Computers


Computers and D-STAR and Ham Radio28 Jul 2017 07:27 pm

This issue came up at work this week.

I received two phone calls from customers who were having issues with their Raspberry Pi-based D-STAR Hotspot: something was corrupting the microSD card.

One wanted to get the built-in halt/reboot options working, and he eventually did with the help of the image’s site.

The second brought his RPi and laptop in for me to check on, and luckily he was using the same image as me, D-STAR Commander. After I set a new microSD card up for him, I popped it into my laptop, which runs Arch Linux, to do some modifications to /etc/fstab to allow for essentially hot unplugging of power. It involves RAM disks.

The procedure is quite easy and can be done before the RPi is booted up if you have an SD-card reader-equipped Linux machine.

If you’re already booted up on the RPi, connect to it via VNC (or SSH), open the Terminal, and follow the following steps:

1. Type “sudo nano /etc/fstab” and hit Enter.
2. Add the following lines to the file:

tmpfs /tmp tmpfs defaults,noatime,nosuid,size=100m 0 0
tmpfs /var/tmp tmpfs defaults,noatime,nosuid,size=30m 0 0
tmpfs /var/log tmpfs defaults,noatime,nosuid,mode=0755,size=100m 0 0
tmpfs /var/spool/mqueue tmpfs defaults,noatime,nosuid,mode=0700,gid=12,size=30m 0 0

(the last two lines are really one line. you can copy and paste if you need to)

3. Hit Ctrl-X and hit “Y” when prompted to exit and save the file.

Now reboot the RPi if it is running or unmount the microSD card and insert it into the RPi.

What this has done is crate three RAM disks: one 30 MB in size, one 100 MB in size, and one 30 MB in size. The directories listed there often are continually written to, which can be catastrophic if power is removed while the microSD card is being written to. If they are in RAM, they disappear once the power is removed.

This solves the corruption issue with the D-STAR images.

Computers07 Jun 2016 04:08 pm

I spend a fairly large amount of time browsing /r/homelab because I, at one point, had a rudimentary “home lab” set up. It wasn’t anything fancy, mostly because back in 2003 or 2004 server virtualization wasn’t a big thing, as far as I can tell. It was mostly a firewall and single whitebox server with a couple of other desktops or laptops. Certainly not anything to really be super proud of, but it was my local server, so it was cool.

Fast forward a decade or so and I learned that people were buying or building servers to run the free version of VMware ESXi with which they’d build a mini datacenter. I started musing on the feasibility of setting one of these up. At that point, I didn’t really have any suitable hardware, so I shelved the idea temporarily but kept reading /r/homelab because the idea fascinated me.

A former coworker of mine gifted me with a Supermicro X8DTL-iF motherboard last October, and in the time since I replaced the CPUs it had with a pair of Xeon E5620s and upgraded it to 48GB of RAM. Right now the machine runs FreeBSD and serves as little more than a fileserver with two VMs running in bhyve: a VPN-connected downloader, and a CrashPlan host. It serves its purpose but isn’t nearly using all the available resources. Enter my mind. I picked up a IBM ServeRAID M1015 SAS RAID card, crossflashed it to be a LSI 9211-8i SAS HBA, and have the necessary breakout cables on the way, along with 4 SSDs and a mobile rack for those.

The plan is to back up /home from the current FreeBSD install, destroy the ZFS array, and migrate the 6 500GB drives to the LSI controller, attach two of the four SSDs to the LSI controller as well, and attach the other two to the onboard SATA ports, with ESXi booting off a USB drive plugged into the connector on the motherboard. Once this is done, I’ll pass the LSI controller through to a FreeNAS VM like Ben Bryan did. Thanks for the great guide, Ben!

After that’s done, I’ll migrate my ham radio machine along with the aforementioned bhyve VMs to VMware, likely having to rebuild these from scratch, which isn’t a big deal at all, just time consuming.

This should be a ton of fun and give me a good platform to build from as I have 8 hyperthreaded cores and quite a bit of RAM!

Computers and D-STAR and Ham Radio24 Apr 2016 09:08 pm

Hi there! This is a landmark first post in almost four years here on w4jdh.net!

