Solution |
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The VPLUS environment control file, VENVCNTL, allows applications to override specific VPLUS defaults.
VPLUS always checks for the existence of VENVCNTL.PUB.SYS or, alternatively, the existence of a file equated to
this formal file designator. If no VENVCNTL file exists, no VPLUS defaults are overridden.
VENVCNTL is a simple text file containing only one line of data.
Each override option may be activated by setting the option byte
number to 1. For example, in the VENVCNTL file below, options 1, 5, and 20 are set.
:print venvcntl
10001000000000000001 |
For MPE V/E, the basic recommendation is either no VENVCNTL file, or, if there are no 264x terminals capable of accessing
the system, a VENVCNTL file with byte 1 set.
For MPE/iX, the basic recommendation is a VENVCNTL file with bytes 1, 5, and 20 set. Since 264x terminals
will not work on MPE/iX, byte 1 should always be set to improve performance.
The table below explains the function and possible side effects
of each VENVCNTL option. Note that many bytes are either diagnostic only
or reserved for future use; these bytes should never be set to 1.
Byte | Explanation | Side Effects / Comments |
|---|
| 1 | VOPENTERM does not try to determine terminal identity if terminal
does not have self-identification capability. | VPLUS will not run on terminalsthat cannot
self-identify (264x terminals). |
| 2 | VPLUS does not lock out terminal Aids/Modes/User
keys during interactions. | User could corrupt terminal configurations
established and expected by VPLUS. |
| 3 | Reserved. | |
| 4 | VPLUS bypasses Modified Data Tag (MDT) feature
of MDT terminals. | MDT terminals will transmit all input field
data, not the subset that user actually keyedin; increases datacomm
and associated processing overhead. |
| 5 | (MPE/iX only) VPLUS strips carriage return
character from terminal status read input. | DO NOT USE this option on MPE V/E; MPE
V/E driver already strips the carriage return characters so this
option is redundant on MPE V/E. |
| 6 | (MPE V/E only) VPLUS extends terminal status
reads to ensure that input termination character is accounted for. | DO NOT ACTIVATE this option unless experiencing
VPLUS "terminal status request failed" errors
due to network delays. |
| 7 | Diagnostic only. | |
| 8 | VPLUS does not force 7009x terminals to 80
columns. | If 7009x terminal is configured for 132 columns,
there is a possibility of data corruption. |
| 9 | VTURNON and VTURNOFF do notreset terminal function keys to default strings. | |
| 10 | (MPE/iX) VPLUS inhibits dual terminator; only
the record separator (instead of either the record separator or the
carriage return) will be recognized as a record terminator. | It will be awkward for user to recover a blockmode
application after a power failure. Also, applications will treat
line feeds as terminators, not as data. |
| 11 | VTURNON does not save 7009x terminal function key configuration
information. | |
| 12 | VOPENTERM does not save and VCLOSETERM does not restore 7009x terminal function configuration
information. | |
| 13 - 18 | Reserved | |
19 | Diagnostic only. | |
| 20 | (MPE/iX only) VPLUS posts pending terminal
driver reconfigurations to overcome timing windows and force synchronization. | |
21 - 29 | Reserved | |
| 30 | VPLUS posts pending terminaldriver reconfigurations
to overcome timing windows and force synchronization in a multi-hop
network environment. | There will be incremental file system overhead
associated with the posting action; this overhead is only necessary
if difficulties are being experienced. |
| 31 | VOPENTERM and VIDTERM do not check JOB/SESSION mode when doing terminal open (available in soon to be
released VPLDV28 (MPE V/E) and VPLEXF7 (MPE/iX) patches). | If executing VPLUS in a job and no valid file
equation to the terminal exists, then job $STDIN file may be corrupted. |
32 - 80 | Reserved | |
