LinuxCNC on rescued SBC-Might work, might not.

Used to work a job as a low-voltage installer/system integrator, and picked up a lot of junk during that time. One of the things was a small single board computer made by IEI electronics. The system that used these used a compact flash card for the OS, the cards died regularly and the manufacturer would always just send a complete SBC and all to replace it. I have had several of these things over the years.

It's an IEI Wafer-800LX, running an AMD Geode LX processor. PC/104 form factor, 500mHz processor and 512mb of DDR2-400mhz Ram.

Has RS-422, RS-485, and parallel port on board, as well as a full PC/104 interface, four USB ports, and dual LAN ports. Can directly drive both TFT and LVDS LCD panels, as well as having a VGA output. Has two SATA ports and raid capable controller, and runs linux quite well-I have several of these systems running linux as radio control units mounted 100's of feet in the air for amateur radio stuff.

But I have no idea if the latency will be low enough to run LinuxCNC, even if I were to run relatively slow stepping speeds. Plan is to try using this to drive some steppers and see if it will work, if it won't well then I'll use it for something else and buy a mini-ITX system to use...but the incentives are high, seeing as this is completely free.

All I can suggest is "try it".

Mesa make a bunch of cards in PC/104 format, some of which work with LinuxCNC.
store.mesanet.com/index.php?route=product/category&path=83_85

However they are so much more expensive than the PCI / parallel / Ethernet cards that it probably negates the free-ness of the PC.

I still have 2 HP very small form factor PC's with Geode processors at 1000Mhz, they do run Ubuntu 10.04 and Wheezy quite usably, so do give it a try. You can also scavenge the net for CoolCNC iso or DebianDog version of linuxcnc, they are older but work nicely and require very low resources, the first will even work on a Pentium 1 at 350 Mhz.

I am not so much into using the PC/104 bus, as I am thinking of using a parallel port system, with RS485 (since it's a native port) to operate modbus devices like the VFD and coolant pump controls. Basically anything that isn't particularly time critical can run on the RS485, but E-stops, limit switches, step/dir outputs, could all run on the parallel port. There is also a GPIO port on the board, with four inputs and four outputs, but while they're supported by Debian as far as being usable, I do not know if or how they'd work with LinuxCNC.

I got Debian installed onto the sytem, on the 8gb compactflash card I stuck in the board. It seems to work ok, but there are still some bugs to work out. Currently the USB ports aren't working, and the processor randomly switches between 233Mhz to 500Mhz on boot up, so I think I may need to flash the BIOS again...this board originally ran a custom BIOS and I had to burn a new EEPROM for it based on what I downloaded from the manufacturer's website. Might have more to do on that front.

I found a Jetway J7F2WE1G5 mini-ITX in the junk pile too, with the 12v input power supply to match and a gig of ram stuck in it. I have no idea if it functions at all but best I can tell it's a [strike]1.5Ghz Atom[/strike] Via C7 CPU, 1GB of ram, and a PCI slot. The way it's configured I may have been thinking Carputer or something, hard to say.

I have mountains of computer junk collected over that 12 years as an integration tech, most of it was just pulled from dumpsters when we did new system installs. (Like the 15 node Beowulf cluster built from 1990 dual-processor Pentium Pro boards I assembled in college for the CS students to rent time on) Somewhere I actually have some OLD ISA-based I/O cards, but I have no clue if they work. I don't have a machine with an ISA slot anymore.

Xnke wrote: I found a Jetway J7F2WE1G5 mini-ITX in the junk pile too, with the 12v input power supply to match and a gig of ram stuck in it. I have no idea if it functions at all but best I can tell it's a [strike]1.5Ghz Atom[/strike] Via C7 CPU, 1GB of ram, and a PCI slot. The way it's configured I may have been thinking Carputer or something, hard to say.

Not sure if LinuxCNC works on Via. If it does, this seems like a good bet. I like mini-ITX with 12V power and PCI for my machines. Lots of choice of Mesa cards there.

I know ubuntu-Netbook completely supports the C7, but I am not sure if LinuxCNC is one of those "don't change the distro or it'll break" things or not.

Last time I fooled with this was back when it was EMC2, and I was using a AMD K6-2 processor, however I did (and still do) run Gentoo on one of the old office desktops. It's been years since I did an "emerge -u world"...it would take weeks to complete, I think...

Currently the plan is to install a minimal version of Ubuntu with support for the C7 and the Chrome 9 video compiled in, get it tweaked to run and support all the hardware, and then try to install LinuxCNC. I'll have to hit the books on what's current in the kernel these days.

On the Geode-LX based SBC front, the live USB boots and runs OK, but trying to install to the compactflash card only gets to around 20% done and fails. It's probably because the distro isn't meant for a CF root, I thought it would be fun to try. I'll have to hunt down a SATA power adapter tomorrow to plug in one of the laptop drives I've got laying around, and I'll try the install again.

I have run Linuxcnc on a Via C7 board. It ran fine, latency was OK but when I installed PREMPT_RT for my mesa card, it was clearly unusable with latency of 300,000 or more. Bit of a shame as it has an 8gb IDE SSD in it so it would have been nice. They do have a parallel port on board and it comes up on Wheezy fine. I just ran a ribbon cable out of the case. I'm keeping it for a simple CNC machine if I ever build one.

So it seems this system is not suitable-once I fitted the laptop hard drive, the install went smoothly and I was able to get the system loaded, and while a little weak in the CPU department, X was snappy and responsive. GLX gears would do 2 frames per second, but I was not able to run the latency-test at all. Kept getting permission errors pointing to APIC not being enabled/present, turns out this board doesn't seem to have an APIC to enable, even if you force-enable it (which is the default behaviour, apparently)

No APIC, no real-time kernel.

You could try rt-preempt.
www.linuxcnc.org/testing-stretch-rtpreempt/

andypugh wrote: You could try rt-preempt.
www.linuxcnc.org/testing-stretch-rtpreempt/

(That is an alternative realtime system and might not require the LAPIC)