Running Ubuntu 15.04 (and up) on a non-PAE cpu

Ubuntu stopped support for non-PAE systems with release 12.04.

But it isn’t that complicated to get an actual ubuntu run on a non-PAE system: Just compile the kernel yourself. So you have to install build-essential linux-source and kernel-package, then extract the kernel source inside /usr/src.

 

Update 2017-03-12

I did create a packer file that does everything needed to setup the a virtual machine patches kernel config and compile the kernel inside it, see https://github.com/pfichtner/non-pae-kernel-compiler

 

After that cd into the linux-source directory and call make menuconfig.

Navigate to “Processor type and features” -> “High memory support” and switch it off, now “PAE” should be deseleted.

Exit menuconfig and run “make-kpkg -j 4 –initrd –append-to-version=-non-pae kernel-image”. This will take some time. After that you can install the resulting kernel deb package (which can be found in /usr/src” by calling “dpkg -i ” on the non-pae system.

Of course there is the problem on how to run the installer on an non-pae system. Two possible solutions:

  • Start the installation with an old ubuntu version, install the non-pae kernel and update the system to the actual ubuntu version
  • take a look at debootstrap (install the whole non-pae system in a directory of another linux system and copy it after that to the target machine)
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Of tomatos, arduino, mqtt and USB

What have all the things in common? Nothing but the involvement in my current project.  🙂

The trigger was that I wanted to have an automated watering system for my plants. Yes, there are existing projects like garduino or gardenbot. Their targets are a little bit more for inhouse use and my plants shouldn’t get watered during times with high solar radiation. So I wanted to collect some sensors data first over couple of days mainly those of the LDR (light dependent resistor). But how to do that?

Continue reading

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Arduino ISP breadboard adapter

You can easily build an ISP adapter for your breadboard based on angle plug.

IMG_5461

Use an ISP adapter with angle plug

IMG_5465

Bend all pins to be straight

IMG_5470

Bend the longer ones directly where they leave the plug. Plug this one into your breadboard…

IMG_5473

…to see where you have to bend the other 90 degree angle

IMG_5475

Added a piece of a PCB to adjust different levels

IMG_5478

The finished ISP breadboard adapter

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Linux live CD with SSH (sshd) enabled

Since grml (https://grml.org/) provides the possibility to pass a command line parameter (ssh=<password>) to start the sshd inside the live system it’s the perfect base for creating an ssh-enabled-live-usb-system.

  • Download your flavour (i586/amd64, the grml-small suites our needs) of grml (https://grml.org/)
  • Install it on your usb stick (see http://wiki.grml.org/doku.php?id=usb)
  • Edit boot/syslinux/grml32_small_default.cfg and append “hostname=sshd ssh=Start123” to the line starting with “append”
  • Boot the machine with the stick after some amount of time you can connect using “ssh root@sshd” (you can decrease the 30 seconds timeout in the bootscreen by editing boot/syslinux/syslinux.cfg)

If you prefer ssh keys over passwords take a look at http://blog.grml.org/archives/367-Create-a-Grml-ISO-image-with-your-own-ssh-keys-for-password-less-login.html

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How to turn a PXE-incapable into a PXE booting computer for under €4.00

I wanted to start a computer using PXE which was not capable booting over the network (PXE). This computer also could not boot USB so my only alternatives were:

  • Put the PXE loader on a floppy and booting that — Hey! It’s 2014! What the hell is a floppy!?
  • Put the PXE loader on a CD and booting that — not much better than the floppy (… and increased power consumption while operating)
  • Put the PXE loader on a HDD and booting that — put, a HDD xx MB/GB HDD for loading a 1 MB boot image!? (… and increased power consumption while operating)

But wait! If we can boot from HDD we can boot from IDE! So let’s consider what we can boot instead of a HDD.

One of the cheapest solutions I found (and this is definite cheap enough) was buying an IDE CF card adapter and a tiny CF card (I got a 8 MB card). The adapter was incl. P&P just 1,26€ the card itself 1€ +1,50€ P+P so it was under 4€ is sum. I dumped ipxe.iso from rom-o-matic (https://rom-o-matic.eu/) using dd onto the card. Then I was able to boot the PC from that “IDE drive”, it loaded the pxe loader and voila: It did PXE. 🙂

So using this solution you can boot any PC using PXE no matter what BIOS (with or w/o PXE-support) not matter what NIC you are using as long your BIOS can boot from an IDE device and your NIC us supported by iPXE (is there any unsupported NIC!?)

 

IMG_20140827_190813 IMG_20140827_190846 IMG_20140827_193009

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Shutting down mythtv slaves while master backend keeps running

It took me several attempts to get it work: I have already have a 24/7 running server. This server should become the master backend so it can server videos, music, etc. but because my old PCI card are incompatible with the new hardware I still have to operate another machine (the old backend) which domiciled the DVB capture cards. This machine now should act as slave backend which should be controlled by the master backend (woken up and shutdown). Continue reading

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Create virtual machines (e.g. vagrant base box)

http://packer.io

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