Re: TS7200_INSTALL kernel problem solved - kernel too big!

[Ken Hornstein <kenh%cmf.nrl.navy.mil@localhost>]

>Thanks for this helpful advice. Actually I don't have a big problem
>with using Redboot but we currently have this problem with 4.0.1 and
>later not being able to run on the TS-7200. This is the problem I am
>trying to resolve and I'm not sure if a different loader will achieve
>this. There is an idea that it is because the kernel is too big for
>the TS-7200 but I have build a stripped down kernel but this has the
>same problem. Do you think a different load would help here or is this
>a different problem.

Patrick, in your case there seems to be something else going on.  I'm
not sure exactly WHAT is the problem, but I was thinking of providing you
known-working kernels to try to help with your problem.

Regarding the size issue, there are actually two different issues:

- The kernel size is currently limited to 6 MB (this includes text,
  data, and bss).  2 MB is reserved for the stack (and other stuff, maybe?).
  This is an issue for the install kernel, as the ramdisk image is included
  in that 6 MB.  A new bootloader wouldn't help with this problem.
  Possible solutions to this are a) make the kernel smaller, b) make
  the ramdisk image smaller, c) allow the kernel to be larger than 6
  MB, possibly by decreasing the consumed stack space, or possibly by
  rejiggering things so the kernel can span more than one chunk of
  SDRAM.  The first two are easy; the last one is hard (I don't think
  it's impossible ... probably annoying).

- The way that NetBSD currently boots on the TS-7200 (for a normal install)
  is a gzipped kernel image is stored in flash memory, along with a
  stub decompressor.  At boot time the compressed kernel image is
  uncompressed into SDRAM and then run as normal.  This gzipped image
  is limited to (I think) 1.4 MB.  This is a problem for the
  distributed normal TS7200 kernel, which ends up being larger than
  what will fit into flash.  Possible solutions include a) shrinking
  the kernel, b) using more flash space (Jesse, is that possible?  I
  think a chunk of the flash is taken up by the Linux flash
  filesystem), c) use an alternate bootloader.  A Linux-based
  bootloader could possibly help with this problem.  But it won't work
  out-of-the-box ... normally NetBSD uses a BSD filesystem, and from
  what Jesse said the bootloader reads files off of an ext2 partition.
  Jesse's bootloader could be modified to read off of a BSD filesystem,
  or we could create a small ext2 filesystem to store the kernel on
  (partitioning might be a problem, as I believe it requires a MBR,
  and normally we don't have one for evbarm platforms).

>What I would like is to have ongoing support for the TS-7200 because I
>am keen to use it in my project. If NetBSD can't support it then I
>would rather move to different hardware rather than a different OS.

Well, I have NetBSD 4.0.1 running on my TS7200.  I feel confident we
can get you going; we just need to figure out what's going wrong.

--Ken