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Re: [Raspberry_Pi_4-Ham_RADIO] Re: framework for self-starting ham application images on Raspberry pi

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  • Kerry McKenzie
    Kristoff and Jim please accept my apologizes for not replying to your post sooner i have it all carefully printed out here and am working through it. I will
    Message 1 of 17 , May 17 3:36 PM
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      Kristoff and Jim
      please accept my apologizes for not replying to your post sooner i have
      it all carefully printed out here and am working through it.
      I will reply properly very shortly (very time poor these last couple of
      weeks)
      However i would like to acknowledge that i have received you information
      and advice and for that i am very grateful for you to take the time out
      and help me out with the pi.
      The positive help i have recieved from the list and a very patient
      friend in Canada has been nothing short of amazing and my downstairs
      radio shack
      has now become a PI emporium!

      Your help is very much appreciated...Kerry


      Kristoff Bonne wrote:
      > Kerry,
      >
      >
      > On 14-05-13 20:03, Kerry McKenzie wrote:
      >
      >> Hi Jim
      >> yes I'm an expert with setups ;-)) and have re burned so many images
      >> from scratch, and have five 8gig cards and five raspberry pies for the
      >> purpose.
      >> I can even compare files between one pi and the next and have 2 monitors
      >> and keyboards etc setup opposite one another so I can compare screens.
      >> So i can get a Pi going no problem there,.. and can ssh or xrdp into it
      >> from all my windoze boxes without a problem. I just cannot use the
      >> bloody things for what i want ie ham radio stuff.
      >>
      >> My web server is current appache and is running in an xp enviroment and
      >> shares the windows fbb bbs.
      >>
      >> I have setup an owncloud headless PI as it was the only prepared image
      >> that i could find on the web,... but cannot see it from the outside
      >> although i have made the ports accessible via my router however i can
      >> http into it from within my network and upload file and create folders
      >> etc, and even setup users.
      >> But it does not exist where i need it on the outside, and because linux
      >> scatters files all over the place makes it very difficult once again to
      >> fault find.
      >>
      > Troubleshooting this kind of issues is pretty easy on linux.
      >
      > Like with any network issue, start with the lowest OSI layers. In this
      > case, layer 3, does the packets arrive on your server.
      >
      > On linux, there is a tool called "tcpdump", which allows you to sniff
      > all the traffic on your network.
      >
      > In this case, do "sudo tcpdump -n -i eth0 port 80"
      > ("-n" means no DNS resolving of names, "-i eth0" is the interface on
      > which you want to sniff", "port 80" is a filter, which means all traffic
      > from/to TCP or UDP port 80).
      >
      > Make a connection from inside your network and you should see the http
      > session.
      > If you try to connect from the outside world and you do not see an
      > incoming tcp session, you know that the traffic probably does not enter
      > your network and you have to look at your router. (if it is a
      > linux-based router -like openwrt of ddwrt- you can also do "tcpdump" on
      > that box, on both interfaces).
      >
      > If the traffic does not come in, you need to look at your pi.
      >
      >
      >
      >
      >> Dont know if you know owncloud at all but it runs the free sql edition
      >> and apache and it is I would imagine just a matter of finding appache
      >> and configuring it to see the outside via my vk4tub.no-ip.org account.
      >> I have a friend in Canada who is also helping with a version of fbb that
      >> he setup for me and I am trying to find my way around that right now as
      >> i have some forwarding issues with it.
      >>
      >
      >
      >
      >> I am having difficulies with the fact that linux scatters files
      >> everywhere and you have to know the paths and where things are kept in
      >> order to fault find problems.
      >>
      > It depends on where the application descides to look for files.
      >
      >
      > Either look at the startup scripts (/etc/init.d/... and
      > /etc/default/...). Sometimes the configuration-files are passed to the
      > application when starting, via a cli. Do "ps auxw | grep
      > name-of-application" if there are no CLI parameters there.
      >
      > There are still other options, like "lsof" ("list of open files") which
      > is a system utility that gives a list of all files that are open by all
      > application.
      >
      > Even more further down is starting the application with "strace" which
      > will start an application but -at the same time- provide a dump of all
      > system calls issues by the application. As a "open file" is a
      > systemcall, you will see see it pop up somewhere (but you need to some
      > tricks to grab the output of strace and be able to search in it).
      > Another trick is using the "proc filesystem", which means that if you go
      > to "/proc/processnumber/ ..." there is a lot of information there like
      > system-parameters, dumps of memory, pointers to all open files, etc.
      >
      >
      > Once you get to know linux; there are really some very powerfull tools
      > which really allow you to look inside application. :-)
      >
      >
      >
      >
      >
      >
      >> None of my books cover this and hence many of my problems stem from the
      >> fact that i want to run radio projects and not games or programming as
      >> this is well covered in all the pie books I have.
      >> I am very disappointed with the fact that these are advertised as
      >> learning tools for school children and one automatically assumes that
      >> they will be a simple thing to use.
      >>
      > As there are some unix application that can have more then 20 years of
      > history, they all have their own way of doing things. :-)
      >
      >
      > Unix has more then 40 years of history and linux is a merge of two
      > different families of unix each with their own history. Plus that unix
      > has a saying "there are usually 10 ways to do something". E.g. linux has
      > at least 4 different audio-systems (which means that every one has its
      > own API), I don't know how much different filesystems; applications can
      > log events via their own system or use the "syslog" deamon process for
      > that, etc.
      >
      >
      > My first experience with this kind of computing was when we ran
      > something called "OS9" on a tandy color computer (not macOS9, but OS9
      > based on the 6809 CPU). There was a book that came with it that really
      > explained how the guys wrote their OS. (I came across that book about a
      > year ago, looking at it now, you could really see that the book was
      > written by the same guys who actually made OS9 themselfs and you could
      > really see the feeling of "pride" when reading it).
      > Anycase, it was a very interesting book because it really explained a
      > lot about what an OS is and what it does: resource management, memory
      > management, CPU management, task management, I/O operations,
      > compilers/linkers/assemblers/debuggers/..., or something like "what does
      > a computer do what it is booted", ...) Later I had unix at school where
      > we learned things like inter-process communication, networking,
      > programming APIs and what have you.
      >
      > You might not strickly need it to run a system, but it does give you a
      > background to know what your computer is doing and why. And it helps you
      > understand that -yes- there are usually 10 ways to get things done. So,
      > if you work on a system with decades of history and applications that
      > even date back to the beginning of the internet; you do expect them all
      > to have their own history and there own way of doing things. :-)
      >
      >
      >
      >
      >
      > 73
      > Kristoff - ON1ARF
      >
      >
      > ------------------------------------
      >
      > (Please trim inclusions from previous messages) Yahoo! Groups Links
      >
      >
      >
      > .
      >
      >


      --
      Kind Regards
      Kerry McKenzie

      PO Box 4492
      Kirwan QLD 4817
      Australia
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