so the new DiskDoctor with OS3.1.4 only 'examines' hard drives so what to use then on drives larger than 4GB's nowadays to try to 'repair' issues ?
SYS:System/Format - there are no tools around to "repair" a broken "modern" FFS.
DiskDoctor is not a good name, it doesn't by any means "doctor" disks, a more describing name would be "FFSDump", as that is all it does - dump the content of a broken FastFileSystem.
The new Disk Doctor can both find and report defects as well as recovering data from the volume, with various options to restrict the set of directories, files and links which you want to keep. The recovery operation preserves all file attributes (date, owner, protection, comment) and will reproduce both soft and hard links (if possible; if the target for the hard link is not copied you won't get the link). It spends far more effort on the task than dumping what it finds on the source volume.
My ambition still is to go beyond the examine/copy operation, which all by themselves turned out to be far more complex than I had anticipated. The learning process was painful and it colours how a possible repair operation would have to work.
Disk Doctor is arguably a poor name, especially in the light that a medical doctor's duty is so different from what, by analogy, the original Workbench 1.2/1.3 Disk Doctor did. For one thing, destructive changes made to the disk contents should require the user's informed consent, but the 1.2/1.3 Disk Doctor never went that far. It just did its best to make a presumably damaged disk accessible to normal file system operations again. It was recommended that when the 1.2/1.3 was "finished" with a disk, that its contents should be copied to a known-good disk and the disk whence the contents came from should be reformatted. The 1.2/1.3 Disk Doctor was
expected to make irreversible changes with negative impact to the disk.
Keeping the name "Disk Doctor" was to make a point of how to properly do the kind of job which the original tool was not designed to handle well. You should be in control of what Disk Doctor does, and you should be informed about the choices you have when you are looking at a possibly damaged volume and want to recover its data. It's uncommon but not wrong to try and apply medical ethics to data recovery.
I wish there was ways to prevent the built in validator from starting, as it often crash for various reasons (low memory situations etc), and just allow _manual_ optimistic read-only mounting of FFS also when running AmigaOS (and not just when running NetBSD or Linux...)
Only write-protecting a volume will keep the validation process from starting. Back in the day when the Disk-Validator was separate from the ROM file system you could prevent it from becoming active by removing it from the boot volume.
Most storage media is auto-mounted and cannot be made to appear write-protected. This is an unsolved problem which is not supposed to happen.