Posts Tagged ‘OSX’

Triple partitioning Mac with OSX and Windows 7

Monday, May 3rd, 2010

If you are configuring your Apple Macintosh to dual boot with Mac OS X and Windows there is a good guide on Apple’s website. However it doesn’t cover certain issues such as how to set up a third partition that can be read and written to by both Mac and Windows. And it doesn’t give help with how much space should be used for each OS.

I recently bought a 2010 MacBook Pro 13 inch, the first time I’ve ever owned a Mac. I wanted to dual boot with Windows 7 Home Premium so I bought that to.

My advice therefore relates to Mac OS X 10.6.3 Snow Leopard and Windows 7, but some of it may be applicable to other versions as well.

When going through the Boot Camp install process I chose to set my Windows 7 partition to 80GB as I wanted plenty of space for installing applications.

boot camp partition screen

After completing the Windows 7 install I booted back into Mac OS X. I loaded up Disk Utility (in Applications / Utilities), selected the Macintosh HD partition and then resized the Mac partition to be 60GB by dragging the lower right corner of the partition. I chose this size to give me a good 100GB shared partition with the 250GB hard drive in my MacBook.

mac os x disk utility

After resizing (which took less than a minute) the hard drive looked like this. You can see there is now a Mac partition, a Windows partition, and a big empty space.

resize mac os x partition

Mac OS X 10.6.3 can shrink the Mac OS partition without destroying any of the drives data. However I can’t tell you if previous versions of Mac OS X support non-destructive partition shrinking.

Once you have shrunk the Mac OS partition you’ll now need to create your shared partition. If you want to be able to read and write to it from both operating systems you’ll need to set the partition type correctly.

Click the plus ‘+’ to add a partition. Set it to be the maximum size for the gap in your hard drive, and set the format to be MS-DOS (FAT). The actual format used will be FAT 32 even though it doesn’t specifically say this.

three partition macbook pro

After you have created your shared partition test it from both Windows and Mac OS by writing a file into it from each operating system, and then checking you can read it from the other.

MacBook Pro three partition summary

In summary you now have three partitions:

  • Macintosh HD – This can be read/written to by Mac OS X. And Windows 7 can read from it. I set it to be 60GB. It is in the Mac HFS format.
  • Shared – Can be read/written to by both Mac OS X and Windows 7. I set it to be 100GB. It is a Fat 32 partition.
  • Bootcamp – Can be read/written to by Windows 7. And Mac OS X can read from it. I set it to be 80GB. This is an NTFS partition.

You can now use the Shared partition to store any data that you want to share between the two operating systems, such as photos, videos, music and documents.

Windows 7 and Mac OS X 10.6.3 install size

In case you are interested in how large each operating system is after install.

If you want to know what the Windows 7 OS is like read my review of using Windows 7 on a MacBook Pro 13 inch.

Upgrading to Lion without losing Bootcamp

I’ve successfully upgraded to Lion without losing my Bootcamp install. I’ve read that a lot of people have had problems as Lion tries to add a recovery partition which can shift your Bootcamp partition up by one. Here is my pre-Lion partition table

   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *250.1 GB   disk0
   1:                        EFI                         209.7 MB   disk0s1
   2:                  Apple_HFS Macintosh HD            61.8 GB    disk0s2
   3:       Microsoft Basic Data SHARED                  101.4 GB   disk0s3
   4:       Microsoft Basic Data BOOTCAMP                86.5 GB    disk0s4

Lion tries to install the recovery partition after the Mac OS X drive (in my case #2) which shifts the Bootcamp partition to #5. You can prevent the recovery partition from being created by first installing Lion on a removable USB hard disk, and then upgrading the Snow Leopard Mac install. I followed the ‘Installing Lion on an external storage device’ and then ‘Install OS X Lion’ steps on Apple’s page.

Remember to back up first!