Re: Disk images and zeroing out space

FROM : David Sinclair
DATE : Sat Nov 30 10:59:06 2002

On Saturday, Nov 30, 2002, at 03:05 US/Pacific, Nick Zitzmann wrote:

> When I've published some new versions of existing programs, I've been
> using the same "master" disk images and copying my new software over
> the old software, then creating a read only copy of the master disk
> and compressing it. This works, but these compressed disk images are
> getting bloated, and I suspect it's because my process here is leaving
> lots of space that is "free space" but contains the remains of files I
> deleted a long time ago.
>
> So, does anyone know any good methods of zeroing out unused space on a
> disk image? Should I just make a new disk image and copy everything
> over to it, or is there some sort of disk utility out there that can
> do this? Some other developer out there has to have done this > before...


Here's what I do:

1. Have a master disk image template.
2. Duplicate it and mount it.
3. Copy the new release onto the mounted disk image.
4. Go back into Disk Copy and choose File > Convert Image....
5. Select your master image in the open panel.
6. In the following save panel choose Compressed from the Image Format
popup.
7. Enter a new name and save.

This will ensure there is no extraneous data on the master image, and
will result in the smallest possible disk image.  There is no need to
compress the image with StuffIt, if your web server is configured to
handle ".dmg" files properly (with a MIME type of
"application/octet-stream" I believe).

Hope this helps!

--

David Sinclair, Dejal Systems, LLC - <email_removed>

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