Re: term & user space console

[Marcus Brinkmann]

Hi,

thanks for your explanations.

An easier question:  devio.c uses the _request and _reply
functions, eg asynchronous I/O, which would work very well in the hurdio
case, too.   However, for hurdio, I think it would work equally well to have a
reader and a writer thread, which do io_select in a loop, and act on it
appropriately.  There must be two threads, because we must always select for
reading, but for writing only if the output is enabled.  So if you resume
output after it has been stopped, the thread might be stuck in a select for
reading, which we can not interrupt.

This has the advantage that it is easier to read and understand, in my eyes,
than the devio code, and it would be synchronous (hi L4 guys ;).  The cost
is two threads, which don't do much.

Assuming both variants do the job, which one is preferred?

> Now, under the transparency principle (1) above, if the underlying
> port is a terminal, it should DTRT.  What do terminals do when carrier
> drops?

That's a good question.  Some terminals seem to return EIO on subsequent
writes.

> Are you clear on the meaning of the DTR and CTS modem bits?

Let's say, I have downloaded a Serial Programming Guide... (and even started
to read it) ;)

Thanks,
Marcus

-- 
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Marcus Brinkmann              GNU    http://www.gnu.org    marcus@gnu.org
Marcus.Brinkmann@ruhr-uni-bochum.de
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