Pretty useful trick in Adobe Photoshop, where we will change the setting for showing dimensions in pixels instead of centimetres while making selections.
If you want to make a clean install of the new OS X Mavericks or even the older versions of Mac OS X, than I strongly suggest you to create a bootable OS X key or a drive.
If you find yourself in a situation when you need to list your Mac specs or you just want know if you really got what you paid for, this is how you find them out.