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
Software Concepts
Envoy Application Programming Manual—427159-001
2-25
Programming Considerations for NonStop™
Himalaya Servers
Example 2-7. Error Handling By Receiver (Page 2 of 2)
Receiver Sender
(expected = 3) |
CALL CONTROL 13 (send EOT) |
| EOT ---> (WRITE completes)
(CONTROL completes) error = 163
error = 0 line state = CONTROL
line state = CONTROL
CALL READ (retransmit last message)
|
| CALL WRITE
| <--- ENQ |
| ACK0 ---> -----
| / | 3 |
| | |-----|
(READ completes) <--- message 3 | | t |
error = 0 (retransmitted) | | e |
line state = READ | | x |
\ | t |
CALL CHECKPOINT -----
|
(expected = 4) |
CALL READ |
| ACK1 ---> (WRITE completes)
| error = 0
| line state = WRITE
|
| CALL WRITE
| |
| -----
| / | 4 |
| | |-----|
(READ completes) <--- message 4 | | t |
error = 0 | | e |
line state = READ | | x |
\ | t |
-----
CALL READ |
| ACK0 ---> (WRITE completes)
|
Note. The expected variable is used to keep track of the sequence of the expected messages.
The variable is not incremented after an application-process failure.