gtpd2m17Data Communications Services Reference

Utility Programs

Aside from the application functions, this package supplies its own form of maintenance and initialization. These functions are system controlled but the user has the ability to request keypointing.

Initialization

The first time the application recovery table (ART) is loaded by GOGO (application core load and restart program), the ART initialization program (ARPI) is activated. Using the information supplied in the ART header (user input via a PILOT), each ART slot is initialized and the indicator set to available in preparation for the online application functions. For reactivation of this program due to restart, if the user has requested no keypointing (SIP input via macro MSGRT: KEYPT=NO) the core table is reinitialized to zeroes as specified above. If keypointing is requested, a maintenance function is activated during the cycle to Norm (ARPC). Each slot in-use is checked for a timeout value (AR0TIM=0). If a timeout value is present, the slot is bypassed so that the tracking can continue using the keypointed timing value. The timeout program (ARPT), to be discussed later, will handle this slot and prevent the possibility of a lost slot due to application error. If there is no timeout, a check is made for the presence of a file address (AR0FAW). If there is no file address or, per user request, the file address is not to be released (AR0SY1=AR0RLSE), the field is zeroed and the slot is returned to the list of available slots. Else the file address and any chains are released by this program prior to zeroing the slot and returning it to the available list.

Timeout

The timeout program (ARPT) will be activated every 5 seconds or at a user specified interval. This is SIP input via macro MSGRT. This program checks the ART slots in-use. If there is no timeout value (AR0TIM=0), the slot is ignored. If a value is found, it is decremented by 1. A zero value at this time causes this program to route the RCPL back to the origin, via CREMC, indicating that this is a returned message (RCPLCTL0=RCPL0RET, for a returned output message and RCPLMSN=RCPL2POS for a possible duplicate input message). The application program will decide on the next course of action. The ART slot may again be located using the 3-byte identifier in the RCPL (Routing Control Parameter List Format, RC0PL).

Keypoint

The Keypoint program (ARPK) is a time initiated utility that is used by the initialization program if the user has specified keypointing. The application may also request keypointing. A bit is provided in each slot (AROSY1=AR0KYPT) which is checked by the keypoint program. If on, the file record which contains this slot is keypointed. Each slot is checked. The keypoint indicator is turned off and, at completion, this program exits.