Eventually-To: emc-developers@
Subject: [DRAFT] Stretch-based LinuxCNC images ready for testing

I've been working on a live+install image of Debian Stretch with
 * The just-released LinuxCNC 2.7.10
 * kernel 4.9.0-3-rt-amd64 or 4.9.0-3-rt-686-pae
 * xfce desktop (same desktop we used on wheezy)
 * goodies like hostmot2 firmwares, truetype-tracer, f-engrave

This image is based on the "PREEMPT RT" kernel, which typically
gives latencies good enough for FPGA-based systems, though often the
latency is too high for software encoder and stepgen systems.
Assuming you have a multi-core system, isolating the highest
numbered CPU with isolcpus=# on the kernel commandline may help
latency, just as with RTAI.

Unless you know your computer only supports 32-bit code, I recommend
using the -amd64 image, which works for both AMD and Intel 64-bit
CPUs.

Like the older images, you can either boot live to test your
hardware, or install to the hard disk, from the same iso image.

The Debian image is a "hybrid" iso, which means you can use the same
iso file for a USB stick or a DVD.  (The image is bigger than a
traditional CD, so you can't install from regular CD anymore.)
Instructions for writing the image to a USB stick from Windows and
Linux are here: 

http://wiki.linuxcnc.org/cgi-bin/wiki.pl?Hybrid_Iso

**NOTE** the Ubuntu "startup disk creator" and unetbootin do NOT
handle hybrid images.  Use the above instructions instead, if you
want to install from USB.  To install from DVD you can use any
traditional method to write the iso image.

You can find it at the temporary URL
http://www.linuxcnc.org/testing-stretch-rtpreempt/

For more notes and for the scripts used to build these images,
see https://github.com/jepler/stretch-live-build

The github repository has an "issues" section.  Please use it only
to file bugs about the image itself, not about bugs in LinuxCNC,
even if the bug in LinuxCNC seems to be specific to Debian Stretch.
(but if you aren't sure, then file it in stretch-live-build and
we'll triage it)

Jeff