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
Burroughs Point-To-Point Protocol
Envoy Application Programming Manual—427159-001
9-11
READ Procedure
Note that the application process may acknowledge the previous message with an RVI
interrupt sequence instead of the normal ACK by performing an enable RVI control
operation (CONTROL 15) before calling READ.
If the remote gives up its master status by sending an EOT instead of another message,
the READ completes with error 163.
Table 9-10
lists the file-system errors that may occur on a continuation READ.
Initial READ (Line in WRITE State)
An initial READ while the line is in the WRITE state causes Envoy, on behalf of the
application process, to send an EOT sequence to the remote station (Example 9-3). This
is the normal method for terminating a transmission to a remote station. Following
transmission of the EOT sequence, the action taken is the same as that for an initial
READ from the CONTROL state (that is, wait for a line bid from the remote station).
Table 9-10. Continuation READ File-System Errors
Error Numbers Description Resultant Line State
0 No error. A terminal was selected and the
message in the buffer of the application pro-
cess is written to it.
WRITE
161 Impossible event occurred for line state. unknown
162 Operation timed out. A line bid was received
and acknowledged, but no message was
received within the timeout and retry limits.
CONTROL
163 EOT received. An EOT was received while
waiting for the line bid or for the message.
CONTROL
172 Reply not proper for protocol. The data
received while waiting for a line bid or for a
message was not proper for the protocol.
CONTROL
173 Transmission error. Text was received with a
character parity error or block-check charac-
ter error. A NAK was sent, and the message
was retransmitted the number of times speci-
fied by the retry value.
CONTROL
177 Text overrun. Either the data received while
waiting for a line bid exceeds three charac-
ters, or the message received exceeds the
length specified in the read count parameter.
The READ was attempted the number of
times specified by the retry value.
CONTROL