Re: BDI-Live boot.img

--- In CAD_CAM_EDM_DRO@yahoogroups.com, "jeff_birt2000" <birt_j@e...>
wrote:

> Sorry to hear TNG is 'dead'. I just downloaded/installed it a few
> days ago. I think it will still serve to let me evaluate EMC
> though. I'll download BDI-Live tomorrow and try it on another
> machine.
>

Just a note to clarify things about the TNG:

"Dead" simply means that there won't be another version of the TNG
released. That doesn't mean it is useless. I'm one of the coders
working on EMC, and I use TNG for my main development box. Newer
versions of EMC _will_ compile and run on TNG for the forseeable
future.

Just a bit of background about the BDI and EMC. Many of you
may already know this stuff, but some probably don't. The key
is to realize that EMC and the BDI are two different things:

EMC is the actual program (group of programs actually) that
controls a CNC machine. It is only a few megs in size.

BDI is a Linux distribution (distro) that makes running EMC
the program easier. It is big (several hundred meg) and is
intended to be burned onto a CD.

EMC needs an operating system that is capable of running
realtime code. Linux alone won't do that, but RTLinux and RTAI
are two packages that modify Linux to make it handle realtime
stuff. If you are so inclined, you can take nearly any Linux
distribution (Suse, Mandrake, Gentoo, RedHat, Knoppix, etc) and
apply the RTLinux or RTAI kernel patches to make a realtime
ready system.

However, applying the patches and making a RT ready system isn't
easy, especially for a beginner. So Paul Corner invented the
BDI. It is a complete Linux distribution, already patched for
realtime and ready to go. Each BDI includes hundreds (maybe
thousands) of general purpose packages, just like any other
distro. It also includes a copy of the EMC program.

There are three BDIs right now.

1) BDI-2.xx (I think the latest is 2.20) - This one is based on
RedHat 6.x, so it's fairly old. However it works find on older
computers, and is pretty stable. It is based on a Linux 2.2
kernel with RTLinux as the realtime part. Because it is older,
it doesn't include drivers for the latest and greatest video
cards, etc. Although the core of the distro doesn't change that
much, Paul is contiuing to support it by releasing new versions
with newer packages, including newer versions of EMC. In my
opinion, this is the way to go if you want to set up an older
computer as a dedicated machine controller.

2) BDI-TNG - This one is based on RedHat 7.x, so it's newer than
BDI-2.xx, but still getting old. It has a Linux 2.4 kernel and
uses RTAI for the realtime stuff. This one takes up 2 CDs, and
gives you a pretty complete installation. As I mentioned before,
I use TNG on my main computer - email, web browsing, programming,
the works. It has newer drivers than the BDI-2.xx, but you still
won't find support for this years newest hardware on it. (But
you might be able to download the drivers - RH7.3 is still pretty
common, and many packages are available for it.

3) BDI-Live (I think the latest is rc23 or 24) - This one is
based on Knoppix. Like TNG it has a 2.4 kernal and uses RTAI
for the realtime part. It is unique in that you can boot it
and run it from the CD without actually installing it on your
hard disk. You can still install to hard disk if you want.
The CDROM booted version is really only intended for trying
things out. Live is more stripped down than TNG - you don't
get as many general purpose packages, but you do get everything
you need for a machine control computer. Because it is newer,
and because Paul is continuing to work on it, you are far more
likely to find drivers for the latest hardware on the BDI-Live
CD than on the older BDIs.

Each BDI comes with a version of EMC that is already compiled
and ready to run. The TNG comes with an older EMC. Live and
2.xx are updated every once in a while. When that happens they
get the latest and greatest EMC. However, once you have a
working Linux box with realtime, it doesn't matter how you
got it - you can always download the latest and greatest EMC.
So even if you have TNG, or a very old BDI-2.xx (like 2.09 or
something), you can replace the EMC on it with the newest version.

It is true that compiling a newer EMC can sometimes be a problem,
but we are working on that. As EMC continues to evolve, making it
compile cleanly on all three BDIs is and will remain a priority.

So to sum up - the BDI is a way to set up a realtime operating
system on your computer. Saying "I'm running BDI-2.19" is like
saying "I'm running RedHat 8" or "I'm running windows95". Once
you have the operating system set up, then you can either use
the version of EMC that came with it, or you can download a newer
version from the net.

Regards,

John Kasunich