Subject:
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Re: Call for debugging support
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Newsgroups:
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lugnet.robotics.rcx.legos
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Date:
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Fri, 17 Dec 1999 01:35:26 GMT
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Viewed:
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1357 times
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"Markus L. Noga" wrote:
>
> Hello everyone,
>
> a while ago several people discussed decent debugging facilities for
> legOS, possibly in the form of remote gdb support. Did work in this
> avenue progress to something faintly usable already? If not, what are
> the key problems?
hello Markus, i´m still working on a (hopefully) portable, robust
version of linux LNP, that allows multiple client tasks or threads on
the PC to communicate with one ore more RCX´s simultanously via one
tower, ( one of them could be gdb, in my imagination ).
The key problem here is linux/i386 deficient realtime capability --
scheduling with 100HZ is just a bit too slow to handle LNP at 2400 baud
-- with 4800 baud, it´s worse. I looked at recent versions of rt-linux
and KURT, and think both could do the trick, but i suspect most people
won´t like to patch their kernel for this reason.
I have a running version of 2400 baud LNP (on standard 2.2.13 kernel)
that looks pretty robust, even in severe contention circumstances, but
requires to disable hardware buffering of the uart. This can be done for
mainstream 16550A uarts on linux, but it´s not portable. I don´t like
this implementation too much for another reason: it uses SIGALRM for
keeping track of inter byte timeouts and tower keepalive, and i think a
general purpose library shouldn´t use SIGALRM, if that can be avoided.
My currently favored approach is to use select() for everything, my
tests show it is not affected by the hardware FIFO of the uart. Of
course, this requires to run the select() loop in a separate thread, but
POSIX threads are portable, hopefully. BTW, can anybody tell me if WINxx
supports
select() and/or POSIX threads ?
Unfortunately, currently there´s very little spare time i can spend on
legOS, but after Xmas i´ll have 7 days of vacancy 8-).
bye, Martin
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Message has 3 Replies:
 | | Re: Call for debugging support
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| Sorry to digress, but I just wanted to ask a question: is "equal sign B 4" supposed to be a code for the apostrophe? (They're not translating to apostrophes on my viewer.) How then would you make other symbols? Does this code reference some (...) (25 years ago, 17-Dec-99, to lugnet.robotics.rcx.legos)
| | | Re: Call for debugging support
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| (...) I doubt that's portable (and I'm a little surprised). (...) Only on sockets. (...) Don't be funny! Windows has its own threads, of course. Cheers, Ben. -- SECURE HOSTING AT THE BUNKER! (URL) grandfather once told me that there are two kinds of (...) (25 years ago, 17-Dec-99, to lugnet.robotics.rcx.legos)
| | | Re: Call for debugging support
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| Hello Martin, pthreads and select sound fairly portable. And, as I mentioned before, there's a way of having Windows dispatch asynchronous serial events to programs, so work on porting would be fairly localized. The library approach has one serious (...) (25 years ago, 18-Dec-99, to lugnet.robotics.rcx.legos)
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Message is in Reply To:
| | Call for debugging support
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| Hello everyone, a while ago several people discussed decent debugging facilities for legOS, possibly in the form of remote gdb support. Did work in this avenue progress to something faintly usable already? If not, what are the key problems? Ciao, (...) (25 years ago, 16-Dec-99, to lugnet.robotics.rcx.legos)
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