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Author Topic: "Vol: has a checksum error on disk block xxxx"  (Read 2295 times)

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Offline TenaciousTopic starter

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"Vol: has a checksum error on disk block xxxx"
« on: January 15, 2016, 11:00:55 PM »
In the past, I would swap out the hard drive after receiving this message.  Now, I'm running out of hard drives.  

After all this time, does our favorite OS offer a way to re-map the bad places on a drive and continue on?  This partition is currently formatted with FFS.
 

Offline Thomas

Re: "Vol: has a checksum error on disk block xxxx"
« Reply #1 on: January 15, 2016, 11:07:01 PM »
A checksum error is not a bad block on the harddisk, it is a logical error in the file system. It can be corrected for example by DiskSalv (if the HDD is smaller than 4 GB).

http://aminet.net/package/disk/salv/DiskSalv

Or backup / format / restore. You should make a backup anyway. Repairing always has the risk of losing some files or whole directories.

Offline zipper

Re: "Vol: has a checksum error on disk block xxxx"
« Reply #2 on: January 16, 2016, 10:09:01 AM »
http://aminet.net/disk/moni/DiskMonTools.lha can fix over 4 GB disks - but it will take ages (tried it)  and backup method warmly recommended! I always kept a fresh copy of every HDD partition and in emergency just formatted the bad one and copied over from the backup.
 

guest11527

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Re: "Vol: has a checksum error on disk block xxxx"
« Reply #3 on: January 16, 2016, 10:49:19 AM »
Quote from: Tenacious;802215
In the past, I would swap out the hard drive after receiving this message.  Now, I'm running out of hard drives.  
As the (other) Thomas already said, this is not (necessarily) an indicator of a hard disk error. It is most likely a soft error due to some other (logical) corruption of the hard disk, i.e. bad program, corruption of data in RAM prior writing them out to disk etc.

Unlike what Thomas said, it could *also* be the result of a hard disk sector loosing its contents, but this is rather untypical. Hard disks have (typically) several levels of error correction mechanisms, including checksums, and would under such circumstances rather return an unreadable block - if they don't replace it in first place by themselves.
Quote from: Tenacious;802215
After all this time, does our favorite OS offer a way to re-map the bad places on a drive and continue on?  This partition is currently formatted with FFS.

Well, let's put it like this: Not in the sense you're expecting to.

If this is a SCSI disk, then those disks typically re-assign bad sectors themselves, unless this feature is turned off. So there is nothing to do. Aminet contains a utility (SCSIQuery) that lists the defect sectors of the disk. Don't be worried if this list looks rather long, this is normal. The drive keeps care of them, and it will replace them transparently to the filing system and the host computer.

If the disk runs really low on spare sectors, you can re-assign the sectors with SCSIFormat, (also on Aminet), which will low-level format the drive and will include (as an option) a media scan that will check for defective sectors and re-assign them. However, I really really recommend against it. It not only wipes the entire drive (not just a partition), it is also usually unnecessary, and in very rare cases, it might even render the disk unusable because some silly drive firmwares also erase their own firmware as part of the formatting process. So, you usually do not want to do that. (Unless you really, really know what you're doing!). So, specifically, not in this case.

Last but not least, while FFS does not allow to remap sectors, in principle one could pre-allocate bad sectors so they are not used for anything. But, as I already said above, this is usually handled by the drive firmware, so there is no need for doing that, and second, I am not even aware of a program which offers this as a service. So while a theoretical possibility, it is not practical at all.

In your specific case, I would not attempt to use DiskSalv. This program may do more harm. Rather, I would copy as many files from the defective partition as possible to another drive or another partition, run an FFS format on the defective partition, and then just copy all the files back. Aminet "SortCopy" can do that, for example.

This will bring back the partition to life, and to a correct structure. Reparing a life filesystem with DiskSalv is not recommendable, and it is not unlikely that it does more damage to the structure. Do not attempt this at home.

Greetings, Thomas
 

Offline TenaciousTopic starter

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Re: "Vol: has a checksum error on disk block xxxx"
« Reply #4 on: January 16, 2016, 08:27:45 PM »
Thanks for the advise and solutions Thomas, Zipper and Thomas!  :)

Yes, it is a SCSI HD, under 4GB in size.  The partition in question is only 700MB.  The machine is an A2000 with a GVP 68030 accelerator and A2091 running OS3.1 with BetterWB.

I used PFS2 years ago and really liked it.  I haven't formatted a new system with it since the free version came out.  But now, I'm tempted by this.  There are probably better tools in PFS for this kind of problem.