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Re: Pi - Windows GUI

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  • John
    LINUX NEWBY NOTE If you are new to Linux as I am you would like to know that ctrl c will break you out of a running process like top . It is also handy to
    Message 1 of 36 , Mar 27, 2013
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      LINUX NEWBY NOTE
      If you are new to Linux as I am you would like to know that "ctrl c" will break you out of a running process like "top". It is also handy to remember that you can start a new bash window process to do a "man top" and find a way out.
      No offense to the poster, we are learning and appreciating!

      de W8CCW John...

      --- In Raspberry_Pi_4-Ham_RADIO@yahoogroups.com, Jeff Francis™ <jeff@...> wrote:
      >
      > On Wed, Mar 27, 2013 at 7:11 AM, Dave B <dave@...> wrote:
      >
      > > **
      > >
      > >
      > > On 27 Mar 2013 at 9:12, Raspberry_Pi_4-Ham_RADIO@yahoogroups.com wrote:
      > >
      > > > __________________________________________________________
      > >
      > > > Re: Pi - Windows GUI
      > > > Posted by: "Jeff Francis¢" jeff@... jeffrey_francis
      > > > Date: Tue Mar 26, 2013 2:18 am ((PDT))
      > >
      > > >
      > > >
      > > > It's not as simple as looking at the percentage of CPU used.
      > > > What's far more valuable is to look at the system load. Type
      > > > 'uptime' at a shell prompt:
      > > >
      > > > jfrancis@pi:~$ uptime
      > > > 22:49:33 up 3 days, 8:18, 1 user, load average: 0.00, 0.19, 0.47
      > > > jfrancis@pi:~$
      > > >
      > > > That's the load on a system that's sitting idle (shows about
      > > > 3-4% CPU utilization). Here's an idle system running X on a virtual
      > > > VNC desktop (with nobody connected to VNC):
      > > >
      > > > jfrancis@pi:~$ uptime
      > > > 22:52:40 up 3 days, 8:21, 1 user, load average: 1.21, 0.60, 0.57
      > > > jfrancis@pi:~$
      > > >
      > > > It's running about 5% CPU, just slightly more than without the
      > > > desktop.
      > > >
      > > > Not that much difference, right? Wrong. Dead wrong. Look at the
      > > > load average. In the first case, it's 0.00. In the second case, it's
      > > > 1.21.
      > >
      > > <Snip>
      > >
      > >
      > > > Run an X server on your big fancy machine
      > > > (there are
      > > > free versions for Mac, Windows, and (obviously) linux). ssh into your
      > > > pi using the -X option and run them that way. You'll get the full
      > > > benefit of the graphical application, but the heavy lifting of running
      > > > the X server falls on your powerful laptop/desktop rather than the pi,
      > > > and leverages that fancy accelerated graphics card you shelled out all
      > > > that cash for.
      > >
      > > <Snip>
      > >
      > > >
      > > > Jeff N0GQ
      > >
      > > Hi Jeff..
      > >
      > > For the rest of us, who are not 'nix guru's, perhaps you'd like to
      > > explain how you got the CPU% from the "uptime" figures. For instance,
      > > just what do the three figures show, in detail?
      > >
      >
      > The easiest way to get CPU percentage is by running 'top'. top also has
      > the added advantage of showing you the breakdown of user, system, etc.
      > 'vmstat' will also give you this information, but it's not presented as
      > pretty. Running as 'top -S -d 1' is probably the most useful. As far as
      > the three load numbers, they represent the average load over the previous
      > one, five, and fifteen minutes (which is useful when diagnosing what's
      > going on). "load" is defined as the average number of processes in the
      > kernel scheduler queue that are ready to run for each tick of the
      > scheduler. There is no "wrong" value here, but higher numbers represent
      > more processes to be run, hence more load and more latency for each
      > application. This number is scaled for the number of cores in your system
      > (ie, 1.0 is "full" for a single core system, 2.0 is "full" for a two core
      > system, etc.). I've seen systems (extremely unhealthy systems) with loads
      > as high as 500. That's bad. As a rule of thumb, when you get over 2.0
      > (for a single core system), most people start noticing a fair bit of
      > sluggishness. Anything under 1.0 is considered "normal use". Anything
      > under 2.0 is still perfectly usable. When you start getting to 3.0,
      > something is wrong/broken/overloaded (note, each of these values is for a
      > single core system - double these numbers for two cores). These are just
      > rules of thumb, and there are certainly use cases where these numbers are
      > wrong.
      >
      > Also pay attention to swap (available either with 'top' or 'vmstat'). If
      > the value of swap is greater than zero, you're paging memory out to disk
      > (or flash). In and of itself, that's not necessarily bad, so long as the
      > swap value is staying the same (ie, something unused got swapped out, and
      > it's staying there). On the other hand, if the swap value is constantly
      > changing (run 'vmstat 1' or watch 'top'), you're pushing your pi pretty
      > hard, and no doubt you're seeing performance problems. Figure out which
      > process is hogging all the ram (if you're running a desktop on a pi, it's
