Using Macintosh Disk Images under NetBSD

NetBSD has some useful tools for dealing with Macintosh disk image files. You can use these to copy files out of or into a Disk Copy disk image, or create a new disk image that can be mounted and read by Disk Copy on a Mac.

The hfsutils package, a collection of tools for reading and manipulating Macintosh HFS volumes.
mkhybrid, a utility for creating disk images (especially CD-ROM images); available as a NetBSD package.
vnd, the vnode disk driver, which allows you to treat a file (e.g. a disk image) as if it were a real disk.
vnconfig, the utility for configuring and unconfiguring disk images for access through a vnd device special file.

If you're used to using Disk Copy on the Mac, you may find using these commands a little involved, but they get the job done.

How to Mount and Read a Macintosh (HFS) Disk Image

Configure a new vnode disk using the disk image as the contents:
```
vnconfig -v -c vnd0d MacDisk.img
```
Mount the vnode disk as an HFS volume:
```
hmount /dev/vnd0d
```
Do whatever you need to with the contents of the disk image (copy files in or out, delete files, etc.):
```
hls
hcopy "Docs:ReadMe" /tmp/readme
...
```
When you've finished, unmount the HFS volume and unconfigure the vnode disk:
```
humount
vnconfig -v -u vnd0d
```

How To Create a New Macintosh Disk Image from a Directory

The easiest way to do this is to use mkhybrid. Here we're taking the directory tree starting at /tmp/mac/system and copying into a new HFS disk image at /tmp/test.img.

mkhybrid  -hfs  -hfs-volid "My Mac Disk"  -o /tmp/test.img  /tmp/mac/system

You can copy the image file to a Mac, set the Type and Creator to rohd and ddsk, and double-click the file to mount it with Disk Copy.

How To Create a New Macintosh Disk Image from Scratch

If necessary, determine the amount of space required for the stuff you intend to copy:

du --block-size=1024 /tmp/mac/system

Create an empty file of the required size:

dd if=/dev/zero of=/tmp/test.img bs=1024 count=6511

(To create a 1.44 MB floppy image, use bs=512 and count=2880)

Configure a loopback file device for the blank disk image:

vnconfig -v -c vnd0d /tmp/test.img

Create an HFS filesystem on the image:

mkhybrid -hfs /dev/rvnd0d

Umount the HFS volume and unconfigure the vnode disk:

humount
vnconfig -v -u vnd0d

The new image can now be copied to a Macintosh and mounted using DiskCopy.