(1) To remotely access objects at the instance level.
(2) To make a device a logical part of a network.
(3) In z/OS, to create a task that can execute concurrently with the attaching code.
(4) In Notes, to store a file with a document or form. The file, or attachment, is stored with the document or form in the database until one of them is deleted.
(5) In Sametime, to include a file on the whiteboard when scheduling a meeting or during a meeting.