User`s guide

3: BSC 3270 DLI Functions
DC 900-1340I 65
Note that with the safe store option enabled, the client application program must send
an acceptance (safe store acknowledge) or rejection (EOT) after every complete mes-
sage is received. Otherwise, normal data communication on the line is suspended.
If the last block of a received message contains a parity or block check error, BSC trans-
mits a NAK response as it would with any other block containing an error.
An unsuccessful Safe Store Acknowledge command can return one of the following
error codes in the
dlRead pOptArgs.iICPStatus field (see Appendix D for error handling):
DLI_ICP_ERR_BAD_MODE
The function request is not available for the requested
access mode.
DLI_ICP_ERR_MODE_NOT_SAFE
The client issues a Send EOT command when BSC is
not expecting one, or an EOT is received from the
remote station (forward abort) before the client sends
the message acceptance/rejection.
DLI_ICP_ERR_XMIT_ABORTED
The remote computer (or BSC) sent EOT. The mes-
sage is discarded.
Safe Store on BSC 3270 Control Stations
If the client application program fails to send an acceptance (safe store acknowledge) or
rejection (EOT) immediately after reading the message, BSC 3270 sends WACK on the
line until a client response is received. The WACKs are transmitted at intervals of one
second less than the configured reply timer length in order to keep the line “active”
while waiting for a client response.
When a control station expects a Safe Store Acknowledge command, the client must
send the command (or EOT) before the link can continue its polling sequence. This is
true even after the remote computer has cancelled the transmission by sending EOT.