The iPad 2 has a message-threading capability, which organizes your emails based on subject; you click an icon to the left of a message header to see the related messages. That adds more clicks to go through messages, but at least finding the messages is substantially easier. (The iPad's iOS 4 lets you disable threading.) The Galaxy Tab 10.1 has no equivalent. Instead, it lets you flag emails, then see all flagged emails via the virtual Starred folder.

Using the basic version of Quickoffice included with the tablet, you can open images on the Galaxy Tab 10.1, as well as PDF and Office files; after tapping the Attachments link, you get a list of attachments and an option to view or save each one. The iPad 2's native Quick Look viewer handles a nice range of formats, and it opens attachments with one tap (downloading them if needed at the same time). Of course, on either device, to edit those files you'll need . The iPad 2 -- still! -- doesn't open Zip files without the aid of a third-party app such as the $1 . For that matter, neither does the Galaxy Tab 10.1, though opening Zip files is a standard capability on Android OS 2.x-based smartphones.

Both the iPad 2 and the Galaxy Tab 10.1 remember the email addresses of senders you reply to, adding them to a database of contacts that's automatically scanned as you tap characters into the To and Cc fields. Both devices let you add email addresses to your contacts list, either by tapping them (on the iPad) or long-tapping them (on the Galaxy Tab).

Both the iPad 2 and the Galaxy Tab 10.1 offer three of the same calendar views: day, week, and month. But only the iPad 2 supports the list (agenda) view. Moving among months is easy on both, as is shifting between weeks on the Galaxy Tab, and both can display multiple calendars simultaneously. The iPad 2 makes it slightly easier to switch through week or month views, thanks to on-screen buttons and sliders, but this is a minor advantage. The two devices also have comparable recurring-event capabilities.

Both the Galaxy Tab 10.1 and the iPad 2 can send invitations to others as you add appointments. But whereas the iPad invitations are sent immediately, the Galaxy Tab invitations take tens of minutes to show up. On the iPad 2, your invitations for Exchange accounts show up in your calendar as a pop-up; you can accept them there within the full context of your other appointments. For both Exchange and other email accounts, you can open the .ics invitation files in Mail, then add them to the calendar of your choice. On the Galaxy Tab, the Calendar app automatically adds Exchange invitations to your calendar with Maybe status, which is not apparent until you open the appointment. You can open Exchange invitations in the Email app, as well as accept or decline the invitation. But you can't open .ics invitations sent to POP or IMAP accounts.