OS X El Capitan: The Missing Manual

Data Synchronization

iCloud began life as a synchronization service. It can keep your calendar, address book, reminders, notes, bookmarks, and documents updated and identical on all your gadgets: Mac, PC, iPhone, iPad, iPod Touch. Also your web passwords and credit card numbers. And all your photos, too, rounded up from all your Apple gadgets.

It’s a huge convenience—almost magical. It’s one of the great payoffs of living within Apple’s ecosystem of gadgets. It offers both a huge convenience factor—all your stuff is always on all your gadgets—and a safety/backup factor, since you have duplicates everywhere.

It works by storing the master copies of your stuff—email, notes, contacts, calendars, web bookmarks, and documents—on the web. (Or “in the cloud,” as the product managers would say.)

Whenever your Macs, PCs, or i-gadgets are online—over Wi-Fi or cellular—they connect to the mother ship and update themselves. Edit an address on your iPhone, and shortly thereafter you’ll find the same change in Contacts (on your Mac) and Outlook (on your PC). Send an email reply from your PC at the office, and you’ll find it in your Sent Mail folder on the Mac at apple. Add a web bookmark anywhere and find it everywhere else. Edit a spreadsheet in Numbers on your iPad and find the same numbers updated on your Mac.

UP TO SPEED: The Price of Free

A free iCloud account gives you 5 gigabytes of online storage. That may not sound like much, especially when you consider how big some music, photo, and video ...