Similarly, Apple recommends having at least 8GB of free space on your Mac's drive, but I recommend playing it
safe by aiming for 15GB or more--the Mountain Lion installer itself is over 4GB and you'll need some room for
temporary files. You may also find, especially if you're upgrading from Snow Leopard, that some of Mountain Lion's
features require more "everyday" free space, as is the case in Lion. If you need to free up space on your drive,
you can use a utility such as WhatSize
or GrandPerspective to help you find big files you can get rid of; and we recently provided some specific suggestions
for freeing up drive space.
Not sure which Mac you own or how much RAM or free drive space it has? Choose About This Mac from the Apple
Menu, and then click More Info. In Lion, the resulting window displays your computer model and year/version; click
the Storage tab to view your drive's free space, and click Memory to check its RAM amount. In Snow Leopard, you get
a System Profiler window--select Memory to check the RAM amount; select Serial-ATA, and then select your drive's
name on the right, to see your free drive space.
Unfortunately, Snow Leopard's System Profiler window doesn't display your Mac's actual model year/version. What
it will show you, in the Hardware Overview screen--click Hardware on the left--is a Model Identifier, which
consists of a Mac name and two numbers separated by a comma. For example, my Mid 2010 iMac's model identifier is
iMac11,3. You can then use the excellent Mactracker (Mac App Store link) to find your official Mac model
name: Just launch the app, click All Models on the left, and then type your Mac's model identifier in the search
field at the bottom of the Mactracker window; the list of Mac models will be filtered to display just yours.
The requirement that your Mac be running OS X 10.6.8 or any version of OS X 10.7 is also important. The main
reason for this restriction is that, like Lion, Mountain Lion will be available only via the Mac App Store--the Mac
App Store requires Mac OS X 10.6.6, and OS X 10.6.8 provides a number of enhancements that make upgrades to 10.7 or
10.8 go more smoothly. In addition, Apple recommends that you install the very latest updates to Snow Leopard or
Lion before upgrading to Mountain Lion, so be sure to check Software Update for any available updates. (See "Pre-install