Today we’re diving into the realm of amateur (ham) radio and Linux, specifically how to set Arch Linux up as both an APRS I-Gate and a dual-band D-STAR hotspot using the G4KLX software compiled from source.

Assuming you don’t have Arch installed, take a look at their spectacular Beginners’ Guide. Once you have the machine set up, head back over here.

You will need to add a non-root user to complete this task. Once that’s done, it’s time to do some fun things.

In order to add software you have to be logged in as root, so use that to get the framework built up by inputting the following command on one single line:

# pacman -S git tigervnc sudo openssh wxgtk portaudio libusb webkitgtk webkitgtk2

After this use visudo to add your user to the sudo permissions by adding a line similar to the following:

<user> ALL=(ALL) ALL

which will require password entry to execute the command. If you wish for passwordless sudo change the final “ALL” to “NOPASSWD:ALL”. Once this is complete, log out from root and log into the user account.

The first order of business is to get XASTIR installed for APRS. Issue the following commands to prepare the environment:

git clone https://aur.archlinux.org/libax25/
git clone https://aur.archlinux.org/xastir/
git clone https://github.com/dl5di/OpenDV/

I added the OpenDV github repository to the end there to prepare for the next step.

To complete the installation of XASTIR, type cd libax25 then type makepkg -sri to install the AX.25 library, which is a dependency of XASTIR. After that, type cd ../xastir to enter XASTIR’s folder. Repeat makepkg -sri to install XASTIR.

Now it’s time for D-STAR. If you are still in the “xastir” directory, type cd ../OpenDV/ to enter the OpenDV repository clone. The first piece of this software suite you should install is ircDDBGateway, so type cd ircDDBGateway and follow it up with ./configure && make and sudo make install once it’s finished building. After installation, type cd ../DStarRepeater and repeat ./configure && make and sudo make install.

The OpenDV suite does something a bit odd now with log files and configuration. Both are put with a prefix of /usr/local, so it is necessary to create folders and change ownership. Use sudo su - to become root and execute the following commands:

mkdir /usr/local/etc/opendv
chown <user>:<user> /usr/local/etc/opendv
mkdir /usr/local/var
mkdir /usr/local/var/log
mkdir /usr/local/var/log/opendv
chown <user>:<user> /usr/local/var/log/opendv

This will set appropriate permissions for the installed software. Why the team did this change I have no idea.

With this, it’s time to select a window manager or desktop environment. I personally like the tiling window manager i3, though there are many many choices. A second choice would be LXDE. Both are available in Arch’s repository. I won’t cover installation of these as this is personal preference and covered quite well by the ArchWiki.

My personal recommendation for a relatively inexperienced user is to use LXDE as it resembles Windows in many ways. Use the “Run” command to start ircddbgatewayconfig to configure ircDDBGateway and dstarrepeaterconfig to configure DStarRepeater. If you have more than one DVAP or GMSK Board, you can use the configuration as dstarrepeaterconfig B for example.

Now the base system for D-STAR is built, and you can launch the software. Run ircddbgateway and dstarrepeater however many times you need to, and enjoy D-STAR!

Moving right along to XASTIR. It is far simpler: simply launch xastir from “Run” and configure it. It is reasonably straightforward.

That is it! While it’s not as “easy” as getting a Raspberry Pi image for D-STAR or installing XASTIR from Ubuntu’s repositories, it is very much more fun in my opinion. For one thing, the system is not nearly as heavily laden with “unnecessary” packages, so it needs far less memory to run. Secondly, as it is built from the most recent sources, it will usually have more features than a premade image. Finally, as it’s not a premade image, it will have a (hopefully) unique login and password for the account running the software. This is especially vital if used on any sort of public network, cellular included.

Cellular and Computers and Conventions and Embedded and Networking07 Sep 2012 09:39 pm

Every year I’ve looked at Anime Weekend Atlanta as more than a chance to hang out with friends from out of town because of the rather unique situation having several laptop wielders in the same hotel room can present. Therefore, I come up with all sorts of hair-brained network schemes to get everyone online from the same connection, be it the wired connection in the hotel room or using a Yagi antenna to grab free WiFi from the lobby thru skylights or the floor. Last year’s was probably the most amusing: a Clear WiMax USB card plugged into a Cradlepoint router, connected to a normal wireless router with a Yagi antenna pointed downstairs to con ops where another router with a high-gain vertical antenna received the signal which was then repeated by a fourth router with an even higher-gain vertical. It was as insane as you can imagine!

