Basic questions re RTEMS and PPCbug

[gregory.menke at gsfc.nasa.gov]

We use ppcbug on a MCP750, an employ NBO to grab the image via tftp.
I ran into trouble once where I was trying to run the un-linked
executables- there are intermediate versions of those files in the
build tree.  Do a find . -name "hello*" or whatever to find out where
they are and which one you're using.

Generally, the executable is ready to run on the target hardware;
RTEMS is linked to your program, the final product being a monolithic
image with some entry point.  It boots itself (might also relocate),
initializes, then runs your program.  If you look closely at the
samples/tests linking after RTEMS does, you should be able to see the
output "bootables" being prepared.  We also use a MIPS R3000 bsp on
RTEMS, it works similarly.

I don't know anything at all about the MVME boards, but fwiw, I
believe the 750's programs are compiled and linked into a PREP
formatted executable that you can retrieve via tftp, read from a disk
or otherwise load into ram and execute.

It is difficult in the beginning.  I found the hardest part was
understanding how the RTEMS compile/build cycle works (I only
partially understand it now).  Once you understand enough to get
something running, RTEMS itself is quite easy to pick up and use.

Gregm


 > I'm inexperienced at working at the BSP/RTOS level and have some basic gaps
 > in my understanding of RTEMS (I'm used to working with VxWorks).
 > I have downloaded and compiled RTEMS for the MVME2307 board (closest thing
 > to my MVME2400 and MVME2700 boards) and am trying to understand what I've
 > got.
 > 
 > I seem to have a number of executables in /opt/rtems/mvme2307/samples (eg
 > hello.exe etc.), but nothing looking like an OS. Is RTEMS linked (or at
 > least the elements of it that are required) to the application? In that
 > case, am I right in understanding that there is no shell associated with
 > RTEMS.
 > 
 > As I said, I have MVME2400 and MVME2700 boards. I've never used PPCbug
 > before, so have just started trying to get to grips with it. Anyway, I'm
 > trying to see if any of the MVME2307 samples will work on either board.
 > I've configured the network with NIOT and changed ENV settings according to
 > README.MVME2300.
 > I then load hello.exe (and others) using NIOP, and it seems to get
 > transferred ok.
 > I try running the programe using GO but always get an INVALID error at the
 > first address.
 > 
 > Due to my inexperience, I'm not sure if the problem is due to
 > incompatibilities between the MVME2307 bsp and my boards (although I think
 > the MVME2700 is really quite close to the MVME2300 series), or whether I'm
 > actually screwing up with my PPCbug commands.
 > 
 > It is difficult at the beginning to get a foothold. 
 > Any advice would be welcome,
 > David 
 > 
 >