I tend to agree with this notion of not going with the cheapest SBC
possible. Unless you are going to incorporate the PI in a number of
devices (i.e. will be buying multiple units), it makes more sense to
toss in the extra hundred dollars and get a more capable SBC. For one
thing, you need the serial port on the SBC in the event things go wrong
with USB.
Regarding running linux on Arm, I've tried a few distributions. By far,
the easiest to get running is opensuse. However, it seems to be the
least efficient. XFCE is a bit too much for a single core Cortex, and
the ICEWM never starts. It is in the image as an alternate window
manager. Fedora is playing catch up on Arm, but they have the bucks to
ultimately do a fine job.
Probably the most ready to rock and roll is Ubuntu. Having used Opensuse
for well over a decade, I have to say Debian is bizarre and Ubuntu is
cryptic. The lack of a root user account on Debian is a head scratcher,
though you can add one. But the real killer is the package management on
Ubuntu. Aptitude is not Yast. In fact, you are better off using the
package search website that Ubuntu set up than to use Aptitude. Don't
even get me started on Ubuntu environment variable schemes.
Regarding Ubuntu on ARM, here are some real time savers. Once you
install the image on a SD card and boot, do the following:
apt-get update
apt-get upgrade
If you are going to install gcc, do this:
apt-get install build-essential
Otherwise, the compiler is installed but the environment variables are
not. Bizarre to say the least. Without running update and upgrade, when
I tried to install gcc, it suggested I use "pentium-builder". No, really!
A few other packages that are useful:
apt-get install icewm
apt-get install xorg
apt-get install midori
For unknown reasons, the Xterm on Ubuntu doesn't cut and paste properly.
There are hints on the internet about how to make it work like "normal"
linux, but they didn't work for me. However, this terminal works fine
with cut and paste.
apt-get install terminator
When you install it, the program shows up as "terminal" not
"terminator." Go figure.
Many of these Arm SBCs do not have a battery for the RTC. On some, there
is a hook to add a battery. Since most people will have them on a
network, this sort of makes sense. There could also be issues regarding
shipping boards with the battery installed. But it seems NTP will not
set the clock during the installation (first boot). I have no idea why
this is true, but once booted again, NTP runs. I haven't checked it for
accuracy.
There is a hardware bug in the Beagleboard XM, so I would suggest not
buying that SBC. I am trying to patch around it, but a patch is not the
same as designing the hardware correctly.
As I mentioned previously, some of these SBCs depend on the graphic chip
to do the heavy lifting. If you are going to do anything computational
in your own software, get a SBC with a Cortex-A chip. Those chips have
"dsp", actually SIMD:
http://www.arm.com/products/processors/technologies/dsp-simd.php
For software defined radio, this is at least a factor of two faster in
my testing, and often three or four depending on the program.
On 2/12/2013 10:11 AM, Didier Juges wrote:
I've put Apache on opensuse on AMD boxes. It is trivial with Yast. They
even set up a sample webpage.
Before you know it, you are going to find that not having php (or Python, or
Perl, or whatever your favorite scripting language is) is crippling. I
recommend you bite the bullet and get a small ARM SBC big enough to run a full
Linux distro. I use a TS-7553 from embeddedarm.com with great satisfaction for
just things like that.
Didier KO4BB
Sent from my Droid Razr 4G LTE wireless tracker.
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