run disk utility.

Random hardware problem.

Heat problem.

Your machine, I'd say re-install.

Try boot from installation dvd.  See if you can get the machine to run awhile. 

do:

utilities > disk utility

utilities > terminal

top

#control c to stop

# press return to run a command.

What we are trying to do is figure out where this is a software or hardware problem.

Since we are lazy and not wanting to do a new install, we will run off of the dvd.

boot from installation dvd. pick your language.  Click on Utilities.  Click on terminal.

Once the terminal is running.

type:

top

press return. ( enter if on pc keyboard )  It runs forever.  To end, type control + c

( hold down the control key then press lower  case c key )

top is a unix commnad. it continuosly displays thread usage information

if top isn't around type pwd press return every once in awhile.

--------------------------------------------------------------

I suspect disk corruptions.

verify & repair your startup drive

To verify & repair you file system on the startup drive, you will need to run disk utility from you installation DVD.

This article  will tell you how to get to disk utility.  Once in a disk utility, you can go and attempt to recover the disk.

http://support.apple.com/kb/TS1417

To repair your startup drive, you will need to run disk utility from your startup DVD.
Mac OS X 10.4: About the utilities available on the Mac OS X 10.4 Install DVD

http://support.apple.com/kb/HT2055

How to run disk utility from your startup DVD.

1. Insert your  startup DVD  into your reader.  Power down your machine.  Hold down to the c key.  Power on your machine.  This will bootup your startup DVD.
2. This will bring you to a panel asking you for your language.  Pick your language.



 

3. You you come to the Install Mac OS panel.  Do not install.
4. Click on Utilities menu item.  This will give you a pulldown list of utilities.
5. Click on the disk utility.
   
6. You are now in disk utility.  Pick your disk.  Click on repair it should be on the lower right of the panel.
7. Once the repair completes successfully, you should update your permissions.

--------------------------------------------------------

Verify a disk

As an alternative, you can verify that the filesystem on the disk is correct. You will not be able to repair the file system.

I suggest that you use disk utility to verify that your startup disk is OK. 
Macintosh-HD -> Applications -> Utilities -> Disk Utility 
Start up disk utility.  On the left pane view, you will see a list of all your disks.  
Click on your startup disk.
Click on the First Aid  Tab.
Click on verify.  

Hopefully your disk will verify.  If not, you have to boot from your installation DVD and run Disk Utility from there to attempt to repair your file-system.

--------------

Format a disk

Macintosh-HD -> Applications -> Utilities -> Disk Utility

Start up disk utility.
On the left pane view, you will see a list of all your disks.  Click on the  disk.
Click on the partition tab.

You will now see how your  disk is currently set up.  Fill in the information as appropriate. You should pick Mac OS Extended (Journaled).

Click on Options...

Select Apple Partition Map to boot a PPC.

More details on formatting.
http://www.kenstone.net/fcp_homepage/partitioning_tiger.html

-------------------

Format a disk using the installation DVD

To format  the startup drive, you will need to run disk utility from your installation DVD.

This article  will tell you how to get to disk utility.  Once in a disk utility, you can go and format the disk.

http://support.apple.com/kb/TS1417

To format your startup drive, you will need to run disk utility from your startup DVD.
Mac OS X 10.4: About the utilities available on the Mac OS X 10.4 Install DVD

http://support.apple.com/kb/HT2055

How to run disk utility from your startup DVD.

1. Insert your  startup DVD  into your reader.  Power down your machine.  Hold down to the c key.  Power on your machine.  This will bootup your startup DVD. ( Alternatively, you may hold down the control key, this brings up the startup manager. Click on the desired volume. Click on the right arrow. )
2. This will bring you to a panel asking you for your language.  Pick your language.
3. 
   
   
4. You you come to the Install Mac OS panel.  Do not install.
5. Click on Utilities menu item.  This will give you a pulldown list of utilities.
   
   
6. Click on the disk utility.

7. Start up disk utility.
   On the left pane view, you will see a list of all your disks.  Click on the external  disk.
   Click on the partition tab.

   
   

   

   
   
   

8. You will now see how your external disk is currently set up.  Fill in the information as appropriate. You should pick Mac OS Extended (Journaled).

More details on formatting.
http://www.kenstone.net/fcp_homepage/partitioning_tiger.html

The idea is to make your machine run awhile ... like one or two hours.  The time should be twice the failure time.

Running from the DVD we are limited.  The terminal isn't that hard.  I think the output from the top command scared you.  Don't worry about the output.  Found we do not need to worry about the top command because it does not exist on the dvd. We want the machine to be doing something for awhile.

How to run terminal from your startup DVD.

1. Insert your  startup DVD  into your reader.  Power down your machine.  Hold down to the c key.  Power on your machine.  This will bootup your startup DVD.
2. This will bring you to a panel asking you for your language.  Pick your language.

3. 

4. Next you come to the Install Mac OS panel.  Do not install.
5. Click on Utilities menu item.  This will give you a pulldown list of utilities.
6. Click on the terminal.

 

7. 

    

    

   Believe it or not, the terminal item is highlighted.

    

8. Clicking brings you into the terminal.  What you see will be a little different, but similar.

    

    

9. Here a command you can use to get things appearing on the terminal.

    

    

   while :; do ps; sleep 2; done

    

   notice the :;

   this is the colon :

   followed by the semi-colon ;

    

   press return when you have typed everything.

    

   to stop you press

   control + c

    

    

   

Ok, I don't see the usefullness of the terminal command you told me earlier. It doesn't work

Sorry, the command did not work. I know now.

Now, should I just reinstall the system to solve the problem quickly? What do you recommend me to do before installing (except backing up files, because I don't have any)?

Well,  we do not know what the problem is. It would be good to try to sort out the problem.  You could reload & see if the problem goes away.

If the reload doesn't work, you need to try to isolate what the problem is.  You need to run without the software from the hd. This is the reason for the terminal commands. We need to get the machine running & see how long it lasts.

to see it run do one or both of these commands.

while :; do ps; sleep 2; done

notice the :;

this is the colon :

followed by the semi-colon ;

press return when you have typed everything.

to stop you press

control + c

or the list command use the l  is ls is the lower case L

ls -R

press return when you have typed everything.

to stop you press

control + c

Robert

I'd reformat the hd.  I like to make two partitions. Then I make one partition. { extra effort to get rid of old partition }

Install the OS.

Robert

This is good news.  Time will tell.

Robert