Memory failure

[mitstoshi]

I have installed two RAMs on my two remaining slots. The system Power-on test shows memory failure on one on the Chips. This is also confirmed by a third party software: Rember. Do I have to run Apple Hardware Test or just replace the chip?

[DeltaMac]

Reseat the chips again. It's very common to mis-seat memory chips.
Swapping those chips between those two slots would be a good test.

[mitstoshi]

Before I got the chance to replace the chips, my booting volume froze and had to be forced start. But restart failed. By checking the disk via DU, the booting disk failed and could not be repaired. The following is the diagnosis from DU:
----------------------------------------------
Verify and Repair disk “Macintosh HD”
Checking HFS Plus volume.
Checking Extents Overflow file.
Checking Catalog file.
Invalid key length
Volume check failed.

Error: The underlying task reported failure on exit


1 HFS volume checked
1 volume could not be repaired because of an error
-----------------------------------------------

Fortunately, I have backup volume on the second internal HD. Now my questions are:

(1) Is this related to the memory failure? From Mac Power-on self test the memory passes the test and all four chips are OK as shown on Memory status. On the other hand, whenever the memory testing software - Rember is used, the system froze. Therefore I thought the memory is OK and there is something wrong with the software.

(2) How to repair the failed disk? What does "Invalid Key length" mean ?

Please help!

[DeltaMac]

First, remove that new memory, and run the Disk Utility again.
If you still get that failure, it's one that Disk Utility can't fix, and a coincidence in spite of your other work.
How to repair? Get Disk Warrior.

[mitstoshi]

I have removed the two new chips. the original booting disk is still unrepairable just like when the two chips were installed (same error message). Do I use DU to erase the disk instead of using DW or other software?

[trevor]

Quote: Originally Posted by mitstoshi Do I use DU to erase the disk instead of using DW or other software?

Your choice is to

1. Erase the disk, then restore from your latest backup, or

2. Just leave it as it is and repair it using DiskWarrior http://alsoft from bootable DVD.

Your choice, but in favor of DiskWarrior I will point out that unless you are so lucky that you backed up immediately before this problem occurred, you will probably lose SOME data from the time between backup and the problem. Also, DiskWarrior is an invaluable utility to have around to keep your Mac's hard drive in good shape, and so it will come in very very handy in the future as well.

Quote: Originally Posted by mitstoshi (1) Is this related to the memory failure? From Mac Power-on self test the memory passes the test and all four chips are OK as shown on Memory status. On the other hand, whenever the memory testing software - Rember is used, the system froze. Therefore I thought the memory is OK and there is something wrong with the software.

The bad memory is probably the cause of the hard drive filesystem "Invalid key length" error. When your memory is bad, that causes far-reaching problems in your overall computer, including hard drive filesystem errors.

Fixing the hard drive is kind of pointless unless you first remove the bad memory, as it will likely just reoccur.

Quote: Originally Posted by mitstoshi What does "Invalid Key length" mean ?

It's a rather technical answer, but here is Apple's explanation of the HFS+ filesystem.

Trevor

[mitstoshi]

There are security options when erase the disk using DU. What option do I use? I am not concern about the security. All I want is to recover the disk to be bootable in a short amount of time.

[trevor]

Don't use any of the security options, they are just a waste of time unless you are selling the computer (or the hard drive). And they are rather hard on the hard drive, too.

Trevor

[DeltaMac]

The security options allow you to write zeroes to all the blocks on the disk. Overwriting the erased data on a formatted drive gives you additional assurance that the data cannot be recovered by any means. You can choose to do that overwrite multiple times, if you want. That's the additional choices in the security tab. The security tab is for erasing in an environment with high security needs, or for the super-paranoid
The problem with doing that on an older hard drive, that process is very hard on the drive, and many experts don't recommend doing that, as it will likely accelerate the death of the hard drive. You would simply erase the hard drive, avoiding the security, because you are continuing to use the same hard drive, and the old, erased data will be over-written as you reinstall your system and other software/files.

[mitstoshi]

There is a default security option: "Don't Erase Data" (the first one). Do I choose this option?

[trevor]

You don't need to click on the "Security Options" button at all, or you can just hit Cancel. But yes, hitting Cancel, or not clicking "Security Options" at all is equivalent to "Don't Erase Data".

Trevor