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| Title: | VAX and Alpha VMS |
| Notice: | This is a new VMSnotes, please read note 2.1 |
| Moderator: | VAXAXP::BERNARDO |
|
| Created: | Wed Jan 22 1997 |
| Last Modified: | Fri Jun 06 1997 |
| Last Successful Update: | Fri Jun 06 1997 |
| Number of topics: | 703 |
| Total number of notes: | 3722 |
412.0. "When is the pseudoterminal ready? (How did DECterm solve this)" by HYDRA::NEWMAN (Chuck Newman, 508/467-5499 (DTN 297), MRO1-3/F26) Wed Apr 02 1997 14:51
Cross posted in DECterm # 1868
Quite a while ago, there was a problem with DECterms at creation time.
When the DECterm was created, there was a timing window where the user had to
leave the DECterm alone. If they provided it with input too soon, loginout got
control of it, if I remember correctly.
What did the DECterm folk do to take care of this problem?
The reason I ask is that a software vendor is using pseudoterminals, and the
terminals ignore input for a short amount of time after the terminal is
created. I'm suspecting that their problem is essentially the same thing
that DECterms had.
Any ideas?
-- Chuck Newman
| T.R | Title | User | Personal
Name | Date | Lines |
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| 412.1 | This should help | STAR::KENNEY | | Wed Apr 02 1997 15:39 | 20 |
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The terminal is ready to take input as soon as the call to
PTD$CREATE is completed. If you send any characters to it at that
point and there are no other channels assigned it will kick off a
login sequence. The DECterm problem was it would send data to the
terminal before the process what was going to use that terminal had
assigned any channels to it.
Your problem is probably the cousin to that one. I suspect that
they send data to the terminal but there is no type-ahead buffer yet.
The arrival of this data will start the processing to create the
type-ahead buffer. But any data sent in that burst will be lost. They
need to make sure that the application using the pseudo terminal has
queued a read to it before sending any data. There is a notification
AST that can be enabled to know when a read is ready. I forget the
exact call to do that. Sorry, I wrote that code back in 1989 and do
not remember all the routine name.
Forrest
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