Which format of partition should be choosen to install OS 10.4.11 on a new partition of an internal HD using 10.6.8 on an intel core 2 duo?

Format it Mac OS Extended, Journaled.

If you completely repartition the drive, then you will lose everything. If you shrink the existing partition and add a new partition in the freed space, then you should not lose anything. But you should backup anyway.

To resize the drive do the following:

1. Open Disk Utility and select the drive entry (mfgr.'s ID and size) from the left side list.

2. Click on the Partition tab in the DU main window. You should see the graphical sizing window showing the existing partitions. A portion may appear as a blue rectangle representing the used space on a partition.

3. In the lower right corner of the sizing rectangle for each partition is a resizing gadget. Select it with the mouse and move the bottom of the rectangle upwards until you have reduced the existing partition enough to create the desired new volume's size. The space below the resized partition will appear gray. Click on the Apply button and wait until the process has completed. (Note: You can only make a partition smaller in order to create new free space.)

4. Click on the [+] button below the sizing window to add a new partition in the gray space you freed up. Give the new volume a name, if you wish, then click on the Apply button. Wait until the process has completed.

You should now have a new volume on the drive.

It would be wise to have a backup of your current system as resizing is not necessarily free of risk for data loss. Your drive must have sufficient contiguous free space for this process to work.

Did your Mac come with Tiger, 10.4.x? If not, and you have retail copy of Tiger, it won't work. The retail version is PowerPC only.

Let's have the model ID and Processor. >About this Mac>More Info>Hardware Overview

If you have a MBP that originally had the Intel version of Tiger, then it came only on the discs distributed with the computer when it was new. No public release of Tiger will work regardless of version. You can install the public release of Leopard which does install both versions.

10.3.x definitely will not run on an Intel Mac. Tiger will only work if the Mac came with an Intel version of 10.4.x on the gray bundled disks.

What version of Pro Tools do you currently have?

I once was able to install the Intel version of Tiger into VMWare Fusion 2.0 and it worked running in Lion. I abandoned the project, as the need for it soon evaporated.

I got the ideas from this blog:

http://blog.michael.kuron-germany.de/2011/09/running-mac-os-x-10-4-10-5-10-6-and -10-7-in-vmware-fusion-4-0/

Even though the article claims Tiger can run in VMWare Fusion 4.0, I was never able to get it to work in v4.0.

I was in communications with the author and he admitted that he was using v2.0 when he installed Tiger and I replicated his success.