Vote for virtualization

In this election year, there is an issue facing Macintosh developers. Ask yourself the following:

How can you develop new products for Leopard when you need to have Tiger installed for supporting your legacy applications? How easy is it to test a new feature on Mac OS X 10.4.11 when you’re running 10.5? How quickly can you reproduce a bug on 10.4.10 if you’re running 10.4.11? Can you run Xcode versions 3.0 and 3.1 at the same time from /Developer?

We all know the way to get Apple’s attention regarding our issues is to submit bugs. So now is the time to vote for virtualization. If you agree with the following, please copy and paste this bug report and submit it so that it becomes a duplicate of Bug ID# 5812840.


A Macintosh developer’s ability to produce world-class products is inhibited by the lack of desktop virtualization.

Steps to Reproduce:

  1. Create a virtual machine using VMware or Parallels on your desktop.
  2. Try to install Mac OS X on this virtual machine.

Expected Results:

You should be able to install and run any version of Mac OS X on this virtual machine as long as the host is a Macintosh.

Actual Results:

The installation does not work.


This ability has never existed, but ever since the arrival of virtual machines in Mac OS X, developers have dreamt of being able to do this.


The ability to run multiple versions of Mac OS X has many benefits for a Macintosh developer and for Apple:

  • Being able to run any version of Mac OS X in a virtual machine makes it much easier for a developer to create features for both older and newer versions of the operating system. Many developers need to support their existing applications on the current platform, while at the same time developing new applications for an upcoming version of Mac OS X. For example, developers would like to have virtual machines that would allow Tiger and Leopard to run at the same time. The benefit to Apple is that there will be many more applications available at each new OS launch because the barriers to developing on that new OS are much lower.
  • Developers constantly need to test their products on various versions of Mac OS X. If a customer reports a problem on 10.4.11 and the developer is running 10.5.2, there is a significant amount of effort required to bring up a system that allows investigation. The result is that many problems are ignored or deferred. With virtualization these barriers are removed and fixing bugs becomes much easier. The benefit to Apple is higher quality software for the Macintosh platform.
  • Apple often releases beta versions of development tools that are not compatible with older versions. One such example is the current Xcode 3.1 release—it cannot be run simultaneously with the 3.0 release. This creates a situation where a developer working on iPhone applications cannot work on their current Macintosh applications at the same time. Again, developer productivity suffers and the availability of products for both of Apple’s platforms is affected.

Virtualization is currently being made available for the Mac OS X Server product. We respectfully ask that Apple make the same features available in the desktop version of the operating system.

Update: Several people have written to inform me that you can run Xcode 3.0 and 3.1 side-by-side. While this is true, I have heard that there are some problems. We all appreciate the excellent job the developers at Apple do with Xcode and the other fine tools we work with, but there will always be growing pains as these tools advance. Virtualization would lessen the impact of change on our development environments.