In order to do maintenance on your main Mac hard drive, you may need to boot into the Recovery partition. This partition is hidden from view in Disk Utility, but you can boot into it by restarting your Mac and holding down the Option key. This will show you a list of bootable disks on your machine. (On newer Macs Command + R is supposed to boot directly into the Recovery partition.) Choose the Recovery HD partition and when you boot to that partition you will be shown a short list of utilities. Disk Utility will allow you to perform a Repair Disk on your main Mac hard drive, which you won’t be able to do when booted from that Mac partition. You can also install OS X from the Internet, or restore from a Time Machine backup, if something happened to your Mac OS X installation.
If you have other bootable partitions, such as Boot Camp running Windows, you can choose one of them from the list of bootable disks on a restart, or you can choose one from the Startup Disk system preference when you are running OS X.
We also covered how to control notifications on an iPhone/iPad. Notifications may appear on your lock screen, the notification screen (pulled down like a window shade by swiping down), in a banner at the top of your screen, a badge number on an app icon, and possibly accompanied by a sound. To control which apps give you notifications and how, just go into Settings > Notification Center on your iOS device and scroll down to find an app you want to control. You can choose an alert style (none, banner, or pop-up) as well as whether alerts will appear on the lock screen and/or the notification screen.