Tripple Boot: Snow Leopard, Mountain Lion and Windows 7 - How to?

[MacPro99]

Dear Mac Community,

I am currently running my Snow Leopard as main OS and have a Windows 7 partition created via bootcamp. This is all happening on my MacBookPro early 2011.

Since I need my computer I would like to create a new partition and install the new Mountain Lion OS on it, in order to explore the new functions first before migrating from Snow Leopard to Mountain Lion.

Previously I installed Lion in an external HDD and booted from there. It worked but the performance was not as good. Therefore I would like to install it Mountain Lion onto my main HDD.

There is not really to much information on how this can be done and in which order or if it is actually possible with the new Mountain Lion.

Thank you all in advance for your support....

Have a good day,
Thanks...

 

[elimqiu]

I think 3 OS's installation should be simple, but what boot loader/manage will work in such case?

 

[dusk007]

Sure it can be done and it is ever bit as simple as one would guess.
Just make a new partition available and install on it.
I have my default MacSSD partition for OSX.
An a clone on a smaller HDD partition both inside. That one is bootable and works out just fine.
I got 4 partitions with 2 on the SSD and 2 on the HDD both internal.

The easiest way imo is to download some older CarbonCopyCloner version. Create the new partition with diskutility and clone your OS on there.

Boot with option boot into that new partition and run an upgrade or a clean install. I don't remember what you can select during the installation process. The upgrade is easy to work with and try but for best performance a clean install might be better.
That is imo the idiot proof way. Generally all you need is make a free big enough HFS+ partition and put the new OS on there. You can option boot all the time and it should work (although that sometimes breaks) to select the default startup disk from any OS.
Just give the partition recognizable names. Most people just leave it at MacIntosh HD but that is stupid if you have two of those. There are no more hints and it gets a guessing game which one is which .
I called mine MacSSD(OSX), WinSSD(bootcamp), MacHDD(OSX clone), Data(exFAT).
You can call those anyway you want it breaks nothing.