Blanks

blanks-0.2.0.zip (16K)

"blanks-0.2.0.zip" is a zip archive containing a folder of zipped empty disk image files of various sizes. Most images are in hfs format, but 3 are in the older mfs format, which is needed for the Macintosh 128K emulation, and also some older programs.

First unzip "blanks-0.2.0.zip" to get the folder "blanks" ("Stuffit Expander" will work on the Macintosh, for example). Then when you need a blank disk image, unzip one of the files in this folder. For example, unzip "hfs800k.zip" to get "hfs800k.DSK", an 800K HFS blank disk image, the size of a floppy disk normally used by the real Macintosh Plus.

For information about using disk images in Mini vMac, see the 'Floppy Drive' section of the Hardware Reference. For information about transferring files from your real computer into and out of disk image files, see the page about Disk Images.

If you're using Mini vMac on a Macintosh, you might want to set the file type and creator of your new disk image file, using "SetFType".

It is a good idea to rename the disks inside the emulated machine, instead of leaving the default name 'untitled'. Because if two different mounted disks have the same name, some programs can become confused. (The name of the disk which you see in the emulated machine is completely separate from the name of the disk image file).

Another issue is that when you make multiple copies of these blank disk images, they will have the same creation date. This can make a difference if you use “Aliases” in System 7. The Macintosh system software can mistakenly decide that an already mounted disk is the disk it is looking for, particularly if it has the same creation date as the correct disk. If you might encounter this problem, before using one of the blank disk images you can erase it (with the “Erase Disk...” command in the Special menu of the Finder) to make sure it has a unique creation date.

You can also create your own blank disk images of any size. If you try to mount a file in Mini vMac which isn't a disk image (preferably all zeroes) the operating system of the emulated machine will ask if you want to initialize it. Choosing 'Initialize' will make a perfectly good disk image. You can create zeroed files in the terminal of Mac OS X, or Linux, with commands such as:

dd if=/dev/zero of=my_image.dsk count=14336

For Microsoft Windows, it is reported that the command line utility MAKEDSK will make zero-filled files. The same archive also contains MAKEIMG which generates formatted disk images. However, according to Disk First Aid and Norton Utilities, the disk images it generates are not quite in standard HFS format, so it may be safer just to use MAKEDSK, and let Mac OS in the emulated computer do the formatting.

When creating your own disk images of arbitrary size, keep in mind that it is not a good idea to create one giant disk image for all your work. One reason is that the HFS file system is limited to a maximum of 65535 allocation blocks. So the minimum block size increases for larger disks, meaning more wasted space. (HFS Plus fixed this problem, but isn't supported on a Macintosh Plus.) Another reason it is bad idea is that a Macintosh Plus doesn't have the memory protection of modern computers, so that a bug in any program can potentially corrupt mounted disks. It is safer to have separate disk images for separate purposes. This way Mini vMac gives the same benefits of memory protection, and more. No matter what program you run in the emulated machine, nothing can be harmed except the disk images that are mounted at the time. (Unless there was a major bug in Mini vMac, of course.)

If you create a zeroed disk image file on a Macintosh, and wish to set the the file type and creator with SetFType, you should first mount the zeroed file in Mini vMac to initialize it, unmount it, and then use SetFType. If you use SetFType before initializing the file, it won't know that the file is supposed to be a disk image.

Here is the md5 checksum for the download:

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