Re: [Raspberry_Pi_4-Ham_RADIO] Re: framework for self-starting ham application images on Raspberry pi
- 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
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
has now become a PI emporium!
Your help is very much appreciated...Kerry
Kristoff Bonne wrote:
> 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
>> 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
> 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
> 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. :-)
> Kristoff - ON1ARF
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