TRANSFER Programming Manual

TRANSFER Asynchronous Requesters (TAREQs)
TRANSFER Application Components
40970 Tandem Computers Incorporated 2–11
TRANSFER Asynchronous
Requesters (TAREQs)
A TAREQ is a collection of SCREEN COBOL programs that handle the actual delivery
of a package to a depot. These programs are supplied by Tandem and run within a
standard PATHWAY TCP. Every node has at least one TAREQ.
A TAREQ requests work assignments from the scheduler and processes one
assignment at a time. TAREQs communicate with the scheduler as though the
scheduler were a group of conversational terminals.
The TAREQs locate the recipients of packages and deliver the packages to local depots
by issuing requests to TISERV. They also arrange for remote deliveries by issuing
requests to the local TWORK processes. (TWORK and the other elements involved in
remote delivery, the TRECV process and the TFRONT pseudoterminals, are described
in the following paragraphs.) To handle a remote delivery, the local TWORK process
establishes connections to the remote TRECV process through a protocol that involves
the remote scheduler and a remote TFRONT pseudoterminal. When the connection to
the remote TRECV is established, the TWORK and TRECV processes cooperate in
copying the package to the remote node and submitting it for delivery on that node, as
illustrated in Figure 2-3.
TAREQs also perform minimal work related to time-staged operations and database
cleanup functions. The TAREQs receive requests for this work from the scheduler and
pass them on to the TWORK server for processing.