      > likely either X, the window manager, or vnc), and figure out how you want
      > to address it. top will show you how much ram each process is using.
      >
      > Last, but not least, watch your disk I/O. Disk I/O is always a killer,
      > but even more so when you're using an SD card for storage. Disk usage
      > information is available with either vmstat or iostat. Both will show you
      > the number of blocks read and written per second. If you're reading a lot,
      > you're probably going slow. If you're writing a lot, you're probably going
      > *really* slow. SD cards, even the fast ones, are slow media. Figure out
      > what's doing all the reading/writing, and see what you can do to mitigate
      > it. Don't run mysql on a pi. Yes, it will work, but that doesn't mean
      > it's a good idea.
      >
      >
      >
      > > Also, though I know how to SSH to the Pi (and other 'nix boxes) with
      > > tools such as PuTTY (even run it as a sort of crude VPN, forwarding ports
      > > each way when needed) I don't have a clue how you'd run an X
      > > server/terminal on a local (to me) machine and connect it to the (remote)
      > > target. I know it can be done, as many have mentioned it on this and
      > > other lists, but as yet, I've not seen any definitive "how to" showing
      > > what to do, to get that working.
      > >
      >
      > Actually, it's quite easy. If you're on a mac, just fire up your X
      > server (ie, click on the X11 icon). Once running, it will pop up and xterm
      > for you to type in. In that xterm, type 'ssh -X user@...' (replace
      > 'user' with the username on your pi and 10.1.0.10 with the IP address of
      > your pi). Enter your password, and you're logged into the pi. Now when
      > you run an application (type 'emacs' if you have that installed) it will
      > graphically display on your mac. If you're logging in from a
      > linux/freebsd/whatever box, open the terminal of your choice (xterm, eterm,
      > whatever) and do the same thing. I don't own a Windows machine, but the
      > process is exactly the same (other than Windows doesn't come with an X
      > server). Fire up your X server, ssh -X into the pi, and type the name of
      > your application. Do a google search for "free windows X server" or some
      > such. I've used cygwin in the past, and it worked just fine.
      >
      >
      > >
      > > Please don't say "read the man pages"... They are c**p for anyone trying
      > > to learn this stuff from scratch, but are very good as a reminder if you
      > > once knew it all and just need a push back in the right direction. Also,
      > > though they often give nausiating detail as to what a tool or funcion
      > > does, they don't actually tell you HOW to use it, and why you'd want or
      > > need to use it.
      > >
      >
      > Buy a generic linux book. Or read generic linux tutorials on the web.
      > The pi is nothing more than a standard linux box, just smaller. It runs
      > debian linux, probably the most common linux on the planet. Anything you
      > learn about standard linux applies to the pi. No need to go buy special pi
      > books.
      >
      >
      >
      > >
      > > Lastly, though all the above is presumably written down somwhwere, it's
      > > rarely if ever in one place, and we all have other lives, jobs, family
      > > etc that have a priority setting way above fiddling with radios and Pi's
      > > etc. At least I'm told that by domestic management... Whatever, there
      > > is little time to do hard reaseach to find out for ourselves first hand,
      > > but if we were "educated" by someone who already knows, perhaps we could
      > > contribute something more, and sooner.
      > >
      > > In particular, some things "Not" to do, and importantly "why" not, is
      > > good to know too. As I wish I knew some of those in the past before
      > > making a time consuming (to correct the issue) mistake resulting in more
      > > than one project being abandoned due to lack of time... That is why for
      > > now, my Pi and it's accessories are in a box on the shelf. I just don't
      > > have the time to figure stuff out from the ground up these days. I know
      > > from talking to many others, they are in much the same boat too.
      > >
      > > Cheers.
      > >
      > > Dave G0WBX.
      > >
      > >
      > >
      >
      >
      >
      > --
      > -=jeff=-
      >
    • Jim Thisdale
      Web-server is up most of the time, NOT 100%.... The URL is correct. If you want to see my repeater dashboard it is:
      Message 36 of 36 , Apr 11 12:45 PM
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        Web-server is up most of the time, NOT 100%.... The URL is correct.

        If you want to see my repeater dashboard it is: http://n1jmm.no-ip.org:81/ircddbgateway.php

        Only 2 of my web-servers are open to internet

        -Jim- N1JMM, KB1YPL_B
        Visit my Pi running ircddb, dvrptr, Apache & many other things:
        http://n1jmm.no-ip.org

        On 3/23/13 10:13 PM, John Ferrell wrote:
        > I cannot get to your website with Explorer 10.
        > A little guidance please???
        > On 3/23/2013 2:36 PM, Jim Thisdale wrote:
        >> -Jim- N1JMM, KB1YPL_B
        >> Visit my Pi running ircddb, dvrptr, Apache & many other things:
        >> http://n1jmm.no-ip.org
        >
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