This year, however, I’ve decided to just be “normal” and scale everything back to a reasonable level: I’ll use my T-Mobile 3.75G card with the aforementioned Cradlepoint for the precious little time I plan to spend in the hotel room.

It’s fortunate, as it saves a lot of room because I won’t be dragging a 16x16x10 or 20x20x12 box with stuff in it with me.

Guess I’m getting old. ;)

Computers and Networking05 Aug 2010 03:30 pm

DEF CON was this past weekend, and in usual fashion, the staff of the convention had projected onto a screen the “Wall of Sheep”: a list of usernames and obfuscated passwords that were transmitted in the clear on the convention’s wireless network. As DEF CON has doubtlessly the most hostile wireless network ever seen, ensuring that all transmissions are conducted in a secure fashion is paramount at this particular convention.

With the proliferation of publicly accessible wireless networks, one must be certain to use caution when checking things such as email. Some email providers have SSL enabled, so that solves that problem, but what about unencrypted web page logins, like forums? How does one secure these?

My solution to secure all traffic uses OpenVPN, a freely available VPN solution that works on pretty much any operating system. I won’t go into excessive detail in this post, but it is actually fairly easy to set up. My first brush with it was when I ran IPCop on my router machine. The OpenVPN add-on for IPCop, ZERINA, generates configuration bundle zip files that make connecting simple. Setting up one from scratch isn’t much more difficult, but it can be time-consuming to set up properly.

OpenVPN works great for a temporary tunnel, but for something more permanent, IPsec is a better choice as it requires less CPU overhead. The configuration of IPsec is beyond the scope of this post, however.

I’ll write a follow-up to this in the next few days explaining my setup, but for now know that if you’re going to be using an open, unencrypted wireless network, be aware that passing cleartext passwords can be a very perilous mistake.

Cellular and Netbooks and Networking and UNIX01 Aug 2010 03:04 pm

Well, I had pfSense working for a wired interface, but once I enabled the wireless interface and a client connected to it, the machine hardlocked. I am not one to be defeated by technology, so I dug out my IPCop install disc and attempted to load that on instead. Sadly IPCop 1.4 does not have support in the installer for the wired connection, so I gave the new beta a try. It works! I had to give the proper INIT string for the aircard and find a working version of WLAN-AP, but once all that was done, I was able to connect both wirelessly and wired.

I am all set to go for the not so distant future!

Cellular and Netbooks and Networking and UNIX30 Jul 2010 03:30 pm

In my last post I talked about building an alternative to Cradlepoint’s routers, and as I’ve decided to use my Dell Mini 10v for my “carry” netbook, I’m looking at what to turn my Eee PC 901 into.

The most obvious choice I’m seeing is loading pfSense on it and using it as a prototype for the embedded router project. It meets the criteria for it: USB ports, a single ethernet port, and a supported wireless card. Having a keyboard and screen is a good benefit for configuring the interfaces.

This will make the transition to the embedded setup easier once I get the pieces for that as the netbook has the same concept as the embedded board, just with more RAM and a faster CPU. One other major boon is a battery for a rudimentary UPS. The 6-cell battery included with the Eee PC 901 offers about 6 hours of run time.

This all hinges on my aircard being supported by the current pfSense 2.0 betas. If it’s not, well, I’ll need to do manual configuration with FreeBSD 8.1-RELEASE. Either way, it should be quite fun!

Cellular and Embedded and Networking and UNIX30 Jun 2010 03:25 pm

A random search of “T-Mobile Rocket Linux” on Google retrieved a post showing how to make the T-Mobile webConnnect Rocket Stick HSPA+ device work in Linux. This is relevant because as of June 17, the Atlanta metro area has HSPA+.

In my adventures with embedded computing, I’ve come across the PC Engines ALIX boards. These are slightly less expensive than Soekris’ and similarly capable. Their alix2d13 board has 3 LAN ports and 2 USB ports. pfSense 2.0 is currently in beta, and as it is based on FreeBSD 8-RELENG (future 8.1), it should have support for my UMG-181.

