can i run multiple osx operating systems on my mac book pro?

Yes. Your computer's hardware still needs to support the older Mac OS X version(unless it's run in emulation).

(65519)

Which version of OS X did your MBP have when it shipped?

If Lion, no.

If anything older then Lion, then yes.

Create a partition and install Snow Leopard.

Allan

The easiest solution is to partition your drive to provide a second partition on which you can install Snow Leopard. It need not be a large partition because you can still access applications on the other partition.

To resize the drive do the following:

1. Restart the computer and after the chime press and hold down the COMMAND and R keys until the menu screen appears. Alternatively, restart the computer and after the chime press and hold down the OPTION key until the boot manager screen appears. Select the Recovery HD and click on the downward pointing arrow button.

After the main menu appears select Disk Utility and click on the Continue button. Select the hard drive's main entry then click on the Partition tab in the DU main window.

2. 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.

1. Can I have 3 partitions, 1 with just OS 10.6.8, 1 with just OS 10.7.5 and a 3rd with all of my other (non OS) files?

2. How do I create the 3rd partition with no OS on it? That is how do I remove the OS from the 3rd partition which is my "original" drive?

2. Will I have reduced performance running aps from the non-booted drives?

4. How can I back up my entire drive instead of just the partition volumes?

jacbec wrote:

1. Can I have 3 partitions, 1 with just OS 10.6.8, 1 with just OS 10.7.5 and a 3rd with all of my other (non OS) files?

Sure, that's fine. For many years I have used a Mac Pro with four drive bays. One drive has main OS, another drive has test OS, third drive is for media files, fourth drive is for swap/cache. This is one reason the Mac Pro has so many internal drives.

jacbec wrote:

2. How do I create the 3rd partition with no OS on it? That is how do I remove the OS from the 3rd partition which is my "original" drive?

If there was an OS on it already, you can back it up, erase it, and then just copy the non-OS files from the backup. If there was no OS on it already, then just don't install one on it.

jacbec wrote:

2. Will I have reduced performance running aps from the non-booted drives?

Performance is not related to whether a drive is booted or not. It is related to the throughput speed and interfaces of the drives you connected. If your applications are stored on a non-boot drive that is faster than your boot drive and connected by a faster interface than your boot drive, the applications might run faster on the non-boot drive.

jacbec wrote:

4. How can I back up my entire drive instead of just the partition volumes?

You would need to be using backup software that lets you designate that you want multiple volumes backed up in the same job. Otherwise you have to back up each volume manually.