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 Multipoint Tributary Protocol
Envoy Application Programming Manual—427159-001
5-27
WRITEREAD Procedure (Conversational Exchange)
WRITEREAD Procedure (Conversational Exchange)
The effect of the WRITEREAD procedure always depends on the current state of the
line, and sometimes depends on the last state of the line.
Initial WRITEREAD (Line in CONTROL State)
This operation is not permitted.
Continuation WRITEREAD (Line in WRITE State)
A continuation WRITEREAD (Example 5-9) causes Envoy, on behalf of the application
process, to send the message in the buffer of the application process to the supervisor
station. At that point, Envoy waits for a positive acknowledgment or a conversational
reply. The call to the WRITEREAD procedure then completes when the supervisor
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 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 zero, and the line state is WRITE.
165 RVI received. The tributary transmitted a reverse
interrupt sequence as a positive acknowledgment.
WRITE
166 ENQ in response to message. WRITE
171 No response to selection. The selection was
attempted the number of times specified by the retry
value.
WRITE
172 Reply not proper for protocol. The data received dur-
ing selection or when the message was transmitted
was not proper for the BISYNC protocol.
WRITE
173 Transmission error. A NAK sequence in response to
the text has been received the number of times speci-
fied by the retry value
WRITE
175 Incorrect ACK received. The ACK received was out
of sequence with the expected ACK value.
WRITE
177 Text overrun. The length of the response received
exceeds two characters. The transmission was
attempted the number of times specified by the retry
value.
CONTROL
Table 5-11. Continuation WRITE File-System Errors (page 2 of 2)
Error State Description Resultant Line State