[time-nuts] lightweight webserver for, e.g., NTP widget

gary lists at lazygranch.com
Tue Feb 12 19:07:23 UTC 2013


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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