TRANSFER Installation and Management Guide

TRANSFER Concepts
Introduction
1–2 13198 Tandem Computers Incorporated
TRANSFER Concepts The following paragraphs briefly review the concepts basic to the TRANSFER
environment.
TRANSFER delivers information from a sender to one or more recipients. Senders and
recipients of information are called correspondents. A correspondent can be a person,
an input or output device, or a process. Local correspondents are those at the same
node or system; remote correspondents are those at other nodes in the network.
TRANSFER collects information in units called items. A correspondent can group
items into a package, which is defined by the TRANSFER application the
correspondent is using. The correspondent then sends the package for delivery to
specified recipients.
Packages TRANSFER builds a package when a user creates a package header item and makes
separate requests to add recipients, data, component items, and delivery parameters.
Only the correspondent who creates the package header item can modify the package.
After a package is sent, not even the creator of the package can modify it.
The package header item is like the label on an actual package that you mail. This
header indicates who is sending the package and to whom, when the package was
sent, what its delivery priority is, and what the component items are.
If a package has component items, the component items can include any type of data.
When the components of a package include a package header item, the result is a
package nested in another package. If an item in a package references other items,
those second-level items are not listed in the package header.
Figure 1-1 shows a package that contains:
A header item, Item ID 412
Two component items:
Item ID 8, which contains two second-level component items:
Item ID 744 (ASCII text)
Item ID 106 (binary data)
Item ID 93, a package containing Item ID 5, a component item of data
This package does not contain any external objects.