Cloning / Archiving a Mac OS 9 HDD on a Modern MacIf you want to preserve an old Mac OS 9 hard drive, especially one containing old software authorizations, I would
not use Finder copy.
For archival purposes the safest simple method on a modern Mac is to make a
raw image of the entire physical disk.
That means:
OLD OS 9 HDD
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v
USB / FireWire / SATA adapter
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v
Modern Mac
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v
Raw whole-disk image
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v
MacOS9_HDD_MASTER.img
This copies the disk sector-for-sector instead of copying individual files.
Finder copy:files -> files
Volume cloning / ASR:filesystem / volume -> filesystem / volume
Raw disk image:sector 0 -> sector 0
sector 1 -> sector 1
sector 2 -> sector 2
...
entire physical disk
1. Connect the old Mac OS 9 driveConnect the HDD to the modern Mac using a suitable USB, FireWire, IDE/SATA adapter, dock, etc.
Open Terminal and run:
diskutil list
Find the old Mac disk.
For example:
/dev/disk4
Apple_partition_scheme
Apple_HFS Mac OS 9
IMPORTANT:Make absolutely sure you have identified the correct disk number.
Using the wrong disk number can overwrite another drive.
2. Unmount the diskDo not eject it. Just unmount it:
diskutil unmountDisk /dev/disk4
Replace
disk4 with your actual disk number.
3. Create a raw image of the complete HDDRun:
sudo dd if=/dev/rdisk4 of="$HOME/Desktop/MacOS9_HDD_MASTER.img" bs=4m status=progress
Again, replace
rdisk4 with the correct drive.
Using
rdisk accesses the raw device and is normally faster than using
disk.
You will now get:
MacOS9_HDD_MASTER.img
on your Desktop.
The image will normally be the same size as the complete physical HDD.
Example:
20 GB HDD = approximately 20 GB image
4. Create a SHA-256 checksumAfter imaging, calculate a checksum:
shasum -a 256 "$HOME/Desktop/MacOS9_HDD_MASTER.img"
Better yet, save it:
shasum -a 256 "$HOME/Desktop/MacOS9_HDD_MASTER.img" > "$HOME/Desktop/MacOS9_HDD_MASTER_SHA256.txt"
You should now have:
MacOS9_HDD_MASTER.img
MacOS9_HDD_MASTER_SHA256.txt
Keep both.
The SHA-256 lets you verify years later that the image has not changed or become corrupted.
5. Restoring the image to another HDDConnect the destination disk and identify it:
diskutil list
Assuming the destination is:
/dev/disk5
Unmount it:
diskutil unmountDisk /dev/disk5
Then restore:
sudo dd if="$HOME/Desktop/MacOS9_HDD_MASTER.img" of=/dev/rdisk5 bs=4m status=progress
WARNING:Everything on the destination drive will be overwritten.
When finished:
diskutil eject /dev/disk5
Why use this method for old Mac software?Some old Mac software authorization systems did not behave like ordinary files.
A normal file copy may preserve:
- Applications
- System Folder
- Documents
but still fail to preserve the authorization state.
A raw disk image makes as few assumptions as possible about the old filesystem and copies the entire accessible physical disk.
For old Pro Tools / TDM / audio systems this makes a good
preservation master.
I would keep the original HDD untouched until the restored disk has been tested.
VerificationDo not consider the backup proven just because the image was created.
Ideally:
Original HDD
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v
Create raw image
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Restore image to spare HDD
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Boot Mac OS 9
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Launch protected software
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Verify authorization is still present
Important limitationThis applies to
hard drives.
It is not the same thing as preserving copy-protected floppy disks.
Old floppy protection can depend on things such as:
- non-standard sector layouts
- deliberately bad sectors
- weak bits
- track timing
- flux-level information
For that kind of preservation, a normal
dd image may not be enough and hardware such as Applesauce FDC may be required.
For a Mac OS 9 HDD, however, a raw whole-disk image is a very useful and simple archival method.