Envoy Application Programming Manual
Table Of Contents
- What’s New in This Manual
- About This Manual
- 1 Application Programming With Envoy
- 7 ADM-2 Multipoint Supervisor Protocol
- 8 TINET Multipoint Supervisor Protocol
- 9 Burroughs Point-To-Point Protocol
- 10 Asynchronous Line Supervisor Protocol
- A ASCII Character Set
- B ASCII to EBCDIC Code Conversion
- C File-System Procedures
- D Statistics Messages
- E S-Series Changes to Envoy
- NonStop™ Himalaya S-Series Server Architecture
- G-Series Migration Considerations
- CBSENSEON and CFSENSEON Modifiers
- LEOTRESYN and NOLEOTRESYN Modifiers
- Treatment of Characters After the Termination Character
- Number of SYN Characters
- DTR Drop
- Reporting of Parity Error
- Half-Duplex Support for Asynchronous Lines
- Controller Replacement
- SYSGEN and COUP
- Unit Numbers
- FDX Line Changes
- No Support for Auto-Call Unit
- Glossary
- Index
BISYNC Centralized Multipoint Supervisor Protocol
Envoy Application Programming Manual—427159-001
4-34
CONTROL Procedure (Send EOT)
Continuation WRITEREAD (Line in READ State and Last State is
READ)
This operation is not permitted for limited conversational mode according to the
BISYNC protocol. A second call to WRITEREAD while the line is in the READ state
would be an attempt to acknowledge two consecutive messages with messages.
A call to WRITEREAD, if the line is in the READ state and the last state is READ,
completes with a condition code of CCL and an error 160 (request is invalid for device
state; protocol error).
Continuation WRITEREAD (Line in WRITE State)
A WRITEREAD while the line is in the WRITE state is a continuation WRITEREAD.
It is used to acknowledge a message from the tributary by returning a message instead of
the normal acknowledgment. A continuation WRITEREAD causes Envoy, on behalf of
the application process, to send the message in the buffer of the application process to
the tributary. The call to the WRITEREAD procedure completes when the tributary
either returns a reply message to the buffer of the application process or acknowledges
the message with a normal ACK0 or ACK1.
The successful transmission of a continuation message is indicated by a condition code
of CCE upon completion of the WRITEREAD. If the supervisor returns a reply
message, the count read parameter at completion is returned as a value greater than zero
and the line state is READ. If only an acknowledgment is received, the count read
parameter is returned with a value of two, and the line state is WRITE.
The file-system errors for a continuation WRITEREAD are the same as the errors for a
continuation WRITE.
CONTROL Procedure (Send EOT)
The EOT sequence is used prior to relinquishing line control at the end of a transmission
or to reset the line following a READ error. EOT is sent by calling the CONTROL
procedure and specifying operation 13 (Example 4-13).
Example 4-13. CONTROL Procedure (Send EOT)
CALL CONTROL (fnum,13)
| EOT -->
(CONTROL completes)
error = 0
line state = CONTROL