Create single disk image from drive with multiple partitions

Question

I'm running Mac OS X 10.11.6. I have a variety of old CD-R's that contain multiple partitions (I would imagine this also applies to an HD). When I insert the disk, each partition mounts as a separate volume on my desktop. Lets say the device is /dev/disk1 - there's /dev/disk1s1, /dev/disk1s2, and so on.

I'd like to create a disk image - dd, dmg, iso, cdr, toast, whatever the format, that contains the partition table for the device, such that when I attach the disk image, all the partitions mount and show up on my desktop as volumes.

I'm having an incredibly difficult time figuring out how to do this. I've tried:

dd if=/dev/disk1 of=~all.dmg

…but when I try to attach this file, I get the "no filesystems found" error. I can use:

hdiutil attach -imagekey diskimage-class=CRawDiskImage -nomount ~/all.dmg

…to attach the image, but from there I can't figure out how to mount the volumes. hdiutil pmap does not show a useable partition table. When I try to create an iso (hdiutil makehybrid -iso -o all.iso /dev/disk1), the iso only contains the first partition.

When I run Disk Utility, which as of 10.11 has become incredibly buggy and unreliable, and select the device (not the volume), and attempt to create an image of the whole device, Disk Utility will fail with a cryptic error, right when it has finished with the first volume, and has started moving on to the second one.

There just doesn't seem to be a way to make a disk image of the whole device, so that I can easily mount these multiple volumes from one disk image file. Am I wrong here?

Answer 1

You can use 'dd' but output to a .iso file or, alternatively, use Disk Utility (the program is in the Utilities folder on any OSX installation) to create a multi-partition disk image. It outputs CDR masters, which are essentially ISO file with extra metadata.