BAD SUPERBLOCK / MAGIC NUMBER WRONG

Mac OS X Speciality level out of ten: 0. Apr 19, PM in response to Chris Chamberlain1 In response to Chris Chamberlain1 A bad superblock is usually a critical error indicative of a hardware failure. Backup the data as soon as possible on the entire drive, not just this specific partition. As to whether this is common or not, I'd have to say no, but there are many FireWire enclosures and I'm sure some of the more expensive options are more expensive for a reason of course, I don't know whether this is one of the cheap or the expensive enclosures.

Reply Helpful Thread reply - more options Link to this Post. User profile for user: Mark Jalbert Mark Jalbert. It's much easier to use diskutil to perform a file consistency check. It will sort out the filesystem, unmount the filesystem, and perform the verification or repair.

You should reference the filesystem by the raw device and not the block device. I was able to use Diskwarrior to regain control over the partition and the data, and now when I run DU - it drives a "green" output statement - ie, everything ok. The article seems to state that both commands will work but they seem to work differently depending on??? User profile for user: nerowolfe nerowolfe. I read somewhere that the fsck command automatically switches to the proper mode when it sees the HD, so it's not a big deal.

However, since you did get the drive working, I strongly suggest cloning it, just in case. Apr 21, PM in response to Chris Chamberlain1 In response to Chris Chamberlain1 The article seems to state that both commands will work but they seem to work differently depending on??? In SUM fsck will detect the filesystem. If the filesystem is UFS then it will run fsck. SUM is a barebones operating system that is quite different then OS X fully loaded- only the root filesystem is mounted, read only.

In this instance it is safe to operate on the filesystem. In fully loaded OS X, volumes must be unmounted to repair them. This identifies the bad blocks and marks them as such so the won't be used again. By writing 0's, you do just that. I can imagine this can be very time-consuming, especially if there are many errors and thus many files to replace. If that's the case, consider replacing the drive, it'll get worse It sounds like most drives will only reallocate a bad block on a write, so that's how all processes 'fix' bad blocks.

If you're willing to reformat, lots of people talk about doing a low-level format that writes zeros Disk Utility will do this. The only tool on the Mac that I found that will do this is "Speed Tools". When it finds a bad block it will write a zero to the block even if it's in a file In an edge case, a fix may make recovery of data impossible. Amongst the utilities that I have used on Macs, one is outstanding for unmistakable alerts such as this:.

This will most likely result in volume or data corruption if a bad block is found and spared. For its unmistakable warnings, for pre-purchase satisfaction and more, this answer is my vote of confidence in:. I don't know of any modern utilities for Mac OS X that actually fix mark bad blocks and let you get on with your day. Such as Version 7. This just sounds hard to do, but it's not. Being a "REAL" Mac technician and fan boy for the last 20 some years, I have machines from the k up to a Dual G5, so the hardware is just lying around for me.

In other words, it's super easy for me. Why do I sound rude? Because I am. I'm very crossed with the current Apple, and I especially hate Steve Jobs for destroying Apple Computer for us 's and 90's Macintosh Users, and turning the Mac into nothing more than a PC that runs a bland version of Unix. He, and the people that think like him, are the reason that Mac's no longer have the utilities you need to repair your HD "properly".

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SMART is extremely flawed. HD's have almost always remapped bad blocks automatically, at least since I can remember and I'm old for a technician. They do a crappy job at it and if you are seeing bad blocks, that's because the HD has run out of the tiny amount of space that is reserved for re-mapping bad blocks automatically.

IE, you need to run a utility that does a better job at it. Sign up to join this community. The best answers are voted up and rise to the top. Home Questions Tags Users Unanswered. Fix bad blocks on Mac hard disk Ask Question.

fsck (Mac)

Asked 9 years, 2 months ago. Active 16 days ago. Viewed k times. What software is available for this? If I know the address of the bad block, is there a low-level terminal utility for marking it? Hennes Andrew Vit Andrew Vit 2 2 gold badges 6 6 silver badges 20 20 bronze badges. Modern HDDs remap bad blocks automatically upon failed read operations. I've worked with plenty of recent hard drives that will keep failing to read the same bad block again and again and again, but as soon as you write to it, the problem is fixed. Spiff - you are correct, I made an error trying to avoid lengthy explanation of how block's data and CRC fields work together to ensure data integrity, and thus requiring a write operation to check if its a physical block problem or just corrupted CRC which is fixable.

Actually, I am not aware of any modern HDDs performing remap on read There is a thing to consider: my experience of 'fixing' Pending sector on a NTFS partition consisted of 1 identifying the exact data sector, 2 writing to it, and 3 resetting internal NTFS bad sectors counter which was the only step I documented at bogdan. I don't know of any tool that will do a surface scan and fix the bad blocks too. What type of a Mac and what type of hard drive are you having problems with? Can that be done without a reformat?

Yes I'm backed up, but in the interest of saving time. In addition to what I said in my update above, my personal preference is to run the drive manufacturer's diagnostics. Perhaps it's more than is really needed, but I figure "Why not? Typically, the diagnostics are distributed as a bootable CD image, but I don't believe any of them will boot on an Intel Mac.

To get around this I usually remove the drive and mount it in a Windows PC. Andrew Vit - it might be the case that writing to that Pending Bad Sector will fix it remove the sector from the list of Pending without adding to the list of Reallocated. For the record, ended up doing exactly that: reformatted with the "write zeros" option which took some time, then cloned back from my backup.

My "pending" bad block that was being reported in SMART Utility went away: it just disappeared and the drive shows no bad blocks now Andrew Vit: Thanks for updating with your status. I always appreciate finding out how the story ends. If it makes you happy, then no doubt it was worth the trouble.

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But IMO the "write zeros" reformat was overkill. Out of curiousity, could you check your SMART values again and see if the sector was in fact remapped? Reallocation count changed from 0 to 1? Or whether it was "just a corrupted CRC", a possibility that chronos mentioned in an earlier comment? Colin 3 3 silver badges 7 7 bronze badges. This is going to take a while: Testing with random pattern: 0.

How can I run fsck on a disk image via Mac Terminal? - Super User

Alternatively, if you have unix tools installed on a different startup disk, you can download and build e2fsprogs. Then just unmount the disk you want to check and run badblocks on it. Matthew Elvey Matthew Elvey 3 3 silver badges 10 10 bronze badges. I don't believe that this does a per-block read and rewrite like badblocks -n, which is frequently necessary to get the disk firmware to actually spare out the block. Alphaman Alphaman 51 1 1 silver badge 1 1 bronze badge. It's bit of an old question, but still valid.

What worked for me is the following: If possible start up from a partition or drive other than your main one. Make sure it's not the Mac's Recovery option if you want to use a 3rd party application to identify the corrupt files Identify all the files on your harddive that are corrupted due to bad blocks. I happen to use Carbon Copy Cloner to create a mirror of my drive as a backup it gives you a list of corrupt files. There are probably other tools around that can do this.

fscking tedious: "Invalid sibling link" (10.4.11)

Locate these files on your drive, and delete them empty the trash as well! Open Disk Utility and erase empty disk space by writing '0's. Please mind, this can still take some time, especially if you have a lot of free space. Gerbie Gerbie 31 2 2 bronze badges. Sadly, SpinRite would likely do more harm than good on an already-failing drive.

GrahamPerrin for one, it doesn't make sense to attempt to recover your data and write it back to the same known defective media. But ignoring that, as soon as SpinRite encounters an unreadable block, it tries and retries repeatedly before continuing.