Virtual disks revisted…

Again for Linux/ OSX users, it’s no big deal as they have access to the ‘dd’ command. Well I was installing AT&T SYSVr4 when it hit me that you can somewhat convert physical disks with Virtual PC & Qemu…
linked disk1
In Virtual PC you can create a ‘virtual disk’ that links to a physical volume..
linked disk2

And again, just select a physical slave disk with your legacy OS already installed.

Once the disk is linked, re-run the utility and you can then convert the linked disk into a dynamic disk. Once you have your .vhd, you can use Qemu’s qemu-img tool to convert the disk image into qcow,qcow2 (Qemu) or even VMDK for VMWare. The syntax is pretty simple..

qemu-img convert –f vpc attsysv.vhd –O qcow attsysv.dsk

I’ve tested it with AT&T SYSVr4 & OS/2 1.3! Much to my amazement with the fixpacks, OS/2 1.3 will actually RUN on Virtual PC 2007. It’s a shame that IBM saw the SDK’s for OS/2 as a revenue generation opportunity, as it’s amazing how quick it is (once it’s done initializing….) but I guess that’s a given of any 16bit OS that’s written in assembly….

For the heck of it, here’s a screenshot.

OS/2 1.3 running from a linked disk

OS/2 1.3 running from a linked disk


6 thoughts on “Virtual disks revisted…

  1. Does this target.vhd converted file from command qemu-img convert source.img -O vpc target.vhd work on Hyper-V and xen hypervisor ??

    • from what I recall hyper-v changed the format to allow disks bigger than what virtual pc allowed, and for some other changes I don’t recall off the top of my head.

      For converting from Hyper-V I used a tool that let me do a block read of a “physical” disk, and catch it on the linux side and redirect it to a 1:1 raw hard file, while running that within the VM. As long as I shut down the services that would normally be running (SQL, IIS, etc) it worked fine.

  2. Some 11-12 years ago (certainly after 2001 but before 2004), back when Virtual PC was not Microsoft’s but still Connectix’s, I’ve used this feature (virtual disks linked to physical ones) to run virtualised XP (with 64 MB of RAM) on top of … the exact same installation of XP (128 MB on host). Virtual-but-linked-to-physical disk was of course read-only. It worked, though slow.

    • It’s incredibly disappointing that Microsoft turned it into a glorified IE6 serving app. At least the old version could run games, VPC 2007 should have been a legacy type solution but I guess the MSDN folks can’t have any of that!

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