HDD Bad Sectors question...

Hi Trish!

Always use the one for the current version you have installed. If possible use the disc with the same sub-version you have installed. This is not always possible. If you bought SL when it first came out then your disc installs 10.6. If you buy today you will likely get one that installs 10.6.4. But the major version is 10.6. I'm using SL in this example but the same goes for whichever major version of OS X you have installed.

I absolutely agree that using a forced shutdown can indeed lead to all sorts of data corruption and logical disc errors.

But, just in light of the original post, I do maintain that it should not lead to any actual hardware issues (e.g. disc damage from a head crash). My understanding is that the final machine power down is handled by EFI Firmware code. Pressing and holding the power button does bypass all of the OS shutdown processes - all the things you mention (caches, temp directories/files and so forth) - but the hardware still powers down normally, which should mean the hard drive heads parking properly and so forth.

I just think the op was given incorrect and bad advice. There is no reason to think that a forced shutdown will or has caused any hardware issues or physically bad sectors to their hard drive. A forced shutdown bypasses the OS and software parts of the process, but the hardware is still "normally" power off - in other words, from a hardware shutdown point of view, it is not at all akin to yanking the plug, but allows things like hard drives to shut down properly and gracefully.

Logical errors and data corruption, if they are not automatically fixed by system checks and so forth during the boot cycle, will be evident at the next boot cycle, and can usually be fixed with software tools as already mentioned.

No. The installer writes the new system onto empty space on the drive, so you need to have sufficient free space for the installation. It then examines what third-party apps need to be moved, finds the support files and moves them, and moves your entire Home folder. System preferences are also moved. Then the old system is removed.

The process is much like an Archive and Install except that no archived system is retained.

I would not expect it would lead to mechanical damage but I wouldn't rule it out given the circumstances. Any time there's an abnormal shutdown there's a risk of damage to the drive assuming the drive wasn't already damaged and caused the lockup. Although modern hard drives are pretty resistant to physical damage it still can happen. The heads don't park properly then bad things may happen. Modern drives are supposed to autopark the heads when they lose power, but no doubt there's at least one time when they don't.

The person advising the OP probably overstated the situation perhaps looking to get the sale of a new drive and some service fees, but that's not necessarily the case. He/she may just be poorly informed - a condition that is often the case with the Genius Bar geniuses. Many are pretty dumb.

If there is no real data corruption and the drive is OK, one expects that the system will restore the last known good state using the journal. The real benefit of using a journaled filesystem.

As always, thanks a million, Kappy!

I've got a 10.6 SL disc, but I guess it would be good practice to get the newer one, with whatever later version is on it.

BIG THANKS 😉

No. If you erase the drive then files are installed in empty space,. But that wasn't what you originally asked. You need to be consistent with the question you ask or be more precise about what you are asking.

There are two potential situations 1. You are installing onto a freshly formatted drive; 2. You are reinstalling on a drive that already has an installed system. Got the picture? In the former situation there are no files to overwrite or replace because they've been erased. In the second scenario you are reinstalling and replacing an existing system. The new system is added then the old system is removed.

Silly to spend $30 for another DVD when you have all you need and can download a free updater. But if you find that more convenient I'm sure Apple can use the extra money.

If you opened Disk Utility in the OS X installer before installing, selected your hard drive, clicked on the Erase tab in the DU main window and clicked on the Erase button, saw the drive disappear from the Desktop for a few moments, watched a progress bar, then announce the process was successful, and the disk icon reappeared, then you erased the drive prior to installing.

The newly installed OS files will be written to drive by the installer. Most likely in the same place as before (I don't know why that would be important.) However, the new system is not installed "over the old OS installation" because the old installation was erased. Maybe for you this is a terminology confusion. When you say "over" that means "over writing" which is not what is actually taking place if you install on a freshly formatted drive because there isn't anything to "over write."

Technically when files are erased only the drive's directory is actually modified. The files themselves still reside on the media but now there's no way to know where they are or in what order. If you Zero a drive during reformatting that writes zeroes to every byte on the drive wiping any trace of the old files because then all the data are overwritten with zeroes. Now, if this is what you are thinking, then you understand it correctly.

You did fine.