Contrary to what has told you, you don't need to rename floppy images to end in ".flp" for them to work in Fusion. ".img" works just fine.
Part of what you were missing is that once you create the diskette image, you still need to format it. Creating the image from /dev/zero only creates a ~1.44MB file full of zeros. It doesn't add in any of the filesystem structures needed to track filenames, or which sectors of the disk belong to which files. Formatting accomplishes this for you, so once you have the image mounted in your DOS VM, you need to run the following:
format a:
Which should result in something like the following:
Insert new diskette for drive A:
and press ENTER when ready...
Format complete.
1,457,664 bytes total disk space
1,457,664 bytes available on disk
512 bytes in each allocation unit.
2,847 allocation units available on disk.
Volume Serial Number is 3214-19F7
With that step out of the way, you can mount the .img file from both within OS X and within any VM that can read FAT-12 formatted diskettes (which is virtually all of them -- DOS, OS/2, Linux, Windows, BeOS, Solaris, etc.). And as OS X can mount the image, you can drag and drop whatever you want on the diskette to the image.
Note that 1.44MB floppies, while the most common floppy size before they died out, isn't the biggest standard floppy size. There is an official standard for a 2.88MB floppy, which DOS supports. Just change your count= statement from 2880 to 5760, change the VM's BIOS settings for "Legacy Drive A:" to a 2.88MB 3.5" floppy (press F2 at boot time to get intot he VM's BIOS settings), and enjoy twice the capacity. I'm attaching a pre-formatted, empty 2.88MB floppy image here for you to use (just note that a VM probably won't be able to mount it until you change the VMs BIOS default from an emulated 1.44MB floppy drive to an emulated 2.88MB floppy drive. Note you only ever have to do this once for any given VM. OS X will mount it just fine without any changes).
As for the image you created not being exactly 1.44MB, floppies of this size never were exactly 1.44MB in size (at least not for a 1024 * 1024 byte MB). This comes from a mixing of two different common uses of the size prefix "M", the one used by computer science (1024), and the SI prefix meaning "1000". For a good rundown on this, see the Wikipedia article on Floppy diskettes:
Reported 3.5\" DSHD FDD storage capacity
Suffice to say, the numbers I gave you previous match the exact physical characteristics of a real double sided, high density floppy diskette (2880 sectors, each 512 bytes in size).
HTH!
Yaz.
Message was edited by: Yaztromo to fix a typo.