The article on making the Rocket Stick work in Linux showed its device ID: its device ID also exists in /src/sys/dev/usb/serial/u3g.c in FreeBSD 8-STABLE. As development on FreeBSD 8.1 continues, it may indeed be functional when 8.1-RELEASE is out.

Needless to say, I put a plan together. An alix2d13 equipped with a wireless card, loaded with pfSense 2.0 or similar, and paired with a USB aircard is the same concept of Cradlepoint’s WWAN routers. It also has the flexibility and extensibility of pfSense and the bonus of being open-source.

From the looks of things, the whole setup will run just under $200. I should be able to squeak this into my budget later on this year, maybe.

My tests of T-Mobile’s upgraded network with my UMG-181 have produced results as high as 4Mbps. My home DSL connection is 6Mbps for comparison. I do believe that I will have sufficiently fast access at this year’s hamfests and at conventions for sure. Now to implement this new project.

Computers and Netbooks and UNIX27 May 2010 03:27 pm

In the end, the lack of xorgcfg and the seeming lack of documentation on writing a proper xorg.conf file led me to install Ubuntu Netbook Edition on the Eee. Works like a champ.

Need to get a touchscreen installed now!

Computers and Netbooks and UNIX26 May 2010 03:11 pm

I’ve been doing some work on my Eee PC lately trying to decide which OS to load on it. I had Windows on it for a while and that worked, then I set it aside when I got the Dell Mini 10v and Hackintoshed it. I was going to set the Eee up for one of my parents, but decided that the larger screen and keys on the Mini 10v would be better for them. So I’ve got that as an ongoing to-do project.

My initial idea was to run FreeBSD on my Eee. I ran into a snag when I realized that FreeBSD’s ACPI support isn’t as mature as Linux’s; therefore, I couldn’t hibernate the system. I grew addicted to hibernate on my old Vostro 1400, and it was a serious boon for productivity on trips and during work days. It’s not been as big an issue on my Macbook Pro as its battery life is far superior to the Vostro’s, though.

I had a working X-less FreeBSD install going, and it was time to get X working. Sadly, I was stymied by a lack of documentation on how to get the Eee’s trackpad working in X. Turns out it involves using moused, but I decided in the end that that was a pain, so I tried PC-BSD. It worked, but KDE is fairly slow, and I didn’t relish the thought of using it. The next try was Gentoo, but I’ve not compiled the Linux kernel in a very long time, and I was unable to find a canned config for the latest version of the kernel, so I decided to try FreeBSD once more. The installer failed to download part of the OS, so I was going to try Gentoo once more.

Then as I sat staring at the kernel configuration menu, I looked at the Arch Linux wiki’s article on the Eee 901. After reading Arch’s “Who We Are” blurb, I decided to give it a whirl.

I’m impressed, to say the least. My long-time bias against running a Linux laptop is the userland interface to netfilter, iptables. It goes without saying that iptables is complicated, and while I consider myself a knowledgable person, the fact that it takes 94 lines to do in iptables what took me just under a dozen to do in pf (OpenBSD’s firewall, which has been ported to the other BSDs) really doesn’t set well with me. Fortunately, some sanity has been brought forth. Ubuntu ships with something called ufw, or Uncomplicated Firewall, and its syntax is quite similar to PF’s. Finding ufw in Arch’s respositories further cemented my use of it.

Getting X installed took a scant 5 minutes as opposed to two hours for Gentoo, and installing the base system was very quick. All this using Arch’s cleverly-named package manager “pacman” (how Namco doesn’t sue them I’ll never know). A proper resolutioned framebuffer console with the stock kernel was a nice touch as well.

Tonight’s plot involves getting other software installed then deciding which window manager to use. My “go to” one for years has been WindowMaker, but for a desktop environment I prefer XFCE or GNOME. The new paradigm of tiled window managers is quite interesting, so we shall see.

I’m just glad I have a hard drive in this machine for all this randomness of installing. I will ultimately set up a large-capacity fast SSD in it, but for now, the hard drive works fine. Now to get all the bluetooth/aircard dialing set up. This will be fun stuff indeed!

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