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 Point-To-Point Protocol
Envoy Application Programming Manual—427159-001
3-25
WRITEREAD Procedure (Limited Conversational
Exchange)
WRITEREAD Procedure (Limited Conversational Exchange)
The WRITEREAD procedure is used for several data communications functions, which
are described in this subsection. The possible completions of this procedure differ
depending upon the state of the Envoy line when the WRITEREAD is issued.
Initial WRITEREAD (Line in CONTROL State)
An initial WRITEREAD (Example 3-8) causes Envoy, on behalf of the application
process, to bid for the line. If the remote station acknowledges the line bid, the message
in the buffer of the application process is transmitted to the remote station. The call to
the WRITEREAD procedure completes when the remote station either returns a
message (which is returned to the application process’s buffer) or acknowledges the
message.
The successful transmission of the initial message is indicated by a condition code of
CCE upon completion of the WRITEREAD. If a message is returned, the count read
parameter at completion is returned as a value greater than zero and the line state is
Table 3-13. Errors on Continuation WRITE With BISYNC Point-to-Point
Error
Number Description
Resultant Line
State
0 No error. Message in the buffer of the application process is
written to the remote station.
WRITE
160 Request is invalid for device state; protocol error. unknown
161 Impossible event occurred for line state. unknown
163 EOT received. An EOT was received while waiting for the
line bid.
CONTROL
165 RVI received. The remote station transmitted a reverse
interrupt sequence as a positive acknowledgment to the
message.
WRITE
166 ENQ in response to message. WRITE
171 No response to the message. Envoy requested a response from
the remote station the number of times specified by the retry
value.
WRITE
172 Reply not proper for protocol. The data received as a response
when the message was transmitted was not proper for the
BISYNC protocol.
WRITE
173 Transmission error. A NAK sequence in response to the text
was received the number of times specified by the retry value.
WRITE
175 Incorrect ACK received. Envoy requested a response from the
remote the number of times specified by the retry value.
WRITE
177 Text overrun. The length of the message received exceeds two
characters. The transmission was attempted the number of
times specified by the retry value.
WRITE