PowerPC Mac floppies to .img on modern Mac

[blanka]

I found a box of 1,44 MB HD floppies from my PowerMac G3 years. They read fine on my MBP with Mojave, with a plug-and-play USB floppy drive. Thing is, I want to use the content in Basilisk II and need .img's of the floppy. How can you make those under OSX? If I use the disk utility they become .dmg which are incompatible (they are probably HFS+).

 

[joevt]

Is a read/write dmg not the same as an img? Just change the extension?

Or you can try the dd command. Something like this:
sudo dd if=/dev/rdisk9 of=myfloppy.img

Compare the result of dd with the result from DiskUtility.app to see if the dmg has the same format.

 

[blanka]

Thanks, those files work and they seem to keep the orginal icons, where the DMG does not keep that information. It is very slow though, much slower than generate a disk image in Disk Utility.

 

[joevt]

You can change the block size so that it's more efficient.
With a floppy you already copied, add bs=1M to the command. This copies 1 megabyte at a time instead of 1 block at a time. Change of=myfloppy.img to a different name. Compare the old img you did previously with the new img (use md5 or diff).

You can also try ddrescue instead of dd. I think you can install it from homebrew. The default options used by ddrescue might be faster than the default options used by dd. ddrescue is also good for working with disks with bad blocks since it will skip bad blocks and retry them later and it can generate a map file that lists the good and bad blocks. hfsutils has a command to translate block number to a file so you can see what file is corrupted.

 

[DOS:]

Cloud Converter may have an option for you. Seems to have tons of conversion types under "Archive". Searched Google for "comvert .dmg to .img"