Introduction to TRANSFER Delivery System

Distributing Transactions over a Period of Time The TRANSFER Delivery System
1-6 109426—Introduction to TRANSFER Delivery System
Distributing Transactions over a Period of Time
The exchange of a package between a sender and a recipient is a transaction. In a
typical interactive transaction processing system, an operator starts a transaction at a
terminal and must wait for the transaction to complete before going on to the next
transaction.
Often it is not feasible, however, for a transaction to complete right away. TRANSFER
makes it possible for an operator in San Francisco to start a transaction destined for
London, knowing that the line to London is not currently connected. The operator can
then move on to request another transaction, log off the system, and go home without
waiting for the London transaction to complete.
To satisfy a wide range of business requirements, TRANSFER lets you specify when a
job should be done relative to when the request is made. TRANSFER allows these
options:
■ “Do the work now.” A database update is one example of a transaction that must
occur right away if the company database is to be accurate at all times.
■ “Do the work later.” A request for a long report might be such a transaction. The
operator need not be available during the transaction.
■ “Do the work by 5 p.m. or not at all.” It might be important to cancel a transaction
if it cannot be completed within the current business day.
■ “Do the work after receiving a cue.” If one transaction depends on the completion
of another transaction, one process can send a package that is recognized as a
trigger.
■ “Do the work before doing any lower priority work.” It might be efficient to group
tasks into priority classes, perhaps specifying other criteria like expiration times.
■ “Do the work now or as soon as possible.” An example of this kind of transaction is
a database update for which the destination node is not available. The application
tries to do the transaction online; but when the destination node is unavailable, the
transaction is sent for later processing.
You can combine these criteria. For example, you might specify: “Do the work now, or
as soon as possible, but not after 3 p.m. on March 3.”