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The Question is:
I have a detached proccess that needs to read raw data from a LAT port
if I set the terminal to /PASTHRU I lose characters.
If I use /PASSALL I don't lose any.
IF /PASSALL is an obsolete setting for a terminal what are the equivalent
/PASTHRU does not function the same as /PASSALL. ?
The Answer is :
/PASSALL is obsolete. /PASTHRU is very similar, save the flow control
characters ^S and ^Q are processed by the terminal driver. With /PASTHRU,
the interpretation of ^S and ^Q is determined by TTSYNC and HOSTSYNC.
So, /PASTHRU/NOTTSYNC/NOHOSTSYNC means all characters are passed as
binary characters in both directions. /PASTHRU/HOSTSYNC/TTSYNC will
receive all characters except flow control which will work in both
directions. Note that the default behaviour and the default setting
for processing flow control is /TTSYNC/NOHOSTSYNC.
Data loss (obviously) indicates a mismatch between the input data stream
and the ability of the program to read input. If the sender understands
flow control, /HOSTSYNC may help. If not, you may want to consider
increasing the size of the typeahead buffer (SYSGEN parameter
TTY_TYPAHDSZ or enabling ALTYPAHEAD and TTY_ALTYPAHD), and/or
multibuffering using asynchronous $QIOs, and/or the implementation of
software flow control (or hardware flow control, if the controllers
permit it).
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