Re: Preferred OS, processor family for running embedded Ada?

["Mike Silva" <snarflemike@yahoo.com>]

On Feb 24, 5:45 am, Stephen Leake <stephen_le...@stephe-leake.org>
wrote:
> "Mike Silva" <snarflem...@yahoo.com> writes:
> > As this is just a hobby/learning thing at the moment, $10k is way,
> > way too much. I'd like to keep the cost including SBC under, say,
> > $1000. Do I dream the impossible dream? I hope not, because I'd
> > really like to give this a try and perhaps learn enough to use
> > embedded Ada commercially down the line (at which time somebody else
> > could fork up the $10k).
>
> My main job at work is building a satellite simulator (GDS;http://fsw.gsfc.nasa.gov/gds/). It's a hard real-time system. Some
> people would say it's not "embedded" because it has an ethernet
> connection to a sophisticated user interface, but that's another
> discussion.
>
> I develop all of the software for GDS on Windows. I've written
> emulation packages for some of the hardware. I do this because it's
> easier to debug top level code without the hardware getting in the
> way, and the development tools (Emacs, GNAT, gdb) work better on
> Windows than on the target OS (Lynx). Once it's working on the
> emulator, then I run it on the real hardware. Sometimes it Just Works,
> sometimes I have to get out the scope and see what's going on. In that
> case, I try to fix the emulator so I won't have to use the scope again
> :). Using the scope can be fun, but it's always way slower than using
> gdb or higher-level tests.

Yes, I have done something similar, writing emulators on a Windows box
for both the master and the slave components of semiconductor
fabrication equipment while the new hardware was being developed.  >
> So I suggest you take a similar approach. Make up some hardware that
> you'd like to play with, and write an emulator for it. Then write some
> code to make that hardware dance.

> You can do all of that on free software and cheap hardware.

It's that "make the hardware dance" part that seems much more
complicated with Ada than with C-plus-an-OS (but the benefits seem
much greater as well).  That is to say, choosing an underlying runtime
enviornment and getting it not only set up on the hardware, but
integrated with the gcc Ada compiler.  So, ignoring the question of
preferred processor families (least amount of unnecessary gotchas),
I'm still wondering about which OS is the best choice to get something
up and running.  Can anybody comment on the relative merits and
troubles of running Ada on Linux, one of the *BSDs, and RTEMS?

>...
> Another area to explore is FPGA programming. We use small FPGAs on an
> IP bus carrier
> (http://www.acromag.com/functions.cfm?Category_ID=24&Group_ID=1) to
> interface to our hardware. There is a free "Web" version of Alterra
> Quartus
> (https://www.altera.com/support/software/download/sof-download_center....),
> or the open-source ghdl VHDL compiler/simulator
> (http://ghdl.free.fr/). FPGA development relies heavily on simulation,
> which does not require real hardware.
>
> If you are ambitious, you can try to tie the ghdl simulator to your
> Ada code, to allow testing the Ada interface to the FPGA in
> simulation. I haven't done that yet, but I wish I could.
>
> Someone who can do both Ada and VHDL would be a very valuable person!

Well, I did pick up a VHDL book a while back.  Maybe it's a sign. :)
But first I want to get Ada running on a SBC.