Autorunning Macintosh CD-ROMs

Summary: Autorunning (autostarting) Macintosh CD-ROMs. How to produce on the PC a Macintosh CD-ROM (pure HFS or HFS/ISO 9660 hybrid) which will autostart (launch an application or open a data file) under Mac OS 9.

Autorun/Autostart and Macintosh OS X

The autostart feature was silently dropped under Mac OS X. See below for some reasons of this choice. It doesn't seem that there are plans to change this.
The read-me file is therefore the only solution if you target Macintosh OS X users.
For computer still having the Classic execution environment, it remains possible to launch it and to check the QuickTime autorun feature in the Apple menu. This would be useful if you're planning a presentation of several CD-ROMs on a Macintosh.
The rest of this page is therefore mainly of historical interest.

How to Produce an Autostarting Macintosh CD-ROM on a PC?

MacImage allows to install such an autostarting feature on the HFS view of the hybrid CD-ROM, or on the HFS volume produced. Please note that Apple silently dropped the autorun feature under Mac OS X, and that there is no hope to see such a feature again on the Macintosh platform. See below for more information.

Hybrid CD-ROM

Create a project for a hybrid CD-ROM in the default mode (Project Mode). In the HFS view, select the file you want to use and do a right click. In the context-sensitive menu, select Properties. In this big dialog box, check the Autostart checkbox. MacImage will do the rest. Compile your project to produce the hybrid HFS/ISO 9660 image. Burn it. That's all.

Pure Macintosh CD-ROM

You can also implement this feature on a Macintosh (HFS) only CD-ROM. In this case, you would create directly the Macintosh partition in Partition Mode. Then select the file you want to use as autostarting (the filename should not be longer than 11 characters) and select the 'Autostart' item in context-sensitive menu (right click). Save the modified partition. Burn it. That's all.

QuickTime and the Autorun Feature

On the Macintosh, the autostart/autorun feature is not implemented as a program or as a script launching an application (like the autorun.inf file under Windows). The autorun can be supported by any file (even data files). The princip is that the Finder does on the designated file the same as if the user had clicked on the icon (of a program, of an alias/shortcut or of a data file).
The autostart feature has been available since the release of QuickTime 2.0. Therefore, strictly speaking, this is not a feature of the operating system but of a higher layer.

Feature Inhibition

You should note that numerous users block this feature (this is even a very common suggestion given in Macintosh magazines) because they fear that this could be an open door to viral attacks. Therefore, you should never consider that your autostarting CD-ROM will actually autostart, and you should add in the root folder a read-me file to instruct the user about what to do.

From Which CD-ROM?

The autostart feature only works from a HFS (Hierarchical File System) volume, that is from a real Macintosh volume. That means that you cannot have an ISO 9660 CD-ROM with autostart features for Macintosh (even in the case of an ISO CD-ROM with Apple Extensions).
If you want to implement both autostart features (for the PC and for the Macintosh), you have to produce a hybrid (HFS/ISO 9660) CD-ROM, for instance with our MacImage.

Technical Aspects

Since the effects of the autostart feature are the same as double-clicking on the icon, one should consider two situations: applications and data files.
Macintosh applications can be started this way if they are correctly installed on the medium. In particular, Macintosh application files should have both forks (data and resource fork). See how to install some frequent Macintosh applications. See also our pages on Flash and Director for some information on those applications.
On the other hand, for data files, the signature of the file should be correct. If not, the user will get a dialog box displayed by the Finder, asking for the application which should open the file. The effects on the end-user are of course very, very bad.

Technical References

The first two bytes of the sector 0 of the HFS volume must be set to zero. At offset 106d (0x6A) begins a magical signature 0x006A7068 (big endian!), followed by a Pascal string (length in the first byte, then the bytes forming the string) designating a file which must be in the root folder (it can also be an alias [shortcut] pointing to a file stored deeper in the folder tree). The total length of the Pascal string is 12 bytes. The maximum length of the filename is therefore 11 bytes.
Apple has published a Technical note on this matter.

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